Re: [mpls] MPLS_RT review of draft-mirsky-mpls-residence-time-06.txt

[Lucy yong <[e-mail]>]

Hi All,

I reviewed draft-mirsky-mpls-residence-time as the member of MPLS Review Team and have the following comments:

is the document coherent?

Yes. It specifies how MPLS supports residence time measurement. 

is it useful (ie, is it likely to be actually useful in operational networks)?

The document claims that such measurement can improve the accuracy of clock synchronization across the network. I am not an operator and author and not sure how useful this feature provides compared to the complexity adding to. 

is the document technically sound? 
Yes. The draft provides a detail solution in control plane and data plane to achieve this purpose.

is the document ready to be considered for WG adoption?
Yes. The document states the problem clearly and provides a solution to address this problem.  

IMHO:  after adopting it as the WG draft, the WG should further evaluate if control plane and data plane solution can be simplified. The areas may be considered:
1) Do we have to use IGP to announce node RTM capability? Can RSVP-TE resolve the issue by itself?
2) Will possible to enhance RRO to serve RSO purpose instead of carrying both RRO and RSO in the message?
3) Since this feature is designed for the LSP that is used for clock synchronization, such LSPs are not majority, so it should be option in LSP setup. Make that very clear.
4) two-step clock mode is quite complex. The description in Section 7 is not clear to me why this mode is necessary. 

Regards,
Lucy