[c-nsp] RTBH and MPLS network

[Oliver Boehmer (oboehmer)]

Daemen, Seth, VF-NL <mailto:Seth.Daemen at vodafone.com> wrote on Friday,
November 25, 2005 2:38 PM:

> No I thinks not that RTBH behaves differently in MPLS networks.
> Butt I have configuration problems.
> 
> In the bgp configuration is a redistribute:
> 
> static route-map black-hole-trigger
> 
> The following route map is created:
> 
> route-map black-hole-trigger, permit, sequence 10
>   Match clauses:
>     tag 66
>   Set clauses:
>     local-preference 200
>     origin igp
>     ip next-hop 192.0.2.1
> 
> Static route:
> 
> ip route vrf VPN_Internet 2.2.2.2 255.255.255.255 Null0 tag 66
> 
> This works well the route 2.2.2.2 is advertised to the other routers
> also the local-preference is applied. Butt the problem is that the ip
> next-hop value is ignored. The next-hop address used is the ip address
> of the advertising router.

Aha, so you want to use this in an MPLS-*VPN* environment (three letters
do make a difference :)

You are right, the PE device in an MPLS-VPN will always do next-hop-self
when it redistributes the routes into the vpnv4 mesh, this is how
RFC2547bis works. You need to set the next-hop inbound or outbound at
your vpnv4 neighbor. Please be aware that a MPLS-VPN PE looks into the
global routing table to resolve the next-hop, so your route to 192.0.2.1
needs to be in the global table..

	oli