BGP Timers

BGP Timers

BGP peers send keepalive message(default interval is 60 seconds) to inform each other of their availability.

They advertise their hold-time interval(default value is 180 seconds) when establishing BGP session.

Peers may advertise different hold-time interval.Lower values are used.

We can change the keepalive and hold-time intervals in BGP configuration mode  using the command timers bgp <keepalive> <holdtime>

Or per neighbor

Neighbor <ip> timers <keepalive> <holdtime>

Here is the example

First router

router bgp 1

 no synchronization

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 10.10.10.1 remote-as 1

 neighbor 10.10.10.1 timers 15 45

R6#show ip bgp nei 10.10.10.1

BGP neighbor is 10.10.10.1,  remote AS 1, internal link

  BGP version 4, remote router ID 192.168.1.1

  BGP state = Established, up for 00:03:41

  Last read 00:00:00, last write 00:00:00, hold time is 30, keepalive interval is 10 seconds

  Configured hold time is 45,keepalive interval is 15 seconds  Minimum holdtime

Second Router

router bgp 1

 no synchronization

 bgp log-neighbor-changes

 timers bgp 10 30

 neighbor 10.10.10.6 remote-as 1

 no auto-summary

R1#show ip bgp neighbor

BGP neighbor is 10.10.10.6,  remote AS 1, internal link

  BGP version 4, remote router ID 192.168.2.6

  BGP state = Established, up for 00:04:36

  Last read 00:00:05, last write 00:00:05, hold time is 30, keepalive interval is 10 seconds

  Configured hold time is 30,keepalive interval is 10 seconds, Minimum holdtime