Examples: Configuring BGP on Logical Systems
Understanding BGP
BGP is an exterior gateway protocol (EGP) that is used to exchange routing information among routing devices in different autonomous systems (ASs). BGP routing information includes the complete route to each destination. BGP uses the routing information to maintain a database of network reachability information, which it exchanges with other BGP systems. BGP uses the network reachability information to construct a graph of AS connectivity, which enables BGP to remove routing loops and enforce policy decisions at the AS level.
Multiprotocol BGP (MBGP) extensions enable BGP to support IP version 6 (IPv6). MBGP defines the attributes MP_REACH_NLRI and MP_UNREACH_NLRI, which are used to carry IPv6 reachability information. Network layer reachability information (NLRI) update messages carry IPv6 address prefixes of feasible routes.
BGP allows for policy-based routing. You can use routing policies to choose among multiple paths to a destination and to control the redistribution of routing information.
BGP uses TCP as its transport protocol, using port 179 for establishing connections. Running over a reliable transport protocol eliminates the need for BGP to implement update fragmentation, retransmission, acknowledgment, and sequencing.
The Junos OS routing protocol software supports BGP version 4. This version of BGP adds support for Classless Interdomain Routing (CIDR), which eliminates the concept of network classes. Instead of assuming which bits of an address represent the network by looking at the first octet, CIDR allows you to explicitly specify the number of bits in the network address, thus providing a means to decrease the size of the routing tables. BGP version 4 also supports aggregation of routes, including the aggregation of AS paths.
This section discusses the following topics:
Autonomous Systems
An autonomous system (AS) is a set of routing devices that are under a single technical administration and normally use a single interior gateway protocol and a common set of metrics to propagate routing information within the set of routing devices. To other ASs, an AS appears to have a single, coherent interior routing plan and presents a consistent picture of what destinations are reachable through it.
AS Paths and Attributes
The routing information that BGP systems exchange includes the complete route to each destination, as well as additional information about the route. The route to each destination is called the AS path, and the additional route information is included in path attributes. BGP uses the AS path and the path attributes to completely determine the network topology. Once BGP understands the topology, it can detect and eliminate routing loops and select among groups of routes to enforce administrative preferences and routing policy decisions.
External and Internal BGP
BGP supports two types of exchanges of routing information: exchanges among different ASs and exchanges within a single AS. When used among ASs, BGP is called external BGP (EBGP) and BGP sessions perform inter-AS routing. When used within an AS, BGP is called internal BGP (IBGP) and BGP sessions perform intra-AS routing. Figure 1 illustrates ASs, IBGP, and EBGP.
Figure 1: ASs, EBGP, and IBGP
A BGP system shares network reachability information with adjacent BGP systems, which are referred to as neighbors or peers.
BGP systems are arranged into groups. In an IBGP group, all peers in the group—called internal peers—are in the same AS. Internal peers can be anywhere in the local AS and do not have to be directly connected to one another. Internal groups use routes from an IGP to resolve forwarding addresses. They also propagate external routes among all other internal routing devices running IBGP, computing the next hop by taking the BGP next hop received with the route and resolving it using information from one of the interior gateway protocols.
In an EBGP group, the peers in the group—called external peers—are in different ASs and normally share a subnet. In an external group, the next hop is computed with respect to the interface that is shared between the external peer and the local routing device.
Multiple Instances of BGP
You can configure multiple instances of BGP at the following hierarchy levels:
- [edit routing-instances routing-instance-name protocols]
- [edit logical-systems logical-system-name routing-instances routing-instance-name protocols]
Multiple instances of BGP are primarily used for Layer 3 VPN support.
IGP peers and external BGP (EBGP) peers (both nonmultihop and multihop) are all supported for routing instances. BGP peering is established over one of the interfaces configured under the routing-instances hierarchy.
 | Note: When a BGP neighbor sends BGP messages to the local routing device, the incoming interface on which these messages are received must be configured in the same routing instance that the BGP neighbor configuration exists in. This is true for neighbors that are a single hop away or multiple hops away. |
Routes learned from the BGP peer are added to the instance-name.inet.0 table by default. You can configure import and export policies to control the flow of information into and out of the instance routing table.
For Layer 3 VPN support, configure BGP on the provider edge (PE) router to receive routes from the customer edge (CE) router and to send the instances’ routes to the CE router if necessary. You can use multiple instances of BGP to maintain separate per-site forwarding tables for keeping VPN traffic separate on the PE router.
You can configure import and export policies that allow the service provider to control and rate-limit traffic to and from the customer.
You can configure an EBGP multihop session for a VRF routing instance. Also, you can set up the EBGP peer between the PE and CE routers by using the loopback address of the CE router instead of the interface addresses.
Example: Configuring Internal BGP Peering Sessions on Logical Systems
This example shows how to configure internal BGP peer sessions on logical systems.
Requirements
In this example, no special configuration beyond device initialization is required.
Overview
In this example, you configure internal BGP (IBGP) peering sessions.
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 2 shows a typical network with internal peer sessions.
Figure 2: 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
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:
- Configure the interfaces.[edit logical-systems A interfaces lt-0/1/0 unit 1]user@R1# set description to-Buser@R1# set encapsulation ethernetuser@R1# set peer-unit 2user@R1# set family inet address 10.10.10.1/30user@R1# set family inet address 192.168.6.5/32user@R1# upuser@R1# up[edit logical-systems A interfaces]user@R1# set lo0 unit 1 family inet address 192.168.6.5/32user@R1# exit[edit]user@R1# edit logical-systems B interfaces lt-0/1/0[edit logical-systems B interfaces lt-0/1/0]user@R1# set unit 2 description to-Auser@R1# set unit 2 encapsulation ethernetuser@R1# set unit 2 peer-unit 1user@R1# set unit 2 family inet address 10.10.10.2/30user@R1# set unit 5 description to-Cuser@R1# set unit 5 encapsulation ethernetuser@R1# set unit 5 peer-unit 6user@R1# set family inet address 10.10.10.5/30user@R1# up[edit logical-systems B interfaces]user@R1# set lo0 unit 2 family inet address 192.163.6.4/32user@R1# exit[edit]user@R1# edit logical-systems C interfaces lt-0/1/0 unit 6[edit logical-systems C interfaces lt-0/1/0 unit 6]set description to-Bset encapsulation ethernetset peer-unit 5set family inet address 10.10.10.6/30user@R1# upuser@R1# up[edit logical-systems C interfaces]set lo0 unit 3 family inet address 192.168.40.4/32
- Configure BGP.
