[c-nsp] Explicit path

[Oliver Boehmer (oboehmer)]

Michel Renfer <> wrote on Monday, February 19, 2007 8:34 PM:

> Hi All
> 
> Assume the following (sample) topology with 7600/Sup720-3b, SFX7
> and MPLS encapsulation between all three 7600:
> 
> 
>  Video SRC ---2 x GE--- 7600 A =====10G====== 7600 ---2 x GE--- Video
> DST
>                            \                   /
>                             \                 /
>                              \               /
>                             1x GE          1x GE
>                                \           /
>                                 \         /
>                                  \       /
>                                   7600 C
> 
> Video SRC sends out encapsulated MPEG2 transportstreams with a
> total bandwidth of approx 1.1G. Traffic between 7600 A and B
> can be transported inside a L3 VPN or with two EoMPLS tunnels)
> 
> How can configure, that the traffic between Video SRC and Video
> DST only used the path between 7600 A and B and never over C?
> It is clear, that in case of a failure of the 10G link, the
> connection between SRC and DST will be broken.
> 
> Can someone give me the right pointer(s), how this can be
> configured?

Hmm, is there a requirement to put the traffic into a L3VPN/VRF, or can
it be in the global table? 

If you can put this into the global table, just do the following
1) set up a TE tunnel with an explicit-path over A-B
2) statically route the destination over the tunnel and use a floating
static Null0 route to drop the traffic in case the tunnel goes down
(using PBR on 7600-A to send traffic over the tunnel doesn't work until
12.2SRB)

If the interfaces on 7600A and B are in a VRF, you need to play around
with the BGP next-hop as follows:
1) set up a TE tunnel as before, but enable LDP on it
2) configure a new loopback interface (/32) on 7600B, and route this one
statically to the tunnel (with a floating Null0 route to drop the
traffic, as before)
3) use an inbound route-map on the vpnv4 iBGP connection to modify the
next-hop of the vpnv4 video-dest-prefix to the new /32

Would this work?

	oli