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Table of Contents Expand all

play_arrow Overview
- BGP Overview
play_arrow Basic BGP Configurations
play_arrow Configuring BGP Session Attributes
play_arrow Configuring BGP Session Policies
- Basic BGP Routing Policies
- Routing Policies for BGP Communities
play_arrow Enabling Load Balancing for BGP
play_arrow Configuring Graceful Restart for BGP
- Understanding Graceful Restart for BGP
play_arrow Configuring Multiprotocol for a BGP Session
- Multiprotocol BGP
play_arrow Configuring BGP CLNS
- BGP Connectionless Network Service (CLNS)
play_arrow Using Route Reflectors and Confederations for BGP Networks
- BGP Route Reflectors
- BGP Confederations for IBGP Scaling
play_arrow Configuring BGP Security
play_arrow Configuring BGP Route Flap Damping and Error Handling
play_arrow Configuring BGP-Based VPN
- BGP-Based VPN
- BGP accept-own Community
play_arrow Monitoring and Troubleshooting
play_arrow Configuration Statements and Operational Commands
- peer-auto-discovery
- Junos CLI Reference Overview

list Table of Contents

English

Understanding the BGP Local AS Attribute
Example: Configuring a Local AS for EBGP Sessions
Example: Configuring a Private Local AS for EBGP Sessions
Understanding the Accumulated IGP Attribute for BGP
Example: Configuring the Accumulated IGP Attribute for BGP
Understanding AS Override
Example: Configuring a Layer 3 VPN with Route Reflection and AS Override
Example: Enabling BGP Route Advertisements
Disabling Attribute Set Messages on Independent AS Domains for BGP Loop Detection
Example: Ignoring the AS Path Attribute When Selecting the Best Path
Understanding Private AS Number Removal from AS Paths
Example: Removing Private AS Numbers from AS Paths
Change History Table

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Autonomous Systems for BGP Sessions

date_range 20-Dec-24

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Understanding the BGP Local AS Attribute

When an Internet service provider (ISP) acquires a network that belongs to a different autonomous system (AS), there is no seamless method for moving the BGP peers of the acquired network to the AS of the acquiring ISP. The process of configuring the BGP peers with the new AS number can be time-consuming and cumbersome. Sometimes customers do not want to or are not immediately able to modify their peer arrangements or configuration. During this kind of transition period, it can be useful to configure BGP-enabled devices in the new AS to use the former AS number in BGP updates. This former AS number is called a local AS.

Using a local AS number permits the routing devices in an acquired network to appear to belong to the former AS.

For example, ISP A, with an AS of 65200, acquires ISP B, with an AS of 65250. ISP B has a customer, ISP C, that does not want to change its configuration. After ISP B becomes part of ISP A, a local AS number of 65250 is configured for use in EBGP peer sessions with ISP C. Consequently, the local AS number of 65250 is either prepended before or used instead of the global AS number of 65200 in the AS path used to export routes to direct external peers in ISP C.

If the route is received from an internal BGP (IBGP) peer, the AS path includes the local AS number prepended before the global AS number.

The local AS number is used instead of the global AS number if the route is an external route, such as a static route or an interior gateway protocol (IGP) route that is imported into BGP. If the route is external and you want the global AS number to be included in the AS path, you can apply a routing policy that uses as-path-expand or as-path-prepend. Use the as-path-expand policy action to place the global AS number behind the local AS number. Use the as-path-prepend policy action to place the global AS number in front of the local AS number.

For example:

content_copy zoom_out_map
user@R2# show policy-options
policy-statement prepend-global {
    term 1 {
        from protocol static;
        then {
            as-path-prepend 65200; # or use as-path-expand
            accept;
        }
    }
}

content_copy zoom_out_map
user@R2# show protocols bgp  
group ext {
    export prepend-global;
    type external;
    local-as 65250;
    neighbor 10.0.0.1 {
        peer-as 65100;
    }
    neighbor 10.1.0.2 {
        peer-as 65300;
    }
}

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user@R2# show routing-options
static {
    route 10.1.1.1/32 next-hop 10.0.0.1;
}
autonomous-system 65200;

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user@R3# run show route 10.1.1.1 protocol bgp
inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.1.1.1/32         *[BGP/170] 00:05:11, localpref 100
                      AS path: 65200 65250 I, validation-state: unverified
                    > to 10.1.0.1 via lt-1/2/0.4

In a Layer 3 VPN scenario, in which a provider edge (PE) device uses external BGP (EBGP) to peer with a customer edge (CE) device, the local-as statement behaves differently than in the non-VPN scenario. In the VPN scenario, the global AS number defined in the master instance is prepended to the AS path by default. To override this behavior, you can configure the no-prepend-global-as in the routing-instance BGP configuration on the PE device, as shown here:

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user@R2# show routing-instances
red {
    instance-type vrf;
    interface fe-1/2/0.2;
    route-distinguisher 10:1;
    vrf-target target:10:1;
    protocols {
        bgp {
            group toR1 {
                type external;
                peer-as 65001;
                local-as 65200 no-prepend-global-as;
                neighbor 10.1.1.1;
            }
        }
    }
}

The Junos operating system (Junos OS) implementation of the local AS attribute supports the following options:

Local AS with private option—When you use the private option, the local AS is used during the establishment of the BGP session with an EBGP neighbor but is hidden in the AS path sent to other IBGP and EBGP peers. Only the global AS is included in the AS path sent to external peers.

The private option is useful for establishing local peering with routing devices that remain configured with their former AS or with a specific customer that has not yet modified its peer arrangements. The local AS is used to establish the BGP session with the EBGP neighbor but is hidden in the AS path sent to external peers in another AS.

Include the private option so that the local AS is not prepended before the global AS in the AS path sent to external peers. When you specify the private option, the local AS is prepended only in the AS path sent to the EBGP neighbor.

For example, in Figure 1, Router 1 and Router 2 are in AS 64496, Router 4 is in AS 64511, and Router 3 is in AS 64510. Router 2 formerly belonged to AS 64497, which has merged with another network and now belongs to AS 64496. Because Router 3 still peers with Router 2 using its former AS (64497), Router 2 needs to be configured with a local AS of 64497 in order to maintain peering with Router 3. Configuring a local AS of 64497 permits Router 2 to add AS 64497 when advertising routes to Router 3. Router 3 sees an AS path of 64497 64496 for the prefix 10/8.

Figure 1: Local AS Configuration

To prevent Router 2 from adding the local AS number in its announcements to other peers, use the local-as 64497 private statement. This statement configures Router 2 to not include local AS 64497 when announcing routes to Router 1 and to Router 4. In this case, Router 4 sees an AS path of 64496 64510 for the prefix 10.222/16.
Local AS with alias option—In Junos OS Release 9.5 and later, you can configure a local AS as an alias. During the establishment of the BGP open session, the AS used in the open message alternates between the local AS and the global AS. If the local AS is used to connect with the EBGP neighbor, then only the local AS is prepended to the AS path when the BGP peer session is established. If the global AS is used to connect with the EBGP neighbor, then only the global AS is prepended to the AS path when the BGP peer session is established. The use of the alias option also means that the local AS is not prepended to the AS path for any routes learned from that EBGP neighbor. Therefore, the local AS remains hidden from other external peers.

Configuring a local AS with the alias option is especially useful when you are migrating the routing devices in an acquired network to the new AS. During the migration process, some routing devices might be configured with the new AS while others remain configured with the former AS. For example, it is good practice to start by first migrating to the new AS any routing devices that function as route reflectors. However, as you migrate the route reflector clients incrementally, each route reflector has to peer with routing devices configured with the former AS, as well as peer with routing devices configured with the new AS. To establish local peer sessions, it can be useful for the BGP peers in the network to use both the local AS and the global AS. At the same time, you want to hide this local AS from external peers and use only the global AS in the AS path when exporting routes to another AS. In this kind of situation, configure the alias option.

Include the alias option to configure the local AS as an alias to the global AS configured at the [edit routing-options] hierarchy level. When you configure a local AS as an alias, during the establishment of the BGP open session, the AS used in the open message alternates between the local AS and the global AS. The local AS is prepended to the AS path only when the peer session with an EBGP neighbor is established using that local AS. The local AS is hidden in the AS path sent to any other external peers. Only the global AS is prepended to the AS path when the BGP session is established using the global AS.

Note:
The private and alias options are mutually exclusive. You cannot configure both options with the same local-as statement.
Local AS with option not to prepend the global AS—In Junos OS Release 9.6 and later, you can configure a local AS with the option not to prepend the global AS. Only the local AS is included in the AS path sent to external peers.

Use the no-prepend-global-as option when you want to strip the global AS number from outbound BGP updates in a virtual private network (VPN) scenario. This option is useful in aVPN scenario in which you want to hide the global AS from the VPN.

Include the no-prepend-global-as option to have the global AS configured at the [edit routing-options] hierarchy level removed from the AS path sent to external peers. When you use this option, only the local AS is included in the AS path for the routes sent to a customer edge (CE) device.
Number of loops option—The local AS feature also supports specifying the number of times that detection of the AS number in the AS_PATH attribute causes the route to be discarded or hidden. For example, if you configure loops 1, the route is hidden if the AS number is detected in the path one or more times. This is the default behavior. If you configure loops 2, the route is hidden if the AS number is detected in the path two or more times.

For the loops number statement, you can configure 1 through 10.

Note:
If you configure the local AS values for any BGP group, the detection of routing loops is performed using both the AS and the local AS values for all BGP groups.

If the local AS for the EBGP or IBGP peer is the same as the current AS, do not use the local-as statement to specify the local AS number.

When you configure the local AS within a VRF, this impacts the AS path loop-detection mechanism. All of the local-as statements configured on the device are part of a single AS domain. The AS path loop-detection mechanism is based on looking for a matching AS present in the domain.

Example: Configuring a Local AS for EBGP Sessions

This example shows how to configure a local autonomous system (AS) for a BGP peer so that both the global AS and the local AS are used in BGP inbound and outbound updates.

Requirements
Overview
Configuration
Verification

Requirements

No special configuration beyond device initialization is required before you configure this example.

Overview

Use the local-as statement when ISPs merge and want to preserve a customer’s configuration, particularly the AS with which the customer is configured to establish a peer relationship. The local-as statement simulates the AS number already in place in customer routers, even if the ISP’s router has moved to a different AS.

This example shows how to use the local-as statement to configure a local AS. The local-as statement is supported for BGP at the global, group, and neighbor hierarchy levels.

When you configure the local-as statement, you must specify an AS number. You can specify a number from 1 through 4,294,967,295 in plain-number format. In Junos OS Release 9.1 and later, the range for AS numbers is extended to provide BGP support for 4-byte AS numbers as defined in RFC 4893, BGP Support for Four-octet AS Number Space. In Junos OS Release 9.3 and later, you can also configure a 4-byte AS number using the AS-dot notation format of two integer values joined by a period: <16-bit high-order value in decimal>.<16-bit low-order value in decimal>. For example, the 4-byte AS number of 65,546 in plain-number format is represented as 1.10 in the AS-dot notation format. You can specify a value from 0.0 through 65535.65535 in AS-dot notation format. Junos OS continues to support 2-byte AS numbers. The 2-byte AS number range is 1 through 65,535 (this is a subset of the 4-byte range).

Figure 2 shows the sample topology.

Figure 2: Topology for Configuring the Local AS

In this example, Device R2 formerly belonged to AS 250 and now is in AS 200. Device R1 and Device R3 are configured to peer with AS 250 instead of with the new AS number (AS 200). Device R2 has the new AS number configured with the autonomous-system 200 statement. To enable the peering sessions to work, the local-as 250 statement is added in the BGP configuration. Because local-as 250 is configured, Device R2 includes both the global AS (200) and the local AS (250) in its BGP inbound and outbound updates.

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

Device R1

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set interfaces fe-1/2/0 unit 1 family inet address 10.0.0.1/30
set interfaces lo0 unit 1 family inet address 192.168.0.1/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext peer-as 250
set protocols bgp group ext neighbor 10.0.0.2
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 10.1.0.0/30 next-hop 10.0.0.2
set routing-options autonomous-system 100

Device R2

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set interfaces fe-1/2/0 unit 2 family inet address 10.0.0.2/30
set interfaces fe-1/2/1 unit 3 family inet address 10.1.0.1/30
set interfaces lo0 unit 2 family inet address 192.168.0.2/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext local-as 250
set protocols bgp group ext neighbor 10.0.0.1 peer-as 100
set protocols bgp group ext neighbor 10.1.0.2 peer-as 300
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options autonomous-system 200

Device R3

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set interfaces fe-1/2/0 unit 4 family inet address 10.1.0.2/30
set interfaces lo0 unit 3 family inet address 192.168.0.3/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext peer-as 250
set protocols bgp group ext neighbor 10.1.0.1
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 10.0.0.0/30 next-hop 10.1.0.1
set routing-options autonomous-system 300

Configuring Device R1

Step-by-Step Procedure
Results

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure Device R1:

Configure the interfaces.

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[edit interfaces]
user@R1# set fe-1/2/0 unit 1 family inet address 10.0.0.1/30
user@R1# set lo0 unit 1 family inet address 192.168.0.1/32

Configure external BGP (EBGP).

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[edit protocols bgp group ext]
user@R1# set type external
user@R1# set export send-direct
user@R1# set export send-static
user@R1# set peer-as 250
user@R1# set neighbor 10.0.0.2

Configure the routing policy.

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[edit policy-options]
user@R1# set policy-statement send-direct term 1 from protocol direct
user@R1# set policy-statement send-direct term 1 then accept
user@R1# set policy-statement send-static term 1 from protocol static
user@R1# set policy-statement send-static term 1 then accept

Configure a static route to the remote network between Device R2 and Device R3.
```
[edit routing-options]
user@R1# set static route 10.1.0.0/30 next-hop 10.0.0.2
```

Configure the global AS number.

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[edit routing-options]
user@R1# set autonomous-system 100

Results

From configuration mode, confirm your configuration by entering the show interfaces, show policy-options, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

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user@R1# show interfaces
fe-1/2/0 {
    unit 1 {
        family inet {
            address 10.0.0.1/30;
        }
    }
}
lo0 {
    unit 1 {
        family inet {
            address 192.168.0.1/32;
        }
    }
}

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user@R1# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}
policy-statement send-static {
    term 1 {
        from protocol static;
        then accept;
    }
}

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user@R1# show protocols
bgp {
    group ext {
        type external;
        export [ send-direct send-static ];
        peer-as 250;
        neighbor 10.0.0.2;
    }
}

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user@R1# show routing-options
static {
    route 10.1.0.0/30 next-hop 10.0.0.2;
}
autonomous-system 100;

When you are done configuring the device, enter commit from configuration mode.

Configuring Device R2

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device R2:

Configure the interfaces.

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[edit interfaces]
user@R2# set fe-1/2/0 unit 2 family inet address 10.0.0.2/30
user@R2# set fe-1/2/1 unit 3 family inet address 10.1.0.1/30
user@R2# set lo0 unit 2 family inet address 192.168.0.2/32

Configure EBGP.

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[edit protocols bgp group ext]
user@R2# set type external
user@R2# set export send-direct
user@R2# set export send-static
user@R2# set neighbor 10.0.0.1 peer-as 100
user@R2# set neighbor 10.1.0.2 peer-as 300

Configure the local autonomous system (AS) number.
```
[edit protocols bgp group ext]
user@R2# set local-as 250
```

Configure the global AS number.

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[edit routing-options]
user@R2# set autonomous-system 200

Configure the routing policy.

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[edit policy-options]
user@R2# set policy-statement send-direct term 1 from protocol direct
user@R2# set policy-statement send-direct term 1 then accept
user@R2# set policy-statement send-static term 1 from protocol static
user@R2# set policy-statement send-static term 1 then accept

Results

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user@R2# show interfaces
fe-1/2/0 {
    unit 2 {
        family inet {
            address 10.0.0.2/30;
        }
    }
}
fe-1/2/1 {
    unit 3 {
        family inet {
            address 10.1.0.1/30;
        }
    }
}
lo0 {
    unit 2 {
        family inet {
            address 192.168.0.2/32;
        }
    }
}

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user@R2# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}
policy-statement send-static {
    term 1 {
        from protocol static;
        then accept;
    }
}

content_copy zoom_out_map
user@R2# show protocols
bgp {
    group ext {
        type external;
        export [ send-direct send-static ];
        local-as 250;
        neighbor 10.0.0.1 {
            peer-as 100;
        }
        neighbor 10.1.0.2 {
            peer-as 300;
        }
    }
}

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user@R2# show routing-options
autonomous-system 200;

When you are done configuring the device, enter commit from configuration mode.

Configuring Device R3

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device R3:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@R3# set fe-1/2/0 unit 4 family inet address 10.1.0.2/30
user@R3# set lo0 unit 3 family inet address 192.168.0.3/32

Configure EBGP.

content_copy zoom_out_map
[edit protocols bgp group ext]
user@R3# set type external
user@R3# set export send-direct
user@R3# set export send-static
user@R3# set peer-as 250
user@R3# set neighbor 10.1.0.1

Configure the global autonomous system (AS) number.
```
[edit routing-options]
user@R3# set autonomous-system 300
```
Configure a static route to the remote network between Device R1 and Device R2.
```
[edit routing-options]
user@R3# set static route 10.0.0.0/30 next-hop 10.1.0.1
```

Configure the routing policy.

content_copy zoom_out_map
[edit policy-options]
user@R3# set policy-statement send-direct term 1 from protocol direct
user@R3# set policy-statement send-direct term 1 then accept
user@R3# set policy-statement send-static term 1 from protocol static
user@R3# set policy-statement send-static term 1 then accept

Results

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user@R3# show interfaces
fe-1/2/0 {
    unit 4 {
        family inet {
            address 10.1.0.2/30;
        }
    }
}
lo0 {
    unit 3 {
        family inet {
            address 192.168.0.3/32;
        }
    }
}

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user@R3# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}
policy-statement send-static {
    term 1 {
        from protocol static;
        then accept;
    }
}

content_copy zoom_out_map
user@R3# show protocols
bgp {
    group ext {
        type external;
        export [ send-direct send-static ];
        peer-as 250;
        neighbor 10.1.0.1;
    }
}

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user@R3# show routing-options
static {
    route 10.0.0.0/30 next-hop 10.1.0.1;
}
autonomous-system 300;

When you are done configuring the device, enter commit from configuration mode.

Verification

Confirm that the configuration is working properly.

Checking the Local and Global AS Settings
Checking the BGP Peering Sessions
Verifying the BGP AS Paths

Checking the Local and Global AS Settings

Purpose
Action
Meaning

Purpose

Make sure that Device R2 has the local and global AS settings configured.

Action

From operational mode, enter the show bgp neighbors command.

