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Example: Configuring Internal BGP Peer Sessions

This example shows how to configure internal BGP peer sessions.

Requirements

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

Overview

In this example, you configure internal BGP (IBGP) peer sessions. The loopback interface (lo0) is used to establish connections between IBGP peers. The loopback interface is always up as long as the device is operating. If there is a route to the loopback address, the IBGP peer session stays up. If a physical interface address is used instead and that interface goes up and down, the IBGP peer session also goes up and down. Thus, if the device has link redundancy, the loopback interface provides fault tolerance in case the physical interface or one of the links goes down.

When a device peers with a remote device’s loopback interface address, the local device expects BGP update messages to come from (be sourced by) the remote device’s loopback interface address. The local-address statement enables you to specify the source information in BGP update messages. If you omit the local-address statement, the expected source of BGP update messages is based on the device’s source address selection rules, which normally results in the egress interface address being the expected source of update messages. When this happens, the peer session is not established because a mismatch exists between the expected source address (the egress interface of the peer) and the actual source (the loopback interface of the peer). To make sure that the expected source address matches the actual source address, specify the loopback interface address in the local-address statement.

Because IBGP supports multihop connections, IBGP neighbors can be located anywhere within the autonomous system (AS) and often do not share a link. A recursive route lookup resolves the loopback peer address to an IP forwarding next hop. In this example, this service is provided by OSPF. Although interior gateway protocol (IGP) neighbors do not need to be directly connected, they do need to be fully meshed. In this case, fully meshed means that each device is logically connected to every other device through neighbor peer relationships. The neighbor statement creates the mesh.

Note: The requirement for a full mesh is waived if you configure a confederation or route reflection.

After the BGP peers are established, BGP routes are not automatically advertised by the BGP peers. At each BGP-enabled device, policy configuration is required to export the local, static, or IGP-learned routes into the BGP routing information base (RIB) and then advertise them as BGP routes to the other peers. BGP's advertisement policy, by default, does not advertise any non-BGP routes (such as local routes) to peers.

In the sample network, the devices in AS 17 are fully meshed in the group internal-peers. The devices have loopback addresses 192.168.6.5, 192.163.6.4, and 192.168.40.4.

Figure 1 shows a typical network with internal peer sessions.

Figure 1: Typical Network with IBGP Sessions

Typical Network with IBGP Sessions

Configuration

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 A

set interfaces ge-0/1/0 unit 1 description to-Bset interfaces ge-0/1/0 unit 1 family inet address 10.10.10.1/30set interfaces lo0 unit 1 family inet address 192.168.6.5/32set protocols bgp group internal-peers type internalset protocols bgp group internal-peers description “connections to B and C”set protocols bgp group internal-peers local-address 192.168.6.5set protocols bgp group internal-peers export send-directset protocols bgp group internal-peers neighbor 192.163.6.4set protocols bgp group internal-peers neighbor 192.168.40.4set protocols ospf area 0.0.0.0 interface lo0.1 passiveset protocols ospf area 0.0.0.0 interface ge-0/1/0.1set policy-options policy-statement send-direct term 2 from protocol directset policy-options policy-statement send-direct term 2 then acceptset routing-options router-id 192.168.6.5set routing-options autonomous-system 17

Device B

set interfaces ge-0/1/0 unit 2 description to-Aset interfaces ge-0/1/0 unit 2 family inet address 10.10.10.2/30set interfaces ge-0/1/1 unit 5 description to-Cset interfaces ge-0/1/1 unit 5 family inet address 10.10.10.5/30set interfaces lo0 unit 2 family inet address 192.163.6.4/32set protocols bgp group internal-peers type internalset protocols bgp group internal-peers description “connections to A and C”set protocols bgp group internal-peers local-address 192.163.6.4set protocols bgp group internal-peers export send-directset protocols bgp group internal-peers neighbor 192.168.40.4set protocols bgp group internal-peers neighbor 192.168.6.5set protocols ospf area 0.0.0.0 interface lo0.2 passiveset protocols ospf area 0.0.0.0 interface ge-0/1/0.2set protocols ospf area 0.0.0.0 interface ge-0/1/1.5set policy-options policy-statement send-direct term 2 from protocol directset policy-options policy-statement send-direct term 2 then acceptset routing-options router-id 192.163.6.4set routing-options autonomous-system 17

