bgp update destroying transit on redback routers ?

Christopher Morrow morrowc.lists at
Fri Dec 2 21:06:31 UTC 2011

On Fri, Dec 2, 2011 at 9:35 AM, Alexandre Snarskii <snar at> wrote:

> This draft says that

...note it's a DRAFT, not a STANDARD...

> If a BGP speaker receives a route which has an AS number of zero in the
> AS_PATH (or AS4_PATH) attribute, it SHOULD be logged and treated as a
> WITHDRAW. This same behavior applies to routes containing zero as the
> Aggregator or AS4 Aggregator.
> but observed behaviour was more like following:
> If a BGP speaker receives [bad route] it MUST close session immediately
> with NOTIFICATION Error Code 'Update Message Error' and subcode 'Error with
> optional attribute'.

hence this old behavor

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