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user@R2> show bgp neighbors
Peer: 10.0.0.1+179 AS 100      Local: 10.0.0.2+61036 AS 250  
  Type: External    State: Established    Flags: <Sync>
  Last State: OpenConfirm   Last Event: RecvKeepAlive
  Last Error: None
  Export: [ send-direct send-static ] 
  Options: <Preference PeerAS LocalAS Refresh>
  Holdtime: 90 Preference: 170 Local AS: 250 Local System AS: 200
  Number of flaps: 0
  Peer ID: 192.168.0.1     Local ID: 192.168.0.2       Active Holdtime: 90
  Keepalive Interval: 30         Peer index: 0   
  BFD: disabled, down
  Local Interface: fe-1/2/0.2                       
  NLRI for restart configured on peer: inet-unicast
  NLRI advertised by peer: inet-unicast
  NLRI for this session: inet-unicast
  Peer supports Refresh capability (2)
  Stale routes from peer are kept for: 300
  Peer does not support Restarter functionality
  NLRI that restart is negotiated for: inet-unicast
  NLRI of received end-of-rib markers: inet-unicast
  NLRI of all end-of-rib markers sent: inet-unicast
  Peer supports 4 byte AS extension (peer-as 100)
  Peer does not support Addpath
  Table inet.0 Bit: 10000
    RIB State: BGP restart is complete
    Send state: in sync
    Active prefixes:              1
    Received prefixes:            3
    Accepted prefixes:            2
    Suppressed due to damping:    0
    Advertised prefixes:          4
  Last traffic (seconds): Received 6    Sent 14   Checked 47  
  Input messages:  Total 258    Updates 3       Refreshes 0     Octets 4969
  Output messages: Total 258    Updates 2       Refreshes 0     Octets 5037
  Output Queue[0]: 0

Peer: 10.1.0.2+179 AS 300      Local: 10.1.0.1+52296 AS 250  
  Type: External    State: Established    Flags: <Sync>
  Last State: OpenConfirm   Last Event: RecvKeepAlive
  Last Error: None
  Export: [ send-direct send-static ] 
  Options: <Preference PeerAS LocalAS Refresh>
  Holdtime: 90 Preference: 170 Local AS: 250 Local System AS: 200
  Number of flaps: 0
  Peer ID: 192.168.0.3     Local ID: 192.168.0.2       Active Holdtime: 90
  Keepalive Interval: 30         Peer index: 1   
  BFD: disabled, down
  Local Interface: fe-1/2/1.3                       
  NLRI for restart configured on peer: inet-unicast
  NLRI advertised by peer: inet-unicast
  NLRI for this session: inet-unicast
  Peer supports Refresh capability (2)
  Stale routes from peer are kept for: 300
  Peer does not support Restarter functionality
  NLRI that restart is negotiated for: inet-unicast
  NLRI of received end-of-rib markers: inet-unicast
  NLRI of all end-of-rib markers sent: inet-unicast
  Peer supports 4 byte AS extension (peer-as 300)
  Peer does not support Addpath
  Table inet.0 Bit: 10000
    RIB State: BGP restart is complete
    Send state: in sync
    Active prefixes:              1
    Received prefixes:            3
    Accepted prefixes:            2
    Suppressed due to damping:    0
    Advertised prefixes:          4
  Last traffic (seconds): Received 19   Sent 26   Checked 9   
  Input messages:  Total 256    Updates 3       Refreshes 0     Octets 4931
  Output messages: Total 256    Updates 2       Refreshes 0     Octets 4999
  Output Queue[0]: 0

Meaning

The Local AS: 250 and Local System AS: 200 output shows that Device R2 has the expected settings. Additionally, the output shows that the options list includes LocalAS.

Checking the BGP Peering Sessions

Purpose
Action
Meaning

Purpose

Ensure that the sessions are established and that the local AS number 250 is displayed.

Action

From operational mode, enter the show bgp summary command.

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user@R1> show bgp summary
Groups: 1 Peers: 1 Down peers: 0
Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
inet.0                 4          2          0          0          0          0
Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.0.0.2                250        232        233       0       4     1:42:37 2/4/4/0              0/0/0/0

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user@R3> show bgp summary
Groups: 1 Peers: 1 Down peers: 0
Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
inet.0                 4          2          0          0          0          0
Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
10.1.0.1                250        235        236       0       4     1:44:25 2/4/4/0              0/0/0/0

Meaning

Device R1 and Device R3 appear to be peering with a device in AS 250, even though Device R2 is actually in AS 200.

Verifying the BGP AS Paths

Purpose
Action
Meaning

Purpose

Make sure that the routes are in the routing tables and that the AS paths show the local AS number 250.

Action

From configuration mode, enter the set route protocol bgp command.

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user@R1> show route protocol bgp
inet.0: 6 destinations, 8 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.0.0.0/30         [BGP/170] 01:46:44, localpref 100
                      AS path: 250 I
                    > to 10.0.0.2 via fe-1/2/0.1
10.1.0.0/30         [BGP/170] 01:46:44, localpref 100
                      AS path: 250 I
                    > to 10.0.0.2 via fe-1/2/0.1
192.168.0.2/32     *[BGP/170] 01:46:44, localpref 100
                      AS path: 250 I
                    > to 10.0.0.2 via fe-1/2/0.1
192.168.0.3/32     *[BGP/170] 01:46:40, localpref 100
                      AS path: 250 300 I
                    > to 10.0.0.2 via fe-1/2/0.1

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user@R3> show route protocol bgp

inet.0: 6 destinations, 8 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.0.0.0/30         [BGP/170] 01:47:10, localpref 100
                      AS path: 250 I
                    > to 10.1.0.1 via fe-1/2/0.4
10.1.0.0/30         [BGP/170] 01:47:10, localpref 100
                      AS path: 250 I
                    > to 10.1.0.1 via fe-1/2/0.4
192.168.0.1/32     *[BGP/170] 01:47:10, localpref 100
                      AS path: 250 100 I
                    > to 10.1.0.1 via fe-1/2/0.4
192.168.0.2/32     *[BGP/170] 01:47:10, localpref 100
                      AS path: 250 I
                    > to 10.1.0.1 via fe-1/2/0.4

Meaning

The output shows that Device R1 and Device R3 appear to have routes with AS paths that include AS 250, even though Device R2 is actually in AS 200.

Example: Configuring a Private Local AS for EBGP Sessions

This example shows how to configure a private local autonomous system (AS) number. The local AS is considered to be private because it is advertised to peers that use the local AS number for peering, but is hidden in the announcements to peers that can use the global AS number for peering.

Requirements
Overview
Configuration
Verification

Requirements

No special configuration beyond device initialization is required before you configure this example.

Overview

When you use the private option, the local AS is used during the establishment of the BGP session with an external BGP (EBGP) neighbor, but is hidden in the AS path sent to other EBGP peers. Only the global AS is included in the AS path sent to external peers.

The private option is useful for establishing local peering with routing devices that remain configured with their former AS or with a specific customer that has not yet modified its peer arrangements. The local AS is used to establish the BGP session with the EBGP neighbor, but is hidden in the AS path sent to external peers in another AS.

Include the private option so that the local AS is not prepended before the global AS in the AS path sent to external peers. When you specify the private option, the local AS is prepended only in the AS path sent to the EBGP neighbor.

Figure 3 shows the sample topology.

Figure 3: Topology for Configuring a Private Local AS

Device R1 is in AS 64496. Device R2 is in AS 64510. Device R3 is in AS 64511. Device R4 is in AS 64512. Device R1 formerly belonged to AS 64497, which has merged with another network and now belongs to AS 64496. Because Device R3 still peers with Device R1, using its former AS, 64497, Device R1 needs to be configured with a local AS of 64497 in order to maintain peering with Device R3. Configuring a local AS of 64497 permits Device R1 to add AS 64497 when advertising routes to Device R3. Device R3 sees an AS path of 64497 64496 for the prefix 10.1.1.2/32, which is Device R2's loopback interface. Device R4, which is behind Device R3, sees an AS path of 64511 64497 64496 64510 to Device R2’s loopback interface. To prevent Device R1 from adding the local AS number in its announcements to other peers, this example includes the local-as 64497 private statement. The private option configures Device R1 to not include the local AS 64497 when announcing routes to Device R2. Device R2 sees an AS path of 64496 64511 to Device R3 and an AS path of 64496 64511 64512 to Device R4. The private option in Device R1's configuration causes the AS number 64497 to be missing from the AS paths that Device R1 readvertises to Device R2.

Device R1 is hiding the private local AS from all the routers, except Device R3. The private option applies to the routes that Device R1 receives (learns) from Device R3 and that Device R1, in turn, readvertises to other routers. When these routes learned from Device R3 are readavertised by Device R1 to Device R2, the private local AS is missing from the AS path advertised to Device R2.

Configuration

CLI Quick Configuration
Configuring Device R1

CLI Quick Configuration

Device R1

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set interfaces fe-1/2/0 unit 3 family inet address 192.168.1.1/24
set interfaces fe-1/2/1 unit 5 family inet address 192.168.10.1/24
set interfaces lo0 unit 2 family inet address 10.1.1.1/32
set protocols bgp group external-AS64511 type external
set protocols bgp group external-AS64511 peer-as 64511
set protocols bgp group external-AS64511 local-as 64497
set protocols bgp group external-AS64511 local-as private
set protocols bgp group external-AS64511 neighbor 192.168.1.2
set protocols bgp group external-AS64510 type external
set protocols bgp group external-AS64510 peer-as 64510
set protocols bgp group external-AS64510 neighbor 192.168.10.2
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64496

Device R2

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set interfaces fe-1/2/0 unit 6 family inet address 192.168.10.2/24
set interfaces lo0 unit 3 family inet address 10.1.1.2/32
set protocols bgp group external type external
set protocols bgp group external export send-direct
set protocols bgp group external peer-as 64496
set protocols bgp group external neighbor 192.168.10.1
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64510

Device R3

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set interfaces fe-1/2/0 unit 4 family inet address 192.168.1.2/24
set interfaces fe-1/2/1 unit 7 family inet address 192.168.5.1/24
set interfaces lo0 unit 4 family inet address 10.1.1.3/32
set protocols bgp group external type external
set protocols bgp group external export send-direct
set protocols bgp group external neighbor 192.168.1.1 peer-as 64497
set protocols bgp group external neighbor 192.168.5.2 peer-as 64512
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64511

Device R4

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set interfaces fe-1/2/0 unit 8 family inet address 192.168.5.2/24
set interfaces lo0 unit 5 family inet address 10.1.1.4/32
set protocols bgp group external type external
set protocols bgp group external export send-direct
set protocols bgp group external peer-as 64511
set protocols bgp group external neighbor 192.168.5.1
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64512

Configuring Device R1

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device R1:

Configure the interfaces.

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[edit interfaces fe-1/2/0 unit 3]
user@R1# set family inet address 192.168.1.1/24
[edit interfaces fe-1/2/1 unit 5]
user@R1# set family inet address 192.168.10.1/24
[edit interfaces lo0 unit 2]
user@R1# set family inet address 10.1.1.1/32

Configure the EBGP peering session with Device R2.

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[edit protocols bgp group external-AS64510]
user@R1# set type external
user@R1# set peer-as 64510
user@R1# set neighbor 192.168.10.2

Configure the EBGP peering session with Device R3.

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[edit protocols bgp group external-AS64511]
user@R1# set type external
user@R1# set peer-as 64511
user@R1# set local-as 64497
user@R1# set local-as private
user@R1# set neighbor 192.168.1.2

Configure the routing policy.

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[edit policy-options policy-statement send-direct term 1]
user@R1# set from protocol direct
user@R1# set then accept

Configure the global autonomous system (AS) number.
```
[edit routing-options]
user@R1# set autonomous-system 64496
```

Results

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user@R1# show interfaces
fe-1/2/0 {
    unit 3 {
        family inet {
            address 192.168.1.1/24;
        }
    }
}
fe-1/2/1 {
    unit 5 {
        family inet {
            address 192.168.10.1/24;
        }
    }
}
lo0 {
    unit 2 {
        family inet {
            address 10.1.1.1/32;
        }
    }
}

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user@R1# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}

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user@R1# show protocols
bgp {
    group external-AS64511 {
        type external;
        peer-as 64511;
        local-as 64497 private;
        neighbor 192.168.1.2;
    }
    group external-AS64510 {
        type external;
        peer-as 64510;
        neighbor 192.168.10.2;
    }
}

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user@R1# show routing-options
autonomous-system 64496;

If you are done configuring the device, enter commit from configuration mode.

Repeat the configuration as needed for the other devices in the topology.

Verification

Confirm that the configuration is working properly.

Checking Device R2’s AS Paths
Checking Device R3’s AS Paths

Checking Device R2’s AS Paths

Purpose
Action
Meaning

Purpose

Make sure that Device R2 does not have AS 64497 in its AS paths to Device R3 and Device R4.

Action

From operational mode, enter the show route protocol bgp command.

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user@R2> show route protocol bgp
inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.1.1.3/32        *[BGP/170] 01:33:11, localpref 100
                      AS path: 64496 64511 I
                    > to 192.168.10.1 via fe-1/2/0.6
10.1.1.4/32        *[BGP/170] 01:33:11, localpref 100
                      AS path: 64496 64511 64512 I
                    > to 192.168.10.1 via fe-1/2/0.6
192.168.5.0/24     *[BGP/170] 01:49:15, localpref 100
                      AS path: 64496 64511 I
                    > to 192.168.10.1 via fe-1/2/0.6

Meaning

Device R2’s AS paths do not include AS 64497.

Checking Device R3’s AS Paths

Purpose
Action
Meaning

Purpose

Make sure that the local AS 64497 is prepended only in the AS path sent to the EBGP neighbor R3 . Device R3 sees an AS path of 64497 64496 for the prefix 10.1.1.2/32, which is Device R2's loopback interface.

Action

From operational mode, enter the show route protocol bgp command.

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user@R3> show route protocol bgp
inet.0: 7 destinations, 8 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.1.1.2/32        *[BGP/170] 01:35:11, localpref 100
                      AS path: 64497 64496 64510 I
                    > to 192.168.1.1 via fe-1/2/0.4
10.1.1.4/32        *[BGP/170] 01:35:11, localpref 100
                      AS path: 64512 I
                    > to 192.168.5.2 via fe-1/2/1.7
192.168.5.0/24      [BGP/170] 01:51:15, localpref 100
                      AS path: 64512 I
                    > to 192.168.5.2 via fe-1/2/1.7

Meaning

Device R3’s route to Device R2 (prefix 10.1.1.2) includes both the local and the global AS configured on Device R1 (64497 and 64496, respectively).

Understanding the Accumulated IGP Attribute for BGP

The interior gateway protocols (IGPs) are designed to handle routing within a single domain or an autonomous system (AS). Each link is assigned a particular value called a metric. The distance between the two nodes is calculated as a sum of all the metric values of links along the path. The IGP selects the shortest path between two nodes based on distance.

BGP is designed to provide routing over a large number of independent ASs with limited or no coordination among respective administrations. BGP does not use metrics in the path selection decisions.

The accumulated IGP (AIGP) metric attribute for BGP enables deployment in which a single administration can run several contiguous BGP ASs. Such deployments allow BGP to make routing decisions based on the IGP metric. In such networks, it is possible for BGP to select paths based on metrics as is done by IGPs. In this case, BGP chooses the shortest path between two nodes, even though the nodes might be in two different ASs.

The AIGP attribute is particularly useful in networks that use tunneling to deliver a packet to its BGP next hop. The Juniper Networks® Junos® operating system (Junos OS) currently supports the AIGP attribute for two BGP address families, family inet labeled-unicast and family inet6 labeled-unicast.

AIGP impacts the BGP best-route decision process. The AIGP attribute preference rule is applied after the local-preference rule. The AIGP distance is compared to break a tie. The BGP best-route decision process also impacts the way the interior cost rule is applied if the resolving next hop has an AIGP attribute. Without AIGP enabled, the interior cost of a route is based on the calculation of the metric to the next hop for the route. With AIGP enabled, the resolving AIGP distance is added to the interior cost.

Starting in Release 20.2R1, Junos OS supports the translation of AIGP metric to MED. You can enable this feature when you want the MED to carry the end to end AIGP metric value, which is used to choose the best path. This is especially useful in Inter-AS MPLS VPNs solution, where customer sites are connected via two different service providers, and customer edge routers want to take IGP metric based decision. You can configure a minimum-aigp to prevent unnecessary update of route when effective-aigp changes past the previously known lowest value. Effective AIGP is the AIGP value advertised with the route plus the IGP cost to reach the nexthop. You can configure effective-aigp and minimum-effective-aigp statements at the [edit protocols bgp group <group-name> metric-out] and [edit policy-options policy-statement <name> then metric] hierarchy levels.

The AIGP attribute is an optional non-transitive BGP path attribute and is specified in Internet draft draft-ietf-idr-aigp-06, The Accumulated IGP Metric Attribute for BGP.

Example: Configuring the Accumulated IGP Attribute for BGP

This example shows how to configure the accumulated IGP (AIGP) metric attribute for BGP.

Requirements
Overview
Configuration
Verification

Requirements

This example uses the following hardware and software components:

Seven BGP-speaking devices.
Junos OS Release 12.1 or later.

Overview

The AIGP attribute enables deployments in which a single administration can run several contiguous BGP autonomous systems (ASs). Such deployments allow BGP to make routing decisions based on the IGP metric. With AIGP enabled, BGP can select paths based on IGP metrics. This enables BGP to choose the shortest path between two nodes, even though the nodes might be in different ASs. The AIGP attribute is particularly useful in networks that use tunneling to deliver a packet to its BGP next hop. This example shows AIGP configured with MPLS label-switched paths.

To enable AIGP, you include the aigp statement in the BGP configuration on a protocol family basis. Configuring AIGP on a particular family enables sending and receiving of the AIGP attribute on that family. By default, AIGP is disabled. An AIGP-disabled neighbor does not send an AIGP attribute and silently discards a received AIGP attribute.

Junos OS supports AIGP for family inet labeled-unicast and family inet6 labeled-unicast. The aigp statement can be configured for a given family at the global BGP, group, or neighbor level.

By default, the value of the AIGP attribute for a local prefix is zero. An AIGP-enabled neighbor can originate an AIGP attribute for a given prefix by export policy, using the aigp-originate policy action. The value of the AIGP attribute reflects the IGP distance to the prefix. Alternatively, you can specify a value, by using the aigp-originate distance distance policy action. The configurable range is 0 through 4,294,967,295. Only one node needs to originate an AIGP attribute. The AIGP attribute is retained and readvertised if the neighbors are AIGP enabled with the aigp statement in the BGP configuration.

The policy action to originate the AIGP attribute has the following requirements:

Neighbor must be AIGP enabled.
Policy must be applied as an export policy.
Prefix must have no current AIGP attribute.
Prefix must export with next-hop self.
Prefix must reside within the AIGP domain. Typically, a loopback IP address is the prefix to originate.

The policy is ignored if these requirements are not met.

Topology Diagram

Figure 4 shows the topology used in this example. OSPF is used as the interior gateway protocol (IGP). Internal BGP (IBGP) is configured between Device PE1 and Device PE4. External BGP (EBGP) is configured between Device PE7 and Device PE1, between Device PE4 and Device PE3, and between Device PE4 and Device PE2. Devices PE4, PE2, and PE3 are configured for multihop. Device PE4 selects a path based on the AIGP value and then readvertises the AIGP value based on the AIGP and policy configuration. Device PE1 readvertises the AIGP value to Device PE7, which is in another administrative domain. Every device has two loopback interface addresses: 10.9.9.x is used for BGP peering and the router ID, and 10.100.1.x is used for the BGP next hop.

The network between Device PE1 and PE3 has IBGP peering and multiple OSPF areas. The external link to Device PE7 is configured to show that the AIGP attribute is readvertised to a neighbor outside of the administrative domain, if that neighbor is AIGP enabled.

Figure 4: Advertisement of Multiple Paths in BGP

For origination of an AIGP attribute, the BGP next hop is required to be itself. If the BGP next hop remains unchanged, the received AIGP attribute is readvertised, as is, to another AIGP neighbor. If the next hop changes, the received AIGP attribute is readvertised with an increased value to another AIGP neighbor. The increase in value reflects the IGP distance to the previous BGP next hop. To demonstrate, this example uses loopback interface addresses for Device PE4’s EBGP peering sessions with Device PE2 and Device PE3. Multihop is enabled on these sessions so that a recursive lookup is performed to determine the point-to-point interface. Because the next hop changes, the IGP distance is added to the AIGP distance.

