BGP Timmers - High CPU

[troiken84]

Hi everyone,
                              I have a BGP peer between two routers 2800. Works perfect. Theproblem is that only one of them is under my administration, the other belongs to anothermanager who lowers the timers below the recommended and increases the load on theCPU. You have been asked several times to change the timers, but he refuses, we find no command to force the other team a lift with default timers. Always wins the shortest time.

Greats

[fkam]

When the minimum acceptable hold-time is configured on a BGP router, a remote BGP peer session is established only if the remote peer is advertising a hold-time that is equal to, or greater than, the minimum acceptable hold-time interval. If the minimum acceptable hold-time interval is greater than the configured hold-time, the next time the remote session tries to establish, it will fail and the local router will send a notification stating "unacceptable hold time."

Do this command help to force the neighbor down with aggressive hold-time?

Sent from Cisco Technical Support iPhone App

[Florin Barhala]

Never heard of this one; always knew that shortest timers of the two BGP peers will be appliend on the next restart of BGP session.

Where did you get this, and for what appliance and what IOS?

[fkam]

http://www.cisco.com/en/US/docs/ios/iproute_bgp/command/reference/irg_bgp4.html#wp1144312

you can refer to the above URL for the command reference.

neighbor [ip-address | peer-group-name] timers keepalive holdtime [min-holdtime]

[Eehab Suliman]

The hold timer is a 2 byte unsigned interger that indicates the maximum ammount of time in seconds that may elapse between the receipt of successive KEEPALIVE or UPDATE message. The hold timer is a counter that increments from 0 to the hold time value.Receipt of a KEEPALIVE or UPDATE message causes the hold timer to reset to 0. If the hold timer for a particular neighbor were exceeded, the neighbor would be considered dead.

The BGP router negotiates with its neighbor to select the hold time at whichever value is lower - its own holdtimer or its neighbor's. The hold timer could be 0, in which case the hold timer and the KEEPALIVE timers are never reset. In other words, these timers never expire, and the connection is considered to be always up.If it isnt set to 0, the minimum hold timer is 3 seconds.

Note that the negotiation done for the BGP version number (by actually resetting the session until both nodes agree on a common version) and the one for the hold timer (use the minumum value of the two BGP speakers) are very different. In both cases, only the OPEN message is sent by each router. However, if the values dont match (incase of hold timer), the session is not reset.

Hope this helps.

Cheers,

Eehab