Re: [CCAMP] [Technical Errata Reported] RFC4872 (3304)

[Sidd Aanand <[e-mail]>]

FWIW, I agree too -- I don't see any issues with the current text.

Thanks,
Sidd

-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On Behalf Of John E Drake
Sent: Wednesday, August 01, 2012 7:38 PM
To: [e-mail]; [e-mail]
Cc: [e-mail]; [e-mail]; [e-mail]
Subject: Re: [CCAMP] [Technical Errata Reported] RFC4872 (3304)

I don't see any problem with the existing text.

Sent from my iPhone


> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf 
> Of Adrian Farrel
> Sent: Tuesday, July 31, 2012 6:28 PM
> To: [e-mail]
> Cc: [e-mail]; [e-mail]; 
> [e-mail]
> Subject: Re: [CCAMP] [Technical Errata Reported] RFC4872 (3304)
> 
> Hi CCAMP,
> 
> I find that this erratum is raised against two sections one of which I 
> supplied text for. If this get contentious, I will call on Stewart to 
> call consensus and handle the Erratum in the system.
> 
> In my opinion, this proposal goes further than the intention of the 
> authors/WG in publishing 4872.
> 
> With regard to the proposed addition to section 11...
> The use of mb4b is already in scope. The existing text says "The new 
> LSP resources can be established using the make-before-break 
> mechanism," so there is no need to re-state "The new LSP can be 
> established without tearing down the old LSP".
> 
> I think your concern here is whether the old LSP is ever torn down. I 
> think that you are worried that if the old LSP is torn down, it might 
> be impossible to perform reversion because, after repair, an attempt 
> to revert (also using mb4b) might find that key resources have been 
> "stolen" by some other LSP. I don't see this as at all different from 
> the issue of the protection LSP itself. That is, it is of the nature 
> of LSP Rerouting as a protection mechanism that:
> a. protection may fail because of lack of resources b. reversion may 
> fail because of lack of resources
> 
> *If* reversion is so important, I don't quite see why protection is 
> not important. If protection is important then you should be using a 
> proper protection mechanism and not waiting for post facto rerouting.
> Furthermore, if you require that the LSP be retained for restoration, 
> why are you not using a protection mechanism?
> 
> But the general paradigm here is that you are willing to use the best 
> available LSP when it is set up in the first place, the best available 
> LSP when you re-route after failure, and the best available LSP when 
> you "revert".
> 
> Lastly, it *does* remain an _option_ to retain the failed LSP in order 
> to switch back. Nothing in the old text precludes that, although I 
> understand that there is an implication that it might be expected to 
> be torn down.
> 
> So I conclude that the proposed addition to section 12 is not what the 
> authors/WG intended.
> 
> We should discuss further.
> 
> Adrian
> 
> > -----Original Message-----
> > From: RFC Errata System [mailto:[e-mail]]
> > Sent: 31 July 2012 17:39
> > To: [e-mail]; [e-mail];
> dimitri.papadimitriou@alcatel-
> > lucent.be; [e-mail]; [e-mail]; 
> > [e-mail]; [e-mail]
> > Cc: [e-mail]; [e-mail]; [e-mail]
> > Subject: [Technical Errata Reported] RFC4872 (3304)
> >
> >
> > The following errata report has been submitted for RFC4872, "RSVP-TE 
> > Extensions in Support of End-to-End Generalized Multi-Protocol Label 
> > Switching (GMPLS) Recovery".
> >
> > --------------------------------------
> > You may review the report below and at:
> > http://www.rfc-editor.org/errata_search.php?rfc=4872&eid=3304
> >
> > --------------------------------------
> > Type: Technical
> > Reported by: Lyndon Ong <[e-mail]>
> >
> > Section: 11 & 12
> >
> > Original Text
> > -------------
> > Section 11 says:
> >
> >
> >    (Full) LSP rerouting will be initiated by the head-end node that
> has
> >    either detected the LSP failure or received a Notify message
> and/or a
> >    PathErr message with the new error code/sub-code "Notify Error/LSP
> >    Locally Failed" for this LSP.  The new LSP resources can be
> >    established using the make-before-break mechanism, where the new
> LSP
> >    is set up before the old LSP is torn down.  This is done by using
> the
> >    mechanisms of the SESSION_ATTRIBUTE object and the Shared-Explicit
> >    (SE) reservation style (see [RFC3209]).  Both the new and old LSPs
> >    can share resources at common nodes.
> >
> > Section 12 says:
> >
> >    [No text on reversion for (full) LSP Rerouting.]
> >
> > Corrected Text
> > --------------
> > Section 11 should say:
> >
> >
> >    (Full) LSP rerouting will be initiated by the head-end node that
> has
> >    either detected the LSP failure or received a Notify message
> and/or a
> >    PathErr message with the new error code/sub-code "Notify Error/LSP
> >    Locally Failed" for this LSP.  The new LSP resources can be
> >    established using the make-before-break mechanism, where the new
> LSP
> >    is set up before the old LSP is torn down.  This is done by using
> the
> >    mechanisms of the SESSION_ATTRIBUTE object and the Shared-Explicit
> >    (SE) reservation style (see [RFC3209]).  Both the new and old LSPs
> >    can share resources at common nodes.  The new LSP can be
> established
> >    without tearing down the old LSP in case of reversion (see 
> > section
> 12).
> >
> > Section 12 should say:
> >
> >    For "(full) LSP Rerouting", reversion implies that the old LSP is
> not
> >    torn down by the head-end node after the new LSP is established.
> For
> >    reversion, the head-end node re-activates the old LSP after this
> has
> >    recovered.
> >
> >
> >
> > Notes
> > -----
> > Current text in RFC 4872 describes reversion in the cases of 1+1 
> > bidirectional Protection, 1:N Protection with Extra Traffic and 
> > Rerouting Without Extra
> Traffic,
> > however it has no description of reversion with (Full) LSP Rerouting.
> > For (full) LSP Rerouting, the description in Section 11 instead 
> > implies that
> the old
> > LSP is torn down. This has led to some confusion as to whether 
> > reversion with
> > (full) LSP Rerouting is allowed or not allowed by the RFC. We 
> > believe this was
> not
> > intentional. The additions would make it clear that reversion can be 
> > supported with (Full) LSP Rerouting.
> >
> > Instructions:
> > -------------
> > This errata is currently posted as "Reported". If necessary, please 
> > use "Reply All" to discuss whether it should be verified or rejected.
> > When a decision is reached, the verifying party (IESG) can log in to 
> > change the status and edit the report, if necessary.
> >
> > --------------------------------------
> > RFC4872 (draft-ietf-ccamp-gmpls-recovery-e2e-signaling-04)
> > --------------------------------------
> > Title               : RSVP-TE Extensions in Support of End-to-End
> Generalized
> Multi-
> > Protocol Label Switching (GMPLS) Recovery
> > Publication Date    : May 2007
> > Author(s)           : J.P. Lang, Ed., Y. Rekhter, Ed., D.
> Papadimitriou, Ed.
> > Category            : PROPOSED STANDARD
> > Source              : Common Control and Measurement Plane
> > Area                : Routing
> > Stream              : IETF
> > Verifying Party     : IESG
> 
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