Configuration

CLI Quick Configuration
Configuring Device P1
Configuring Device P2
Configuring Device PE4
Configuring Device PE1
Configuring Device PE2
Configuring Device PE3
Configuring Device PE7

CLI Quick Configuration

Device P1

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set interfaces fe-1/2/0 unit 1 description P1-to-PE1
set interfaces fe-1/2/0 unit 1 family inet address 10.0.0.2/30
set interfaces fe-1/2/0 unit 1 family mpls
set interfaces fe-1/2/1 unit 4 description P1-to-P2
set interfaces fe-1/2/1 unit 4 family inet address 10.0.0.29/30
set interfaces fe-1/2/1 unit 4 family mpls
set interfaces fe-1/2/2 unit 8 description P1-to-PE4
set interfaces fe-1/2/2 unit 8 family inet address 10.0.0.17/30
set interfaces fe-1/2/2 unit 8 family mpls
set interfaces lo0 unit 3 family inet address 10.9.9.2/32
set interfaces lo0 unit 3 family inet address 10.100.1.2/32
set protocols rsvp interface fe-1/2/0.1
set protocols rsvp interface fe-1/2/2.8
set protocols rsvp interface fe-1/2/1.4
set protocols mpls label-switched-path P1-to-P2 to 10.9.9.3
set protocols mpls label-switched-path P1-to-PE1 to 10.9.9.1
set protocols mpls label-switched-path P1-to-PE4 to 10.9.9.4
set protocols mpls interface fe-1/2/0.1
set protocols mpls interface fe-1/2/2.8
set protocols mpls interface fe-1/2/1.4
set protocols bgp group internal type internal
set protocols bgp group internal local-address 10.9.9.2
set protocols bgp group internal family inet labeled-unicast aigp
set protocols bgp group internal neighbor 10.9.9.1
set protocols bgp group internal neighbor 10.9.9.3
set protocols bgp group internal neighbor 10.9.9.4
set protocols ospf area 0.0.0.1 interface fe-1/2/0.1 metric 1
set protocols ospf area 0.0.0.1 interface fe-1/2/1.4 metric 1
set protocols ospf area 0.0.0.0 interface fe-1/2/2.8 metric 1
set protocols ospf area 0.0.0.0 interface 10.9.9.2 passive
set protocols ospf area 0.0.0.0 interface 10.9.9.2 metric 1
set protocols ospf area 0.0.0.0 interface 10.100.1.2 passive
set protocols ospf area 0.0.0.0 interface 10.100.1.2 metric 1
set routing-options router-id 10.9.9.2
set routing-options autonomous-system 13979

Device P2

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set interfaces fe-1/2/0 unit 3 description P2-to-PE1
set interfaces fe-1/2/0 unit 3 family inet address 10.0.0.6/30
set interfaces fe-1/2/0 unit 3 family mpls
set interfaces fe-1/2/1 unit 5 description P2-to-P1
set interfaces fe-1/2/1 unit 5 family inet address 10.0.0.30/30
set interfaces fe-1/2/1 unit 5 family mpls
set interfaces fe-1/2/2 unit 6 description P2-to-PE4
set interfaces fe-1/2/2 unit 6 family inet address 10.0.0.13/30
set interfaces fe-1/2/2 unit 6 family mpls
set interfaces lo0 unit 5 family inet address 10.9.9.3/32
set interfaces lo0 unit 5 family inet address 10.100.1.3/32
set protocols rsvp interface fe-1/2/1.5
set protocols rsvp interface fe-1/2/2.6
set protocols rsvp interface fe-1/2/0.3
set protocols mpls label-switched-path P2-to-PE1 to 10.9.9.1
set protocols mpls label-switched-path P2-to-P1 to 10.9.9.2
set protocols mpls label-switched-path P2-to-PE4 to 10.9.9.4
set protocols mpls interface fe-1/2/1.5
set protocols mpls interface fe-1/2/2.6
set protocols mpls interface fe-1/2/0.3
set protocols bgp group internal type internal
set protocols bgp group internal local-address 10.9.9.3
set protocols bgp group internal family inet labeled-unicast aigp
set protocols bgp group internal neighbor 10.9.9.1
set protocols bgp group internal neighbor 10.9.9.2
set protocols bgp group internal neighbor 10.9.9.4
set protocols ospf area 0.0.0.0 interface fe-1/2/2.6 metric 1
set protocols ospf area 0.0.0.0 interface 10.9.9.3 passive
set protocols ospf area 0.0.0.0 interface 10.9.9.3 metric 1
set protocols ospf area 0.0.0.0 interface 10.100.1.3 passive
set protocols ospf area 0.0.0.0 interface 10.100.1.3 metric 1
set routing-options router-id 10.9.9.3
set routing-options autonomous-system 13979

Device PE4

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set interfaces fe-1/2/0 unit 7 description PE4-to-P2
set interfaces fe-1/2/0 unit 7 family inet address 10.0.0.14/30
set interfaces fe-1/2/0 unit 7 family mpls
set interfaces fe-1/2/1 unit 9 description PE4-to-P1
set interfaces fe-1/2/1 unit 9 family inet address 10.0.0.18/30
set interfaces fe-1/2/1 unit 9 family mpls
set interfaces fe-1/2/2 unit 10 description PE4-to-PE2
set interfaces fe-1/2/2 unit 10 family inet address 10.0.0.21/30
set interfaces fe-1/2/2 unit 10 family mpls
set interfaces fe-1/0/2 unit 12 description PE4-to-PE3
set interfaces fe-1/0/2 unit 12 family inet address 10.0.0.25/30
set interfaces fe-1/0/2 unit 12 family mpls
set interfaces lo0 unit 7 family inet address 10.9.9.4/32
set interfaces lo0 unit 7 family inet address 10.100.1.4/32
set protocols rsvp interface fe-1/2/0.7
set protocols rsvp interface fe-1/2/1.9
set protocols rsvp interface fe-1/2/2.10
set protocols rsvp interface fe-1/0/2.12
set protocols mpls label-switched-path PE4-to-PE2 to 10.9.9.5
set protocols mpls label-switched-path PE4-to-PE3 to 10.9.9.6
set protocols mpls label-switched-path PE4-to-P1 to 10.9.9.2
set protocols mpls label-switched-path PE4-to-P2 to 10.9.9.3
set protocols mpls interface fe-1/2/0.7
set protocols mpls interface fe-1/2/1.9
set protocols mpls interface fe-1/2/2.10
set protocols mpls interface fe-1/0/2.12
set protocols bgp export next-hop
set protocols bgp export aigp
set protocols bgp group internal type internal
set protocols bgp group internal local-address 10.9.9.4
set protocols bgp group internal family inet labeled-unicast aigp
set protocols bgp group internal neighbor 10.9.9.1
set protocols bgp group internal neighbor 10.9.9.3
set protocols bgp group internal neighbor 10.9.9.2
set protocols bgp group external type external
set protocols bgp group external multihop ttl 2
set protocols bgp group external local-address 10.9.9.4
set protocols bgp group external family inet labeled-unicast aigp
set protocols bgp group external peer-as 7018
set protocols bgp group external neighbor 10.9.9.5
set protocols bgp group external neighbor 10.9.9.6
set protocols ospf area 0.0.0.0 interface fe-1/2/1.9 metric 1
set protocols ospf area 0.0.0.0 interface fe-1/2/0.7 metric 1
set protocols ospf area 0.0.0.0 interface 10.9.9.4 passive
set protocols ospf area 0.0.0.0 interface 10.9.9.4 metric 1
set protocols ospf area 0.0.0.0 interface 10.100.1.4 passive
set protocols ospf area 0.0.0.0 interface 10.100.1.4 metric 1
set protocols ospf area 0.0.0.2 interface fe-1/2/2.10 metric 1
set protocols ospf area 0.0.0.3 interface fe-1/0/2.12 metric 1
set policy-options policy-statement aigp term 10 from protocol static
set policy-options policy-statement aigp term 10 from route-filter 44.0.0.0/24 exact
set policy-options policy-statement aigp term 10 then aigp-originate distance 200
set policy-options policy-statement aigp term 10 then next-hop 10.100.1.4
set policy-options policy-statement aigp term 10 then accept
set policy-options policy-statement next-hop term 10 from protocol bgp
set policy-options policy-statement next-hop term 10 then next-hop 10.100.1.4
set policy-options policy-statement next-hop term 10 then accept
set policy-options policy-statement next-hop term 20 from protocol direct
set policy-options policy-statement next-hop term 20 from route-filter 10.9.9.4/32 exact
set policy-options policy-statement next-hop term 20 from route-filter 10.100.1.4/32 exact
set policy-options policy-statement next-hop term 20 then next-hop 10.100.1.4
set policy-options policy-statement next-hop term 20 then accept
set routing-options static route 44.0.0.0/24 discard
set routing-options router-id 10.9.9.4
set routing-options autonomous-system 13979

Device PE1

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set interfaces fe-1/2/0 unit 0 description PE1-to-P1
set interfaces fe-1/2/0 unit 0 family inet address 10.0.0.1/30
set interfaces fe-1/2/0 unit 0 family mpls
set interfaces fe-1/2/1 unit 2 description PE1-to-P2
set interfaces fe-1/2/1 unit 2 family inet address 10.0.0.5/30
set interfaces fe-1/2/1 unit 2 family mpls
set interfaces fe-1/2/2 unit 14 description PE1-to-PE7
set interfaces fe-1/2/2 unit 14 family inet address 10.0.0.9/30
set interfaces lo0 unit 1 family inet address 10.9.9.1/32
set interfaces lo0 unit 1 family inet address 10.100.1.1/32
set protocols rsvp interface fe-1/2/0.0
set protocols rsvp interface fe-1/2/1.2
set protocols rsvp interface fe-1/2/2.14
set protocols mpls label-switched-path PE1-to-P1 to 10.9.9.2
set protocols mpls label-switched-path PE1-to-P2 to 10.9.9.3
set protocols mpls interface fe-1/2/0.0
set protocols mpls interface fe-1/2/1.2
set protocols mpls interface fe-1/2/2.14
set protocols bgp group internal type internal
set protocols bgp group internal local-address 10.9.9.1
set protocols bgp group internal family inet labeled-unicast aigp
set protocols bgp group internal export SET_EXPORT_ROUTES
set protocols bgp group internal vpn-apply-export
set protocols bgp group internal neighbor 10.9.9.4
set protocols bgp group internal neighbor 10.9.9.2
set protocols bgp group internal neighbor 10.9.9.3
set protocols bgp group external type external
set protocols bgp group external family inet labeled-unicast aigp
set protocols bgp group external export SET_EXPORT_ROUTES
set protocols bgp group external peer-as 7019
set protocols bgp group external neighbor 10.0.0.10
set protocols ospf area 0.0.0.1 interface fe-1/2/0.0 metric 1
set protocols ospf area 0.0.0.1 interface fe-1/2/1.2 metric 1
set protocols ospf area 0.0.0.1 interface 10.9.9.1 passive
set protocols ospf area 0.0.0.1 interface 10.9.9.1 metric 1
set protocols ospf area 0.0.0.1 interface 10.100.1.1 passive
set protocols ospf area 0.0.0.1 interface 10.100.1.1 metric 1
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol direct
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol bgp
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.1
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then accept
set routing-options router-id 10.9.9.1
set routing-options autonomous-system 13979

Device PE2

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set interfaces fe-1/2/0 unit 11 description PE2-to-PE4
set interfaces fe-1/2/0 unit 11 family inet address 10.0.0.22/30
set interfaces fe-1/2/0 unit 11 family mpls
set interfaces lo0 unit 9 family inet address 10.9.9.5/32 primary
set interfaces lo0 unit 9 family inet address 10.100.1.5/32
set protocols rsvp interface fe-1/2/0.11
set protocols mpls label-switched-path PE2-to-PE4 to 10.9.9.4
set protocols mpls interface fe-1/2/0.11
set protocols bgp group external type external
set protocols bgp group external multihop ttl 2
set protocols bgp group external local-address 10.9.9.5
set protocols bgp group external family inet labeled-unicast aigp
set protocols bgp group external export next-hop
set protocols bgp group external export aigp
set protocols bgp group external export SET_EXPORT_ROUTES
set protocols bgp group external vpn-apply-export
set protocols bgp group external peer-as 13979
set protocols bgp group external neighbor 10.9.9.4
set protocols ospf area 0.0.0.2 interface 10.9.9.5 passive
set protocols ospf area 0.0.0.2 interface 10.9.9.5 metric 1
set protocols ospf area 0.0.0.2 interface 10.100.1.5 passive
set protocols ospf area 0.0.0.2 interface 10.100.1.5 metric 1
set protocols ospf area 0.0.0.2 interface fe-1/2/0.11 metric 1
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol direct
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol static
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol bgp
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.5
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then accept
set policy-options policy-statement aigp term 10 from route-filter 55.0.0.0/24 exact
set policy-options policy-statement aigp term 10 then aigp-originate distance 20
set policy-options policy-statement aigp term 10 then next-hop 10.100.1.5
set policy-options policy-statement aigp term 10 then accept
set policy-options policy-statement aigp term 20 from route-filter 99.0.0.0/24 exact
set policy-options policy-statement aigp term 20 then aigp-originate distance 30
set policy-options policy-statement aigp term 20 then next-hop 10.100.1.5
set policy-options policy-statement aigp term 20 then accept
set policy-options policy-statement next-hop term 10 from protocol bgp
set policy-options policy-statement next-hop term 10 then next-hop 10.100.1.5
set policy-options policy-statement next-hop term 10 then accept
set policy-options policy-statement next-hop term 20 from protocol direct
set policy-options policy-statement next-hop term 20 from route-filter 10.9.9.5/32 exact
set policy-options policy-statement next-hop term 20 from route-filter 10.100.1.5/32 exact
set policy-options policy-statement next-hop term 20 then next-hop 10.100.1.5
set policy-options policy-statement next-hop term 20 then accept
set routing-options static route 99.0.0.0/24 discard
set routing-options static route 55.0.0.0/24 discard
set routing-options router-id 10.9.9.5
set routing-options autonomous-system 7018

Device PE3

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set interfaces fe-1/2/0 unit 13 description PE3-to-PE4
set interfaces fe-1/2/0 unit 13 family inet address 10.0.0.26/30
set interfaces fe-1/2/0 unit 13 family mpls
set interfaces lo0 unit 11 family inet address 10.9.9.6/32
set interfaces lo0 unit 11 family inet address 10.100.1.6/32
set protocols rsvp interface fe-1/2/0.13
set protocols mpls label-switched-path PE3-to-PE4 to 10.9.9.4
set protocols mpls interface fe-1/2/0.13
set protocols bgp group external type external
set protocols bgp group external multihop ttl 2
set protocols bgp group external local-address 10.9.9.6
set protocols bgp group external family inet labeled-unicast aigp
set protocols bgp group external export next-hop
set protocols bgp group external export SET_EXPORT_ROUTES
set protocols bgp group external vpn-apply-export
set protocols bgp group external peer-as 13979
set protocols bgp group external neighbor 10.9.9.4
set protocols ospf area 0.0.0.3 interface 10.9.9.6 passive
set protocols ospf area 0.0.0.3 interface 10.9.9.6 metric 1
set protocols ospf area 0.0.0.3 interface 10.100.1.6 passive
set protocols ospf area 0.0.0.3 interface 10.100.1.6 metric 1
set protocols ospf area 0.0.0.3 interface fe-1/2/0.13 metric 1
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol direct
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol static
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol bgp
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.6
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then accept
set policy-options policy-statement next-hop term 10 from protocol bgp
set policy-options policy-statement next-hop term 10 then next-hop 10.100.1.6
set policy-options policy-statement next-hop term 10 then accept
set policy-options policy-statement next-hop term 20 from protocol direct
set policy-options policy-statement next-hop term 20 from route-filter 10.9.9.6/32 exact
set policy-options policy-statement next-hop term 20 from route-filter 10.100.1.6/32 exact
set policy-options policy-statement next-hop term 20 then next-hop 10.100.1.6
set policy-options policy-statement next-hop term 20 then accept
set routing-options router-id 10.9.9.6
set routing-options autonomous-system 7018

Device PE7

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set interfaces fe-1/2/0 unit 15 description PE7-to-PE1
set interfaces fe-1/2/0 unit 15 family inet address 10.0.0.10/30
set interfaces lo0 unit 13 family inet address 10.9.9.7/32
set interfaces lo0 unit 13 family inet address 10.100.1.7/32
set protocols bgp group external type external
set protocols bgp group external family inet labeled-unicast aigp
set protocols bgp group external export SET_EXPORT_ROUTES
set protocols bgp group external peer-as 13979
set protocols bgp group external neighbor 10.0.0.9
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol direct
set policy-options policy-statement SET_EXPORT_ROUTES term 10 from protocol bgp
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.7
set policy-options policy-statement SET_EXPORT_ROUTES term 10 then accept
set routing-options router-id 10.9.9.7
set routing-options autonomous-system 7019

Configuring Device P1

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device P1:

Configure the interfaces.

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[edit interfaces]
user@P1# set fe-1/2/0 unit 1 description P1-to-PE1
user@P1# set fe-1/2/0 unit 1 family inet address 10.0.0.2/30
user@P1# set fe-1/2/0 unit 1 family mpls
user@P1# set fe-1/2/1 unit 4 description P1-to-P2
user@P1# set fe-1/2/1 unit 4 family inet address 10.0.0.29/30
user@P1# set fe-1/2/1 unit 4 family mpls
user@P1# set fe-1/2/2 unit 8 description P1-to-PE4
user@P1# set fe-1/2/2 unit 8 family inet address 10.0.0.17/30
user@P1# set fe-1/2/2 unit 8 family mpls
user@P1# set lo0 unit 3 family inet address 10.9.9.2/32
user@P1# set lo0 unit 3 family inet address 10.100.1.2/32

Configure MPLS and a signaling protocol, such as RSVP or LDP.

content_copy zoom_out_map
[edit protocols]
user@P1# set rsvp interface fe-1/2/0.1
user@P1# set rsvp interface fe-1/2/2.8
user@P1# set rsvp interface fe-1/2/1.4
user@P1# set mpls label-switched-path P1-to-P2 to 10.9.9.3
user@P1# set mpls label-switched-path P1-to-PE1 to 10.9.9.1
user@P1# set mpls label-switched-path P1-to-PE4 to 10.9.9.4
user@P1# set mpls interface fe-1/2/0.1
user@P1# set mpls interface fe-1/2/2.8
user@P1# set mpls interface fe-1/2/1.4

Configure BGP.

content_copy zoom_out_map
[edit protocols bgp group internal]
user@P1# set type internal
user@P1# set local-address 10.9.9.2
user@P1# set neighbor 10.9.9.1
user@P1# set neighbor 10.9.9.3
user@P1# set neighbor 10.9.9.4

Enable AIGP.

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[edit protocols bgp group internal]
user@P1# set family inet labeled-unicast aigp

Configure an IGP, such as OSPF, RIP, or IS-IS.

content_copy zoom_out_map
[edit protocols ospf]
user@P1# set area 0.0.0.1 interface fe-1/2/0.1 metric 1
user@P1# set area 0.0.0.1 interface fe-1/2/1.4 metric 1
user@P1# set area 0.0.0.0 interface fe-1/2/2.8 metric 1
user@P1# set area 0.0.0.0 interface 10.9.9.2 passive
user@P1# set area 0.0.0.0 interface 10.9.9.2 metric 1
user@P1# set area 0.0.0.0 interface 10.100.1.2 passive
user@P1# set area 0.0.0.0 interface 10.100.1.2 metric 1

Configure the router ID and the autonomous system number.

