Wednesday, June 20, 2018

MP-iBGP route reflector policy issue(?)

Hi, been banging my head for a bit. I decided to lab up some L3VPNs after a while and do something new, while I'm at it.

https://imgur.com/a/rn0oJ9u

Both PEs just have a couple loopbacks stuck in the VRFs I'm pulling through to the other side. The P routers double as RRs with different cluster IDs, both have a session to each PE. The peerings are VPNv4 MP-iBGP. Now the problem that I've come across is that I want each PE to prefer prefixes advertised by one RR (P1, in my case). I've assumed (can't find much in way of documentation for attribute manipulation via policies on RRs, much less with VPNv4 peerings...) that to that end, I'd need to set up a route-map on P1 facing out towards the clients, setting the LP to 200 (tried MED, too). The prefixes, however, arrive at the PEs with the default LP of 100.

Tried to set MED in case I'm crazy, but no joy there either. This is on c7200 15.2(4)M7 in GNS3. I'm due to try this on colleagues VIRL/EVEng setup and might get lab access to actual hardware as well, but neither can happen right now. Also at new job so no access to core yet and even then, they don't run dual RRs...

Am I crazy or is it actually supposed to be done this way (and work)? Thanks



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