Bgp slow peer for PE/RR

Question

Hi,
Recently came into one concenpt, " bgp slow peer " for PE or RR
In our network we have 2 no RR & all RR are having ibgp with PE router
So, in that above case the feature will give any faster convergence
What are the pros/cons of this feature
Br/subhojit

Answer 1

Hi,
Slow peer in BGP is a feature that works in conjunction with BGP update groups. Update groups are formed automatically in BGP for iBGP and eBGP neighbors. Neighbors with the same outbound policy end up in the same update group. The BGP update is then created once and replicate to all other neighbors in the update group. This is more efficient than creating one BGP update for each neighbor seperately. Slow peer feature will detect if a peer is slowing in processing received BGP messages. That peer will be moved out of the update group. The reason is that one slow peer can slow down the whole update group, which has potentially many neighbors. So, the more neighbors in an update group, the effect will be greater of the slow peer feature. In the end, slow peer feature makes convergence go faster, if there is one or more slow BGP peer. This feature can benefit BGP everywhere, on RR, PE or any BGP router. Remember, the more BGP neighbors with the same outbound policy, the greater the effect can be. Likely, the RRs do not have different or any outbound policy on the iBGP sessions, so there it can be very useful. Also, it might benefit the PE-CE sessions, if you have more than one per VRF at least.
Thanks,
Luc