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[edit routing-options]
user@P1# set router-id 10.9.9.2
user@P1# set autonomous-system 13979

If you are done configuring the device, commit the configuration.
```
user@P1# commit
```

Results

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

content_copy zoom_out_map
user@P1# show interfaces
fe-1/2/0 {
    unit 1 {
        description P1-to-PE1;
        family inet {
            address 10.0.0.2/30;
        }
        family mpls;
    }
}
fe-1/2/1 {
    unit 4 {
        description P1-to-P2;
        family inet {
            address 10.0.0.29/30;
        }
        family mpls;
    }
}
fe-1/2/2 {
    unit 8 {
        description P1-to-PE4;
        family inet {
            address 10.0.0.17/30;
        }
        family mpls;
    }
}
lo0 {
    unit 3 {
        family inet {
            address 10.9.9.2/32;
            address 10.100.1.2/32;
        }
    }
}

content_copy zoom_out_map
user@P1# show protocols
rsvp {
    interface fe-1/2/0.1;
    interface fe-1/2/2.8;
    interface fe-1/2/1.4;
}
mpls {
    label-switched-path P1-to-P2 {
        to 10.9.9.3;
    }
    label-switched-path P1-to-PE1 {
        to 10.9.9.1;
    }
    label-switched-path P1-to-PE4 {
        to 10.9.9.4;
    }
    interface fe-1/2/0.1;
    interface fe-1/2/2.8;
    interface fe-1/2/1.4;
}
bgp {
    group internal {
        type internal;
        local-address 10.9.9.2;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        neighbor 10.9.9.1;
        neighbor 10.9.9.3;
        neighbor 10.9.9.4;
    }
}
ospf {
    area 0.0.0.1 {
        interface fe-1/2/0.1 {
            metric 1;
        }
        interface fe-1/2/1.4 {
            metric 1;
        }
    }
    area 0.0.0.0 {
        interface fe-1/2/2.8 {
            metric 1;
        }
        interface 10.9.9.2 {
            passive;
            metric 1;
        }
        interface 10.100.1.2 {
            passive;
            metric 1;
        }
    }
}

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user@P1# show routing-options
router-id 10.9.9.2;
autonomous-system 13979;

Configuring Device P2

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device P2:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@P2# set fe-1/2/0 unit 3 description P2-to-PE1
user@P2# set fe-1/2/0 unit 3 family inet address 10.0.0.6/30
user@P2# set fe-1/2/0 unit 3 family mpls
user@P2# set fe-1/2/1 unit 5 description P2-to-P1
user@P2# set fe-1/2/1 unit 5 family inet address 10.0.0.30/30
user@P2# set fe-1/2/1 unit 5 family mpls
user@P2# set fe-1/2/2 unit 6 description P2-to-PE4
user@P2# set fe-1/2/2 unit 6 family inet address 10.0.0.13/30
user@P2# set fe-1/2/2 unit 6 family mpls
user@P2# set lo0 unit 5 family inet address 10.9.9.3/32
user@P2# set lo0 unit 5 family inet address 10.100.1.3/32

Configure MPLS and a signaling protocol, such as RSVP or LDP.

content_copy zoom_out_map
[edit protocols]
user@P2# set rsvp interface fe-1/2/1.5
user@P2# set rsvp interface fe-1/2/2.6
user@P2# set rsvp interface fe-1/2/0.3
user@P2# set mpls label-switched-path P2-to-PE1 to 10.9.9.1
user@P2# set mpls label-switched-path P2-to-P1 to 10.9.9.2
user@P2# set mpls label-switched-path P2-to-PE4 to 10.9.9.4
user@P2# set mpls interface fe-1/2/1.5
user@P2# set mpls interface fe-1/2/2.6
user@P2# set mpls interface fe-1/2/0.3

Configure BGP.

content_copy zoom_out_map
[edit protocols bgp group internal]
user@P2# set type internal
user@P2# set local-address 10.9.9.3
user@P2# set neighbor 10.9.9.1
user@P2# set neighbor 10.9.9.2
user@P2# set neighbor 10.9.9.4

Enable AIGP.

content_copy zoom_out_map
[edit protocols bgp group internal]
user@P2# set family inet labeled-unicast aigp

Configure an IGP, such as OSPF, RIP, or IS-IS.

content_copy zoom_out_map
[edit protocols ospf]
user@P2# set area 0.0.0.0 interface fe-1/2/2.6 metric 1
user@P2# set area 0.0.0.0 interface 10.9.9.3 passive
user@P2# set area 0.0.0.0 interface 10.9.9.3 metric 1
user@P2# set area 0.0.0.0 interface 10.100.1.3 passive
user@P2# set area 0.0.0.0 interface 10.100.1.3 metric 1

Configure the router ID and the autonomous system number.

content_copy zoom_out_map
[edit routing-options]
user@P2# set router-id 10.9.9.3
user@P2# set autonomous-system 13979

If you are done configuring the device, commit the configuration.
```
user@P2# commit
```

Results

content_copy zoom_out_map
user@P2# show interfaces
fe-1/2/0 {
    unit 3 {
        description P2-to-PE1;
        family inet {
            address 10.0.0.6/30;
        }
        family mpls;
    }
}
fe-1/2/1 {
    unit 5 {
        description P2-to-P1;
        family inet {
            address 10.0.0.30/30;
        }
        family mpls;
    }
}
fe-1/2/2 {
    unit 6 {
        description P2-to-PE4;
        family inet {
            address 10.0.0.13/30;
        }
        family mpls;
    }
}
lo0 {
    unit 5 {
        family inet {
            address 10.9.9.3/32;
            address 10.100.1.3/32;
        }
    }
}

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user@P2# show protocols
rsvp {
    interface fe-1/2/1.5;
    interface fe-1/2/2.6;
    interface fe-1/2/0.3;
}
mpls {
    label-switched-path P2-to-PE1 {
        to 10.9.9.1;
    }
    label-switched-path P2-to-P1 {
        to 10.9.9.2;
    }
    label-switched-path P2-to-PE4 {
        to 10.9.9.4;
    }
    interface fe-1/2/1.5;
    interface fe-1/2/2.6;
    interface fe-1/2/0.3;
}
bgp {
    group internal {
        type internal;
        local-address 10.9.9.3;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        neighbor 10.9.9.1;
        neighbor 10.9.9.2;
        neighbor 10.9.9.4;
    }
}
ospf {
    area 0.0.0.0 {
        interface fe-1/2/2.6 {
            metric 1;
        }
        interface 10.9.9.3 {
            passive;
            metric 1;
        }
        interface 10.100.1.3 {
            passive;
            metric 1;
        }
    }
}

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user@P2# show routing-options
router-id 10.9.9.3;
autonomous-system 13979;

Configuring Device PE4

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device PE4:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@PE4# set fe-1/2/0 unit 7 description PE4-to-P2
user@PE4# set fe-1/2/0 unit 7 family inet address 10.0.0.14/30
user@PE4# set fe-1/2/0 unit 7 family mpls
user@PE4# set fe-1/2/1 unit 9 description PE4-to-P1
user@PE4# set fe-1/2/1 unit 9 family inet address 10.0.0.18/30
user@PE4# set fe-1/2/1 unit 9 family mpls
user@PE4# set fe-1/2/2 unit 10 description PE4-to-PE2
user@PE4# set fe-1/2/2 unit 10 family inet address 10.0.0.21/30
user@PE4# set fe-1/2/2 unit 10 family mpls
user@PE4# set fe-1/0/2 unit 12 description PE4-to-PE3
user@PE4# set fe-1/0/2 unit 12 family inet address 10.0.0.25/30
user@PE4# set fe-1/0/2 unit 12 family mpls
user@PE4# set lo0 unit 7 family inet address 10.9.9.4/32
user@PE4# set lo0 unit 7 family inet address 10.100.1.4/32

Configure MPLS and a signaling protocol, such as RSVP or LDP.

content_copy zoom_out_map
[edit protocols]
user@PE4# set rsvp interface fe-1/2/0.7
user@PE4# set rsvp interface fe-1/2/1.9
user@PE4# set rsvp interface fe-1/2/2.10
user@PE4# set rsvp interface fe-1/0/2.12
user@PE4# set mpls label-switched-path PE4-to-PE2 to 10.9.9.5
user@PE4# set mpls label-switched-path PE4-to-PE3 to 10.9.9.6
user@PE4# set mpls label-switched-path PE4-to-P1 to 10.9.9.2
user@PE4# set mpls label-switched-path PE4-to-P2 to 10.9.9.3
user@PE4# set mpls interface fe-1/2/0.7
user@PE4# set mpls interface fe-1/2/1.9
user@PE4# set mpls interface fe-1/2/2.10
user@PE4# set mpls interface fe-1/0/2.12

Configure BGP.

content_copy zoom_out_map
[edit protocols bgp]
user@PE4# set export next-hop
user@PE4# set export aigp
user@PE4# set group internal type internal
user@PE4# set group internal local-address 10.9.9.4
user@PE4# set group internal neighbor 10.9.9.1
user@PE4# set group internal neighbor 10.9.9.3
user@PE4# set group internal neighbor 10.9.9.2
user@PE4# set group external type external
user@PE4# set group external multihop ttl 2
user@PE4# set group external local-address 10.9.9.4
user@PE4# set group external peer-as 7018
user@PE4# set group external neighbor 10.9.9.5
user@PE4# set group external neighbor 10.9.9.6

Enable AIGP.

content_copy zoom_out_map
[edit protocols bgp]
user@PE4# set group external family inet labeled-unicast aigp
user@PE4# set group internal family inet labeled-unicast aigp

Originate a prefix, and configure an AIGP distance.

By default, a prefix is originated using the current IGP distance. Optionally, you can configure a distance for the AIGP attribute, using the distance option, as shown here.

content_copy zoom_out_map
[edit policy-options policy-statement aigp term 10]
user@PE4# set from protocol static
user@PE4# set from route-filter 44.0.0.0/24 exact
user@PE4# set then aigp-originate distance 200
user@PE4# set then next-hop 10.100.1.4
user@PE4# set then accept

Enable the policies.

content_copy zoom_out_map
[edit policy-options policy-statement next-hop]
user@PE4# set term 10 from protocol bgp
user@PE4# set term 10 then next-hop 10.100.1.4
user@PE4# set term 10 then accept
user@PE4# set term 20 from protocol direct
user@PE4# set term 20 from route-filter 10.9.9.4/32 exact
user@PE4# set term 20 from route-filter 10.100.1.4/32 exact
user@PE4# set term 20 then next-hop 10.100.1.4
user@PE4# set term 20 then accept

Configure a static route.

content_copy zoom_out_map
[edit routing-options]
user@PE4# set static route 44.0.0.0/24 discard

Configure an IGP, such as OSPF, RIP, or IS-IS.

content_copy zoom_out_map
[edit protocols ospf]
user@PE4# set area 0.0.0.0 interface fe-1/2/1.9 metric 1
user@PE4# set area 0.0.0.0 interface fe-1/2/0.7 metric 1
user@PE4# set area 0.0.0.0 interface 10.9.9.4 passive
user@PE4# set area 0.0.0.0 interface 10.9.9.4 metric 1
user@PE4# set area 0.0.0.0 interface 10.100.1.4 passive
user@PE4# set area 0.0.0.0 interface 10.100.1.4 metric 1
user@PE4# set area 0.0.0.2 interface fe-1/2/2.10 metric 1
user@PE4# set area 0.0.0.3 interface fe-1/0/2.12 metric 1

Configure the router ID and the autonomous system number.

content_copy zoom_out_map
[edit routing-options]
user@PE4# set router-id 10.9.9.4
user@PE4# set autonomous-system 13979

If you are done configuring the device, commit the configuration.
```
user@PE4# commit
```

Results

content_copy zoom_out_map
user@PE4# show interfaces
fe-1/0/2 {
    unit 12 {
        description PE4-to-PE3;
        family inet {
            address 10.0.0.25/30;
        }
        family mpls;
    }
}
fe-1/2/0 {
    unit 7 {
        description PE4-to-P2;
        family inet {
            address 10.0.0.14/30;
        }
        family mpls;
    }
}
fe-1/2/1 {
    unit 9 {
        description PE4-to-P1;
        family inet {
            address 10.0.0.18/30;
        }
        family mpls;
    }
}
fe-1/2/2 {
    unit 10 {
        description PE4-to-PE2;
        family inet {
            address 10.0.0.21/30;
        }
        family mpls;
    }
}
lo0 {
    unit 7 {
        family inet {
            address 10.9.9.4/32;
            address 10.100.1.4/32;
        }
    }
}

content_copy zoom_out_map
user@PE4# show policy-options
policy-statement aigp {
    term 10 {
        from {
            protocol static;
            route-filter 44.0.0.0/24 exact;
        }
        then {
            aigp-originate distance 200;
            next-hop 10.100.1.4;
            accept;
        }
    }
}
policy-statement next-hop {
    term 10 {
        from protocol bgp;
        then {
            next-hop 10.100.1.4;
            accept;
        }
    }
    term 20 {
        from {
            protocol direct;
            route-filter 10.9.9.4/32 exact;
            route-filter 10.100.1.4/32 exact;
        }
        then {
            next-hop 10.100.1.4;
            accept;
        }
    }
}

content_copy zoom_out_map
user@PE4# show protocols
rsvp {
    interface fe-1/2/0.7;
    interface fe-1/2/1.9;
    interface fe-1/2/2.10;
    interface fe-1/0/2.12;
}
mpls {
    label-switched-path PE4-to-PE2 {
        to 10.9.9.5;
    }
    label-switched-path PE4-to-PE3 {
        to 10.9.9.6;
    }
    label-switched-path PE4-to-P1 {
        to 10.9.9.2;
    }
    label-switched-path PE4-to-P2 {
        to 10.9.9.3;
    }
    interface fe-1/2/0.7;
    interface fe-1/2/1.9;
    interface fe-1/2/2.10;
    interface fe-1/0/2.12;
}
bgp {
    export [ next-hop aigp ];
    group internal {
        type internal;
        local-address 10.9.9.4;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        neighbor 10.9.9.1;
        neighbor 10.9.9.3;
        neighbor 10.9.9.2;
    }
    group external {
        type external;
        multihop {
            ttl 2;
        }
        local-address 10.9.9.4;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        peer-as 7018;
        neighbor 10.9.9.5;
        neighbor 10.9.9.6;
    }
}
ospf {
    area 0.0.0.0 {
        interface fe-1/2/1.9 {
            metric 1;
        }
        interface fe-1/2/0.7 {
            metric 1;
        }
        interface 10.9.9.4 {
            passive;
            metric 1;
        }
        interface 10.100.1.4 {
            passive;
            metric 1;
        }
    }
    area 0.0.0.2 {
        interface fe-1/2/2.10 {
            metric 1;
        }
    }
    area 0.0.0.3 {
        interface fe-1/0/2.12 {
            metric 1;
        }
    }
}

content_copy zoom_out_map
user@PE4# show routing-options
static {
    route 44.0.0.0/24 discard;
}
router-id 10.9.9.4;
autonomous-system 13979;

Configuring Device PE1

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device PE1:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@PE1# set fe-1/2/0 unit 0 description PE1-to-P1
user@PE1# set fe-1/2/0 unit 0 family inet address 10.0.0.1/30
user@PE1# set fe-1/2/0 unit 0 family mpls
user@PE1# set fe-1/2/1 unit 2 description PE1-to-P2
user@PE1# set fe-1/2/1 unit 2 family inet address 10.0.0.5/30
user@PE1# set fe-1/2/1 unit 2 family mpls
user@PE1# set fe-1/2/2 unit 14 description PE1-to-PE7
user@PE1# set fe-1/2/2 unit 14 family inet address 10.0.0.9/30
user@PE1# set lo0 unit 1 family inet address 10.9.9.1/32
user@PE1# set lo0 unit 1 family inet address 10.100.1.1/32

Configure MPLS and a signaling protocol, such as RSVP or LDP.

content_copy zoom_out_map
[edit protocols]
user@PE1# set rsvp interface fe-1/2/0.0
user@PE1# set rsvp interface fe-1/2/1.2
user@PE1# set rsvp interface fe-1/2/2.14
user@PE1# set mpls label-switched-path PE1-to-P1 to 10.9.9.2
user@PE1# set mpls label-switched-path PE1-to-P2 to 10.9.9.3
user@PE1# set mpls interface fe-1/2/0.0
user@PE1# set mpls interface fe-1/2/1.2
user@PE1# set mpls interface fe-1/2/2.14

Configure BGP.

content_copy zoom_out_map
[edit protocols bgp]
user@PE1# set group internal type internal
user@PE1# set group internal local-address 10.9.9.1
user@PE1# set group internal export SET_EXPORT_ROUTES
user@PE1# set group internal vpn-apply-export
user@PE1# set group internal neighbor 10.9.9.4
user@PE1# set group internal neighbor 10.9.9.2
user@PE1# set group internal neighbor 10.9.9.3
user@PE1# set group external type external
user@PE1# set group external export SET_EXPORT_ROUTES
user@PE1# set group external peer-as 7019
user@PE1# set group external neighbor 10.0.0.10

Enable AIGP.

content_copy zoom_out_map
[edit protocols bgp]
user@PE1# set group internal family inet labeled-unicast aigp
user@PE1# set group external family inet labeled-unicast aigp

Enable the policies.

content_copy zoom_out_map
[edit policy-options policy-statement SET_EXPORT_ROUTES term 10]
user@PE1# set from protocol direct
user@PE1# set from protocol bgp
user@PE1# set then next-hop 10.100.1.1
user@PE1# set then accept

Configure an IGP, such as OSPF, RIP, or IS-IS.

content_copy zoom_out_map
[edit protocols ospf area 0.0.0.1]
user@PE1# set interface fe-1/2/0.0 metric 1
user@PE1# set interface fe-1/2/1.2 metric 1
user@PE1# set interface 10.9.9.1 passive
user@PE1# set interface 10.9.9.1 metric 1
user@PE1# set interface 10.100.1.1 passive
user@PE1# set interface 10.100.1.1 metric 1

Configure the router ID and the autonomous system number.

content_copy zoom_out_map
[edit routing-options]
user@PE1# set router-id 10.9.9.1
user@PE1# set autonomous-system 13979

If you are done configuring the device, commit the configuration.
```
user@PE1# commit
```

Results

content_copy zoom_out_map
user@PE1# show interfaces
fe-1/2/0 {
    unit 0 {
        description PE1-to-P1;
        family inet {
            address 10.0.0.1/30;
        }
        family mpls;
    }
}
fe-1/2/1 {
    unit 2 {
        description PE1-to-P2;
        family inet {
            address 10.0.0.5/30;
        }
        family mpls;
    }
}
fe-1/2/2 {
    unit 14 {
        description PE1-to-PE7;
        family inet {
            address 10.0.0.9/30;
        }
    }
}
lo0 {
    unit 1 {
        family inet {
            address 10.9.9.1/32;
            address 10.100.1.1/32;
        }
    }
}

content_copy zoom_out_map
user@PE1# show policy-options
policy-statement SET_EXPORT_ROUTES {
    term 10 {
        from protocol [ direct bgp ];
        then {
            next-hop 10.100.1.1;
            accept;
        }
    }
}

content_copy zoom_out_map
user@PE1# show protocols
rsvp {
    interface fe-1/2/0.0;
    interface fe-1/2/1.2;
    interface fe-1/2/2.14;
}
mpls {
    label-switched-path PE1-to-P1 {
        to 10.9.9.2;
    }
    label-switched-path PE1-to-P2 {
        to 10.9.9.3;
    }
    interface fe-1/2/0.0;
    interface fe-1/2/1.2;
    interface fe-1/2/2.14;
}
bgp {
    group internal {
        type internal;
        local-address 10.9.9.1;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        export SET_EXPORT_ROUTES;
        vpn-apply-export;
        neighbor 10.9.9.4;
        neighbor 10.9.9.2;
        neighbor 10.9.9.3;
    }
    group external {
        type external;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        export SET_EXPORT_ROUTES;
        peer-as 7019;
        neighbor 10.0.0.10;
    }
}
ospf {
    area 0.0.0.1 {
        interface fe-1/2/0.0 {
            metric 1;
        }
        interface fe-1/2/1.2 {
            metric 1;
        }
        interface 10.9.9.1 {
            passive;
            metric 1;
        }
        interface 10.100.1.1 {
            passive;
            metric 1;
        }
    }
}

content_copy zoom_out_map
user@PE1# show routing-options
router-id 10.9.9.1;
autonomous-system 13979;

Configuring Device PE2

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device PE2:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@PE2# set fe-1/2/0 unit 11 description PE2-to-PE4
user@PE2# set fe-1/2/0 unit 11 family inet address 10.0.0.22/30
user@PE2# set fe-1/2/0 unit 11 family mpls
user@PE2# set lo0 unit 9 family inet address 10.9.9.5/32 primary
user@PE2# set lo0 unit 9 family inet address 10.100.1.5/32

Configure MPLS and a signaling protocol, such as RSVP or LDP.

content_copy zoom_out_map
[edit protocols]
user@PE2# set rsvp interface fe-1/2/0.11
user@PE2# set mpls label-switched-path PE2-to-PE4 to 10.9.9.4
user@PE2# set mpls interface fe-1/2/0.11

Configure BGP.

content_copy zoom_out_map
[edit protocols bgp]
user@PE2# set group external type external
user@PE2# set group external multihop ttl 2
user@PE2# set group external local-address 10.9.9.5
user@PE2# set group external export next-hop
user@PE2# set group external export aigp
user@PE2# set group external export SET_EXPORT_ROUTES
user@PE2# set group external vpn-apply-export
user@PE2# set group external peer-as 13979
user@PE2# set group external neighbor 10.9.9.4

Enable AIGP.

content_copy zoom_out_map
[edit protocols bgp]
user@PE2# set group external family inet labeled-unicast aigp

Originate a prefix, and configure an AIGP distance.