On Logical System A, the neighbor statements are included for both Device B and Device C, even though Logical System A is not directly connected to Device C.
[edit logical-systems A protocols bgp group internal-peers]user@R1# set type internaluser@R1# set local-address 192.168.6.5user@R1# set export send-directuser@R1# set neighbor 192.163.6.4user@R1# set neighbor 192.168.40.4
[edit logical-systems B protocols bgp group internal-peers]user@R1# set type internaluser@R1# set local-address 192.163.6.4user@R1# set export send-directuser@R1# set neighbor 192.168.40.4user@R1# set neighbor 192.168.6.5
[edit logical-systems C protocols bgp group internal-peers]user@R1# set type internaluser@R1# set local-address 192.168.40.4user@R1# set export send-directuser@R1# set neighbor 192.163.6.4user@R1# set neighbor 192.168.6.5 - Configure OSPF.[edit logical-systems A protocols ospf area 0.0.0.0]user@R1# set interface lo0.1 passiveuser@R1# set interface lt-0/1/0.1
[edit logical-systems A protocols ospf area 0.0.0.0]user@R1# set interface lo0.2 passiveuser@R1# set interface lt-0/1/0.2user@R1# set interface lt-0/1/0.5
[edit logical-systems A protocols ospf area 0.0.0.0]user@R1# set interface lo0.3 passiveuser@R1# set interface lt-0/1/0.6 - 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 logical-systems A policy-options policy-statement send-direct term 2]user@R1# set from protocol directuser@R1# set then accept
[edit logical-systems B policy-options policy-statement send-direct term 2]user@R1# set from protocol directuser@R1# set then accept
[edit logical-systems C policy-options policy-statement send-direct term 2]user@R1# set from protocol directuser@R1# set then accept - Configure the router ID and the autonomous system (AS)
number.[edit logical-systems A routing-options]user@R1# set router-id 192.168.6.5user@R1# set autonomous-system 17
[edit logical-systems B routing-options]user@R1# set router-id 192.163.6.4user@R1# set autonomous-system 17
[edit logical-systems C routing-options]user@R1# set router-id 192.168.40.4user@R1# set autonomous-system 17
Results
From configuration mode, confirm your configuration by entering the show logical-systems command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.
If you are done configuring the device, enter commit from configuration mode.
Verification
Confirm that the configuration is working properly.
- Verifying BGP Neighbors
- Verifying BGP Groups
- Verifying BGP Summary Information
- Verifying That BGP Routes Are Installed in the Routing Table
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 the operational mode, enter the show bgp neighbor command.
user@R1> show bgp neighbor logical-system APeer: 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 16 Sent 1 Checked 63
Input messages: Total 15713 Updates 4 Refreshes 0 Octets 298622
Output messages: Total 15690 Updates 2 Refreshes 0 Octets 298222
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 15 Sent 22 Checked 68
Input messages: Total 15688 Updates 2 Refreshes 0 Octets 298111
Output messages: Total 15688 Updates 2 Refreshes 0 Octets 298184
Output Queue[0]: 0Verifying BGP Groups
Purpose
Verify that the BGP groups are configured correctly.
Action
From the operational mode, enter the show bgp group command.
user@A> show bgp group logical-system AGroup 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 the operational mode, enter the show bgp summary command.
user@A> show bgp summary logical-system AGroups: 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 15723 15700 0 0 4d 22:13:15 0/3/3/0 0/0/0/0 192.168.40.4 17 15698 15699 0 0 4d 22:13:11 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 working.
Action
From the operational mode, enter the show route protocol bgp command.
user@A> show route protocol bgp logical-system
Ainet.0: 7 destinations, 12 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
10.10.10.0/30 [BGP/170] 4d 11:05:55, localpref 100, from 192.163.6.4
AS path: I
> to 10.10.10.2 via lt-0/1/0.1
10.10.10.4/30 [BGP/170] 4d 11:05:55, localpref 100, from 192.163.6.4
AS path: I
> to 10.10.10.2 via lt-0/1/0.1
[BGP/170] 4d 11:03:10, localpref 100, from 192.168.40.4
AS path: I
> to 10.10.10.2 via lt-0/1/0.1
192.163.6.4/32 [BGP/170] 4d 11:05:55, localpref 100, from 192.163.6.4
AS path: I
> to 10.10.10.2 via lt-0/1/0.1
192.168.40.4/32 [BGP/170] 4d 11:03:10, localpref 100, from 192.168.40.4
AS path: I
> to 10.10.10.2 via lt-0/1/0.1Example: Configuring External BGP on Logical Systems with IPv6 Interfaces
This example shows how to configure external BGP (EBGP) point-to-point peer sessions on logical systems with IPv6 interfaces.
Requirements
In this example, no special configuration beyond device initialization is required.
Overview
Junos OS supports EBGP peer sessions by means of IPv6 addresses. An IPv6 peer session can be configured when an IPv6 address is specified in the neighbor statement. This example uses EUI-64 to generate IPv6 addresses that are automatically applied to the interfaces. An EUI-64 address is an IPv6 address that uses the IEEE EUI-64 format for the interface identifier portion of the address (the last 64 bits).
| Note: Alternatively, you can configure EBGP sessions using manually assigned 128-bit IPv6 addresses. If you use 128-bit link-local addresses for the interfaces, you must include the local-interface statement. This statement is valid only for 128-bit IPv6 link-local addresses and is mandatory for configuring an IPv6 EBGP link-local peer session. Configuring EBGP peering using link-local addresses is only applicable for directly connected interfaces. There is no support for multihop peering. |
After your interfaces are up, you can use the show interfaces terse command to view the EUI-64-generated IPv6 addresses on the interfaces. You must use these generated addresses in the BGP neighbor statements. This example demonstrates the full end-to-end procedure.
