[c-nsp] Conditional advertise-map

[Heath Jones]

Richard,
Is the arrangement that 36997 will provide a backup service for you, so its
a last resort to pull traffic through them? If that is the case, have you
tried prepending your advertisments towards 36997?
Also, I can see from global bgp they are not peering with eachother so its
not a situation where communities could help. The other solution is to
advertise a supernet to 36997 and break this in half and advertise both
subnets to 5511 (assuming you have a decent sized prefix >/24).

Perhaps you have already tried these solutions, or don't want to head that
way, i'm not sure :)

I'll check this one out actually (your advertise map) - its a good situation
to lab up and try!
If you are having problems because of the access lists trying to prevent
re-advertisment of routes, you could tag them when they come in instead (add
community), and filter them out on egress...

Hope this helps.







On 15 September 2010 09:08, Richard Mikisa <rmikisa at gmail.com> wrote:

> Hi all,
>
> I have a scenario where I have two upstreams ASN5511 and ASN36997.
> Both do send me a default route and I choose ASN5511 as the best path.
> All my outbound traffic is via ASN5511 and the return is distributed
> between the two. What I want however is to use an advertise map so I
> ONLY advertise my prefixes to ASN5511 so I only use his link but
> fail-over to advertising my prefixes to ASN36997 in the event ASN5511
> fails.
>
> I have created the the two route-maps to be matched NO_DEFAULT_FT and
> AS_LIST and configured as below.
>
> ## access list below is to avoid me feeding back to my up-streams
> the routes learned from other up-streams. That way I only advertise
> to the up-streams only prefixes from me and my down-streams.
>
> ip as-path access-list 10 deny ^5511_
> ip as-path access-list 10 deny ^12455_
> ip as-path access-list 10 deny ^36997_
> ip as-path access-list 10 permit .*
> !!
> ## Match against filter below. If anything from ASN5511 is available,
>
> ip as-path access-list 20 permit ^5511_
> !!
>
> route-map NO_DEFAULT_FT permit 10
> match as-path 20
> !!
> route-map AS_LIST permit 10
> match as-path 10
> !!
> neighbor 41.222.1.33 advertise-map AS_LIST non-exist-map NO_DEFAULT_FT
>
>
> Any ideas why it doesn't work.
>
> PS. Am working on drawing :)
>
> --
> cheers
> Richard
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