Re: [RTG-DIR] RtgDir review:draft-ietf-mpls-ldp-gtsm-06.txt

[Eric Gray <[e-mail]>]

It was the second sentence of the second paragraph under Figure 1:

"                               Similarly, an LSR that does recognize
   the G flag but that it does not support GTSM (either because it is
   not implemented, or because it is so configured), would clear the G
   flag (i.e.,g G=0) on send and would effectively ignore the G flag on
   receipt."

One of the cases for "not support" of GTSM - explicitly included - is
the case where an implementation recognizes the G flag (implements at
least this much of the negotiation), but does not implement GTSM.

It struck me as odd, because GTSM does not seem to be hard to do, and
we're talking about control plain activities for both the negotiation
and the subsequent message processing.

It's a very minor issue, because this case could have been implicitly
included without begging this question, if worded differently.  The
thing that triggered this for me was the choice of the words "not
supported" (to me, if you have to configure an LSR to _not_ do some
function, the LSR supports that function, but it is disabled).

I am fine (as is implicit in my saying that the draft is ready to be
published) with not making any changes.  The NITs can be added to the
instructions to the RFC Editor by the IESG.  My other comments are to
deal with or not deal with at the discretion of the IESG and authors.

--
Eric

-----Original Message-----
From: Rajiv Asati (rajiva) [mailto:[e-mail]] 
Sent: Friday, May 25, 2012 2:46 PM
To: Eric Gray; [e-mail]; BRUNGARD, DEBORAH A
Cc: [e-mail]; [e-mail]
Subject: RE: RtgDir review:draft-ietf-mpls-ldp-gtsm-06.txt
Importance: High

Hi Eric,

Thank you so much for your review.

I agree to the nits and

> I am curious why the text under Figure 1 explicitly includes the
possibility
> that an LSR might implement GTSM capability negotiation but not
> implement GTSM.  But, again, this is a very minor issue.

Could you paste the para that you are referring to? I see the following
text under Figure 1:

   The G flag is meaingful only if the T flag is set to 0 (which must be
   the case for Basic Discovery), otherwise, the value of G flag SHOULD
   be ignored on receipt.

But I don't think that this is the text you refer to. Any way, Does the
note below (PS:) help?

> To maintain readability, the draft should still say where this field
is (that it is
> part of the Common Hello Parameter TLV).
> This way of representing the changes makes it clearer what the actual
> changes are.  However, this is a very minor issue.

I am divided on this one. I like having the complete TLV illustrated,
otherwise, I would no longer get the complete picture of the TLV itself.

Cheers,
Rajiv


PS: Perhaps, we could update the 2nd last para of the Section 1
introduction as shown below to clarify the rationale:

   "Since" GTSM [RFC5082] specifies that "it SHOULD NOT be enabled by
default in order to
   remain backward-compatible with the unmodified protocol" (see Section
   3 of [RFC5082]), this document maintains the backward compatibility
by
   including  a dynamic GTSM negotiation for LDP to suggest the use of
GTSM 
   (without relying on LDP Capabilities [RFCxxxx]).  This means that
GTSM
   will be used as specified in this document provided both peers on an
   LDP session can detect each others' support for GTSM procedures and
   agree to use it.  That is, the desire to use GTSM (i.e., its
   negotiation mechanics) is enabled by default.
 


> -----Original Message-----
> From: Eric Gray [mailto:[e-mail]]
> Sent: Friday, May 25, 2012 2:18 PM
> To: [e-mail]; BRUNGARD, DEBORAH A
> Cc: [e-mail]; [e-mail]
> Subject: RtgDir review:draft-ietf-mpls-ldp-gtsm-06.txt
> 
> 
> Hello,
> 
> I have been selected as the Routing Directorate reviewer for this
draft. The
> Routing Directorate seeks to review all routing or routing-related
drafts as
> they pass through IETF last call and IESG review, and sometimes on
special
> request. The purpose of the review is to provide assistance to the
Routing
> ADs. For more information about the Routing Directorate, please see
> http://www.ietf.org/iesg/directorate/routing.html
> 
> Although these comments are primarily for the use of the Routing ADs,
it
> would be helpful if you could consider them along with any other IETF
Last
> Call comments that you receive, and strive to resolve them through
> discussion or by updating the draft.
> 
> Document: draft-ietf-mpls-ldp-gtsm-06.txt
> Reviewer: Eric Gray
> Review Date: 25-May-2012
> Intended Status: Standard
> 
> Summary:
> 
> No major issues found. This document is essentially ready for
publication.
> 
> Comments:
> 
> This document is mostly clearly written and easily understood.
> 
> Major Issues:
> 
> No major issues found.
> 
> Minor Issues:
> ============
> 
> Because this draft defines only a new bit assignment as an update to
RFC
> 5036, it would have been cleaner to have only included the flags field
as
> shown here:
> 
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> |T|R|G|   Reserved              |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> To maintain readability, the draft should still say where this field
is (that it is
> part of the Common Hello Parameter TLV).
> 
> In addition, since the definitions of T and R are exactly as given in
RFC 5036,
> the text that currently repeats the definitions for T and R could
better have
> been written as:
> 
> "T and R
>    As specified in [RFC5036]."
> 
> This way of representing the changes makes it clearer what the actual
> changes are.  However, this is a very minor issue.
> ___________________________________________________________________
> ______________
> 
> I am curious why the text under Figure 1 explicitly includes the
possibility
> that an LSR might implement GTSM capability negotiation but not
> implement GTSM.  But, again, this is a very minor issue.
> ___________________________________________________________________
> ______________
> 
> NITs:
> ====
> 
> In the abstract, "packets" should be "packet's."
> 
> First sentence, first paragraph under Figure 1 - "meaingful" should be
> "meaningful."
> 
> Second sentence, second paragraph under Figure 1 - "but that it does
not"
> should be "but that does not."
> 
> --
> Eric Gray
>