[quagga-users 11245] Re: Routing one special AS through a backup provider

Steve Bertrand steve at ibctech.ca
Fri Dec 11 13:40:08 GMT 2009


gal.9430 at googlemail.com wrote:
> Hi,
> 
> I've two upstreams, let's assume upstream 1 (AS1111) and upstream 2
> (AS2222). Normaly I use AS1111 to route all traffic out, AS2222 is only
> backup. Now I want to route only one special AS (AS3333) through our
> backup upstream.
> 
> I have tried the following config:
> 
> neighbor 1.1.1.1 remote-as 1111
> neighbor 1.1.1.1 description Main Upstream
> neighbor 1.1.1.1 soft-reconfiguration inbound
> neighbor 1.1.1.1 prefix-list ipv4-in-filter in
> neighbor 1.1.1.1 prefix-list ipv4-out-filter out
> neighbor 1.1.1.1 route-map mainTransit-in in
> neighbor 1.1.1.1 route-map mainTransit-out out
> 
> neighbor 2.2.2.2 remote-as 2222
> neighbor 2.2.2.2 description Backup Upstream
> neighbor 2.2.2.2 soft-reconfiguration inbound
> neighbor 2.2.2.2 prefix-list ipv4-in-filter in
> neighbor 2.2.2.2 prefix-list ipv4-out-filter out
> neighbor 2.2.2.2 route-map backupTransit-in in
> neighbor 2.2.2.2 route-map backupTransit-out out
> 
> route-map mainTransit-in permit 10
>  set community xxxx:xxxx additive
>  set local-preference 190
> 
> route-map mainTransit-out permit 10
>  match as-path 1
> 

If I understand your problem correctly, then you need to remove the
'match as-path 2' from backupTransit-in route-map:

> route-map backupTransit-in permit 10
>  set community xxxx:xxxx additive
>  match as-path 2

[snip]

> ip as-path access-list 2 permit ^2222_3333
> 
> "as-path access-list 2" does what I want. Traffic to AS3333 is now going
> through the backup provider. Now the problem is, that I only receive the
> announced prefixes from AS3333 from our backup provider and not the
> whole routing table. 

...because you apply the same as-path ACL to both the in and out
relationships with the peer (from what I can tell).

Steve


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