Device C

set interfaces ge-0/1/0 unit 6 description to-Bset interfaces ge-0/1/0 unit 6 family inet address 10.10.10.6/30set interfaces lo0 unit 3 family inet address 192.168.40.4/32set protocols bgp group internal-peers type internalset protocols bgp group internal-peers description “connections to A and B”set protocols bgp group internal-peers local-address 192.168.40.4set protocols bgp group internal-peers export send-directset protocols bgp group internal-peers neighbor 192.163.6.4set protocols bgp group internal-peers neighbor 192.168.6.5set protocols ospf area 0.0.0.0 interface lo0.3 passiveset protocols ospf area 0.0.0.0 interface ge-0/1/0.6set policy-options policy-statement send-direct term 2 from protocol directset policy-options policy-statement send-direct term 2 then acceptset routing-options router-id 192.168.40.4set routing-options autonomous-system 17

Configuring Device A

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 CLI User Guide.

To configure internal BGP peer sessions on Device A:

  1. Configure the interfaces.
    [edit interfaces ge-0/1/0 unit 1]user@A# set description to-Buser@A# set family inet address 10.10.10.1/30
    [edit interfaces]user@A# set lo0 unit 1 family inet address 192.168.6.5/32
  2. Configure BGP.

    The neighbor statements are included for both Device B and Device C, even though Device A is not directly connected to Device C.

    [edit protocols bgp group internal-peers]user@A# set type internaluser@A# set description “connections to B and C”user@A# set local-address 192.168.6.5user@A# set export send-directuser@A# set neighbor 192.163.6.4user@A# set neighbor 192.168.40.4
  3. Configure OSPF.
    [edit protocols ospf area 0.0.0.0]user@A# set interface lo0.1 passiveuser@A# set interface ge-0/1/0.1
  4. Configure a policy that accepts direct routes.

    Other useful options for this scenario might be to accept routes learned through OSPF or local routes.

    [edit policy-options policy-statement send-direct term 2]user@A# set from protocol directuser@A# set then accept
  5. Configure the router ID and the AS number.
    [edit routing-options]user@A# set router-id 192.168.6.5user@A# set autonomous-system 17

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.

user@A# show interfacesge-0/1/0 {unit 1 {description to-B;family inet {address 10.10.10.1/30;}}}lo0 {unit 1 {family inet {address 192.168.6.5/32;}}}
user@A# show policy-optionspolicy-statement send-direct {term 2 {from protocol direct;then accept;}}
user@A# show protocolsbgp {group internal-peers {type internal;description “connections to B and C”;local-address 192.168.6.5;export send-direct;neighbor 192.163.6.4;neighbor 192.168.40.4;}}ospf {area 0.0.0.0 {interface lo0.1 {passive;}interface ge-0/1/0.1;}}
user@A# show routing-optionsrouter-id 192.168.6.5;autonomous-system 17;

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

Configuring Device B

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.

To configure internal BGP peer sessions on Device B:

  1. Configure the interfaces.
    [edit interfaces ge-0/1/0 unit 2]user@B# set description to-Auser@B# set family inet address 10.10.10.2/30
    [edit interfaces ge-0/1/1]user@B# set unit 5 description to-Cuser@B# set unit 5 family inet address 10.10.10.5/30
    [edit interfaces]user@B# set lo0 unit 2 family inet address 192.163.6.4/32
  2. Configure BGP.

    The neighbor statements are included for both Device B and Device C, even though Device A is not directly connected to Device C.

    [edit protocols bgp group internal-peers]user@B# set type internaluser@B# set description “connections to A and C”user@B# set local-address 192.163.6.4user@B# set export send-directuser@B# set neighbor 192.168.40.4user@B# set neighbor 192.168.6.5
  3. Configure OSPF.
    [edit protocols ospf area 0.0.0.0]user@B# set interface lo0.2 passiveuser@B# set interface ge-0/1/0.2user@B# set interface ge-0/1/1.5
  4. Configure a policy that accepts direct routes.

    Other useful options for this scenario might be to accept routes learned through OSPF or local routes.