In this example, Frame Relay interface encapsulation is applied to the logical tunnel (lt) interfaces. This is a requirement because only Frame Relay encapsulation is supported when IPv6 addresses are configured on the lt interfaces.
Figure 3 shows a network with BGP peer sessions. In the sample network, Router R1 has five logical systems configured. Device E in autonomous system (AS) 17 has BGP peer sessions to a group of peers called external-peers. Peers A, B, and C reside in AS 22. This example shows the step-by-step configuration on Logical System A and Logical System E.
Figure 3: Typical Network with BGP Peer 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
Device B
Device C
Device D
Device E
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 the BGP peer sessions:
- Run the show interfaces terse command to verify
that the physical router has a logical tunnel (lt) interface.
user@R1> show interfaces terseInterface Admin Link Proto Local Remote ... lt-0/1/0 up up ...
- On Logical System A, configure the interface encapsulation,
peer-unit number, and DLCI to reach Logical System E.user@R1> set cli logical-system ALogical system: A[edit]user@R1:A> editEntering configuration mode[edit]user@R1:A# edit interfaces[edit interfaces]user@R1:A# set lt-0/1/0 unit 1 encapsulation frame-relayuser@R1:A# set lt-0/1/0 unit 1 dlci 1user@R1:A# set lt-0/1/0 unit 1 peer-unit 25
- On Logical System A, configure the network address for the link
to Peer E, and configure a loopback interface.[edit interfaces]user@R1:A# set lt-0/1/0 unit 1 description to-Euser@R1:A# set lt-0/1/0 unit 1 family inet6 address 2001:db8:0:1::/64 eui-64user@R1:A# set lo0 unit 1 family inet6 address 2001:db8::1/128
- On Logical System E, configure the interface encapsulation,
peer-unit number, and DLCI to reach Logical System A.user@R1> set cli logical-system ELogical system: E[edit]user@R1:E> editEntering configuration mode[edit]user@R1:E# edit interfaces[edit interfaces]user@R1:E# set lt-0/1/0 unit 25 encapsulation frame-relayuser@R1:E# set lt-0/1/0 unit 25 dlci 1user@R1:E# set lt-0/1/0 unit 25 peer-unit 1
- On Logical System E, configure the network address for the link
to Peer A, and configure a loopback interface.[edit interfaces]user@R1:E# set lt-0/1/0 unit 25 description to-Auser@R1:E# set lt-0/1/0 unit 25 family inet6 address 2001:db8:0:1::/64 eui-64user@R1:E# set lo0 unit 5 family inet6 address 2001:db8::5/128
- Run the show interfaces terse command to see
the IPv6 addresses that are generated by EUI-64.
The 2001 addresses are used in this example in the BGP neighbor statements.
Note: The fe80 addresses are link-local addresses and are not used in this example.
user@R1:A> show interfaces terseInterface Admin Link Proto Local Remote Logical system: A betsy@tp8:A> show interfaces terse Interface Admin Link Proto Local Remote lt-0/1/0 lt-0/1/0.1 up up inet6 2001:db8:0:1:2a0:a502:0:1da/64 fe80::2a0:a502:0:1da/64 lo0 lo0.1 up up inet6 2001:db8::1 fe80::2a0:a50f:fc56:1dauser@R1:E> show interfaces terseInterface Admin Link Proto Local Remote lt-0/1/0 lt-0/1/0.25 up up inet6 2001:db8:0:1:2a0:a502:0:19da/64 fe80::2a0:a502:0:19da/64 lo0 lo0.5 up up inet6 2001:db8::5 fe80::2a0:a50f:fc56:1da - Repeat the interface configuration on the other logical systems.
Configuring the External BGP Sessions
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 the BGP peer sessions:
- On Logical System A, create the BGP group, and add the
external neighbor address.[edit protocols bgp group external-peers]user@R1:A# set neighbor 2001:db8:0:1:2a0:a502:0:19da
- On Logical System E, create the BGP group, and add the
external neighbor address.[edit protocols bgp group external-peers]user@R1:E# set neighbor 2001:db8:0:1:2a0:a502:0:1da
- On Logical System A, specify the autonomous system (AS)
number of the external AS.[edit protocols bgp group external-peers]user@R1:A# set peer-as 17
- On Logical System E, specify the autonomous system (AS)
number of the external AS.[edit protocols bgp group external-peers]user@R1:E# set peer-as 22
- On Logical System A, set the peer type to EBGP.[edit protocols bgp group external-peers]user@R1:A# set type external
- On Logical System E, set the peer type to EBGP.[edit protocols bgp group external-peers]user@R1:E# set type external
- On Logical System A, set the autonomous system (AS) number
and router ID.
- On Logical System E, set the AS number and router ID.[edit routing-options]user@R1:E# set router-id 5.5.5.5user@R1:E# set autonomous-system 17
- Repeat these steps for Peers A, B, C, and D.
Results
From configuration mode, confirm your configuration by entering the show logical-systems command. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
If you are done configuring the device, enter commit from configuration mode.
Verification
Confirm that the configuration is working properly.
