[c-nsp] Modifying eBGP routes prior to exporting

[Steve Bertrand]

Hi everyone,

I think I'm overlooking something here, but can't pinpoint what.

>From a couple of eBGP peers, I'm receiving a few dozen routes which I
then pass along to specific PE routers via iBGP.

What I've done up until this point is accept the routes, and then tag
them with specific internal communities and next-hop on the way back out
to the iBGP peers.

I've run into an issue where I now need to send routes from different
external peers (from the same router) to the iBGP peers, so I can't
blindly "set" the attributes on all outgoing prefixes.

I could do this with multiple levels of route-maps and/or complex
prefix-lists on the outbound interface to the iBGP peers, but that
doesn't seem scalable.

What I'd like to do, is re-tag the routes inbound from the eBGP peers,
and then let the PE deal with things when the routes are received.

I've tried setting attributes via route-map as the prefixes are received
from the eBGP peers, but for some reason, they don't appear to stick
(per what the iBGP peer puts into it's FIB).

Could someone provide a config snip of what this kind of thing should
look like? When one does a "sh ip bgp route x.x.x.x", do the *incoming*
applied route-map set clauses appear here? If not, how to I check for them?

tcpdump is what I would normally use for something like this, but since
my internal BGP peers aren't affected by the announcing router, the BGP
updates on the wire are useless.

Steve