bgp update destroying transit on redback routers ?

Alexandre Snarskii snar at snar.spb.ru
Fri Dec 2 08:35:54 CST 2011


On Thu, Dec 01, 2011 at 04:56:43PM -0500, Jeff Tantsura wrote:
> Hi,
> 
> Let me take it over from now on, I'm the IP Routing/MPLS Product Manager 
> at Ericsson responsible for all routing protocols.
> There's nothing wrong in checking ASN in AGGREGATOR, we don't really want 
> see ASN 0 anywhere, that's how draft-wkumari-idr-as0 (draft-ietf-idr-as0-00) 
> came into the worlds.

This draft says that

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'.

-- 
In theory, there is no difference between theory and practice. 
But, in practice, there is. 




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