BGP failover configuration on a BGP peer

The default BGP failover time is 2-3 minutes. However, you can reduce this time by changing some parameters on both ends of the BGP session.

You must make the change in mn-conf(1) on the MidoNet side, and the remote end BGP peer configuration.

The basic BGP timers are 'keepalive' and 'holdtime'. By default, keepalive timer is 60 seconds. The hold-down timer is, by convention, 3 times the keepalive interval, 180 seconds. You can go as low as 1 and 3 seconds for these values, but keep in mind that this may potentially result in the BGP session flapping.

Another important BGP timer that you can tweak is the BGP 'connect_retry' timer, also called the 'connect' timer. You can use this timer to set the amount of time between retries to establish a connection to configured peers which have gone down for some reason.

The example below shows how to reduce the default BGP values to 1, 1, and 3 seconds, for keep-alive, hold-time, and connect-retry, respectively, on the BGP peer’s session end (e.g. Quagga or Cisco):

neighbor 192.0.2.1 timers 1 3
neighbor 192.0.2.1 timers connect 1

To match those settings you would have to set the following parameters on the MidoNet end of the BGP session:

agent {
    midolman {
        bgp_connect_retry : 1s
        bgp_holdtime : 3s
        bgp_keepalive : 1s
    }
}
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