Re: [Lsr] LSR WG Adoption Call for "Algorithm Related IGP-Adjacency SID Advertisement"

Hi,

I don't support the adoption of this document. 

It seems this document aims to introduce per Flex-Algo Adj-SID to SR-MPLS, its typical use case is to provide protection path with Flex-Algo constraints for Adj-SID of a particular Flex-Algo, which is described in the case 3 of section 3. 

However, section 3 and section 5 shows that it also aims to introduce further changes to the usage and operation of Flex-Algo, which is to provide resource reservation based on Flex-Algo. IMO these changes to Flex-Algo deserves further discussion and is not only related to the per Flex-Algo Adj-SID extension.

Here are some comments about this change to Flex-Algo:

1. Flex-Algo defines the constraints for path computation in a distributed manner, it is not for resource reservation. 

2. Reserving resources for each Flex-Algo on a link does not make sense. The correlation between Flex-Algo and the network links is based on administrative groups (color), and the color of the link may or may not be included in the Flex-Algo definition. To follow the color based link correlation, a more practical approach would be to use Flex-Algo with L2 bundle as defined in draft-zhu-lsr-isis-sr-vtn-flexalgo, which uses color to correlate the L3 link and the L2 member link to a Flex-Algo, this avoids the extension for per-FlexAlgo resource reservation. 

3. The Flex-Algo link TE attributes are advertised using ASLA, the TE attributes are shared by all Flex-Algos which include the link according to the FAD, and based on previous discussion, it seems there is no intention to introduce per Flex-Algo ID link attributes.

Best regards,
Jie

> -----Original Message-----
> From: Lsr [mailto:lsr-bounces@ietf.org] On Behalf Of Christian Hopps
> Sent: Thursday, May 27, 2021 4:57 AM
> To: lsr@ietf.org
> Cc: chopps@chopps.org
> Subject: [Lsr] LSR WG Adoption Call for "Algorithm Related IGP-Adjacency SID
> Advertisement"
> 
> 
> Hi Folks,
> 
> This begins a 2 week WG Adoption Call for the following draft:
> 
> https://datatracker.ietf.org/doc/draft-peng-lsr-algorithm-related-adjacency-sid
> /
> 
> Please indicate your support or objections by June 9th, 2021
> 
> Authors, please respond to the list indicating whether you are aware of any IPR
> that applies to this draft.
> 
> Thanks,
> Acee and Chris.
> 
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