Cisco BGP-4 Command and Configuration Handbook

8-31 neighbor { ip-address peer- group - name } timers keepalive holdtime

Syntax Description:

• ip-address Neighbor's IP address.

• peer-group-name Name of the peer group. See section 8-19.

• keepalive 1 to 4,294,967,295 seconds.

• holdtime 1 to 4,294,967,295 seconds.

Purpose: Keepalive and holdtime are common among IP routing protocols. The keepalive time indicates how often a router sends a keepalive message to a neighbor to inform the neighbor that the router is still alive and well. The holdtime is used as a deathwatch. If a keepalive message is not received within the holdtime, the neighbor is declared dead, and the session is terminated . The default value for the keepalive time is 60 seconds. The holdtime is 3 times the keepalive time, or 180 seconds. Generally, these values do not need to be changed. If you do change them, it is a good rule to make the holdtime equal to 3 times whatever keepalive value you use. Of course, the holdtime should always be greater than the keepalive time. A good practice to follow is to configure the same keepalive and holdtimes on both sides of the link.

Cisco IOS Software Release: 12.0

Configuration Example: Changing the Keepalive and Holdtime Values

Change the default settings for keepalive and holdtime to 50 and 150 seconds, respectively:

Router A router bgp 1 neighbor 10.1.1.2 remote-as 2 neighbor 10.1.1.2 timers 50 150 no auto-summary

Verification

Verify the new keepalive and holdtime values by using the show ip bgp neighbors command:

rtrA# show ip bgp neighbors BGP neighbor is 10.1.1.2, remote AS 2, external link Index 1, Offset 0, Mask 0x2 BGP version 4, remote router ID 10.1.1.2 BGP state = Established, table version = 7, up for 00:53:07 Last read 00:00:08, hold time is 150, keepalive interval is 50 seconds Minimum time between advertisement runs is 30 seconds Received 375 messages, 0 notifications, 0 in queue Sent 343 messages, 0 notifications, 0 in queue Prefix advertised 0, suppressed 0, withdrawn 0 Connections established 20; dropped 19 Last reset 00:53:28, due to User reset 6 accepted prefixes consume 192 bytes, maximum limit 8 Threshold for warning message 75% 0 history paths consume 0 bytes Connection state is ESTAB, I/O status: 1, unread input bytes: 0 Local host: 10.1.1.1, Local port: 11015 Foreign host: 10.1.1.2, Foreign port: 179

Troubleshooting

1. Verify that the BGP neighbors are in the Established state using the show ip bgp neighbors command.

   If the neighbor relationship is not in the Established state, see section 8-23.

2. Verify the keepalive and holdtime values using show ip bgp neighbors.