[c-nsp] BGP convergence in VRF vs. global routing table on7600router

Christian Bering CB at nianet.dk
Fri Oct 19 09:45:04 EDT 2007

Hi Rodney/Oliver,


>The bug I was referencing is:
>CPU Utilization at 100% in BGP Router process in 12.2(33)SRB1

We are seeing it on SRA and previous releases as well. 


>Ok. So PE1 will receive many withdraws and/or updates and needs to
>change the path from PE3 to PE2? Or will the next-hop stay the same?

The path will switch from one border router to another so the next-hop
will change accordingly.

[7301 being fast]

>.. and the RRs don't need to change any routing/forwarding 
>entries, this is control-plane only.

Thank God for that. :)

>Did you compare the convergence in a VRF to a convergence in an MPLS
>environment in the global table? I.e. did you label-switch the BGP
>packets in the global table, or used IP only?

Not tried label switching in the global table in the lab yet but it's on
the list as the next thing to try. The amount of label allocation should
be the same, though, right? So if that setup yields better convergence,
we're down to BGP converging better in the global routing table than in
a VRF. 

The whole point of my original questions was to get a feel for what to
expect in such a setup before actually trying it in the lab. What would
you expect to see?


 Christian Bering
 IP engineer, nianet a/s
 Phone: (+45) 7020 8730

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