By default, a prefix is originated using the current IGP distance. Optionally, you can configure a distance for the AIGP attribute, using the distance option, as shown here.

content_copy zoom_out_map
[edit policy-options policy-statement aigp]
user@PE2# set term 10 from route-filter 55.0.0.0/24 exact
user@PE2# set term 10 then aigp-originate distance 20
user@PE2# set term 10 then next-hop 10.100.1.5
user@PE2# set term 10 then accept
user@PE2# set term 20 from route-filter 99.0.0.0/24 exact
user@PE2# set term 20 then aigp-originate distance 30
user@PE2# set term 20 then next-hop 10.100.1.5
user@PE2# set term 20 then accept

Enable the policies.

content_copy zoom_out_map
[edit policy-options]
user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 from protocol direct
user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 from protocol static
user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 from protocol bgp
user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.5
user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 then accept
user@PE2# set policy-statement next-hop term 10 from protocol bgp
user@PE2# set policy-statement next-hop term 10 then next-hop 10.100.1.5
user@PE2# set policy-statement next-hop term 10 then accept
user@PE2# set policy-statement next-hop term 20 from protocol direct
user@PE2# set policy-statement next-hop term 20 from route-filter 10.9.9.5/32 exact
user@PE2# set policy-statement next-hop term 20 from route-filter 10.100.1.5/32 exact
user@PE2# set policy-statement next-hop term 20 then next-hop 10.100.1.5
user@PE2# set policy-statement next-hop term 20 then accept

Enable some static routes.

content_copy zoom_out_map
[edit routing-options]
user@PE2# set static route 99.0.0.0/24 discard
user@PE2# set static route 55.0.0.0/24 discard

Configure an IGP, such as OSPF, RIP, or IS-IS.

content_copy zoom_out_map
[edit protocols ospf area 0.0.0.2]
user@PE2# set interface 10.9.9.5 passive
user@PE2# set interface 10.9.9.5 metric 1
user@PE2# set interface 10.100.1.5 passive
user@PE2# set interface 10.100.1.5 metric 1
user@PE2# set interface fe-1/2/0.11 metric 1

Configure the router ID and the autonomous system number.

content_copy zoom_out_map
[edit routing-options]
user@PE2# set router-id 10.9.9.5
user@PE2# set autonomous-system 7018

If you are done configuring the device, commit the configuration.
```
user@PE2# commit
```

Results

content_copy zoom_out_map
user@PE2# show interfaces
fe-1/2/0 {
    unit 11 {
        description PE2-to-PE4;
        family inet {
            address 10.0.0.22/30;
        }
        family mpls;
    }
}
lo0 {
    unit 9 {
        family inet {
            address 10.9.9.5/32 {
                primary;
            }
            address 10.100.1.5/32;
        }
    }
}

content_copy zoom_out_map
user@PE2# show policy-options
policy-statement SET_EXPORT_ROUTES {
    term 10 {
        from protocol [ direct static bgp ];
        then {
            next-hop 10.100.1.5;
            accept;
        }
    }
}
policy-statement aigp {
    term 10 {
        from {
            route-filter 55.0.0.0/24 exact;
        }
        then {
            aigp-originate distance 20;
            next-hop 10.100.1.5;
            accept;
        }
    }
    term 20 {
        from {
            route-filter 99.0.0.0/24 exact;
        }
        then {
            aigp-originate distance 30;
            next-hop 10.100.1.5;
            accept;
        }
    }
}
policy-statement next-hop {
    term 10 {
        from protocol bgp;
        then {
            next-hop 10.100.1.5;
            accept;
        }
    }
    term 20 {
        from {
            protocol direct;
            route-filter 10.9.9.5/32 exact;
            route-filter 10.100.1.5/32 exact;
        }
        then {
            next-hop 10.100.1.5;
            accept;
        }
    }
}

content_copy zoom_out_map
user@PE2# show protocols
rsvp {
    interface fe-1/2/0.11;
}
mpls {
    label-switched-path PE2-to-PE4 {
        to 10.9.9.4;
    }
    interface fe-1/2/0.11;
}
bgp {
    group external {
        type external;
        multihop {
            ttl 2;
        }
        local-address 10.9.9.5;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        export [ next-hop aigp SET_EXPORT_ROUTES ];
        vpn-apply-export;
        peer-as 13979;
        neighbor 10.9.9.4;
    }
}
ospf {
    area 0.0.0.2 {
        interface 10.9.9.5 {
            passive;
            metric 1;
        }
        interface 10.100.1.5 {
            passive;
            metric 1;
        }
        interface fe-1/2/0.11 {
            metric 1;
        }
    }
}

content_copy zoom_out_map
user@PE2# show routing-options
static {
    route 99.0.0.0/24 discard;
    route 55.0.0.0/24 discard;
}
router-id 10.9.9.5;
autonomous-system 7018;

Configuring Device PE3

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device PE3:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@PE3# set fe-1/2/0 unit 13 description PE3-to-PE4
user@PE3# set fe-1/2/0 unit 13 family inet address 10.0.0.26/30
user@PE3# set fe-1/2/0 unit 13 family mpls
user@PE3# set lo0 unit 11 family inet address 10.9.9.6/32
user@PE3# set lo0 unit 11 family inet address 10.100.1.6/32

Configure MPLS and a signaling protocol, such as RSVP or LDP.

content_copy zoom_out_map
[edit protocols]
user@PE3# set rsvp interface fe-1/2/0.13
user@PE3# set mpls label-switched-path PE3-to-PE4 to 10.9.9.4
user@PE3# set mpls interface fe-1/2/0.13

Configure BGP.

content_copy zoom_out_map
[edit protocols bgp group external]
user@PE3# set type external
user@PE3# set multihop ttl 2
user@PE3# set local-address 10.9.9.6
user@PE3# set export next-hop
user@PE3# set export SET_EXPORT_ROUTES
user@PE3# set vpn-apply-export
user@PE3# set peer-as 13979
user@PE3# set neighbor 10.9.9.4

Enable AIGP.

content_copy zoom_out_map
[edit protocols bgp group external]
user@PE3# set family inet labeled-unicast aigp

Enable the policies.

content_copy zoom_out_map
[edit policy-options]
user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 from protocol direct
user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 from protocol static
user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 from protocol bgp
user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.6
user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 then accept
user@PE3# set policy-statement next-hop term 10 from protocol bgp
user@PE3# set policy-statement next-hop term 10 then next-hop 10.100.1.6
user@PE3# set policy-statement next-hop term 10 then accept
user@PE3# set policy-statement next-hop term 20 from protocol direct
user@PE3# set policy-statement next-hop term 20 from route-filter 10.9.9.6/32 exact
user@PE3# set policy-statement next-hop term 20 from route-filter 10.100.1.6/32 exact
user@PE3# set policy-statement next-hop term 20 then next-hop 10.100.1.6
user@PE3# set policy-statement next-hop term 20 then accept

Configure an IGP, such as OSPF, RIP, or IS-IS.

content_copy zoom_out_map
[edit protocols ospf area 0.0.0.3]
user@PE3# set interface 10.9.9.6 passive
user@PE3# set interface 10.9.9.6 metric 1
user@PE3# set interface 10.100.1.6 passive
user@PE3# set interface 10.100.1.6 metric 1
user@PE3# set interface fe-1/2/0.13 metric 1

Configure the router ID and the autonomous system number.

content_copy zoom_out_map
[edit routing-options]
user@PE3# set router-id 10.9.9.6
user@PE3# set autonomous-system 7018

If you are done configuring the device, commit the configuration.
```
user@PE3# commit
```

Results

content_copy zoom_out_map
user@PE3# show interfaces
fe-1/2/0 {
    unit 13 {
        description PE3-to-PE4;
        family inet {
            address 10.0.0.26/30;
        }
        family mpls;
    }
}
lo0 {
    unit 11 {
        family inet {
            address 10.9.9.6/32;
            address 10.100.1.6/32;
        }
    }
}

content_copy zoom_out_map
user@PE3# show policy-options
policy-statement SET_EXPORT_ROUTES {
    term 10 {
        from protocol [ direct static bgp ];
        then {
            next-hop 10.100.1.6;
            accept;
        }
    }
}
policy-statement next-hop {
    term 10 {
        from protocol bgp;
        then {
            next-hop 10.100.1.6;
            accept;
        }
    }
    term 20 {
        from {
            protocol direct;
            route-filter 10.9.9.6/32 exact;
            route-filter 10.100.1.6/32 exact;
        }
        then {
            next-hop 10.100.1.6;
            accept;
        }
    }
}

content_copy zoom_out_map
user@PE3# show protocols
rsvp {
    interface fe-1/2/0.13;
}
mpls {
    label-switched-path PE3-to-PE4 {
        to 10.9.9.4;
    }
    interface fe-1/2/0.13;
}
bgp {
    group external {
        type external;
        multihop {
            ttl 2;
        }
        local-address 10.9.9.6;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        export [ next-hop SET_EXPORT_ROUTES ];
        vpn-apply-export;
        peer-as 13979;
        neighbor 10.9.9.4;
    }
}
ospf {
    area 0.0.0.3 {
        interface 10.9.9.6 {
            passive;
            metric 1;
        }
        interface 10.100.1.6 {
            passive;
            metric 1;
        }
        interface fe-1/2/0.13 {
            metric 1;
        }
    }
}

content_copy zoom_out_map
user@PE3# show routing-options
router-id 10.9.9.6;
autonomous-system 7018;

Configuring Device PE7

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device PE7:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@PE7# set fe-1/2/0 unit 15 description PE7-to-PE1
user@PE7# set fe-1/2/0 unit 15 family inet address 10.0.0.10/30
user@PE7# set lo0 unit 13 family inet address 10.9.9.7/32
user@PE7# set lo0 unit 13 family inet address 10.100.1.7/32

Configure BGP.

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[edit protocols bgp group external]
user@PE7# set type external
user@PE7# set export SET_EXPORT_ROUTES
user@PE7# set peer-as 13979
user@PE7# set neighbor 10.0.0.9

Enable AIGP.

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[edit protocols bgp group external]
user@PE7# set family inet labeled-unicast aigp

Configure the routing policy.

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[edit policy-options policy-statement SET_EXPORT_ROUTES term 10]
user@PE7# set from protocol direct
user@PE7# set from protocol bgp
user@PE7# set then next-hop 10.100.1.7
user@PE7# set then accept

Configure the router ID and the autonomous system number.

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[edit routing-options]
user@PE7# set router-id 10.9.9.7
user@PE7# set autonomous-system 7019

If you are done configuring the device, commit the configuration.
```
user@PE7# commit
```

Results

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user@PE7# show interfaces
interfaces {
    fe-1/2/0 {
        unit 15 {
            description PE7-to-PE1;
            family inet {
                address 10.0.0.10/30;
            }
        }
    }
    lo0 {
        unit 13 {
            family inet {
                address 10.9.9.7/32;
                address 10.100.1.7/32;
            }
        }
    }
}

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user@PE7# show policy-options
policy-statement SET_EXPORT_ROUTES {
    term 10 {
        from protocol [ direct bgp ];
        then {
            next-hop 10.100.1.7;
            accept;
        }
    }
}

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user@PE7# show protocols
bgp {
    group external {
        type external;
        family inet {
            labeled-unicast {
                aigp;
            }
        }
        export SET_EXPORT_ROUTES;
        peer-as 13979;
        neighbor 10.0.0.9;
    }
}

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user@PE7# show routing-options
router-id 10.9.9.7;
autonomous-system 7019;

Verification

Confirm that the configuration is working properly.

Verifying That Device PE4 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE2
Checking the IGP Metric
Verifying That Device PE4 Adds the IGP Metric to the AIGP Attribute
Verifying That Device PE7 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE1
Verifying the Resolving AIGP Metric
Verifying the Presence of AIGP Attributes in BGP Updates

Verifying That Device PE4 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE2

Purpose
Action
Meaning

Purpose

Make sure that the AIGP policy on Device PE2 is working.

Action

content_copy zoom_out_map
user@PE4> show route receive-protocol bgp 10.9.9.5 extensive
* 55.0.0.0/24 (1 entry, 1 announced)
     Accepted
     Route Label: 299888
     Nexthop: 10.100.1.5
     AS path: 7018 I
     AIGP: 20

* 99.0.0.0/24 (1 entry, 1 announced)
     Accepted
     Route Label: 299888
     Nexthop: 10.100.1.5
     AS path: 7018 I
     AIGP: 30

Meaning

On Device PE2, the aigp-originate statement is configured with a distance of 20 (aigp-originate distance 20). This statement is applied to route 55.0.0.0/24. Likewise, the aigp-originate distance 30 statement is applied to route 99.0.0.0/24. Thus, when Device PE4 receives these routes, the AIGP attribute is attached with the configured metrics.

Checking the IGP Metric

Purpose
Action
Meaning

Purpose

From Device PE4, check the IGP metric to the BGP next hop 10.100.1.5.

Action

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user@PE4> show route 10.100.1.5
inet.0: 30 destinations, 40 routes (30 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.100.1.5/32      *[OSPF/10] 05:35:50, metric 2
                    > to 10.0.0.22 via fe-1/2/2.10
                    [BGP/170] 03:45:07, localpref 100, from 10.9.9.5
                      AS path: 7018 I
                    > to 10.0.0.22 via fe-1/2/2.10

Meaning

The IGP metric for this route is 2.

Verifying That Device PE4 Adds the IGP Metric to the AIGP Attribute

Purpose
Action
Meaning

Purpose

Make sure that Device PE4 adds the IGP metric to the AIGP attribute when it readvertises routes to its IBGP neighbor, Device PE1.

Action

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user@PE4> show route advertising-protocol bgp 10.9.9.1 extensive

* 55.0.0.0/24 (1 entry, 1 announced)
 BGP group internal type Internal
     Route Label: 300544
     Nexthop: 10.100.1.4
     Flags: Nexthop Change
     Localpref: 100
     AS path: [13979] 7018 I
     AIGP: 22

* 99.0.0.0/24 (1 entry, 1 announced)
 BGP group internal type Internal
     Route Label: 300544
     Nexthop: 10.100.1.4
     Flags: Nexthop Change
     Localpref: 100
     AS path: [13979] 7018 I
     AIGP: 32

Meaning

The IGP metric is added to the AIGP metric (20 + 2 = 22 and 30 + 2 = 32), because the next hop is changed for these routes.

Verifying That Device PE7 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE1

Purpose
Action
Meaning

Purpose

Make sure that the AIGP policy on Device PE1 is working.

Action

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user@PE7> show route receive-protocol bgp 10.0.0.9 extensive
* 44.0.0.0/24 (1 entry, 1 announced)
     Accepted
     Route Label: 300096
     Nexthop: 10.0.0.9
     AS path: 13979 I
     AIGP: 203

* 55.0.0.0/24 (1 entry, 1 announced)
     Accepted
     Route Label: 300112
     Nexthop: 10.0.0.9
     AS path: 13979 7018 I
     AIGP: 25

* 99.0.0.0/24 (1 entry, 1 announced)
     Accepted
     Route Label: 300112                
     Nexthop: 10.0.0.9
     AS path: 13979 7018 I
     AIGP: 35

Meaning

The 44.0.0.0/24 route is originated at Device PE4. The 55.0.0.0/24 and 99.0.0.0/24 routes are originated at Device PE2. The IGP distances are added to the configured AIGP distances.

Verifying the Resolving AIGP Metric

Purpose
Action

Purpose

Confirm that if the prefix is resolved through recursion and the recursive next hops have AIGP metrics, the prefix has the sum of the AIGP values that are on the recursive BGP next hops.

Action

Add a static route to 66.0.0.0/24.

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[edit routing-options]
user@PE2# set static route 66.0.0.0/24 discard

Delete the existing terms in the aigp policy statement on Device PE2.

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[edit policy-options policy-statement aigp]
user@PE2# delete term 10
user@PE2# delete term 20

Configure a recursive route lookup for the route to 66.0.0.0.

The policy shows the AIGP metric for prefix 66.0.0.0/24 (none) and its recursive next hop. Prefix 66.0.0.0/24 is resolved by 55.0.0.1. Prefix 66.0.0.0/24 does not have its own AIGP metric being originated, but its recursive next hop, 55.0.0.1, has an AIGP value.

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[edit policy-options policy-statement aigp]
user@PE2# set term 10 from route-filter 55.0.0.1/24 exact 
user@PE2# set term 10 then aigp-originate distance 20 
user@PE2# set term 10 then next-hop 10.100.1.5 
user@PE2# set term 10 then accept 
user@PE2# set term 20 from route-filter 66.0.0.0/24 exact 
user@PE2# set term 20 then next-hop 55.0.0.1 
user@PE2# set term 20 then accept 

On Device PE4, run the show route 55.0.0.0 extensive command.

The value of Metric2 is the IGP metric to the BGP next hop. When Device PE4 readvertises these routes to its IBGP peer, Device PE1, the AIGP metric is the sum of AIGP + its Resolving AIGP metric + Metric2.

Prefix 55.0.0.0 shows its own IGP metric 20, as defined and advertised by Device PE2. It does not show a resolving AIGP value because it does not have a recursive BGP next hop. The value of Metric2 is 2.

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user@PE4> show route 55.0.0.0 extensive
inet.0: 31 destinations, 41 routes (31 active, 0 holddown, 0 hidden)
55.0.0.0/24 (1 entry, 1 announced)
TSI:
KRT in-kernel 55.0.0.0/24 -> {indirect(262151)}
Page 0 idx 0 Type 1 val 928d1b8
    Flags: Nexthop Change
    Nexthop: 10.100.1.4
    Localpref: 100
    AS path: [13979] 7018 I
    Communities:
    AIGP: 22
Path 55.0.0.0 from 10.9.9.5 Vector len 4.  Val: 0
        *BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0x925da38
                Next-hop reference count: 4
                Source: 10.9.9.5
                Next hop type: Router, Next hop index: 1004
                Next hop: 10.0.0.22 via fe-1/2/2.10, selected
                Label operation: Push 299888
                Label TTL action: prop-ttl
                Protocol next hop: 10.100.1.5
                Push 299888
                Indirect next hop: 93514d8 262151
                State: <Active Ext>
                Local AS: 13979 Peer AS:  7018
                Age: 22:03:26   Metric2: 2 
                AIGP: 20 
                Task: BGP_7018.10.9.9.5+58560
                Announcement bits (3): 3-KRT 4-BGP_RT_Background 5-Resolve tree 1 
                AS path: 7018 I
                Accepted
                Route Label: 299888
                Localpref: 100
                Router ID: 10.9.9.5
                Indirect next hops: 1
                        Protocol next hop: 10.100.1.5 Metric: 2
                        Push 299888
                        Indirect next hop: 93514d8 262151
                        Indirect path forwarding next hops: 1
                                Next hop type: Router
                                Next hop: 10.0.0.22 via fe-1/2/2.10
                        10.100.1.5/32 Originating RIB: inet.0
                          Metric: 2                       Node path count: 1
                          Forwarding nexthops: 1
                                Nexthop: 10.0.0.22 via fe-1/2/2.10

On Device PE4, run the show route 66.0.0.0 extensive command.

Prefix 66.0.0.0/24 shows the Resolving AIGP, which is the sum of its own AIGP metric and its recursive BGP next hop:

66.0.0.1 = 0, 55.0.0.1 = 20, 0+20 = 20

content_copy zoom_out_map
user@PE4> show route 66.0.0.0 extensive 
inet.0: 31 destinations, 41 routes (31 active, 0 holddown, 0 hidden)
66.0.0.0/24 (1 entry, 1 announced)
TSI:
KRT in-kernel 66.0.0.0/24 -> {indirect(262162)}
Page 0 idx 0 Type 1 val 928cefc
    Flags: Nexthop Change
    Nexthop: 10.100.1.4
    Localpref: 100
    AS path: [13979] 7018 I
    Communities:
Path 66.0.0.0 from 10.9.9.5 Vector len 4.  Val: 0
        *BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0x925d4e0
                Next-hop reference count: 4
                Source: 10.9.9.5
                Next hop type: Router, Next hop index: 1006
                Next hop: 10.0.0.22 via fe-1/2/2.10, selected
                Label operation: Push 299888, Push 299888(top)
                Label TTL action: prop-ttl, prop-ttl(top)
                Protocol next hop: 55.0.0.1
                Push 299888
                Indirect next hop: 9353e88 262162
                State: <Active Ext>
                Local AS: 13979 Peer AS:  7018
                Age: 31:42      Metric2: 2 
                Resolving-AIGP: 20 
                Task: BGP_7018.10.9.9.5+58560
                Announcement bits (3): 3-KRT 4-BGP_RT_Background 5-Resolve tree 1 
                AS path: 7018 I
                Accepted
                Route Label: 299888
                Localpref: 100
                Router ID: 10.9.9.5
                Indirect next hops: 1
                        Protocol next hop: 55.0.0.1 Metric: 2 AIGP: 20
                        Push 299888
                        Indirect next hop: 9353e88 262162
                        Indirect path forwarding next hops: 1
                                Next hop type: Router
                                Next hop: 10.0.0.22 via fe-1/2/2.10
                        55.0.0.0/24 Originating RIB: inet.0
                          Metric: 2                       Node path count: 1
                          Indirect nexthops: 1
                                Protocol Nexthop: 10.100.1.5 Metric: 2 Push 299888
                                Indirect nexthop: 93514d8 262151
                                Indirect path forwarding nexthops: 1
                                        Nexthop: 10.0.0.22 via fe-1/2/2.10
                                10.100.1.5/32 Originating RIB: inet.0
                                  Metric: 2                               Node path count: 1
                                  Forwarding nexthops: 1
                                        Nexthop: 10.0.0.22 via fe-1/2/2.10

Verifying the Presence of AIGP Attributes in BGP Updates

Purpose
Action
Meaning

Purpose

If the AIGP attribute is not enabled under BGP (or the group or neighbor hierarchies), the AIGP attribute is silently discarded. Enable traceoptions and include the packets flag in the detail option in the configuration to confirm the presence of the AIGP attribute in transmitted or received BGP updates. This is useful when debugging AIGP issues.

