[c-nsp] Prefer (outbound) certain bgp peer for AS or subnet ?

Tom Lanyon tom+c-nsp at oneshoeco.com
Mon Oct 14 23:08:03 EDT 2013


On 15/10/2013, at 12:47 PM, CiscoNSP List <cisconsp_list at hotmail.com> wrote:
> Hi,
> 
> Have 2 BGP peers with upstreams(full tables from each)  on an ASR1000, and we are seeing asymmetric routing for an AS (and /24) - Customer believes this is causing performance issues.
> 
> Egress traffic to this AS + /24 is going via upstream A (As it only has 3 AS's - Upstream B has 4 AS's to this destination), but return traffic is coming in via upstream B.
> 
> What is the best method to prefer upstream B egress (For AS or  /24)?  (But still maintain redundancy if upstream B should go down)?

How about using a route-map on the upstream B peer to set a higher local-preference for that originating AS (using a as-path access-list) or prefix (using an ip prefix-list)?

Tom




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