- Verifying BGP Neighbors
- Verifying BGP Groups
- Verifying BGP Summary Information
- Checking the Routing Table
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, run the show bgp neighbor command.
user@R1:E> show bgp neighborPeer: 2001:db8:0:1:2a0:a502:0:1da+54987 AS 22 Local: 2001:db8:0:1:2a0:a502:0:19da+179 AS 17
Type: External State: Established Flags: <Sync>
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: Open Message Error
Options: <Preference PeerAS Refresh>
Holdtime: 90 Preference: 170
Number of flaps: 0
Error: 'Open Message Error' Sent: 20 Recv: 0
Peer ID: 1.1.1.1 Local ID: 5.5.5.5 Active Holdtime: 90
Keepalive Interval: 30 Peer index: 0
BFD: disabled, down
Local Interface: lt-0/1/0.25
NLRI for restart configured on peer: inet6-unicast
NLRI advertised by peer: inet6-unicast
NLRI for this session: inet6-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: inet6-unicast
NLRI of received end-of-rib markers: inet6-unicast
NLRI of all end-of-rib markers sent: inet6-unicast
Peer supports 4 byte AS extension (peer-as 22)
Peer does not support Addpath
Table inet6.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 0
Received prefixes: 0
Accepted prefixes: 0
Suppressed due to damping: 0
Advertised prefixes: 0
Last traffic (seconds): Received 7 Sent 18 Checked 81
Input messages: Total 1611 Updates 1 Refreshes 0 Octets 30660
Output messages: Total 1594 Updates 0 Refreshes 0 Octets 30356
Output Queue[0]: 0
Peer: 2001:db8:0:2:2a0:a502:0:6da+179 AS 22 Local: 2001:db8:0:2:2a0:a502:0:5da+55502 AS 17
Type: External State: Established Flags: <Sync>
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: Open Message Error
Options: <Preference PeerAS Refresh>
Holdtime: 90 Preference: 170
Number of flaps: 0
Error: 'Open Message Error' Sent: 26 Recv: 0
Peer ID: 2.2.2.2 Local ID: 5.5.5.5 Active Holdtime: 90
Keepalive Interval: 30 Peer index: 2
BFD: disabled, down
Local Interface: lt-0/1/0.5
NLRI for restart configured on peer: inet6-unicast
NLRI advertised by peer: inet6-unicast
NLRI for this session: inet6-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: inet6-unicast
NLRI of received end-of-rib markers: inet6-unicast
NLRI of all end-of-rib markers sent: inet6-unicast
Peer supports 4 byte AS extension (peer-as 22)
Peer does not support Addpath
Table inet6.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 0
Received prefixes: 0
Accepted prefixes: 0
Suppressed due to damping: 0
Advertised prefixes: 0
Last traffic (seconds): Received 15 Sent 8 Checked 8
Input messages: Total 1610 Updates 1 Refreshes 0 Octets 30601
Output messages: Total 1645 Updates 0 Refreshes 0 Octets 32417
Output Queue[0]: 0
Peer: 2001:db8:0:3:2a0:a502:0:ada+55983 AS 22 Local: 2001:db8:0:3:2a0:a502:0:9da+179 AS 17
Type: External State: Established Flags: <Sync>
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: None
Options: <Preference PeerAS Refresh>
Holdtime: 90 Preference: 170
Number of flaps: 0
Peer ID: 3.3.3.3 Local ID: 5.5.5.5 Active Holdtime: 90
Keepalive Interval: 30 Peer index: 3
BFD: disabled, down
Local Interface: lt-0/1/0.9
NLRI for restart configured on peer: inet6-unicast
NLRI advertised by peer: inet6-unicast
NLRI for this session: inet6-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: inet6-unicast
NLRI of received end-of-rib markers: inet6-unicast
NLRI of all end-of-rib markers sent: inet6-unicast
Peer supports 4 byte AS extension (peer-as 22)
Peer does not support Addpath
Table inet6.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 0
Received prefixes: 0
Accepted prefixes: 0
Suppressed due to damping: 0
Advertised prefixes: 0
Last traffic (seconds): Received 21 Sent 21 Checked 67
Input messages: Total 1610 Updates 1 Refreshes 0 Octets 30641
Output messages: Total 1587 Updates 0 Refreshes 0 Octets 30223
Output Queue[0]: 0
Peer: 2001:db8:0:4:2a0:a502:0:7da+49255 AS 79 Local: 2001:db8:0:4:2a0:a502:0:15da+179 AS 17
Type: External State: Established Flags: <Sync>
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: None
Options: <Preference PeerAS Refresh>
Holdtime: 90 Preference: 170
Number of flaps: 0
Peer ID: 4.4.4.4 Local ID: 5.5.5.5 Active Holdtime: 90
Keepalive Interval: 30 Peer index: 1
BFD: disabled, down
Local Interface: lt-0/1/0.21
NLRI for restart configured on peer: inet6-unicast
NLRI advertised by peer: inet6-unicast
NLRI for this session: inet6-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: inet6-unicast
NLRI of received end-of-rib markers: inet6-unicast
NLRI of all end-of-rib markers sent: inet6-unicast
Peer supports 4 byte AS extension (peer-as 79)
Peer does not support Addpath
Table inet6.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 0
Received prefixes: 0
Accepted prefixes: 0
Suppressed due to damping: 0
Advertised prefixes: 0
Last traffic (seconds): Received 6 Sent 17 Checked 25
Input messages: Total 1615 Updates 1 Refreshes 0 Octets 30736
Output messages: Total 1593 Updates 0 Refreshes 0 Octets 30337
Output Queue[0]: 0Meaning
IPv6 unicast network layer reachability information (NLRI) is being exchanged between the neighbors.
Verifying BGP Groups
Purpose
Verify that the BGP groups are configured correctly.
Action
From operational mode, run the show bgp group command.
user@R1:E> show bgp groupGroup Type: External Local AS: 17 Name: external-peers Index: 0 Flags: <> Holdtime: 0 Total peers: 4 Established: 4 2001:db8:0:1:2a0:a502:0:1da+54987 2001:db8:0:2:2a0:a502:0:6da+179 2001:db8:0:3:2a0:a502:0:ada+55983 2001:db8:0:4:2a0:a502:0:7da+49255 inet6.0: 0/0/0/0 Groups: 1 Peers: 4 External: 4 Internal: 0 Down peers: 0 Flaps: 0 Table Tot Paths Act Paths Suppressed History Damp State Pending inet6.0 0 0 0 0 0 0 inet6.2 0 0 0 0 0 0
Meaning
The group type is external, and the group has four peers.
