[c-nsp] BGP not advertising supernet to RR's

[James Bensley]

On 27 September 2017 at 17:44, CiscoNSP List <CiscoNSP_list at hotmail.com> wrote:
>
> To answer my own question, I tested this by trying a /22 within the supernet statically routed to a next hop on the router....community tags applied correctly, prefix advertised to RR's, so then I tried routing the /22 to Null0 (Expecting it not to work - but it did? Community tags applied/RR advertisement worked).....so I tried the supernet again to null0, and again, it didnt get tagged with the correct communities, and no RR advertisement.....Need to revisit this again tomorrow, but the route-map / PL "looks" ok to me...matching the /20 le 32 - If the le 32 was the issue, you'd think the /22 would be impacted? I cant see anything else that would be causing the /20 to not get tagged though?
>
>
> Any suggestions are greatly appreciated.

What about when you set the static /20 route to a valid next-hopt IP,
not Null0? (e.g. a static route of a.fake.ip.addr which points to
Null0, and your /20 which points to a.fake.ip.addr).

Have you taken the usual action of performing a "soft clear out" on
the PE or "soft clear in" on the RR?

The /20 to Null0 route, do you see that on the PE in the output of
"show bgp ipv4 uni nei x.x.x.x advertised-routes" ?

If you see the /20 in the "advertised-routes" output, what do you see
on the RR when using "debug bgp ipv4 unicast updates pe.ip.addr.ess"
on the RR? (you will need to "flap" that static route).

If you don't see the /20 on in the "advertised-routes" output, what do
you see on the PE when using "debug bgp ipv4 unicast updates" [1] when
you remove and then re-add the static route, re-triggering the BGP
UPDATE?

Can you capture the BGP UPDATE message on the wire?

Can you replicate this in the lab, have you, what were the result?

Cheers,
James.

[1] Note that this could cause a lot of debugging output