This is a draft proposing that an egress PE reroutes traffic, without waiting for BGP or IGP to re-converge, to another pre-calculated egress PE in a BGP-free core when the egress PE detects that the external NH is no longer reachable. Because traffic coming from the core is redirected back to the core, we propose using a specially advertised label to make sure that the traffic does not get re-routed multiple times into the core, thus avoiding loops.
This is a new version of the draft based on comments that we got so far The primary modification from the previous version is that repairing PEs are only egress PEs All comments are most welcomed Thanks Ahmed On 10/30/2011 4:26 PM, [email protected] wrote: > > A new version of I-D, draft-bashandy-idr-bgp-repair-label-03.txt has > been successfully submitted by Ahmed Bashandy and posted to the IETF > repository. > > Filename: draft-bashandy-idr-bgp-repair-label > Revision: 03 > Title: Scalable, Loop-Free BGP FRR using Repair Label > Creation date: 2011-10-30 > WG ID: Individual Submission > Number of pages: 13 > > Abstract: > Consider a BGP free core scenario. Suppose the provider edge BGP > speakers PE1, PE2,..., PEn know about a prefix P/p via the external > routers CE1, CE2,..., CEm. If the PE router PEi loses connectivity to > the primary path, it is desirable to immediately restore traffic by > rerouting packets arriving from the core to PEi and destined to the > prefix P/p to one of the other PE routers that advertised P/p, say PEj, > until BGP re-converges. However if the loss of connectivity of PEi to > the primary path also resulted in the loss of connectivity between PEj > and CEj, rerouting a packet before the control plane converges may > result in a loop. In this document, we propose using a repair label for > traffic restoration while avoiding loops. We propose advertising the > "repair" label through BGP. > > > > > > The IETF Secretariat >
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