Verifying BGP Summary Information
Purpose
Verify that the BGP that the peer relationships are established.
Action
From operational mode, run the show bgp summary command.
user@R1:E> show bgp summaryGroups: 1 Peers: 4 Down peers: 0 Table Tot Paths Act Paths Suppressed History Damp State Pending inet6.0 0 0 0 0 0 0 inet6.2 0 0 0 0 0 0 Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped... 2001:db8:0:1:2a0:a502:0:1da 22 1617 1600 0 0 12:07:00 Establ inet6.0: 0/0/0/0 2001:db8:0:2:2a0:a502:0:6da 22 1616 1651 0 0 12:06:56 Establ inet6.0: 0/0/0/0 2001:db8:0:3:2a0:a502:0:ada 22 1617 1594 0 0 12:04:32 Establ inet6.0: 0/0/0/0 2001:db8:0:4:2a0:a502:0:7da 79 1621 1599 0 0 12:07:00 Establ inet6.0: 0/0/0/0
Meaning
The Down peers: 0 output shows that the BGP peers are in the established state.
Checking the Routing Table
Purpose
Verify that the inet6.0 routing table is populated with local and direct routes.
Action
From operational mode, run the show route command.
user@R1:E> show routeinet6.0: 15 destinations, 18 routes (15 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
2001:db8::5/128 *[Direct/0] 12:41:18
> via lo0.5
2001:db8:0:1::/64 *[Direct/0] 14:40:01
> via lt-0/1/0.25
2001:db8:0:1:2a0:a502:0:19da/128
*[Local/0] 14:40:01
Local via lt-0/1/0.25
2001:db8:0:2::/64 *[Direct/0] 14:40:02
> via lt-0/1/0.5
2001:db8:0:2:2a0:a502:0:5da/128
*[Local/0] 14:40:02
Local via lt-0/1/0.5
2001:db8:0:3::/64 *[Direct/0] 14:40:02
> via lt-0/1/0.9
2001:db8:0:3:2a0:a502:0:9da/128
*[Local/0] 14:40:02
Local via lt-0/1/0.9
2001:db8:0:4::/64 *[Direct/0] 14:40:01
> via lt-0/1/0.21
2001:db8:0:4:2a0:a502:0:15da/128
*[Local/0] 14:40:01
Local via lt-0/1/0.21
fe80::/64 *[Direct/0] 14:40:02
> via lt-0/1/0.5
[Direct/0] 14:40:02
> via lt-0/1/0.9
[Direct/0] 14:40:01
> via lt-0/1/0.21
[Direct/0] 14:40:01
> via lt-0/1/0.25
fe80::2a0:a502:0:5da/128
*[Local/0] 14:40:02
Local via lt-0/1/0.5
fe80::2a0:a502:0:9da/128
*[Local/0] 14:40:02
Local via lt-0/1/0.9
fe80::2a0:a502:0:15da/128
*[Local/0] 14:40:01
Local via lt-0/1/0.21
fe80::2a0:a502:0:19da/128
*[Local/0] 14:40:01
Local via lt-0/1/0.25
fe80::2a0:a50f:fc56:1da/128
*[Direct/0] 12:41:18
> via lo0.5Meaning
The inet6.0 routing table contains local and direct routes. To populate the routing table with other types of routes, you must configure routing policies.
Example: Configuring BFD on Internal BGP Peer Sessions
This example shows how to configure internal BGP (IBGP) peer sessions with the Bidirectional Forwarding Detection (BFD) protocol to detect failures in a network.
Requirements
No special configuration beyond device initialization is required before you configure this example.
Overview
The minimum configuration to enable BFD on IBGP sessions is to include the bfd-liveness-detection minimum-interval statement in the BGP configuration of all neighbors participating in the BFD session. The minimum-interval statement specifies the minimum transmit and receive intervals for failure detection. Specifically, this value represents the minimum interval after which the local routing device transmits hello packets as well as the minimum interval that the routing device expects to receive a reply from a neighbor with which it has established a BFD session. You can configure a value from 1 through 255,000 milliseconds.
Optionally, you can specify the minimum transmit and receive intervals separately using the transmit-interval minimum-interval and minimum-receive-interval statements. For information about these and other optional BFD configuration statements, see bfd-liveness-detection.
| Note: BFD is an intensive protocol that consumes system resources. Specifying a minimum interval for BFD less than 100 ms for Routing Engine-based sessions and less than 10 ms for distributed BFD sessions can cause undesired BFD flapping. Depending on your network environment, these additional recommendations might apply:
|
BFD is supported on the default routing instance (the main router), routing instances, and logical systems. This example shows BFD on logical systems.
Figure 4 shows a typical network with internal peer sessions.
Figure 4: 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
Device B
Device C
Configuring Device A
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 CLI User Guide.
To configure Device A:
- Set the CLI to Logical System A.user@host> set cli logical-system A
- Configure the interfaces.[edit interfaces lt-1/2/0 unit 1]user@host:A# set description to-B user@host:A# set encapsulation ethernet user@host:A# set peer-unit 2 user@host:A# set family inet address 10.10.10.1/30
[edit interfaces lo0 unit 1]user@host:A# set family inet address 192.168.6.5/32 - 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@host:A# set type internal user@host:A# set local-address 192.168.6.5 user@host:A# set export send-direct user@host:A# set neighbor 192.163.6.4 user@host:A# set neighbor 192.168.40.4 - Configure BFD.[edit protocols bgp group internal-peers]user@host:A# set bfd-liveness-detection minimum-interval 1000
You must configure the same minimum interval on the connecting peer.