Action

Configure Device PE2 and Device PE4 for traceoptions.

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user@host> show protocols bgp
    traceoptions {
        file bgp size 1m files 5;
        flag packets detail;
    }

Check the traceoptions file on Device PE2.

The following sample shows Device PE2 advertising prefix 99.0.0.0/24 to Device PE4 (10.9.9.4) with an AIGP metric of 20:

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user@PE2> show log bgp
Mar 22 09:27:18.982150 BGP SEND 10.9.9.5+49652 -> 10.9.9.4+179
Mar 22 09:27:18.982178 BGP SEND message type 2 (Update) length 70
Mar 22 09:27:18.982198 BGP SEND Update PDU length 70
Mar 22 09:27:18.982248 BGP SEND flags 0x40 code Origin(1): IGP
Mar 22 09:27:18.982273 BGP SEND flags 0x40 code ASPath(2) length 6: 7018
Mar 22 09:27:18.982295 BGP SEND flags 0x80 code AIGP(26): AIGP: 20 
Mar 22 09:27:18.982316 BGP SEND flags 0x90 code MP_reach(14): AFI/SAFI 1/4
Mar 22 09:27:18.982341 BGP SEND         nhop 10.100.1.5 len 4
Mar 22 09:27:18.982372 BGP SEND         99.0.0.0/24 (label 301664)
Mar 22 09:27:33.665412 bgp_send: sending 19 bytes to abcd::10:255:170:84 (External AS 13979)

Verify that the route was received on Device PE4 using the show route receive-protocol command.

AIGP is not enabled on Device PE4, so the AIGP attribute is silently discarded for prefix 99.0.0.0/24 and does not appear in the following output:
```
user@PE4> show route receive-protocol bgp 10.9.9.5 extensive | find 55.0.0.0
* 99.0.0.0/24 (2 entries, 1 announced)
     Accepted
     Route Label: 301728
     Nexthop: 10.100.1.5
     AS path: 7018 I
```

Check the traceoptions file on Device PE4.

The following output from the traceoptions log shows that the 99.0.0.0/24 prefix was received with the AIGP attribute attached:

content_copy zoom_out_map
user@PE4> show log bgp
Mar 22 09:41:39.650295 BGP RECV 10.9.9.5+64690 -> 10.9.9.4+179
Mar 22 09:41:39.650331 BGP RECV message type 2 (Update) length 70
Mar 22 09:41:39.650350 BGP RECV Update PDU length 70
Mar 22 09:41:39.650370 BGP RECV flags 0x40 code Origin(1): IGP
Mar 22 09:41:39.650394 BGP RECV flags 0x40 code ASPath(2) length 6: 7018
Mar 22 09:41:39.650415 BGP RECV flags 0x80 code AIGP(26): AIGP: 20
Mar 22 09:41:39.650436 BGP RECV flags 0x90 code MP_reach(14): AFI/SAFI 1/4
Mar 22 09:41:39.650459 BGP RECV         nhop 10.100.1.5 len 4
Mar 22 09:41:39.650495 BGP RECV         99.0.0.0/24 (label 301728)
Mar 22 09:41:39.650574 bgp_rcv_nlri: 99.0.0.0/24
Mar 22 09:41:39.650607 bgp_rcv_nlri: 99.0.0.0/24 belongs to meshgroup
Mar 22 09:41:39.650629 bgp_rcv_nlri: 99.0.0.0/24 qualified bnp->ribact 0x0 l2afcb 0x0

Meaning

Performing this verification helps with AIGP troubleshooting and debugging issues. It enables you to verify which devices in your network send and receive AIGP attributes.

Understanding AS Override

The AS override feature allows a provider edge (PE) router to change the private autonomous system (AS) number used by a customer edge (CE) device on an external BGP (EBGP) session running on a VPN routing and forwarding (VRF) access link. The private AS number is changed to the PE AS number. Another CE device connected to another PE device sees the EBGP route coming from the first site with an AS path of provider-ASN provider-ASN, instead of provider-ASN site1-ASN. This allows enterprise networks to use the same private ASN on all sites.

The AS override feature offers a clear management advantage to the service provider because BGP by default does not accept BGP routes with an AS path attribute that contains the local AS number.

In an enterprise network with multiple sites, you might wish to use a single AS number across sites. Suppose, for example that two CE devices are in AS 64512 and that the provider network is in AS 65534.

When the service provider configures a Layer 3 VPN with this setup, even if the MPLS network has routes towards Device CE1 and Device CE2, Device CE1 and Device CE2 do not have routes to each other because the AS path attribute would appear as 64512 65534 64512. BGP uses the AS path attribute as its loop avoidance mechanism. If a site sees its own AS number more than once in the AS path, the route is considered invalid.

One way to overcome this difficulty is with the as-override statement, which is applied to the PE devices. The as-override statement replaces the CE device's AS number with that of the PE device, thus preventing the customer AS number from appearing more than once in the AS path attribute.

If a customer uses AS path prepending to make certain paths less desirable and the service provider uses AS override, each CE AS number occurrence in the AS-path is changed to the service provider AS number. For example, suppose that all customer sites use the same AS number, say 64512. If the ISP uses AS number 65534, one customer site sees the path to another site as 65534 65534. If the customer prepends 64512 on a particular path to make it less desirable, another customer site sees that path as 65534 65534 65534.

Example: Configuring a Layer 3 VPN with Route Reflection and AS Override

Suppose that you are a service provider providing a managed MPLS-based Layer 3 VPN service. Your customer has several sites and requires BGP routing to customer edge (CE) devices at each site.

Requirements
Overview
Configuration
Verification

Requirements

No special configuration beyond device initialization is required before configuring this example.

Overview

This example has two CE devices, two provider edge (PE) devices, and several provider core devices. The provider network is also using IS-IS to support LDP and BGP loopback reachability Device P2 is acting as a route reflector (RR). Both CE devices are in autonomous system (AS) 64512. The provider network is in AS 65534.

The as-override statement is applied to the PE devices, thus replacing the CE device's AS number with that of the PE device. This prevents the customer AS number from appearing more than once in the AS path attribute.

Figure 5 shows the topology used in this example.

Figure 5: AS Override Topology

CLI Quick Configuration shows the configuration for all of the devices in Figure 5. The section Step-by-Step Procedure describes the steps on Device PE1.

Topology

Configuration

Procedure

CLI Quick Configuration
Step-by-Step Procedure
Results

CLI Quick Configuration

Device CE1

content_copy zoom_out_map
set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.1/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces lo0 unit 0 family inet address 10.255.1.1/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0101.00
set protocols bgp group PE type external
set protocols bgp group PE family inet unicast
set protocols bgp group PE export ToBGP
set protocols bgp group PE peer-as 65534
set protocols bgp group PE neighbor 10.0.0.2
set policy-options policy-statement ToBGP term Direct from protocol direct
set policy-options policy-statement ToBGP term Direct then accept
set routing-options router-id 10.255.1.1
set routing-options autonomous-system 64512

Device P1

content_copy zoom_out_map
set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.6/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces ge-1/2/0 unit 0 family mpls
set interfaces ge-1/2/1 unit 0 family inet address 10.0.0.9/30
set interfaces ge-1/2/1 unit 0 family iso
set interfaces ge-1/2/1 unit 0 family mpls
set interfaces ge-1/2/2 unit 0 family inet address 10.0.0.25/30
set interfaces ge-1/2/2 unit 0 family iso
set interfaces ge-1/2/2 unit 0 family mpls
set interfaces lo0 unit 0 family inet address 10.255.3.3/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0303.00
set protocols mpls interface all
set protocols mpls interface fxp0.0 disable
set protocols bgp group l3vpn type internal
set protocols bgp group l3vpn local-address 10.255.3.3
set protocols bgp group l3vpn family inet-vpn unicast
set protocols bgp group l3vpn peer-as 65534
set protocols bgp group l3vpn local-as 65534
set protocols bgp group l3vpn neighbor 10.255.4.4
set protocols isis interface all level 2 metric 10
set protocols isis interface all level 1 disable
set protocols isis interface fxp0.0 disable
set protocols isis interface lo0.0 level 2 metric 0
set protocols ldp deaggregate
set protocols ldp interface all
set protocols ldp interface fxp0.0 disable
set routing-options router-id 10.255.3.3

Device P2

content_copy zoom_out_map
set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.10/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces ge-1/2/0 unit 0 family mpls
set interfaces ge-1/2/1 unit 0 family inet address 10.0.0.13/30
set interfaces ge-1/2/1 unit 0 family iso
set interfaces ge-1/2/1 unit 0 family mpls
set interfaces lo0 unit 0 family inet address 10.255.4.4/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0404.00
set protocols mpls interface all
set protocols mpls interface fxp0.0 disable
set protocols bgp group Core-RRClients type internal
set protocols bgp group Core-RRClients local-address 10.255.4.4
set protocols bgp group Core-RRClients family inet-vpn unicast
set protocols bgp group Core-RRClients cluster 10.255.4.4
set protocols bgp group Core-RRClients peer-as 65534
set protocols bgp group Core-RRClients neighbor 10.255.3.3
set protocols bgp group Core-RRClients neighbor 10.255.7.7
set protocols bgp group Core-RRClients neighbor 10.255.2.2
set protocols bgp group Core-RRClients neighbor 10.255.5.5
set protocols isis interface all level 2 metric 10
set protocols isis interface all level 1 disable
set protocols isis interface fxp0.0 disable
set protocols isis interface lo0.0 level 2 metric 0
set protocols ldp deaggregate
set protocols ldp interface all
set protocols ldp interface fxp0.0 disable
set routing-options router-id 10.255.4.4
set routing-options autonomous-system 65534

Device P3

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set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.22/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces ge-1/2/0 unit 0 family mpls
set interfaces ge-1/2/1 unit 0 family inet address 10.0.0.26/30
set interfaces ge-1/2/1 unit 0 family iso
set interfaces ge-1/2/1 unit 0 family mpls
set interfaces ge-1/2/2 unit 0 family inet address 10.0.0.30/30
set interfaces ge-1/2/2 unit 0 family iso
set interfaces ge-1/2/2 unit 0 family mpls
set interfaces lo0 unit 0 family inet address 10.255.7.7/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0707.00
set protocols mpls interface all
set protocols mpls interface fxp0.0 disable
set protocols bgp group l3vpn type internal
set protocols bgp group l3vpn local-address 10.255.7.7
set protocols bgp group l3vpn family inet-vpn unicast
set protocols bgp group l3vpn peer-as 65534
set protocols bgp group l3vpn local-as 65534
set protocols bgp group l3vpn neighbor 10.255.4.4
set protocols isis interface all level 2 metric 10
set protocols isis interface all level 1 disable
set protocols isis interface fxp0.0 disable
set protocols isis interface lo0.0 level 2 metric 0
set protocols ldp deaggregate
set protocols ldp interface all
set protocols ldp interface fxp0.0 disable
set routing-options router-id 10.255.7.7

Device PE1

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set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.2/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces ge-1/2/0 unit 0 family mpls
set interfaces ge-1/2/1 unit 0 family inet address 10.0.0.5/30
set interfaces ge-1/2/1 unit 0 family iso
set interfaces ge-1/2/1 unit 0 family mpls
set interfaces ge-1/2/2 unit 0 family inet address 10.0.0.21/30
set interfaces ge-1/2/2 unit 0 family iso
set interfaces ge-1/2/2 unit 0 family mpls
set interfaces lo0 unit 0 family inet address 10.255.2.2/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0202.00
set protocols mpls interface ge-1/2/2.0
set protocols mpls interface ge-1/2/1.0
set protocols mpls interface lo0.0
set protocols mpls interface fxp0.0 disable
set protocols bgp group l3vpn type internal
set protocols bgp group l3vpn local-address 10.255.2.2
set protocols bgp group l3vpn family inet-vpn unicast
set protocols bgp group l3vpn peer-as 65534
set protocols bgp group l3vpn local-as 65534
set protocols bgp group l3vpn neighbor 10.255.4.4
set protocols isis interface ge-1/2/1.0 level 2 metric 10
set protocols isis interface ge-1/2/1.0 level 1 disable
set protocols isis interface ge-1/2/2.0 level 2 metric 10
set protocols isis interface ge-1/2/2.0 level 1 disable
set protocols isis interface fxp0.0 disable
set protocols isis interface lo0.0 level 2 metric 0
set protocols ldp deaggregate
set protocols ldp interface ge-1/2/1.0
set protocols ldp interface ge-1/2/2.0
set protocols ldp interface fxp0.0 disable
set protocols ldp interface lo0.0
set routing-instances VPN-A instance-type vrf
set routing-instances VPN-A interface ge-1/2/0.0
set routing-instances VPN-A route-distinguisher 65534:1234
set routing-instances VPN-A vrf-target target:65534:1234
set routing-instances VPN-A protocols bgp group CE type external
set routing-instances VPN-A protocols bgp group CE family inet unicast
set routing-instances VPN-A protocols bgp group CE neighbor 10.0.0.1 peer-as 64512
set routing-instances VPN-A protocols bgp group CE neighbor 10.0.0.1 as-override
set routing-options router-id 10.255.2.2
set routing-options autonomous-system 65534

Device PE2

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set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.14/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces ge-1/2/0 unit 0 family mpls
set interfaces ge-1/2/1 unit 0 family inet address 10.0.0.17/30
set interfaces ge-1/2/1 unit 0 family iso
set interfaces ge-1/2/2 unit 0 family inet address 10.0.0.29/30
set interfaces ge-1/2/2 unit 0 family iso
set interfaces ge-1/2/2 unit 0 family mpls
set interfaces lo0 unit 0 family inet address 10.255.5.5/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0505.00
set protocols mpls interface ge-1/2/0.0
set protocols mpls interface ge-1/2/2.0
set protocols mpls interface lo0.0
set protocols mpls interface fxp0.0 disable
set protocols bgp group l3vpn type internal
set protocols bgp group l3vpn local-address 10.255.5.5
set protocols bgp group l3vpn family inet-vpn unicast
set protocols bgp group l3vpn peer-as 65534
set protocols bgp group l3vpn local-as 65534
set protocols bgp group l3vpn neighbor 10.255.4.4
set protocols isis interface ge-1/2/0.0 level 2 metric 10
set protocols isis interface ge-1/2/0.0 level 1 disable
set protocols isis interface ge-1/2/2.0 level 2 metric 10
set protocols isis interface ge-1/2/2.0 level 1 disable
set protocols isis interface fxp0.0 disable
set protocols isis interface lo0.0 level 2 metric 0
set protocols ldp deaggregate
set protocols ldp interface ge-1/2/0.0
set protocols ldp interface ge-1/2/2.0
set protocols ldp interface fxp0.0 disable
set protocols ldp interface lo0.0
set routing-instances VPN-A instance-type vrf
set routing-instances VPN-A interface ge-1/2/1.0
set routing-instances VPN-A route-distinguisher 65534:1234
set routing-instances VPN-A vrf-target target:65534:1234
set routing-instances VPN-A protocols bgp group CE type external
set routing-instances VPN-A protocols bgp group CE family inet unicast
set routing-instances VPN-A protocols bgp group CE neighbor 10.0.0.18 peer-as 64512
set routing-instances VPN-A protocols bgp group CE neighbor 10.0.0.18 as-override
set routing-options router-id 10.255.5.5
set routing-options autonomous-system 65534

Device CE2

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set interfaces ge-1/2/0 unit 0 family inet address 10.0.0.18/30
set interfaces ge-1/2/0 unit 0 family iso
set interfaces lo0 unit 0 family inet address 10.255.6.6/32
set interfaces lo0 unit 0 family iso address 49.0001.0010.0000.0606.00
set protocols bgp group PE type external
set protocols bgp group PE family inet unicast
set protocols bgp group PE export ToBGP
set protocols bgp group PE peer-as 65534
set protocols bgp group PE neighbor 10.0.0.17
set policy-options policy-statement ToBGP term Direct from protocol direct
set policy-options policy-statement ToBGP term Direct then accept
set routing-options router-id 10.255.6.6
set routing-options autonomous-system 64512

Step-by-Step Procedure

To configure AS override:

Configure the interfaces.

To enable MPLS, include the protocol family on the interface so that the interface does not discard incoming MPLS traffic.

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[edit interfaces]
user@PE1# set ge-1/2/0 unit 0 family inet address 10.0.0.2/30
user@PE1# set ge-1/2/0 unit 0 family iso
user@PE1# set ge-1/2/0 unit 0 family mpls
user@PE1# set ge-1/2/1 unit 0 family inet address 10.0.0.5/30
user@PE1# set ge-1/2/1 unit 0 family iso
user@PE1# set ge-1/2/1 unit 0 family mpls
user@PE1# set ge-1/2/2 unit 0 family inet address 10.0.0.21/30
user@PE1# set ge-1/2/2 unit 0 family iso
user@PE1# set ge-1/2/2 unit 0 family mpls
user@PE1# set lo0 unit 0 family inet address 10.255.2.2/32
user@PE1# set lo0 unit 0 family iso address 49.0001.0010.0000.0202.00

Add the interface to the MPLS protocol to establish the control plane level connectivity.

Set up the IGP so that the provider devices can communicate with each other.

To establish a mechanism to distribute MPLS labels, enable LDP. Optionally, for LDP, enable forwarding equivalence class (FEC) deaggregation, which results in faster global convergence.

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[edit protocols]
user@PE1# set mpls interface ge-1/2/2.0
user@PE1# set mpls interface ge-1/2/1.0
user@PE1# set mpls interface lo0.0
user@PE1# set mpls interface fxp0.0 disable
user@PE1# set isis interface ge-1/2/1.0 level 2 metric 10
user@PE1# set isis interface ge-1/2/1.0 level 1 disable
user@PE1# set isis interface ge-1/2/2.0 level 2 metric 10
user@PE1# set isis interface ge-1/2/2.0 level 1 disable
user@PE1# set isis interface fxp0.0 disable
user@PE1# set isis interface lo0.0 level 2 metric 0
user@PE1# set ldp deaggregate
user@PE1# set ldp interface ge-1/2/1.0
user@PE1# set ldp interface ge-1/2/2.0
user@PE1# set ldp interface fxp0.0 disable
user@PE1# set ldp interface lo0.0

Enable the internal BGP (IBGP) connection to peer with the RR only, using the IPv4 VPN unicast address family.

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[edit protocols bgp group l3vpn]
user@PE1# set type internal
user@PE1# set local-address 10.255.2.2
user@PE1# set family inet-vpn unicast
user@PE1# set peer-as 65534
user@PE1# set local-as 65534
user@PE1# set neighbor 10.255.4.4

Configure the routing instance, including the as-override statement.

Create the routing-Instance (VRF) on the PE device, setting up the BGP configuration to peer with Device CE1.

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[edit routing-instances VPN-A]
user@PE1# set instance-type vrf
user@PE1# set interface ge-1/2/0.0
user@PE1# set route-distinguisher 65534:1234
user@PE1# set vrf-target target:65534:1234
user@PE1# set protocols bgp group CE type external
user@PE1# set protocols bgp group CE family inet unicast
user@PE1# set protocols bgp group CE neighbor 10.0.0.1 peer-as 64512
user@PE1# set protocols bgp group CE neighbor 10.0.0.1 as-override

Configure the router ID and the AS number.