    [edit policy-options policy-statement send-direct term 2]user@B# set from protocol directuser@B# set then accept
  5. Configure the router ID and the AS number.
    [edit routing-options]user@B# set router-id 192.163.6.4user@B# set autonomous-system 17

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.

user@B# show interfacesge-0/1/0 {unit 2 {description to-A;family inet {address 10.10.10.2/30;}}}ge-0/1/1 {unit 5 {description to-C;family inet {address 10.10.10.5/30;}}}lo0 {unit 2 {family inet {address 192.163.6.4/32;}}}
user@B# show policy-optionspolicy-statement send-direct {term 2 {from protocol direct;then accept;}}
user@B# show protocolsbgp {group internal-peers {type internal;description “connections to A and C”;local-address 192.163.6.4;export send-direct;neighbor 192.168.40.4;neighbor 192.168.6.5;}}ospf {area 0.0.0.0 {interface lo0.2 {passive;}interface ge-0/1/0.2;interface ge-0/1/1.5;}}
user@B# show routing-optionsrouter-id 192.163.6.4; autonomous-system 17;

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

Configuring Device C

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 CLI User Guide.

To configure internal BGP peer sessions on Device C:

  1. Configure the interfaces.
    [edit interfaces ge-0/1/0 unit 6]user@C# set description to-Buser@C# set family inet address 10.10.10.6/30
    [edit interfaces]user@C# set lo0 unit 3 family inet address 192.168.40.4/32
  2. Configure BGP.

    The neighbor statements are included for both Device B and Device C, even though Device A is not directly connected to Device C.

    [edit protocols bgp group internal-peers]user@C# set type internaluser@C# set description “connections to A and B”user@C# set local-address 192.168.40.4user@C# set export send-directuser@C# set neighbor 192.163.6.4user@C# set neighbor 192.168.6.5
  3. Configure OSPF.
    [edit protocols ospf area 0.0.0.0]user@C# set interface lo0.3 passiveuser@C# set interface ge-0/1/0.6
  4. Configure a policy that accepts direct routes.

    Other useful options for this scenario might be to accept routes learned through OSPF or local routes.

    [edit policy-options policy-statement send-direct term 2]user@C# set from protocol directuser@C# set then accept
  5. Configure the router ID and the AS number.
    [edit routing-options]user@C# set router-id 192.168.40.4user@C# set autonomous-system 17

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.

user@C# show interfacesge-0/1/0 {unit 6 {description to-B;family inet {address 10.10.10.6/30;}}}lo0 {unit 3 {family inet {address 192.168.40.4/32;}}}
user@C# show policy-optionspolicy-statement send-direct {term 2 {from protocol direct;then accept;}}
user@C# show protocolsbgp {group internal-peers {type internal;description “connections to A and B”;local-address 192.168.40.4;export send-direct;neighbor 192.163.6.4;neighbor 192.168.6.5;}}ospf {area 0.0.0.0 {interface lo0.3 {passive;}interface ge-0/1/0.6;}}
user@C# show routing-optionsrouter-id 192.168.40.4;autonomous-system 17;

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

Verification

Confirm that the configuration is working properly.

Verifying BGP Neighbors

Purpose

Verify that BGP is running on configured interfaces and that the BGP session is active for each neighbor address.

Action

From operational mode, enter the show bgp neighbor command.

user@A> show bgp neighbor
Peer: 192.163.6.4+179 AS 17    Local: 192.168.6.5+58852 AS 17   
  Type: Internal    State: Established    Flags: Sync
  Last State: OpenConfirm   Last Event: RecvKeepAlive
  Last Error: None
  Export: [ send-direct ] 
  Options: Preference LocalAddress Refresh
  Local Address: 192.168.6.5 Holdtime: 90 Preference: 170
  Number of flaps: 0
  Peer ID: 192.163.6.4     Local ID: 192.168.6.5       Active Holdtime: 90
  Keepalive Interval: 30         Peer index: 0   
  BFD: disabled, down
  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)
  Restart time configured on the peer: 120
  Stale routes from peer are kept for: 300
  Restart time requested by this peer: 120
  NLRI that peer supports restart for: inet-unicast
  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 17)
  Peer does not support Addpath
  Table inet.0 Bit: 10000
    RIB State: BGP restart is complete
    Send state: in sync
    Active prefixes:              0
    Received prefixes:            3
    Accepted prefixes:            3
    Suppressed due to damping:    0
    Advertised prefixes:          2
  Last traffic (seconds): Received 25   Sent 19   Checked 67  
  Input messages:  Total 2420   Updates 4       Refreshes 0     Octets 46055
  Output messages: Total 2411   Updates 2       Refreshes 0     Octets 45921
  Output Queue[0]: 0

