[c-nsp] Cisco ASR BGP within the box question

Tue Aug 3 08:13:15 UTC 2010

thanks oliver, 

will try and keep you (and the list) updated.

-steven

-----Original Message-----
From: Oliver Boehmer (oboehmer) [mailto:oboehmer at cisco.com] 
Sent: Tuesday, August 03, 2010 8:06 AM
To: Glogger Steven, SCS-NIT-NIO-PIO-DNW-NEO; cisco-nsp at puck.nether.net; nanog at nanog.org
Subject: RE: [c-nsp] Cisco ASR BGP within the box question

Steven,

> just a short question (related to a quite new feature from cisco).
> with the new cisco ASR software (15.0(1)S - released some days ago) it
is
> able to do BGP on the same box.
> we need this feature because we use the VASI interfaces to bring and
filter
> traffic from one VRF to another VRF and performing firewalling (ZBF).
> 
> basically we have on the box:
> [VRF_A via vasileft1]--[VRF_B via vasiright1]
> 
> and the box itself speaks BGP on VRF_B with some RR's:
> [ASRBox] ---- (RR) ---- [anotherbox]
> 
> the fun part is, if you want to announce (e.g. 0.0.0.0/0) from VRF_B
> (announced from anotherbox) to VRF_A it should be possible now with
that new
> feature.
> 
> according to BGP I need to configure the VRF_A peer as
route-reflector-
> client so the routes from the anotherbox get reflected via RR to
VRF_B.
> 
> but, it seems that the router itself needs to be tricked, since he
thinks
> that both peers are in the same route-reflector cluster ("DENIED due
to:
> reflected from the same cluster"):
>[...] 
> so, does anyone knows a nice hidden command to disable this
cluster-checking
> on a per-peer basis or so?

I'm not aware of an enhancement to set the cluster-id on a per-vrf
basis, it is currently global.. But you could turn this into an eBGP
session using local-as, for example

router bgp 65501
 address-family ipv4 vrf IABIP-
  neighbor 10.0.0.2 remote-as 65502
  neighbor 10.0.0.2 local-as 65503 no-prepend replace-as
 address-family ipv4 vrf IACYP-
  neighbor 10.0.0.1 remote-as 65503
  neighbor 10.0.0.1 local-as 65502 no-prepend replace-as

not sure if this helps..

	oli