[c-nsp] BGP Convergance

[Oliver Boehmer (oboehmer)]

Chintan Shah <> wrote on Thursday, October 16, 2008 9:22 PM:

> Hi Guys,
> 
> I havd setup like this :
> 
> IPV4 :
> 
> PE ---P(RR) ------P(RR)-----PE
> 
> P is core router of each country and act as RR for IPV4.
> [...]
> VPNV4 peering from each PE is with seperate RR for MP-BGP....
> 
> Now question is , If I have BGP NHT enable on all P/VRR/PE I will
> have BGP convergance IGP + 5 sec NHT default if any remote PE
> fails.... 

sort of, depending on vpnv4 table size on PEs, you need to add some time
for table scans and stuff.. and this also assumes the alternate path (to
the "other" PE) is already imported in your VRF.

> But If I don't have NHT enable across all and has partial, Can
> Advertisement Interval be useful ? Assume RR are having BGP NHT
> enable but not some of PE. 

Yes, NHT on the RR would also help to speed up convergence for the cases
where not all PEs have NHT capability..
Have you tuned your IGP for faster convergence? 

	oli