[c-nsp] Multiprotocol BGP with Cisco

[Steve Bertrand]

On 2010.04.16 14:29, Grzegorz Janoszka wrote:
> 
> Does anybody know how to receive both v4 and v6 prefixes onto one BGP
> session? There is a RFC document about it RFC2858 which is quite old (10
> years). I know some other vendors support it, as we have just got a peer
> which feeds us with both families prefixes on one BGP session, at least
> it tries, as we always see only one type of addresses - v4 either v6,
> never both. Any tricks to do it with Cisco? We use IOS XR (CRS-1's), but
> we may also get this feed on a "normal" IOS (6500).

You just have to activate the neighbor in both address-family, and have
the appropriate prefix lists and other policy config applied in both.

So, in router bgp context:

 neighbor cymru-bogon-v6 peer-group
 neighbor cymru-bogon-v6 description Cymru BOGON peers over IPv6
 neighbor cymru-bogon-v6 ebgp-multihop 255
 neighbor cymru-bogon-v6 update-source Loopback6
 neighbor 2607:F118:2:8000::2 remote-as 65332
 neighbor 2607:F118:2:8000::2 peer-group cymru-bogon-v6

addr-fam v4

  neighbor cymru-bogon-v6 route-map CYMRU-MAP-IN in
  neighbor cymru-bogon-v6 route-map BLOCK-ALL-OUT out
  neighbor 2607:F118:2:8000::2 activate

addr-fam v6

  neighbor cymru-bogon-v6 route-map CYMRU-MAP-IN in
  neighbor cymru-bogon-v6 route-map BLOCK-ALL-OUT out
  neighbor 2607:F118:1::C1 activate
  neighbor 2607:F118:2:8000::2 activate

...and for me it's easier to wrap the prefix-lists and other shared
policy stuff for both protocols in a single route-map:

route-map BLOCK-ALL-OUT permit 10
 match ip address prefix-list CYMRU-OUT
 match ipv6 address prefix-list CYMRU-OUT-V6

ip prefix-list CYMRU-OUT seq 5 deny 0.0.0.0/0 le 32
ipv6 prefix-list CYMRU-OUT-V6 seq 10 deny ::/0 le 128


# sh ip bgp sum
2607:F118:2:8000::2
                4 65332   40591   32654    67329    0    0 5d14h        6601
...

# sh bgp ipv6 un sum
2607:F118:2:8000::2
                4 65332   40592   32654   805424    0    0 5d14h       18706

Let me know if you want more context.

Steve