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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
> >
>
>
>
>