[c-nsp] Filtered BGP routes

[Peter Rathlev]

On Sun, 2007-12-16 at 08:01 +1100, James wrote:
> > As Robert writes, you can do it with the completely similar command:
> > "show ip bgp neighbors IP_ADDRESS received-routes". Just remember that
> > you have to enable inbound soft reconfiguration ("neighbor IP_ADDRESS
> > soft-reconfiguration inbound"). Beware that this makes your router store
> > a copy of all the prefixes received from this neighbor, and that may use
> > a lot of memory.
> 
> Not entirely true. Recent versions of bgp support the route refresh option.
> This sends a request to the peer to resend it's prefixes when a
> router#clear ip bgp soft in
> is issued.
> 
> The only caveat is that both sides of the bgp conversation have to
> support route refresh.  A
> router#show ip bgp neighbor
> will indicate whether it is supported or not.

I don't see where you're going. Route refresh is a nice feature and all,
but doesn't solve the problem at hand. You can't see filtered routes
without inbound soft reconfig, route refresh or not. And soft reconfig
stores a local copy of the received routes, route refresh or not. So I'm
a little confused as to what is "not entirely true"?

Of course inbound soft reconfig was the "old" method of not tearing down
BGP sessions when applying new filters, and thus could do a thing
similar to what route refresh does, but that's not what the thread was
about. :-)

Regards,
Peter Rathlev