Re: MPLS WG Last Call on two related WG documents (PathErr and SoftPreemption)

["Adrian Farrel" <adrian@olddog.co.uk>]

Hi MPLS WG,

I passed on information about your WG last call on these drafts to CCAMP who 
probably have an interest in this topic as well. We have received the 
comments below. Please consider them as part of the last call.

Thanks,
Adrian
----- Original Message ----- 
From: "PAPADIMITRIOU Dimitri" <Dimitri.Papadimitriou@alcatel-lucent.be>
To: "Adrian Farrel" <adrian@olddog.co.uk>; <ccamp@ops.ietf.org>
Sent: Saturday, February 23, 2008 2:16 PM
Subject: RE: MPLS WG Last Call on two related WG documents (PathErr and 
SoftPreemption)


adrian. a base question:

2205 defines a mechanism for hard-preemption by tearing down state and a
soft-preemption by error msg exchange only (no state modification) -->
note that section 2.4 states:

"A teardown request may be initiated either by an application in an end
system (sender or receiver), or by a router as the result of state
timeout or service preemption."

3209 defines a preemption mechanism with the following conditions:
- If the requested bandwidth is not available a PathErr message is
returned with an Error Code of 01, Admission Control Failure, and an
Error Value of 0x0002.
- If the requested bandwidth is available, but is in use by lower
priority sessions, then lower priority sessions (beginning with the
lowest priority) MAY be preempted to free the necessary bandwidth. [...]
A ResvErr and/or PathErr with the code "Policy Control failure" SHOULD
be sent toward the downstream receivers and upstream senders.

but looking at 2205 these are following the soft-preemption rules.

-> section 2 in the error doc. is confusing "This text is a
clarification and re-statement of the procedures set out in [RFC3209]
and does not define any new behavior."

now, with these docs an error msg exchange (fatal) for hard-preemption
(that remove states at detecting node and leaves subsequent decision at
sender) and an error msg exchange (non-fatal) for soft-preemption (that
does not remove state at detecting node and leaves subsequent decision
at sender)

-> section 2.3 of the error doc. "Any node clearing either or both the
Path or the Resv state of a TE LSP MUST also free up the data plane
resources allocated to the corresponding TE LSP." is basically
confirming the initial 2205 mechanism behind hard-preemption (why
keeping upstream state without resource at the detecting node ?).

thanks,
-d.

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org
> [mailto:owner-ccamp@ops.ietf.org] On Behalf Of Adrian Farrel
> Sent: Saturday, February 23, 2008 12:55 PM
> To: ccamp@ops.ietf.org
> Subject: Fw: MPLS WG Last Call on two related WG documents
> (PathErr and SoftPreemption)
>
> Heads up in CCAMP.
>
> These I-Ds describe interpretations of RSVP-TE and have
> implications for
> GMPLS.
>
> Please review and comment to the MPLS mailing list.
>
> Thanks,
> Adrian
> ----- Original Message ----- 
> From: "Loa Andersson" <loa@pi.se>
> To: <mpls@ietf.org>
> Cc: "Ross Callon" <rcallon@juniper.net>; "David Ward"
> <dward@cisco.com>
> Sent: Monday, February 18, 2008 4:26 PM
> Subject: [mpls] WG Last Call on two related WG documents (PathErr and
> SoftPreemption)
>
>
> > Working Group,
> >
> > this is to initiate a working group last call on two working group
> > documents:
> >
> > "Node behavior upon originating and receiving Resource ReserVation
> > Protocol (RSVP) Path Error message"
> >
> > <draft-ietf-mpls-3209-patherr-02.txt>
> >
> > and
> >
> > "MPLS Traffic Engineering Soft Preemption"
> >
> > <draft-ietf-mpls-soft-preemption-10.txt>
> >
> > The soft preemption ID became a WG document in Feb 2003. It has been
> > "on-hold" for a longer period waiting for another ID defining the
> > term "Hard preemption"; the working group considered that
> that document
> > was required to progress the soft preemption document. This document
> > is the "PathErr-draft" and has now have became a stable WG document.
> > Therefore it is now possible to start this working group last call.
> >
> > Please send your comments to the working group mailing list prior to
> > EOB March 3.
> >
> > Loa and George
> >
> >
> >
> >
> >
> >
> > -- 
> > Loa Andersson
> >
> > Principal Networking Architect
> > Acreo AB                           phone:  +46 8 632 77 14
> > Isafjordsgatan 22                  mobile: +46 739 81 21 64
> > Kista, Sweden                      email:  loa.andersson@acreo.se
> >                                            loa@pi.se
> > _______________________________________________
> > mpls mailing list
> > mpls@ietf.org
> > http://www.ietf.org/mailman/listinfo/mpls
> >