VSP9k export BGP routes to ISIS / SPBm with BGP community filter

[yves_weyns]

Hi all,

As described above we are trying to get the routes from BGP transmitted by ISIS to the rest of the network. This ofc works, however there is one major thing to take into consideration. We need to apply metrics / weight / cost / ... to the ISIS routes in order to avoid routing loops. We want to use BGP communities in order to filter and tried the following:

The communities are being send by the BGP peer:
The total number of routes is 2

NETWORK/MASK PEER REM ADDR NEXTHOP ADDRESS ORG LOC PREF
--------------------------------------------------------------------------------
4.4.4.0/24 10.90.103.207 10.90.103.207 IGP 100
AS_PATH: (65200)

The community list is created:
================================================================================
Community List - GlobalRouter
================================================================================
community-list id: 1
memberId: 65200 permit 65001:1
community-list id: 2
memberId: 65200 permit 65001:2


We have the route-maps in place:
route-map "bgp-comm" 1
enable
match community 10

set ip-preference 20
set metric 20
set local-preference 20
set weight 20
route-map "bgp-comm" 2
enable
match community 11
set metric 10
set ip-preference 10
set local-preference 10
set weight 10
route-map "test" 1
enable

With this setup we cannot see the route on the other router. When we disable the match on the community we do, but we then loose the filter ability. Has anyone created such a setup and can give some pointers?

kr
Yves

[yves_weyns]

Hi Ludo,

Thanks for the reply, but it does not quite help us out here.
What we need is filters that when we export a BGP route into ISIS we can add a metric. This metric is different based on the community that is attached to the BGP route.

Also, we are doing this with one VSP 9k and one ERS 8k.

kr
Yves

[Ludovico_Steven]

So, if you are simply trying to prevent a BGP route, already redistributed into ISIS by one of your VSP9000s, to get redistributed back to BGP (where it came from) from the other VSP9000s, then we have some slides decks showing how to tackle this. I have attached 2; the 1st one shows how we recommend doing things with VOSS VSPs where we have the ability to leverage ISIS External routes (you would be looking at slides 130-146). Alas, the VSP9000 does not support ISIS External routes as these were introduced on VOSS later on. So also attached is an older version of the same deck, which should only be used for VSP9000 (slides 152-189). Note that these decks are by no means the only way of doing things, they just show a number of use cases and examples of what is possible, which can then be adapted as needed.
Another thing to keep in mind is that VOSS and the VSP9000 only support iBGP on GRT (not on VRFs), so doing the same thing on a VRF is a complete different challenge; but as you are already playing with local-pref I trust your use case is on GRT. On a positive note the next VOSS 8.1 will support iBGP on VRF as well.
Let us know if this helps you find the right config.
Best regards
Ludovico Stevens