best way to make bgp converge fast

[lcd_shouldit]

Hi guys , what would you do to make bgp converge fast , what is the best way or recommands ?

[John Blakley · Accepted solution]

It's never going to converge as fast as an igp (even ibgp is slow). The best way to do it is to change the timers. You can do this under the routing process:

router bgp 100

bgp timers 7 21

7 is the hello time and 21 is the hold time. This is different from the 60 and 180 that is the default. Once you change the timers, you possibly will need to clear the peering in order for the changes to take effect. The lower timers of the two peers are used. To see the current timer, you can do a "show ip bgp neighbor x.x.x.x" and look for the timers listed on the second line (I believe although could be incorrect).

HTH,
John

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[Joseph W. Doherty · Accepted solution]

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Posting

Something that may help with the initial BGP load, if there's numerous prefixes, is to enable PMTUD and increase the TCP receive window size.