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[edit routing-options]
user@PE1# set router-id 10.255.2.2
user@PE1# set autonomous-system 65534

Results

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, show routing-instances, and show routing-options commands. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

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user@PE1# show interfaces
ge-1/2/0 {
    unit 2 {
        family inet {
            address 10.0.0.2/30;
        }
        family iso;
        family mpls;
    }
}
ge-1/2/1 {
    unit 5 {
        family inet {
            address 10.0.0.5/30;
        }
        family iso;
        family mpls;
    }
}
ge-1/2/2 {
    unit 21 {
        family inet {
            address 10.0.0.21/30;
        }
        family iso;
        family mpls;
    }
}
lo0 {
    unit 0 {
        family inet {
            address 10.255.2.2/32;
        }
        family iso {
            address 49.0001.0010.0000.0202.00;
        }
    }
}

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user@PE1# show protocols
mpls {
    interface ge-1/2/2.0;
    interface ge-1/2/1.0;
    interface lo0.0;
    interface fxp0.0 {
        disable;
    }
}
bgp {
    group l3vpn {
        type internal;
        local-address 10.255.2.2;
        family inet-vpn {
            unicast;
        }
        peer-as 65534;
        local-as 65534;
        neighbor 10.255.4.4;
    }
}
isis {
    interface ge-1/2/1.0 {
        level 2 metric 10;
        level 1 disable;
    }
    interface ge-1/2/2.0 {
        level 2 metric 10;
        level 1 disable;
    }
    interface fxp0.0 {
        disable;
    }
    interface lo0.0 {
        level 2 metric 0;
    }
}
ldp {
    deaggregate;
    interface ge-1/2/1.0;
    interface ge-1/2/2.0;
    interface fxp0.0 {
        disable;
    }
    interface lo0.0;
}

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user@PE1# show routing-instances
VPN-A {
    instance-type vrf;
    interface ge-1/2/0.0;
    route-distinguisher 65534:1234;
    vrf-target target:65534:1234;
    protocols {
        bgp {
            group CE {
                type external;
                family inet {
                    unicast;
                }
                neighbor 10.0.0.1 {
                    peer-as 64512;
                    as-override;
                }
            }
        }
    }
}

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user@PE1# show routing-options
router-id 10.255.2.2;
autonomous-system 65534;

If you are done configuring the device, enter commit from configuration mode.

Verification

Confirm that the configuration is working properly.

Checking AS Path to the CE Devices
Checking How the Route to Device CE2 Is Advertised
Checking the Route on Device CE1

Checking AS Path to the CE Devices

Purpose
Action
Meaning

Purpose

Display information on Device PE1 about the AS path attribute for the route to Device CE2’s loopback interface.

Action

On Device PE1, from operational mode, enter the show route table VPN-A.inet.0 10.255.6.6 command.

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user@PE1> show route table VPN-A.inet.0 10.255.6.6
 

VPN-A.inet.0: 5 destinations, 6 routes (5 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.255.6.6/32      *[BGP/170] 02:19:35, localpref 100, from 10.255.4.4
                      AS path: 64512 I, validation-state: unverified
                    > to 10.0.0.22 via ge-1/2/2.0, Push 300032, Push 299776(top)

Meaning

The output shows that Device PE1 has an AS path for 10.255.6.6/32 as coming from AS 64512.

Checking How the Route to Device CE2 Is Advertised

Purpose
Action
Meaning

Purpose

Make sure the route to Device CE2 is advertised to Device CE1 as if it is coming from the MPLS core.

Action

On Device PE1, from operational mode, enter the show route advertising-protocol bgp 10.0.0.1 command.

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user@PE1> show route advertising-protocol bgp 10.0.0.1
 
VPN-A.inet.0: 5 destinations, 6 routes (5 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.0.0.16/30            Self                                    I
* 10.255.1.1/32           10.0.0.1                                65534 I
* 10.255.6.6/32           Self                                    65534 I

Meaning

The output indicates that Device PE1 is advertising only its own AS number in the AS path.

Checking the Route on Device CE1

Purpose
Action
Meaning

Purpose

Make sure that Device CE1 contains only the provider AS number in the AS path for the route to Device CE2.

Action

From operational mode, enter the show route table inet.0 terse 10.255.6.6 command.

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user@CE1> show route table inet.0 terse 10.255.6.6

inet.0: 5 destinations, 6 routes (5 active, 0 holddown, 1 hidden)
+ = Active Route, - = Last Active, * = Both

A V Destination        P Prf   Metric 1   Metric 2  Next hop        AS path
* ? 10.255.6.6/32      B 170        100                             65534 65534 I
  unverified                                       >10.0.0.2

Meaning

The output indicates that Device CE1 has a route to Device CE2. The loop issue is resolved with the use of the as-override statement.

One route is hidden on the CE device. This is because Junos OS does not perform a BGP split horizon. Generally, split horizon in BGP is unnecessary, because any routes that might be received back by the originator are less preferred due to AS path length (for EBGP), AS path loop detection (IBGP), or other BGP metrics. Advertising routes back to the neighbor from which they were learned has a negligible effect on the router's performance, and is the correct thing to do.

Example: Enabling BGP Route Advertisements

Junos OS does not advertise the routes learned from one EBGP peer back to the same external BGP (EBGP) peer. In addition, the software does not advertise those routes back to any EBGP peers that are in the same autonomous system (AS) as the originating peer, regardless of the routing instance. You can modify this behavior by including the advertise-peer-as statement in the configuration.

If you include the advertise-peer-as statement in the configuration, BGP advertises the route regardless of this check.

To restore the default behavior, include the no-advertise-peer-as statement in the configuration:

no-advertise-peer-as;

The route suppression default behavior is disabled if the as-override statement is included in the configuration. If you include both the as-override and no-advertise-peer-as statements in the configuration, the no-advertise-peer-as statement is ignored.

Requirements
Overview
Configuration
Verification

Requirements

No special configuration beyond device initialization is required before you configure this example.

Note:

This example was updated and re-validated on Junos release 21.2R1.

Overview

This example shows three routing devices with external BGP (EBGP) connections. Device R2 has an EBGP connection to Device R1 and another EBGP connection to Device R3. Although separated by Device R2 which is in AS 64511, Device R1 and Device R3 are in the same AS (AS 64512). Device R1 and Device R3 advertise into BGP direct routes to their own loopback interface addresses.

Device R2 receives these loopback interface routes, and the advertise peer-as statement allows Device R2 to advertise them. Specifically, Device R1 sends the 192.168.0.1 route to Device R2, and because Device R2 has the advertise peer-as configured, Device R2 can send the 192.168.0.1 route to Device R3. Likewise, Device R3 sends the 192.168.0.3 route to Device R2, and advertise peer-as enables Device R2 to forward the route to Device R1.

To enable Device R1 and Device R3 to accept routes that contain their own AS number in the AS path, the loops 2 statement is required on Device R1 and Device R3.

Topology

Figure 6: BGP Topology for advertise-peer-as

Configuration

CLI Quick Configuration
Procedure

CLI Quick Configuration

Device R1

content_copy zoom_out_map
set interfaces xe-0/2/0 description R1-to-R2
set interfaces xe-0/2/0 unit 0 family inet address 10.0.0.1/30
set interfaces lo0 unit 0 family inet address 192.168.0.1/32
set protocols bgp family inet unicast loops 2
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext peer-as 64511
set protocols bgp group ext neighbor 10.0.0.2
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64512

Device R2

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set interfaces xe-0/2/0 description R2-to-R1
set interfaces xe-0/2/0 unit 0 family inet address 10.0.0.2/30
set interfaces xe-0/2/1 description R2-to-R3
set interfaces xe-0/2/1 unit 0 family inet address 10.1.0.1/30
set interfaces lo0 unit 0 family inet address 192.168.0.2/32
set protocols bgp group ext type external
set protocols bgp group ext advertise-peer-as
set protocols bgp group ext export send-direct
set protocols bgp group ext neighbor 10.0.0.1 peer-as 64512
set protocols bgp group ext neighbor 10.1.0.2 peer-as 64512
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64511

Device R3

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set interfaces xe-0/2/0 description R3-to-R2
set interfaces xe-0/2/0 unit 0 family inet address 10.1.0.2/30
set interfaces lo0 unit 0 family inet address 192.168.0.3/32
set protocols bgp family inet unicast loops 2
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext peer-as 64511
set protocols bgp group ext neighbor 10.1.0.1
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set routing-options autonomous-system 64512

Procedure

Step-by-Step Procedure
Step-by-Step Procedure
Results

Step-by-Step Procedure

The following example requires that you navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure Device R1:

Configure the device interfaces.

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[edit interfaces]
user@R1# set xe-0/2/0 description R1-to-R2
user@R1# set xe-0/2/0 unit 0 family inet address 10.0.0.1/30
user@R1# set lo0 unit 0 family inet address 192.168.0.1/32

Configure BGP.

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[edit protocols bgp group ext]
user@R1# set type external
user@R1# set peer-as 64511
user@R1# set neighbor 10.0.0.2

Prevent routes from Device R3 from being hidden on Device R1 by including the loops 2 statement.

The loops 2 statement means that the local device’s own AS number can appear in the AS path up to one time without causing the route to be hidden. The route is hidden if the local device’s AS number is detected in the path two or more times.
```
[edit protocols bgp family inet unicast]
user@R1# set loops 2
```

Configure the routing policy that sends direct routes.

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[edit policy-options policy-statement send-direct term 1]
user@R1# set from protocol direct
user@R1# set then accept

Apply the export policy to the BGP peering session with Device R2.
```
[edit protocols bgp group ext]
user@R1# set export send-direct
```
Configure the autonomous system (AS) number.
```
[edit routing-options ]
user@R1# set autonomous-system 64512
```

Step-by-Step Procedure

To configure Device R2:

Configure the device interfaces.

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[edit interfaces]
user@R2# set xe-0/2/0 description R2-to-R1
user@R2# set xe-0/2/0 unit 0 family inet address 10.0.0.2/30
user@R2# set xe-0/2/1 description R2-to-R3
user@R2# set xe-0/2/1 unit 0 family inet address 10.1.0.1/30
user@R2# set lo0 unit 0 family inet address 192.168.0.2/32

Configure BGP.

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[edit  protocols bgp group ext]
user@R2# set type external
user@R2# set neighbor 10.0.0.1 peer-as 64512
user@R2# set neighbor 10.1.0.2 peer-as 64512

Configure Device R2 to advertise routes learned from one EBGP peer to another EBGP peer in the same AS.

In other words, advertise to Device R1 routes learned from Device R3 (and the reverse), even though Device R1 and Device R3 are in the same AS.
```
[edit  protocols bgp group ext]
user@R2# set advertise-peer-as
```

Configure a routing policy that sends direct routes.

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[edit policy-options policy-statement send-direct term 1]
user@R2# set from protocol direct
user@R2# set then accept

Apply the export policy.

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[edit protocols bgp group ext]
user@R2# set export send-direct

Configure the AS number.

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[edit routing-options]
user@R2# set autonomous-system 64511

Results

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, show policy-options, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

Device R1

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user@R1# show interfaces
xe-0/2/0 {
    description R1-to-R2;
    unit 0 {
        family inet {
            address 10.0.0.1/30;
        }
    }
}
lo0 {
    unit 0 {
        family inet {
            address 192.168.0.1/32;
        }
    }
}

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user@R1# show protocols
bgp {
    family inet {
        unicast {
            loops 2;
        }
    }
    group ext {
        type external;
        export send-direct;
        peer-as 64511;
        neighbor 10.0.0.2;
    }
}

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user@R1# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}

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user@R1# show routing-options
autonomous-system 64512;

Device R2

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user@R2# show interfaces
xe-0/2/0 {
    description R2-to-R1;
    unit 0 {
        family inet {
            address 10.0.0.2/30;
        }
    }
}
xe-0/2/1 {
    description R2-to-R3;
    unit 0 {
        family inet {
            address 10.1.0.1/30;
        }
    }
}
lo0 {
    unit 0 {
        family inet {
            address 192.168.0.2/32;
        }
    }
}

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user@R2# show protocols
bgp {
    group ext {
        type external;
        advertise-peer-as;
        export send-direct;
        neighbor 10.0.0.1 {
            peer-as 64512;
        }
        neighbor 10.1.0.2 {
            peer-as 64512;
        }
    }
}

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user@R2# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}

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user@R2# show routing-options
autonomous-system 64511;

If you are done configuring the devices, enter commit from configuration mode.

Verification

Confirm that the configuration is working properly.

Verifying the BGP Routes

Purpose
Action
Meaning

Purpose

Make sure that the routing tables on Device R1 and Device R3 contain the expected routes.

Action

On Device R2, deactivate the advertise-peer-as statement in the BGP configuration.
```
[edit  protocols bgp group ext]
user@R2# deactivate advertise-peer-as
user@R2# commit
```
On Device R3, deactivate the loops statement in the BGP configuration.
```
[edit  protocols bgp family inet unicast ]
user@R3# deactivate unicast loops 
user@R3# commit
```

On Device R1, check to see what routes are advertised to Device R2.

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user@R1> show route advertising-protocol bgp 10.0.0.2
inet.0: 5 destinations, 6 routes (5 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.0.0.0/30             Self                                    I
* 192.168.0.1/32          Self                                    I

On Device R2, check to see what routes are received from Device R1.

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user@R2> show route receive-protocol bgp 10.0.0.1
inet.0: 7 destinations, 9 routes (7 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
  10.0.0.0/30             10.0.0.1                                64512 I
* 192.168.0.1/32          10.0.0.1                                64512 I

On Device R2, check to see what routes are advertised to Device R3.

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user@R2> show route advertising-protocol bgp 10.1.0.2
inet.0: 7 destinations, 9 routes (7 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.0.0.0/30             Self                                    I
* 10.1.0.0/30             Self                                    I
* 192.168.0.2/32          Self                                    I

On Device R2, activate the advertise-peer-as statement in the BGP configuration.
```
[edit  protocols bgp group ext]
user@R2# activate advertise-peer-as
user@R2# commit
```

On Device R2, recheck the routes that are advertised to Device R3.

content_copy zoom_out_map
user@R2> show route advertising-protocol bgp 10.1.0.2
inet.0: 7 destinations, 9 routes (7 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.0.0.0/30             Self                                    I
* 10.1.0.0/30             Self                                    I
* 192.168.0.1/32          Self             64512 I
* 192.168.0.2/32          Self                                    I
* 192.168.0.3/32          10.1.0.2         64512 I

On Device R3, check the routes that are received from Device R2.

content_copy zoom_out_map
user@R3> show route receive-protocol bgp 10.1.0.1
inet.0: 5 destinations, 6 routes (5 active, 0 holddown, 0 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.0.0.0/30             10.1.0.1                                64511 I
  10.1.0.0/30             10.1.0.1                                64511 I
* 192.168.0.2/32          10.1.0.1                                64511 I

On Device R3, activate the loops statement in the BGP configuration.
```
[edit  protocols bgp family inet unicast ]
user@R3# activate unicast loops 
user@R3# commit
```

On Device R3, recheck the routes that are received from Device R2.

content_copy zoom_out_map
user@R3> show route receive-protocol bgp 10.1.0.1
inet.0: 6 destinations, 8 routes (6 active, 0 holddown, 1 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 10.0.0.0/30             10.1.0.1                                64511 I
  10.1.0.0/30             10.1.0.1                                64511 I
* 192.168.0.1/32          10.1.0.1                                64511 64512 I
* 192.168.0.2/32          10.1.0.1                                64511 I

Meaning

First the advertise-peer-as statement and the loops statement are deactivated so that the default behavior can be examined. Device R1 sends to Device R2 a route to Device R1’s loopback interface address, 192.168.0.1/32. Device R2 does not advertise this route to Device R3. After activating the advertise-peer-as statement, Device R2 does advertise the 192.168.0.1/32 route to Device R3. Device R3 does not accept this route until after the loops statement is activated.

Disabling Attribute Set Messages on Independent AS Domains for BGP Loop Detection

BGP loop detection for a specific route uses the local autonomous system (AS) domain for the routing instance. By default, all routing instances belong to a single primary routing instance domain. Therefore, BGP loop detection uses the local ASs configured on all of the routing instances. Depending on your network configuration, this default behavior can cause routes to be looped and hidden.

To limit the local ASs in the primary routing instance, you can configure an independent AS domain for a routing instance. The independent domain is separate from the primary routing instance and keeps the AS paths of the independent domain from being shared with the AS path and the AS path attributes of other domains.

By default, independent domains use transitive path attribute 128 (attribute set) messages to tunnel the independent domain’s BGP attributes through the internal BGP (IBGP) core. However, the attribute set message behavior for independent domains is undesired in many cases. If you only want to configure independent domains to maintain the independence of local ASs in the routing instance, and perform BGP loop detection only for the specified local ASs in the routing instance, you can disable the attribute set messages.

To disable attribute set messages on an independent domain, include the independent-domain no-attrset statement:

Select the routing instance that contains the independent domain you want to modify. You can select the routing instance from the following hierarchy levels:
- [edit routing-instances routing-instance-name]
- [edit logical-systems logical-system-name routing-instances routing-instance-name]
Disable attribute set messages on the independent domain.
```
[edit routing-instances instance-name]
user@host# set routing-options autonomous-system as-number independent-domain no-attrset
```
Tip:
When you disable attribute set messages, we recommend that you specify the AS number of the primary routing instance. This ensures that the primary routing instance AS is treated as a local AS in the routing instance and is used for BGP loop detection.

After you specify a routing instance for an independent domain, the local ASs are only associated with that routing instance. That means BGP loop detection uses only the local ASs defined in the routing instance.

Example: Ignoring the AS Path Attribute When Selecting the Best Path

If multiple BGP routes to the same destination exist, BGP selects the best path based on the route attributes of the paths. One of the route attributes that affects the best-path decision is the length of the AS paths of each route. Routes with shorter AS paths are preferred over those with longer AS paths. Although not typically practical, some scenarios might require that the AS path length be ignored in the route selection process. This example shows how to configure a routing device to ignore the AS path attribute.

Requirements
Overview
Configuration
Verification

Requirements

No special configuration beyond device initialization is required before you configure this example.

Overview

On externally connected routing devices, the purpose of skipping the AS path comparison might be to force an external BGP (EBGP) versus internal BGP (IBGP) decision to remove traffic from your network as soon as possible. On internally connected routing devices, you might want your IBGP-only routers to default to the local externally connected gateway. The local IBGP-only (internal) routers skip the AS path comparison and move down the decision tree to use the closest interior gateway protocol (IGP) gateway (lowest IGP metric). Doing this might be an effective way to force these routers to use a LAN connection instead of their WAN connection.

CAUTION:

When you include the as-path-ignore statement on a routing device in your network, you might need to include it on all other BGP-enabled devices in your network to prevent routing loops and convergence issues. This is especially true for IBGP path comparisons.

In this example, Device R2 is learning about the loopback interface address on Device R4 (10.4.4.4/32) from Device R1 and Device R3. Device R1 is advertising 10.4.4.4/32 with an AS-path of 65001 65005 65004, and Device R3 is advertising 10.4.4.4/32 with an AS-path of 65003 65004. Device R2 selects the path for 10.4.4.4/32 from Device R3 as the best path because the AS path is shorter than the AS path from Device R1.

This example modifies the BGP configuration on Device R2 so that the AS-path length is not used in the best-path selection.

Device R1 has a lower router ID (10.1.1.1) than Device R3 (10.3.3.3). If all other path selection criteria are equal (or, as in this case, ignored), the route learned from Device R1 is used. Because the AS-path attribute is being ignored, the best path is toward Device R1 because of its lower router ID value.

Figure 7 shows the sample topology.

