Hi WG, chairs,

I just read the latest version of this document. In general incorporating 
Algorithm into PCEP could be useful. While I have the below questions on this 
version and it would be helpful if they can be resolved before adoption.


1.       This document introduces the algorithm constraint in the LSPA object, 
which means the algorithm needs to be considered in the computation of the 
path. IMO this is important for computing a loop-free path. While the draft 
also says that the “the PCE MAY insert prefix SIDs with a different Algorithm 
in order to successfully compute a path.” Mixing SIDs with different algorithms 
in a path has the risk of loops. It is suggested that the document provides 
some analysis about such risk, and the example of scenarios where mixing SIDs 
with different algorithms is safe and desired.


2.       This is related to the first question. If the analysis shows that 
using SIDs with different algorithms in a path is not a good idea, then it 
would be unnecessary to carry the algorithm ID in SERO subobjects, instead 
carrying it as a path attribute would be enough.



3.       Assuming the answer to question 2 is YES, the SR-ERO and SRv6-ERO 
subobjects were defined with a fixed format (do not support sub-TLVs), this 
document introduces an additional optional field to those sub-objects, and use 
a new flag to indicate the existence of the new optional field. To my 
understanding this is not a usual approach for protocol extension. Usually a 
new Type needs to be defined for a new format. It would be necessary to 
understand the implication of using flags to indicate the modification to the 
format of an existing object.



4.       The term “SID Algorithm” in this document is different from that is 
used in the RFCs of SR/SRv6 IGP/BGP extensions, where it is called 
“SR-Algorithm”. Suggest to make them consistent.

Best regards,
Jie

From: Pce [mailto:[email protected]] On Behalf Of Dhruv Dhody
Sent: Friday, February 18, 2022 12:08 PM
To: [email protected]
Cc: [email protected]; Mahendra Negi <[email protected]>
Subject: Re: [Pce] WG Adoption of draft-tokar-pce-sid-algo-05

Hi WG,

A reminder to please respond to the WG adoption poll by Monday!

Please be more vocal. The silence makes it difficult to judge consensus.

Also, the IPR responses from Alex, Shuping, and Mahendra are missing still.

Thanks!
Dhruv & Julien

On Fri, Feb 4, 2022 at 10:44 PM Dhruv Dhody 
<[email protected]<mailto:[email protected]>> wrote:
Hi WG,

This email begins the WG adoption poll for draft-tokar-pce-sid-algo-05.

https://datatracker.ietf.org/doc/draft-tokar-pce-sid-algo/

Should this draft be adopted by the PCE WG? Please state your reasons - Why / 
Why not? What needs to be fixed before or after adoption? Are you willing to 
work on this draft? Review comments should be posted to the list.

Please respond by Monday 21st Feb 2022.

Have a great weekend.

Thanks!
Dhruv & Julien
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