- (Optional) Configure BFD tracing.[edit protocols bgp group internal-peers]user@host:A# set traceoptions file bgp-bfd user@host:A# set traceoptions flag bfd detail
- Configure OSPF.[edit protocols ospf area 0.0.0.0]user@host:A# set interface lo0.1 passive user@host:A# set interface lt-1/2/0.1
- 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@host:A# set from protocol direct user@host:A# set then accept - Configure the router ID and the autonomous system (AS)
number.[edit routing-options]user@host:A# set router-id 192.168.6.5 user@host:A# set autonomous-system 17
- If you are done configuring the device, enter commit from configuration mode.
Repeat these steps to configure Device B and Device C.
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.
Verification
Confirm that the configuration is working properly.
- Verifying That BFD Is Enabled
- Verifying That BFD Sessions Are Up
- Viewing Detailed BFD Events
- Viewing Detailed BFD Events After Deactivating and Reactivating a Loopback Interface
Verifying That BFD Is Enabled
Purpose
Verify that BFD is enabled between the IBGP peers.
Action
From operational mode, enter the show bgp neighbor command. You can use the | match bfd filter to narrow the output.
user@host:A> show bgp neighbor | match bfdOptions: <BfdEnabled> BFD: enabled, up Trace file: /var/log/A/bgp-bfd size 131072 files 10 Options: <BfdEnabled> BFD: enabled, up Trace file: /var/log/A/bgp-bfd size 131072 files 10
Meaning
The output shows that Logical System A has two neighbors with BFD enabled. When BFD is not enabled, the output displays BFD: disabled, down, and the <BfdEnabled> option is absent. If BFD is enabled and the session is down, the output displays BFD: enabled, down. The output also shows that BFD-related events are being written to a log file because trace operations are configured.
Verifying That BFD Sessions Are Up
Purpose
Verify that the BFD sessions are up, and view details about the BFD sessions.
Action
From operational mode, enter the show bfd session extensive command.
user@host:A> show bfd session extensive Detect Transmit
Address State Interface Time Interval Multiplier
192.163.6.4 Up 3.000 1.000 3
Client BGP, TX interval 1.000, RX interval 1.000
Session up time 00:54:40
Local diagnostic None, remote diagnostic None
Remote state Up, version 1
Logical system 12, routing table index 25
Min async interval 1.000, min slow interval 1.000
Adaptive async TX interval 1.000, RX interval 1.000
Local min TX interval 1.000, minimum RX interval 1.000, multiplier 3
Remote min TX interval 1.000, min RX interval 1.000, multiplier 3
Local discriminator 10, remote discriminator 9
Echo mode disabled/inactive
Multi-hop route table 25, local-address 192.168.6.5
Detect Transmit
Address State Interface Time Interval Multiplier
192.168.40.4 Up 3.000 1.000 3
Client BGP, TX interval 1.000, RX interval 1.000
Session up time 00:48:03
Local diagnostic None, remote diagnostic None
Remote state Up, version 1
Logical system 12, routing table index 25
Min async interval 1.000, min slow interval 1.000
Adaptive async TX interval 1.000, RX interval 1.000
Local min TX interval 1.000, minimum RX interval 1.000, multiplier 3
Remote min TX interval 1.000, min RX interval 1.000, multiplier 3
Local discriminator 14, remote discriminator 13
Echo mode disabled/inactive
Multi-hop route table 25, local-address 192.168.6.5
2 sessions, 2 clients
Cumulative transmit rate 2.0 pps, cumulative receive rate 2.0 ppsMeaning
The TX interval 1.000, RX interval 1.000 output represents the setting configured with the minimum-interval statement. All of the other output represents the default settings for BFD. To modify the default settings, include the optional statements under the bfd-liveness-detection statement.
Viewing Detailed BFD Events
Purpose
View the contents of the BFD trace file to assist in troubleshooting, if needed.
Action
From operational mode, enter the file show /var/log/A/bgp-bfd command.
user@host:A> file show /var/log/A/bgp-bfdAug 15 17:07:25 trace_on: Tracing to "/var/log/A/bgp-bfd" started Aug 15 17:07:26.492190 bgp_peer_init: BGP peer 192.163.6.4 (Internal AS 17) local address 192.168.6.5 not found. Leaving peer idled Aug 15 17:07:26.493176 bgp_peer_init: BGP peer 192.168.40.4 (Internal AS 17) local address 192.168.6.5 not found. Leaving peer idled Aug 15 17:07:32.597979 task_connect: task BGP_17.192.163.6.4+179 addr 192.163.6.4+179: No route to host Aug 15 17:07:32.599623 bgp_connect_start: connect 192.163.6.4 (Internal AS 17): No route to host Aug 15 17:07:36.869394 task_connect: task BGP_17.192.168.40.4+179 addr 192.168.40.4+179: No route to host Aug 15 17:07:36.870624 bgp_connect_start: connect 192.168.40.4 (Internal AS 17): No route to host Aug 15 17:08:04.599220 task_connect: task BGP_17.192.163.6.4+179 addr 192.163.6.4+179: No route to host Aug 15 17:08:04.601135 bgp_connect_start: connect 192.163.6.4 (Internal AS 17): No route to host Aug 15 17:08:08.869717 task_connect: task BGP_17.192.168.40.4+179 addr 192.168.40.4+179: No route to host Aug 15 17:08:08.869934 bgp_connect_start: connect 192.168.40.4 (Internal AS 17): No route to host Aug 15 17:08:36.603544 advertising receiving-speaker only capabilty to neighbor 192.163.6.4 (Internal AS 17) Aug 15 17:08:36.606726 bgp_read_message: 192.163.6.4 (Internal AS 17): 0 bytes buffered Aug 15 17:08:36.609119 Initiated BFD session to peer 192.163.6.4 (Internal AS 17): address=192.163.6.4 ifindex=0 ifname=(none) txivl=1000 rxivl=1000 mult=3 ver=255 Aug 15 17:08:36.734033 advertising receiving-speaker only capabilty to neighbor 192.168.40.4 (Internal AS 17) Aug 15 17:08:36.738436 Initiated BFD session to peer 192.168.40.4 (Internal AS 17): address=192.168.40.4 ifindex=0 ifname=(none) txivl=1000 rxivl=1000 mult=3 ver=255 Aug 15 17:08:40.537552 BFD session to peer 192.163.6.4 (Internal AS 17) up Aug 15 17:08:40.694410 BFD session to peer 192.168.40.4 (Internal AS 17) up
Meaning
Before the routes are established, the No route to host message appears in the output. After the routes are established, the last two lines show that both BFD sessions come up.
