Re: [Lsr] draft-draft-peng-lsr-algorithm-related-adjacency-sid

Peter Psenak <ppsenak@cisco.com> Thu, 11 March 2021 09:56 UTC

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To: chen.ran@zte.com.cn, tonysietf@gmail.com
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From: Peter Psenak <ppsenak@cisco.com>
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Date: Thu, 11 Mar 2021 10:56:24 +0100
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Subject: Re: [Lsr] draft-draft-peng-lsr-algorithm-related-adjacency-sid
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Hi Ran, Tony,

I believe the primary use case for algorithm specific adj-SID is for the 
protected Adj-SID. The backup path of such Adj-SID follows the algo 
specific constraints.

thanks,
Peter




On 11/03/2021 09:51, chen.ran@zte.com.cn wrote:
> Hi Tony,
> 
>     Thanks for your comments. The reason why this draft is proposed is that:
> 
>     Currently, the current FA draft only defines that the algorithm 
> identifier is included as part of a  Prefix-SID advertisement,that maybe 
> not satisfy some scenarios where multiple algorithm share the same link 
> resource.
> 
>      For example, an SR-TE policy may be instantiated within specific 
> Flex-algo plane, i.e.,the SID list requires to include algorithm related 
> SIDs.  An algorithm-unware Adjacency-SID included in the SID list can 
> just steer the packet towards the link, but can not apply different QoS 
> policy for different algorithm.
> 
>       Another example is that the TI-LFA backup path computed in 
> Flex-algo plane may also contain an algorithm-unware Adjacency-SID, 
> which maybe also used in other SR-TE instance that carries other service.
> 
>      This document complement that the algorithm identifier can be also 
>   included as part of an Adjacency-SID advertisement for SR-MPLS.
> 
> 
> Best Regards,
> 
> Ran
> 
>