Re: [Idr] draft-bashandy-idr-bgp-repair-label-03

[Ahmed Bashandy <[e-mail]>]

The correct reference is for PE-CE link protection is the paper titled
"Achieving sub-50 milliseconds recovery upon bgp peering link failures,"
published in IEEE/ACM Transactions on Networking, 15(5):1123--1135, 2007

Thanks

Ahmed

On 4/2/2012 4:36 PM, Ahmed Bashandy (bashandy) wrote:
>
> The concept of PE-CE protection is not new. AFAIK it, was introduced
> in the paper titled "Achieving sub-second IGP convergence in large IP
> Networks" published in ACM SIGCOMM Computer Communication Review,
> 35(3):33-44, July 2005. the idea of having a special label was also
> mentioned in the paper
>
> draft-bashandy-idr-bgp-repair-label-03 specifies PE-CE protection
> using repair label in a very concrete manner so that it can be
> implemented. That is why draft-bashandy-idr-bgp-repair-label-03 is a
> standards track draft. For example some of the concrete information in
> draft-bashandy-idr-bgp-repair-label-03 :
> - proposes advertising the repair label as an optional non-transitive
> attribute.
> - specifies the syntax of the proposed attribute section 3.1.2.
> - Unambiguously specifies the semantics of the repair label and the
> forwarding behavior on the nodes participating in the scheme
> - recommends using per-CE repair label allocation
>
> In addition, the loop prevention specified in
> draft-bashandy-idr-bgp-repair-label-03 is independent of the method of
> choosing a repair path. For example, the repair path can be ECMP, 
> best external, or some other future mechanism.
>
> Besides, the concept of repair label is very general and can be used
> in other BGP FRR mechanisms such as draft-bashandy-bgp-edge-node-frr-02.
>
> Thanks
>
> Ahmed
>
>
> On 3/26/2012 1:20 AM, Xuxiaohu wrote:
>>
>> Hi co-authors of the abvove draft,
>>
>>  
>>
>> In you draft, it said"As usual, each PE allocates a local label for
>> each prefix it can reach through an external neighbor CE. This is the
>> primary label used for normal traffic forwarding." and "To provide
>> repair path information to all PEs, the PE also allocates a repair
>> label to the prefix if it can reach that prefix via an external
>> neighbor."
>>
>>  
>>
>> Does it mean the external path which the repair label is associated
>> with is a best external path? If so, could you explain what's
>> difference between the above draft and this draft
>> (http://tools.ietf.org/html/
>> <http://tools.ietf.org/html/draft-xu-idr-best-external-loop-avoidance-00>draft-xu-idr-best-external-loop-avoidance-00
>> <http://tools.ietf.org/html/draft-xu-idr-best-external-loop-avoidance-00>).
>>
>>  
>>
>> BR,
>>
>> Xiaohu
>>
>>
>>
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