Viewing Detailed BFD Events After Deactivating and Reactivating a Loopback Interface
Purpose
Check to see what happens after bringing down a router or switch and then bringing it back up. To simulate bringing down a router or switch, deactivate the loopback interface on Logical System B.
Action
- From configuration mode, enter the deactivate logical-systems B interfaces lo0 unit 2 family inet command.
user@host:A# deactivate logical-systems B interfaces lo0 unit 2 family inetuser@host:A# commit - From operational mode, enter the file show /var/log/A/bgp-bfd command.
user@host:A> file show /var/log/A/bgp-bfd... Aug 15 17:20:55.995648 bgp_read_v4_message:9747: NOTIFICATION received from 192.163.6.4 (Internal AS 17): code 6 (Cease) subcode 6 (Other Configuration Change) Aug 15 17:20:56.004508 Terminated BFD session to peer 192.163.6.4 (Internal AS 17) Aug 15 17:21:28.007755 task_connect: task BGP_17.192.163.6.4+179 addr 192.163.6.4+179: No route to host Aug 15 17:21:28.008597 bgp_connect_start: connect 192.163.6.4 (Internal AS 17): No route to host
- From configuration mode, enter the activate logical-systems B interfaces lo0 unit 2 family inet command.
user@host:A# activate logical-systems B interfaces lo0 unit 2 family inetuser@host:A# commit - From operational mode, enter the file show /var/log/A/bgp-bfd command.
user@host:A> file show /var/log/A/bgp-bfd... Aug 15 17:25:53.623743 advertising receiving-speaker only capabilty to neighbor 192.163.6.4 (Internal AS 17) Aug 15 17:25:53.631314 Initiated BFD session to peer 192.163.6.4 (Internal AS 17): address=192.163.6.4 ifindex=0 ifname=(none) txivl=1000 rxivl=1000 mult=3 ver=255 Aug 15 17:25:57.570932 BFD session to peer 192.163.6.4 (Internal AS 17) up
Example: Configuring EBGP Multihop Sessions on Logical Systems
This example shows how to configure an external BGP (EBGP) peer that is more than one hop away from the local router. This type of session is called a multihop EBGP session.
Requirements
In this example, no special configuration beyond device initialization is required.
Overview
When EBGP peers are not directly connected to each other, they must cross one or more non-BGP routing devices to reach each other. Configuring multihop EBGP enables the peers to pass through the other routing devices to form peer relationships and exchange update messages. This type of configuration is typically used when a Juniper Networks routing device needs to run EBGP with a third-party routing device that does not allow direct connection of the two EBGP peers. EBGP multihop enables a neighbor connection between two EBGP peers that do not have a direct connection.
The configuration to enable multihop EBGP sessions requires connectivity between the two EBGP peers. This example uses static routes to provide connectivity between the devices.
For directly connected EBGP sessions, physical addresses are typically used in the neighbor statements. For multihop EBGP, you must use loopback interface addresses, and specify the loopback interface address of the indirectly connected peer. In the use of loopback interfaces addresses, EBGP multihop is similar to internal BGP (IBGP).
Finally, you must add the multihop statement. Optionally, you can set a maximum time-to-live (TTL) value with the ttl statement. The TTL is carried in the IP header of BGP packets. If you do not specify a TTL value, the system’s default maximum TTL value is used. The default TTL value is 64 for multihop EBGP sessions. Another option is to retain the BGP next-hop value for route advertisements by including the no-nexthop-change statement.
Figure 5 shows a typical EBGP multihop network.
Device C and Device E have an established EBGP session. Device D is not a BGP-enabled device. All of the devices have connectivity via static routes.
Figure 5: Typical Network with EBGP Multihop 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 C
Device D
Device E
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 Device C:
- Set the CLI to Logical System C.user@host> set cli logical-system C
- Configure the interface to the directly-connected device
(to-D), and configure the loopback interface.[edit interfaces lt-1/2/0 unit 9]user@host:C# set description to-Duser@host:C# set encapsulation ethernetuser@host:C# set peer-unit 10user@host:C# set family inet address 10.10.10.9/30
[edit interfaces lo0 unit 3]user@host:C# set family inet address 192.168.40.4/32 - Configure an EBGP session with Logical System E.
The neighbor statement points to the loopback interface on Logical System E.
[edit protocols bgp group external-peers]user@host:C# set type externaluser@host:C# set local-address 192.168.40.4user@host:C# set export send-staticuser@host:C# set peer-as 18user@host:C# set neighbor 192.168.6.7 - Configure the multihop statement to enable Logical System
C and Logical System E to become EBGP peers.
Because the peers are two hops away from each other, the example uses the ttl 2 statement.
[edit protocols bgp group external-peers]user@host:C# set multihop ttl 2 - Configure connectivity to Logical System E, using static
routes.
You must configure a route to both the loopback interface address and to the address on the physical interface.
[edit logical-systems C routing-options]user@host:C# set static route 10.10.10.14/32 next-hop 10.10.10.10user@host:C# set static route 192.168.6.7/32 next-hop 10.10.10.10 - Configure the local router ID and the autonomous system
(AS) number.[edit routing-options]user@host:C# set router-id 192.168.40.4user@host:C# set autonomous-system 17
- 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-static term 1]user@host:C# set from protocol staticuser@host:C# set then accept
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.
If you are done configuring the device, enter commit from configuration mode. Repeat these steps for all BFD sessions in the topology.
