Configure Listen Limit on BGP Dynamic Peer

XCO enables configuration of global router BGP listen-limit which depends on the router BGP dynamic peer scale requirements. Listen-limit configuration defined under the “global router bgp” context signifies the maximum number of dynamic BGP peers that can be operational across the VRFs in the SLX.

About this task

Follow this procedure to configure listen limit.

Default value of the global router BGP listen-limit is 100, which you can modify with any value in the range of 1-2400.

Note

For the SLX version 20.3.4 or lower, the supported listen-limit range is <1-1024>.
For the SLX version 20.4.1 or higher, the supported listen-limit range is <1-2400>.

Ensure that the listen-limit configuration defined at the “dynamic peer listen-range” level is less than or equal to the “listen-limit” configuration defined under the “global router bgp”.

The maximum number of dynamic BGP peers is limited to the SLX default (100), when provisioned through XCO.

Configure the new fabric setting for each fabric using the bgp-dynamic-peer-listen-limit command. The fabric setting is applicable for Clos and small data center fabrics, and for all types of devices (leaf, border-leaf, spine, super-spine).

Configure the bgp-dynamic-peer-listen-limit value on all the devices of fabric when you configure the fabric.

You can configure the bgp-dynamic-peer-listen-limit value on an already provisioned fabric. For the new value to be effective, run the fabric configure command, followed by the efa fabric setting update command. This enables you to configure bgp-dynamic-peer-listen-limit on the existing pre-2.5.0 deployments.

Note

You can only increase (but not decrease) the value of bgp-dynamic-peer-listen-limit on an already provisioned fabric.

Procedure

To configure listen limit on BGP dynamic peer, run the following command:
```
efa fabric setting update –name <fabric-name> --bgp-dynamic-peer-listen-limit <1-2400>
```

Verify the switch configuration on the SLX device.

Rack1-Device1# show running-config router bgp router bgp local-as 4200000000 capability as4-enable fast-external-fallover listen-limit 200 neighbor 10.20.20.5 remote-as 4200000000 neighbor 10.20.20.5 next-hop-self address-family ipv4 unicast network 172.31.254.139/32 network 172.31.254.226/32 maximum-paths 8 graceful-restart ! address-family ipv6 unicast ! address-family l2vpn evpn graceful-restart ! !	Rack1-Device2# show running-config router bgp router bgp local-as 4200000000 capability as4-enable fast-external-fallover listen-limit 200 neighbor 10.20.20.4 remote-as 4200000000 neighbor 10.20.20.4 next-hop-self address-family ipv4 unicast network 172.31.254.115/32 network 172.31.254.226/32 maximum-paths 8 graceful-restart ! address-family ipv6 unicast ! address-family l2vpn evpn graceful-restart ! !

Rack1-Device1# show running-config router bgp
router bgp
 local-as 4200000000
 capability as4-enable
 fast-external-fallover
 listen-limit 200
 neighbor 10.20.20.5 remote-as 4200000000
 neighbor 10.20.20.5 next-hop-self
 address-family ipv4 unicast
  network 172.31.254.139/32
  network 172.31.254.226/32
  maximum-paths 8
  graceful-restart
 !
 address-family ipv6 unicast
 !
 address-family l2vpn evpn
  graceful-restart
 !
!

Rack1-Device2# show running-config router bgp
router bgp
 local-as 4200000000
 capability as4-enable
 fast-external-fallover
 listen-limit 200
 neighbor 10.20.20.4 remote-as 4200000000
 neighbor 10.20.20.4 next-hop-self
 address-family ipv4 unicast
  network 172.31.254.115/32
  network 172.31.254.226/32
  maximum-paths 8
  graceful-restart
 !
 address-family ipv6 unicast
 !
 address-family l2vpn evpn
  graceful-restart
 !
!