Figure 7: Topology for Ignoring the AS-Path length

Configuration

CLI Quick Configuration
Configuring Device R2

CLI Quick Configuration

Device R1

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set interfaces fe-1/2/0 unit 1 family inet address 192.168.10.1/24
set interfaces fe-1/2/1 unit 10 family inet address 192.168.50.2/24
set interfaces lo0 unit 1 family inet address 10.1.1.1/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext export send-local
set protocols bgp group ext neighbor 192.168.10.2 peer-as 65002
set protocols bgp group ext neighbor 192.168.50.1 peer-as 65005
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-local term 1 from protocol local
set policy-options policy-statement send-local term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.20.0/24 next-hop 192.168.10.2
set routing-options static route 192.168.30.0/24 next-hop 192.168.10.2
set routing-options static route 192.168.40.0/24 next-hop 192.168.50.1
set routing-options router-id 10.1.1.1
set routing-options autonomous-system 65001

Device R2

content_copy zoom_out_map
set interfaces fe-1/2/0 unit 2 family inet address 192.168.10.2/24
set interfaces fe-1/2/1 unit 3 family inet address 192.168.20.2/24
set interfaces lo0 unit 2 family inet address 10.2.2.2/32
set protocols bgp path-selection as-path-ignore
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext export send-local
set protocols bgp group ext neighbor 192.168.10.1 peer-as 65001
set protocols bgp group ext neighbor 192.168.20.1 peer-as 65003
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-local term 1 from protocol local
set policy-options policy-statement send-local term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.50.0/24 next-hop 192.168.10.1
set routing-options static route 192.168.40.0/24 next-hop 192.168.10.1
set routing-options static route 192.168.30.0/24 next-hop 192.168.20.1
set routing-options router-id 10.2.2.2
set routing-options autonomous-system 65002

Device R3

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set interfaces fe-1/2/0 unit 4 family inet address 192.168.20.1/24
set interfaces fe-1/2/1 unit 5 family inet address 192.168.30.1/24
set interfaces lo0 unit 3 family inet address 10.3.3.3/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext export send-local
set protocols bgp group ext neighbor 192.168.20.2 peer-as 65002
set protocols bgp group ext neighbor 192.168.30.2 peer-as 65004
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-local term 1 from protocol local
set policy-options policy-statement send-local term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.10.0/24 next-hop 192.168.20.2
set routing-options static route 192.168.50.0/24 next-hop 192.168.20.2
set routing-options static route 192.168.40.0/24 next-hop 192.168.30.2
set routing-options router-id 10.3.3.3
set routing-options autonomous-system 65003

Device R4

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set interfaces fe-1/2/0 unit 6 family inet address 192.168.30.2/24
set interfaces fe-1/2/1 unit 7 family inet address 192.168.40.1/24
set interfaces lo0 unit 4 family inet address 10.4.4.4/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext export send-local
set protocols bgp group ext neighbor 192.168.30.1 peer-as 65003
set protocols bgp group ext neighbor 192.168.40.2 peer-as 65005
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-local term 1 from protocol local
set policy-options policy-statement send-local term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.10.0/24 next-hop 192.168.40.2
set routing-options static route 192.168.50.0/24 next-hop 192.168.40.2
set routing-options static route 192.168.40.0/24 next-hop 192.168.30.1
set routing-options router-id 10.4.4.4
set routing-options autonomous-system 65004

Device R5

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set interfaces fe-1/2/0 unit 8 family inet address 192.168.40.2/24
set interfaces fe-1/2/1 unit 9 family inet address 192.168.50.1/24
set interfaces lo0 unit 5 family inet address 10.5.5.5/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext export send-local
set protocols bgp group ext neighbor 192.168.40.1 peer-as 65004
set protocols bgp group ext neighbor 192.168.50.2 peer-as 65001
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-local term 1 from protocol local
set policy-options policy-statement send-local term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.10.0/24 next-hop 192.168.50.2
set routing-options static route 192.168.20.0/24 next-hop 192.168.50.2
set routing-options static route 192.168.30.0/24 next-hop 192.168.40.1
set routing-options router-id 10.5.5.5
set routing-options autonomous-system 65005

Configuring Device R2

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device R2:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@R2# set fe-1/2/0 unit 2 family inet address 192.168.10.2/24
user@R2# set fe-1/2/1 unit 3 family inet address 192.168.20.2/24
user@R2# set lo0 unit 2 family inet address 10.2.2.2/32

Configure EBGP.

content_copy zoom_out_map
[edit protocols bgp group ext]
user@R2# set type external
user@R2# set export send-direct
user@R2# set export send-static
user@R2# set export send-local
user@R2# set neighbor 192.168.10.1 peer-as 65001
user@R2# set neighbor 192.168.20.1 peer-as 65003

Configure the autonomous system (AS) path attribute to be ignored in the Junos OS path selection algorithm.
```
[edit protocols bgp]
user@R2# set path-selection as-path-ignore
```

Configure the routing policy.

content_copy zoom_out_map
[edit policy-options]
user@R2# set policy-statement send-direct term 1 from protocol direct
user@R2# set policy-statement send-direct term 1 then accept
user@R2# set policy-statement send-local term 1 from protocol local
user@R2# set policy-statement send-local term 1 then accept
user@R2# set policy-statement send-static term 1 from protocol static
user@R2# set policy-statement send-static term 1 then accept

Configure some static routes.

content_copy zoom_out_map
[edit routing-options static]
user@R2# set route 192.168.50.0/24 next-hop 192.168.10.1
user@R2# set route 192.168.40.0/24 next-hop 192.168.10.1
user@R2# set route 192.168.30.0/24 next-hop 192.168.20.1

Configure the autonomous system (AS) number and the router ID.

content_copy zoom_out_map
[edit routing-options]
user@R2# set router-id 10.2.2.2
user@R2# set autonomous-system 65002

Results

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user@R2# show interfaces
fe-1/2/0 {
    unit 2 {
        family inet {
            address 192.168.10.2/24;
        }
    }
}
fe-1/2/1 {
    unit 3 {
        family inet {
            address 192.168.20.2/24;
        }
    }
}
lo0 {
    unit 2 {
        family inet {
            address 10.2.2.2/32;
        }
    }
}

content_copy zoom_out_map
user@R2# show policy-options
policy-statement send-direct {
    term 1 {
        from protocol direct;
        then accept;
    }
}
policy-statement send-local {
    term 1 {
        from protocol local;
        then accept;
    }
}
policy-statement send-static {
    term 1 {
        from protocol static;
        then accept;
    }
}

content_copy zoom_out_map
user@R2# show protocols
bgp {
    path-selection as-path-ignore;
    group ext {
        type external;
        export [ send-direct send-static send-local ];
        neighbor 192.168.10.1 {
            peer-as 65001;
        }
        neighbor 192.168.20.1 {
            peer-as 65003;
        }
    }
}

content_copy zoom_out_map
user@R2# show routing-options
static {
    route 192.168.50.0/24 next-hop 192.168.10.1;
    route 192.168.40.0/24 next-hop 192.168.10.1;
    route 192.168.30.0/24 next-hop 192.168.20.1;
}
router-id 10.2.2.2;
autonomous-system 65002;

If you are done configuring the device, enter commit from configuration mode. Repeat the configuration on the other devices in the network, changing the interface names and IP addresses, as needed.

Verification

Confirm that the configuration is working properly.

Checking the Neighbor Status

Purpose
Action
Meaning

Purpose

Make sure that from Device R2, the active path to get to AS 4 is through AS 65001 and AS 65005, not through AS 65003.

Note:

To verify the functionality of the as-path-ignore statement, you might need to run the restart routing command to force reevaluation of the active path. This is because for BGP, if both paths are external, the Junos OS behavior is to prefer the currently active path. This behavior helps to minimize route-flapping. Use caution when restarting the routing protocol process in a production network.

Action

From operational mode, enter the restart routing command.

content_copy zoom_out_map
user@R2> restart routing
Routing protocols process started, pid 49396

From operational mode, enter the show route 10.4.4.4 protocol bgp command.

content_copy zoom_out_map
user@R2> show route 10.4.4.4 protocol bgp
inet.0: 12 destinations, 25 routes (12 active, 0 holddown, 4 hidden)
+ = Active Route, - = Last Active, * = Both

10.4.4.4/32         *[BGP/170] 00:00:12, localpref 100
                      AS path: 65001 65005 65004 I
                    > to 192.168.10.1 via fe-1/2/0.2
                    [BGP/170] 00:00:08, localpref 100
                      AS path: 65003 65004 I
                    > to 192.168.20.1 via fe-1/2/1.3

Meaning

The asterisk (*) is next to the path learned from R1, meaning that this is the active path. The AS path for the active path is 65001 65005 65004, which is longer than the AS path (65003 65004) for the nonactive path learned from Router R3.

Understanding Private AS Number Removal from AS Paths

By default, when BGP advertises AS paths to remote systems, it includes all AS numbers, including private AS numbers. You can configure the software so that it removes private AS numbers from AS paths. Doing this is useful when any of the following circumstances are true:

A remote AS for which you provide connectivity is multihomed, but only to the local AS.
The remote AS does not have an officially allocated AS number.
It is not appropriate to make the remote AS a confederation member AS of the local AS.

Most companies acquire their own AS number. Some companies also use private AS numbers to connect to their public AS network. These companies might use a different private AS number for each region in which their company does business. In any implementation, announcing a private AS number to the Internet must be avoided. Service providers can use the remove-private statement to prevent advertising private AS numbers to the Internet.

In an enterprise scenario, suppose that you have multiple AS numbers in your company, some of which are private AS numbers, and one with a public AS number. The one with a public AS number has a direct connection to the service provider. In the AS that connects directly to the service provider, you can use the remove-private statement to filter out any private AS numbers in the advertisements that are sent to the service provider.

The AS numbers are stripped from the AS path starting at the left end of the AS path (the end where AS paths have been most recently added). The routing device stops searching for private ASs when it finds the first nonprivate AS or a peer’s private AS. If the AS path contains the AS number of the external BGP (EBGP) neighbor, BGP does not remove the private AS number.

Note:

As of Junos OS 10.0R2 and later, if there is a need to send prefixes to an EBGP peer that has an AS number that matches an AS number in the AS path, consider using the as-override statement instead of the remove-private statement.

The operation takes place after any confederation member ASs have already been removed from the AS path, if applicable.

The software is preconfigured with knowledge of the set of AS numbers that is considered private, a range that is defined in the Internet Assigned Numbers Authority (IANA) assigned numbers document. The set of 16 bit AS numbers reserved as private are in the range from 64,512 through 65,534, inclusive. The 32 bit AS numbers reserved as private are in the range from 4,200,000,000 through 4,294,967,294 inclusive.

Example: Removing Private AS Numbers from AS Paths

This example demonstrates the removal of a private AS number from the advertised AS path to avoid announcing the private AS number to the Internet.

Requirements
Overview
Configuration
Verification

Requirements

No special configuration beyond device initialization is required before you configure this example.

Overview

Service providers and enterprise networks use the remove-private statement to prevent advertising private AS numbers to the Internet. The remove-private statement works in the outbound direction. You configure the remove-private statement on a device that has a public AS number and that is connected to one or more devices that have private AS numbers. Generally, you would not configure this statement on a device that has a private AS number.

Figure 8 shows the sample topology.

Figure 8: Topology for Removing a Private AS from the Advertised AS Path

In this example, Device R1 is connected to its service provider using private AS number 65530. The example shows the remove-private statement configured on Device ISP to prevent Device R1’s private AS number from being announced to Device R2. Device R2 sees only the AS number of the service provider.

Note:

Adding or deleting the BGP option remove-private will cause the affected BGP peering sessions to flap.

Configuration

CLI Quick Configuration
Device ISP

CLI Quick Configuration

Device R1

content_copy zoom_out_map
set interfaces fe-1/2/0 unit 1 family inet address 192.168.10.1/24
set interfaces lo0 unit 1 family inet address 10.10.10.1/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext peer-as 100
set protocols bgp group ext neighbor 192.168.10.10
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.20.0/24 next-hop 192.168.10.10
set routing-options autonomous-system 65530

Device ISP

content_copy zoom_out_map
set interfaces fe-1/2/0 unit 2 family inet address 192.168.10.10/24
set interfaces fe-1/2/1 unit 3 family inet address 192.168.20.20/24
set interfaces lo0 unit 2 family inet address 10.10.0.1/32
set protocols bgp group ext type external
set protocols bgp group ext neighbor 192.168.10.1 peer-as 65530
set protocols bgp group ext neighbor 192.168.20.1 remove-private
set protocols bgp group ext neighbor 192.168.20.1 peer-as 200
set routing-options autonomous-system 100

Device R2

content_copy zoom_out_map
set interfaces fe-1/2/0 unit 4 family inet address 192.168.20.1/24
set interfaces lo0 unit 3 family inet address 10.10.20.1/32
set protocols bgp group ext type external
set protocols bgp group ext export send-direct
set protocols bgp group ext export send-static
set protocols bgp group ext peer-as 100
set protocols bgp group ext neighbor 192.168.20.20
set policy-options policy-statement send-direct term 1 from protocol direct
set policy-options policy-statement send-direct term 1 then accept
set policy-options policy-statement send-static term 1 from protocol static
set policy-options policy-statement send-static term 1 then accept
set routing-options static route 192.168.10.0/24 next-hop 192.168.20.20
set routing-options autonomous-system 200

Device ISP

Step-by-Step Procedure
Results

Step-by-Step Procedure

To configure Device ISP:

Configure the interfaces.

content_copy zoom_out_map
[edit interfaces]
user@ISP# set fe-1/2/0 unit 2 family inet address 192.168.10.10/24
user@ISP# set fe-1/2/1 unit 3 family inet address 192.168.20.20/24
user@ISP# set lo0 unit 2 family inet address 10.10.0.1/32

Configure EBGP.

content_copy zoom_out_map
[edit protocols bgp group ext]
user@ISP# set type external
user@ISP# set neighbor 192.168.10.1 peer-as 65530
user@ISP# set neighbor 192.168.20.1 peer-as 200

For the neighbor in autonomous system (AS) 200 (Device R2), remove private AS numbers from the advertised AS paths.
```
[edit protocols bgp group ext]
user@ISP# set neighbor 192.168.20.1 remove-private
```

Configure the AS number.

content_copy zoom_out_map
[edit routing-options]
user@ISP# set autonomous-system 100

Results

content_copy zoom_out_map
user@ISP# show interfaces
fe-1/2/0 {
    unit 2 {
        family inet {
            address 192.168.10.10/24;
        }
    }
}
fe-1/2/1 {
    unit 3 {
        family inet {
            address 192.168.20.20/24;
        }
    }
}
lo0 {
    unit 2 {
        family inet {
            address 10.10.0.1/32;
        }
    }
}

content_copy zoom_out_map
user@ISP# show protocols
bgp {
    group ext {
        type external;
        neighbor 192.168.10.1 {
            peer-as 65530;
        }
        neighbor 192.168.20.1 {
            remove-private;
            peer-as 200;
        }
    }
}

content_copy zoom_out_map
user@ISP# show routing-options
autonomous-system 100;

If you are done configuring the device, enter commit from configuration mode. Repeat the configuration on Device R1 and Device R2, changing the interface names and IP address, as needed, and adding the routing policy configuration.

Verification

Confirm that the configuration is working properly.

Checking the Neighbor Status
Checking the Routing Tables
Checking the AS Path When the remove-private Statement Is Deactivated

Checking the Neighbor Status

Purpose
Action
Meaning

Purpose

Make sure that Device ISP has the remove-private setting enabled in its neighbor session with Device R2.

Action

From operational mode, enter the show bgp neighbor 192.168.20.1 command.

content_copy zoom_out_map
user@ISP> show bgp neighbor 192.168.20.1
Peer: 192.168.20.1+179 AS 200  Local: 192.168.20.20+60216 AS 100  
  Type: External    State: Established    Flags: <ImportEval Sync>
  Last State: OpenConfirm   Last Event: RecvKeepAlive
  Last Error: None
  Options: <Preference RemovePrivateAS PeerAS Refresh>
  Holdtime: 90 Preference: 170
  Number of flaps: 0
  Peer ID: 10.10.20.1      Local ID: 10.10.0.1         Active Holdtime: 90
  Keepalive Interval: 30         Peer index: 0   
  BFD: disabled, down
  Local Interface: fe-1/2/1.3                       
  NLRI for restart configured on peer: inet-unicast
  NLRI advertised by peer: inet-unicast
  NLRI for this session: inet-unicast
  Peer supports Refresh capability (2)
  Stale routes from peer are kept for: 300
  Peer does not support Restarter functionality
  NLRI that restart is negotiated for: inet-unicast
  NLRI of received end-of-rib markers: inet-unicast
  NLRI of all end-of-rib markers sent: inet-unicast
  Peer supports 4 byte AS extension (peer-as 200)
  Peer does not support Addpath
  Table inet.0 Bit: 10001
    RIB State: BGP restart is complete
    Send state: in sync
    Active prefixes:              1
    Received prefixes:            3
    Accepted prefixes:            2
    Suppressed due to damping:    0
    Advertised prefixes:          1
  Last traffic (seconds): Received 10   Sent 16   Checked 55  
  Input messages:  Total 54     Updates 3       Refreshes 0     Octets 1091
  Output messages: Total 54     Updates 1       Refreshes 0     Octets 1118
  Output Queue[0]: 0

Meaning

The RemovePrivateAS option shows that Device ISP has the expected setting.

Checking the Routing Tables

Purpose
Action
Meaning

Purpose

Make sure that the devices have the expected routes and AS paths.

Action

From operational mode, enter the show route protocol bgp command.

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user@R1> show route protocol bgp
inet.0: 5 destinations, 5 routes (5 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.10.20.1/32      *[BGP/170] 00:28:57, localpref 100
                      AS path: 100 200 I
                    > to 192.168.10.10 via fe-1/2/0.1

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user@ISP> show route protocol bgp

inet.0: 7 destinations, 11 routes (7 active, 0 holddown, 2 hidden)
+ = Active Route, - = Last Active, * = Both

10.10.10.1/32      *[BGP/170] 00:29:40, localpref 100
                      AS path: 65530 I
                    > to 192.168.10.1 via fe-1/2/0.2
10.10.20.1/32      *[BGP/170] 00:29:36, localpref 100
                      AS path: 200 I
                    > to 192.168.20.1 via fe-1/2/1.3
192.168.10.0/24     [BGP/170] 00:29:40, localpref 100
                      AS path: 65530 I
                    > to 192.168.10.1 via fe-1/2/0.2
192.168.20.0/24     [BGP/170] 00:29:36, localpref 100
                      AS path: 200 I
                    > to 192.168.20.1 via fe-1/2/1.3

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user@R2> show route protocol bgp
inet.0: 5 destinations, 5 routes (5 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.10.10.1/32      *[BGP/170] 00:29:53, localpref 100
                      AS path: 100 I
                    > to 192.168.20.20 via fe-1/2/0.4

Meaning

Device ISP has the private AS number 65530 in its AS path to Device R1. However, Device ISP does not advertise this private AS number to Device R2. This is shown in the routing table of Device R2. Device R2’s path to Device R1 contains only the AS number for Device ISP.

Checking the AS Path When the remove-private Statement Is Deactivated

Purpose
Action
Meaning

Purpose

Verify that without the remove-private statement, the private AS number appears in Device R2’s routing table.

Action

From configuration mode on Device ISP, enter the deactivate remove-private command and then recheck the routing table on Device R2.

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[protocols bgp group ext neighbor 192.168.20.1]
user@ISP# deactivate remove-private
user@ISP# commit

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user@R2> show route protocol bgp
inet.0: 5 destinations, 5 routes (5 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.10.10.1/32      *[BGP/170] 00:00:54, localpref 100
                      AS path: 100 65530 I
                    > to 192.168.20.20 via fe-1/2/0.4

Meaning

Private AS number 65530 appears in Device R2’s AS path to Device R1.

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release

Description

20.2R1

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BGP User Guide

ON THIS PAGE

Autonomous Systems for BGP Sessions

Understanding the BGP Local AS Attribute

See Also

Example: Configuring a Local AS for EBGP Sessions

Requirements

Overview

Configuration

CLI Quick Configuration

Configuring Device R1

Step-by-Step Procedure

Results

Configuring Device R2

Step-by-Step Procedure

Results

Configuring Device R3

Step-by-Step Procedure

Results

Verification

Checking the Local and Global AS Settings

Purpose

Action

Meaning

Checking the BGP Peering Sessions

Purpose

Action

Meaning

Verifying the BGP AS Paths

Purpose

Action

Meaning

See Also

Example: Configuring a Private Local AS for EBGP Sessions

Requirements

Overview

Configuration

CLI Quick Configuration

Configuring Device R1

Step-by-Step Procedure

Results

Verification

Checking Device R2’s AS Paths

Purpose

Action

Meaning

Checking Device R3’s AS Paths

Purpose

Action

Meaning

See Also

Understanding the Accumulated IGP Attribute for BGP

See Also

Example: Configuring the Accumulated IGP Attribute for BGP

Requirements

Overview

Topology Diagram

Configuration

CLI Quick Configuration

Configuring Device P1

Step-by-Step Procedure

Results

Configuring Device P2

Step-by-Step Procedure

Results

Configuring Device PE4

Step-by-Step Procedure

Results

Configuring Device PE1

Step-by-Step Procedure

Results

Configuring Device PE2

Step-by-Step Procedure

Results

Configuring Device PE3

Step-by-Step Procedure

Results

Configuring Device PE7

Step-by-Step Procedure

Results