bgp update destroying transit on redback routers ?

Jeff Tantsura jeff.tantsura at
Thu Dec 1 21:56:43 UTC 2011


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.

To my knowledge - the only vendor which allows changing ASN in AGGREGATOR is Juniper, see "no-aggregator-id", in the past I've tried to talk to Yakov about it, without any results though. 
So for those who have it configured - please rethink whether you really need it.

As for SEOS - understanding that this badly affects our customers and not having draft-ietf-idr-error-handling fully implemented yet, we will temporarily disable this check in our code.
Patch will be made available.

Please contact me for any further clarifications.


P.S. Warren has recently  included AGGREGATOR in the draft, please see

 2. Behavior
   This document specifies that a BGP speaker MUST NOT originate or
   propagate a route with an AS number of zero.  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.

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