Hi Daniele, 

Thank you for the valuable comments, we have updated the document to -12 and 
addressed the following comments. 

For the general question on hierarchical PCEs, we believe the point is valid – 
from this document we prefer to clarify that we don’t have the opinion ‘peer 
sync is better than hierarchy’ but we only ‘keep this doc focusing on the peer 
sync scenario’. The text is updated accordingly, please check if there is 
further concerns.

Best wishes,
Haomian

-----邮件原件-----
发件人: Daniele Ceccarelli via Datatracker <[email protected]> 
发送时间: 2025年2月3日 17:08
收件人: [email protected]
抄送: [email protected]; [email protected]
主题: Opsdir early review of draft-ietf-pce-state-sync-11

Reviewer: Daniele Ceccarelli
Review result: Has Nits

Hello,

please find below my OPS-DIR review.
The draft is well written and easy to read but would benefit from the 
explanation of some decisions taken in the design and statements provided 
without a justification. I really like the extensive usage of examples, which 
clearly explain situations that might be hard to be understood using the text 
only.

The synchronization among multiple stateful PCEs and avoidance of computation 
loops is for sure a valid use case but i was wondering why the hierarchical PCE 
approach is not taken into account (it's also explicitly said in the document).
Wouldn't it be easier to have a hierarchical PCE coordinating the various PCEs 
instead of having them talking to each others? I guess the authors have done 
this analysis already and providing a comparison between the two approaches in 
the draft would be beneficial.

Some more comments related to specific parts of the text below:

- Abstract: For completeness, a stateful PCE can be used also for GMPLS, not 
only for MPLS-TE. - Intro: "he hierarchical PCE use case is out of the scope of 
this document." see my general comment above. - Intro, figure 1: "when there is 
a change in LSP1, the PCC should report to PCE1.  From PCE2's perspective, PCC1 
reporting the update of LSP1 to PCE2 is lower than sync it from PCE1 to PCE2."
This statement should be justified. Why the communication PCC1-PCE2 should be 
slower than PCE1-PCE2 ? - Section 3.1 only includes 3.1.1 and no extra text, 
probably you don't need 3.1.1 and just 3.1 is fine. - Section 3.3: " When 
propagating LSP state changes from a PCE to other PCEs, it MUST ensure that a 
PCE always uses the freshest state coming from the PCC." i'm not sure i 
understand who the subject is, and how it can ensure that the freshest state is 
used. - Figure 6: Lenght isn't 16? How long is the LSP state DB version number?
64 bit? do you expect that many version number updates during the lifetime of 
an LSP? - Section 3.5: You say taht PCC doesn't need to be aware of teh 
computation priority. Then who tells the PCE what is the priority of each 
association group? - Section 6: The need of a Path-Vector TLV makes me think 
that the hierarchical approach would be simpler. With the hierarchical approach 
you wouldn't need a message loop detection mechanisms.

Thanks
Daniele



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