RE: [mpls] [PWE3] IETF Last Call comment on draft-ietf-pwe3-gal-in-pw

[Alexander Vainshtein <[e-mail]>]

Stewart,
Lots of thanks for a prompt response.

My original email contained a typo (S-PE instead of T-PE  named as inserting ) which I've acknowledged and corrected in this thread (please see http://www.ietf.org/mail-archive/web/pwe3/current/msg12586.html).

With this correction in mind, the example I've presented (an MS-PW that originates in a T-PE in a MPLS-TP domain and them crosses - at S-PE - into an IP/MPLS domain) matches, IMHO, Yaakov's question. And if the operator wishes to improve traffic distribution in the IP/MPLS domain which employs ECMP, flow labels would be inserted by T-PE.

I believe that the change in draft-ietf-pwe3-gal-in-pw that you've proposed in http://www.ietf.org/mail-archive/web/pwe3/current/msg12613.html resolves the original issue I've raised of both GAL and flow label "competing" for the BoS position.

However, a conceptual question - can any MPLS-TP restrictions be placed on PWs?- remains open as noted in Greg's comment (please see http://www.ietf.org/mail-archive/web/pwe3/current/msg12620.html). IMHO and FWIW we should acknowledge the fact (implicitly recognized  already in RFC 5920) that there is simply no such thing as a MPLS-TP PW.

Hopefully this note clarifies my position on the subject.

Regards, and apologies for the original typo,
     Sasha

________________________________
From: Stewart Bryant [[e-mail]]
Sent: Thursday, September 01, 2011 8:33 PM
To: Alexander Vainshtein
Cc: Yaakov Stein; [e-mail]; pwe3; [e-mail]; [e-mail]; Luca Martini; IETF Discussion
Subject: Re: [mpls] [PWE3] IETF Last Call comment on draft-ietf-pwe3-gal-in-pw


On 01/09/2011 17:07, Alexander Vainshtein wrote:
Yaakov,
You've written
PW that starts in an MPLS-TP domain, can easily leak into a non-TP domain
This is exactly the point that I've raised in my IETF LC comment on the draft (for MS-PW) - please see my email (to several lists) that explains that in some detail, at http://www.ietf.org/mail-archive/web/pwe3/current/msg12581.html.

Regards,
Sasha

The operator intends to improve traffic distribution in the IP/MPLS domain, hence he enables insertion and discard of "flow labels" at the two S-PEs.

Speaking as an author of the FAT-PW draft I do not recall any text that proposes that S-PEs insert FLs in the stack, and it never occurred to me that anyone anyone would try, since would require a change to the design of the S-PEs.

Stewart




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