internet routing table in a vrf

Saku Ytti saku at ytti.fi
Fri Mar 8 17:23:24 UTC 2013


On (2013-03-08 16:40 +0000), Matt Newsom wrote:

> 2) forward plane (recursive lookup issues)
>           Most platforms program prefix's with associated labels slower so your base convergence will suffer. 

Do you have any reference you could share? What level of penalty per prefix
have you observed in each platform tested?

>In addition if you want to run PIC you will likely be left with a bit of custom engineering to make it  	work. VPN's hide the next hop behind the loopback of the PE so next hop failure awareness of an edge tie will be lost. If you can stomach the double lookup you can run per-vrf labels (per prefix isn't feasible on most platforms) and weight up your edge ties and force a bounce back to another PE, otherwise you will be stuck with bgp control plane based convergence with per-ce labels.

PIC is about converging each prefix at the same time. It does not make
statement where next_hop is pointing, is it loop0 (next-hop-self in INET)
or is it edge CE.

If your IGP carries all edge links, and you don't run next-hop-self, far
end PE can converge faster in INET scenario. But current efforts are not to
fix this, current efforts are to make the local PE do hitless repair when
arriving frame is pointing to dead edge interface.
It seems to be very rare to run INET in this way, majority don't carry edge
links in IGP and do run next-hop-self.

-- 
  ++ytti




More information about the NANOG mailing list