Peer: 192.168.40.4+179 AS 17   Local: 192.168.6.5+56466 AS 17   
  Type: Internal    State: Established    Flags: Sync
  Last State: OpenConfirm   Last Event: RecvKeepAlive
  Last Error: None
  Export: [ send-direct ] 
  Options: Preference LocalAddress Refresh
  Local Address: 192.168.6.5 Holdtime: 90 Preference: 170
  Number of flaps: 0
  Peer ID: 192.168.40.4    Local ID: 192.168.6.5       Active Holdtime: 90
  Keepalive Interval: 30         Peer index: 1   
  BFD: disabled, down
  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)
  Restart time configured on the peer: 120
  Stale routes from peer are kept for: 300
  Restart time requested by this peer: 120
  NLRI that peer supports restart for: inet-unicast
  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 17)
  Peer does not support Addpath
  Table inet.0 Bit: 10000
    RIB State: BGP restart is complete
    Send state: in sync
    Active prefixes:              0
    Received prefixes:            2
    Accepted prefixes:            2
    Suppressed due to damping:    0
    Advertised prefixes:          2
  Last traffic (seconds): Received 7    Sent 21   Checked 24  
  Input messages:  Total 2412   Updates 2       Refreshes 0     Octets 45867
  Output messages: Total 2409   Updates 2       Refreshes 0     Octets 45883
  Output Queue[0]: 0

Verifying BGP Groups

Purpose

Verify that the BGP groups are configured correctly.

Action

From operational mode, enter the show bgp group command.

user@A> show bgp group
Group Type: Internal    AS: 17                     Local AS: 17
  Name: internal-peers  Index: 0                   Flags: <Export Eval>
  Export: [ send-direct ] 
  Holdtime: 0
  Total peers: 2        Established: 2
  192.163.6.4+179
  192.168.40.4+179
  inet.0: 0/5/5/0

Groups: 1  Peers: 2    External: 0    Internal: 2    Down peers: 0   Flaps: 0
Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
inet.0                 5          0          0          0          0          0

Verifying BGP Summary Information

Purpose

Verify that the BGP configuration is correct.

Action

From operational mode, enter the show bgp summary command.

user@A> show bgp summary
Groups: 1 Peers: 2 Down peers: 0
Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
inet.0                 5          0          0          0          0          0
Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
192.163.6.4              17       2441       2432       0       0    18:18:52 0/3/3/0              0/0/0/0
192.168.40.4             17       2432       2430       0       0    18:18:48 0/2/2/0              0/0/0/0

Verifying That BGP Routes Are Installed in the Routing Table

Purpose

Verify that the export policy configuration is causing the BGP routes to be installed in the routing tables of the peers.

Action

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

user@A> show route protocol bgp
inet.0: 7 destinations, 12 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.10.10.0/30       [BGP/170] 07:09:57, localpref 100, from 192.163.6.4
                      AS path: I
                    > to 10.10.10.2 via ge-0/1/0.1
10.10.10.4/30       [BGP/170] 07:09:57, localpref 100, from 192.163.6.4
                      AS path: I
                    > to 10.10.10.2 via ge-0/1/0.1
                    [BGP/170] 07:07:12, localpref 100, from 192.168.40.4
                      AS path: I
                    > to 10.10.10.2 via ge-0/1/0.1
192.163.6.4/32      [BGP/170] 07:09:57, localpref 100, from 192.163.6.4
                      AS path: I
                    > to 10.10.10.2 via ge-0/1/0.1
192.168.40.4/32     [BGP/170] 07:07:12, localpref 100, from 192.168.40.4
                      AS path: I
                    > to 10.10.10.2 via ge-0/1/0.1
 

Related Documentation

 

Published: 2012-12-08

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