Device D
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 Device D:
- Set the CLI to Logical System D.user@host> set cli logical-system D
- Configure the interfaces to the directly-connected devices,
and configure a loopback interface.[edit interfaces lt-1/2/0 unit 10]user@host:D# set description to-Cuser@host:D# set encapsulation ethernetuser@host:D# set peer-unit 9user@host:D# set family inet address 10.10.10.10/30
[edit interfaces lt-1/2/0 unit 13]user@host:D# set description to-Euser@host:D# set encapsulation ethernetuser@host:D# set peer-unit 14user@host:D# set family inet address 10.10.10.13/30
[edit interfaces lo0 unit 4]user@host:D# set family inet address 192.168.6.6/32 - Configure connectivity to the other devices using a static
routes to the loopback interface addresses.
On Logical System D, you do not need static routes to the physical addresses because Logical System D is directly connected to Logical System C and Logical System E.
[edit routing-options]user@host:D# set static route 192.168.40.4/32 next-hop 10.10.10.9user@host:D# set static route 192.168.6.7/32 next-hop 10.10.10.14 - Configure the local router ID and the autonomous system
(AS) number.[edit routing-options]user@host:D# set router-id 192.168.6.6
Results
From configuration mode, confirm your configuration by entering the show interfaces and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
If you are done configuring the device, enter commit from configuration mode. Repeat these steps for all BFD sessions in the topology.
Device E
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 Device E:
- Set the CLI to Logical System E.user@host> set cli logical-system E
- Configure the interface to the directly-connected device
(to-D), and configure the loopback interface.[edit interfaces lt-1/2/0 unit 14]user@host:E# set description to-Duser@host:E# set encapsulation ethernetuser@host:E# set peer-unit 13user@host:E# set family inet address 10.10.10.14/30
[edit interfaces lo0 unit 5]user@host:E# set family inet address 192.168.6.7/32 - Configure an EBGP session with Logical System E.
The neighbor statement points to the loopback interface on Logical System C.
[edit protocols bgp group external-peers]user@host:E# set local-address 192.168.6.7user@host:E# set export send-staticuser@host:E# set peer-as 17user@host:E# set neighbor 192.168.40.4 - Configure the multihop statement to enable
Logical System C and Logical System E to become EBGP peers.
Because the peers are two hops away from each other, the example uses the ttl 2 statement.
[edit protocols bgp group external-peers]user@host:E# set multihop ttl 2 - Configure connectivity to Logical System E, using static
routes.
You must configure a route to both the loopback interface address and to the address on the physical interface.
[edit routing-options]user@host:E# set static route 10.10.10.8/30 next-hop 10.10.10.13user@host:E# set static route 192.168.40.4/32 next-hop 10.10.10.13 - Configure the local router ID and the autonomous system
(AS) number.[edit routing-options]user@host:E# set router-id 192.168.6.7user@host:E# set autonomous-system 18
- 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-static term 1]user@host:E# set from protocol staticuser@host:E# set send-static then accept
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.
If you are done configuring the device, enter commit from configuration mode.
Verification
Confirm that the configuration is working properly.
Verifying Connectivity
Purpose
Make sure that Device C can ping Device E, specifying the loopback interface address as the source of the ping request.
The loopback interface address is the source address that BGP will be using.
Action
From operational mode, enter the ping 10.10.10.14 source 192.168.40.4 command from Logical System C, and enter the ping 10.10.10.9 source 192.168.6.7 command from Logical System E.
user@host:C> ping 10.10.10.14 source 192.168.40.4PING 10.10.10.14 (10.10.10.14): 56 data bytes 64 bytes from 10.10.10.14: icmp_seq=0 ttl=63 time=1.262 ms 64 bytes from 10.10.10.14: icmp_seq=1 ttl=63 time=1.202 ms ^C --- 10.10.10.14 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 1.202/1.232/1.262/0.030 ms
user@host:E> ping 10.10.10.9 source 192.168.6.7PING 10.10.10.9 (10.10.10.9): 56 data bytes 64 bytes from 10.10.10.9: icmp_seq=0 ttl=63 time=1.255 ms 64 bytes from 10.10.10.9: icmp_seq=1 ttl=63 time=1.158 ms ^C --- 10.10.10.9 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 1.158/1.206/1.255/0.049 ms
Meaning
The static routes are working if the pings work.
Verifying the BGP Sessions Are Established
Purpose
Verify that the BGP sessions are up.
Action
From operational mode, enter the show bgp summary command.
user@host:C> show bgp summaryGroups: 1 Peers: 1 Down peers: 0 Table Tot Paths Act Paths Suppressed History Damp State Pending inet.0 2 0 0 0 0 0 Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped... 192.168.6.7 18 147 147 0 1 1:04:27 0/2/2/0 0/0/0/0
user@host:E> show bgp summaryGroups: 1 Peers: 1 Down peers: 0 Table Tot Paths Act Paths Suppressed History Damp State Pending inet.0 2 0 0 0 0 0 Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped... 192.168.40.4 17 202 202 0 1 1:02:18 0/2/2/0 0/0/0/0
Meaning
The output shows that both devices have one peer each. No peers are down.
Viewing Advertised Routes
Purpose
Checking to make sure that routes are being advertised by BGP.
Action
From operational mode, enter the show route advertising-protocol bgp neighbor command.
user@host:C> show route advertising-protocol
bgp 192.168.6.7inet.0: 5 destinations, 7 routes (5 active, 0 holddown, 0 hidden) Prefix Nexthop MED Lclpref AS path * 10.10.10.14/32 Self I * 192.168.6.7/32 Self I
user@host:E> show route advertising-protocol
bgp 192.168.40.4inet.0: 5 destinations, 7 routes (5 active, 0 holddown, 0 hidden) Prefix Nexthop MED Lclpref AS path * 10.10.10.8/30 Self I * 192.168.40.4/32 Self I
Meaning
The send-static routing policy is exporting the static routes from the routing table into BGP. BGP is advertising these routes between the peers because the BGP peer session is established.
