[c-nsp] BGP route won't advertise

[Jason Lixfeld]

I presume a.b.c.0/22 is the prefix you are receiving from your customer and AS1xx7 is your customer's AS?

Is there any outbound route policy on R1 facing your transit provider there which might be preventing the re-advertisment?

--

Sent from my mobile device


On 2013-02-27, at 6:24 PM, Jerry Bacon <wireless at starbeam.com> wrote:

> 
> I have the following layout:
> 
> Internet <--> R1 <--> R2 <--> R3 <--> R4 <--> Internet
> 
> I have a customer attached to R3 for whom I am doing transit.
> 
> R1, R2, & R4 are GSR 12008 running 12.0(32)S14
> R3 is a 3825 running 12.3(11)T5
> 
> At R4 everything is fine:
> 
> R4#sh ip rou a.b.c.0
> Routing entry for a.b.c.0/22, supernet
>  Known via "bgp 1xx77", distance 200, metric 0
>  Tag 11xx1, type internal
>  Last update from x.y.z.242 1w5d ago
>  Routing Descriptor Blocks:
>  * x.y.z.242, from x.y.z.242, 1w5d ago
>      Route metric is 0, traffic share count is 1
>      AS Hops 1, BGP network version 0
>      Route tag 11xx1
> 
> R4#sh ip bgp a.b.c.0/22
> BGP routing table entry for a.b.c.0/22, version 40711009
> Bestpath Modifiers: always-compare-med, deterministic-med
> Paths: (1 available, best #1)
>  Advertised to update-groups:
>     5
>  11xx1
>    x.y.z.242 (metric 143104) from x.y.z.242 (x.y.z.242)
>      Origin IGP, metric 0, localpref 100, valid, internal, best
> 
> 
> However, at R1 the same route won't advertise:
> 
> R1#sh ip rou a.b.c.0
> Routing entry for a.b.c.0/22, supernet
>  Known via "bgp 1xx77", distance 200, metric 0
>  Tag 11xx1, type internal
>  Last update from x.y.z.242 16:03:41 ago
>  Routing Descriptor Blocks:
>  * x.y.z.242, from x.y.z.242, 16:03:41 ago
>      Route metric is 0, traffic share count is 1
>      AS Hops 1, BGP network version 0
>      Route tag 11xx1
> 
> R1#sh ip bgp a.b.c.0/22
> BGP routing table entry for a.b.c.0/22, version 406152
> Bestpath Modifiers: always-compare-med, deterministic-med
> Paths: (1 available, best #1)
>  Not advertised to any peer
>  11xx1
>    x.y.z.242 (metric 143360) from x.y.z.242 (x.y.z.242)
>      Origin IGP, metric 0, localpref 100, valid, internal, best
> 
> None of the issues that I have been able to find that might cause this behaviour seem to apply. Any ideas on what more to look for?
> 
> -- 
> Jerry Bacon
> Senior Network Engineer
> 
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