RE: Basic doubts on 1:1 path protection signaling.

["Vishal Sharma" <v.sharma@ieee.org>]

Dimitri, Balu,

Good discussion/clarification. A question in-line.

-Vishal

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org]On
> Behalf Of Dimitri.Papadimitriou@alcatel.be
> Sent: Tuesday, April 27, 2004 8:42 AM
> To: Balasubramania N. Pillai
> Cc: 'ccamp@ops.ietf.org'
> Subject: Re: Basic doubts on 1:1 path protection signaling.
>
>
>
>
> Balasubramania N. Pillai wrote:
> > Thanks Dimitri and John for trying to help me.
> >
> > Thanks for the detailed reply. I am clear on the first two
> questions. But I
> > am still a little bit confused with my third question. May be I didn't
> > understand the concept right. So let me try again.
> >
> > I was most confused with how do we do signaling to setup the
> "Extra Traffic"
> > LSP. Are you suggesting that there is not additional signaling
> to setup the
> > "Extra Traffic LSP". Setup the protection LSP along with the
> working LSP. At
> > this point the two LSP are setup and the user is free to use
> the protection
> > LSP to carry extra traffic.
> >
> > My confusion is around this issue. Once the protection LSP is
> setup, do we
> > need to do extra signaling to setup the "Extra Traffic LSP" on
> top of the
> > protection LSP.
>
> as the protecting LSP is activated you don't need such operation which
> is performed during the signaling phase (as said in section 7: "working
> and protecting LSPs are signaled as primary LSPs; both are fully
> instantiated during the provisioning phase. [..] preemptable traffic may
> be carried end-to-end using this (read: protecting) LSP (i.e. the
> protecting LSP is capable of carrying extra-traffic)"

This seems to make the assumption that the extra-traffic LSP will
be between the same ingress/egress point as the original working LSP.

In general, when using the capacity of the protection path in 1:1 protection
for extra-traffic this is not really needed. It should be possible
for extra-traffic to use only a segment of the protection LSP.
Indeed, several extra-traffic LSPs may be use the capacity of the
protection LSP, each using a different segment.
(In fact, this is what I thought the P&R analysis/terminology drafts
described, when I last looked at them.)

Is this not supported by the scheme in the e2e draft?

> > -----Original Message-----
> > From: Dimitri.Papadimitriou@alcatel.be
> > [mailto:Dimitri.Papadimitriou@alcatel.be]
> > Sent: Tuesday, April 27, 2004 3:13 AM
> > To: Balasubramania N. Pillai
> > Cc: 'ccamp@ops.ietf.org'
> > Subject: Re: Basic doubts on 1:1 path protection signaling.
> >
> >
> >
> >
> > Balasubramania N. Pillai wrote:
> >
> >>Hi All,
> >>
> >>I was reading the
> draft-ietf-ccamp-gmpls-recovery-e2e-signaling-00.txt and
> >
> > I
> >
> >>have some basic doubts regarding signaling 1:1 protected LSP with extra
> >>traffic.
> >>
> >>
> >>1. My understanding is that Section 7 talks about 1:1 Protection (the
> >>protection path is fully setup and cross-connects are made) and not 1:1
> >>Restoration (no cross-connects for protection path)
> >
> >
> > as the title indicates and explained in the text
> >
> >
> >>2. Since the protection LSP is setup (cross-connected), I guess
> we should
> >>advertise that the resources used by the Protection LSP as "in use" in
> >>routing.
> >
> >
> > if it is cross-connected it is "in use"
> >
> >
> >>3. Section 7, Paragraph 3 says that
> >>
> >>	Although the resources for the protecting LSP are pre-allocated,
> >>	preemptable traffic may be carried end-to-end using this LSP (i.e.
> >>	the protecting LSP is capable of carrying extra-traffic) with the
> >>	caveat that this traffic will be preempted if the working LSP fails.
> >>
> >>Take the case where a 1:1 LSP is setup. Both the working LSP and the
> >>protection LSP are setup and cross-connected. Now if we want to add a
> >>extra-traffic, how do we signal, to setup the LSP carrying the Extra
> >>traffic.
> >
> >
> > the protecting lsp allows carrying extra-traffic (in a sense
> you may see
> > for the 1:1 protection case, the protecting lsp as the "extra-traffic
> > lsp" but this terminology is misleading reason why it is not used)
> >
> >
> >>What objects do we use to associate the "Extra Traffic LSP" to the
> >>protection LSP.
> >
> >
> > the association object is used to bind the protected and the
> protecting lsp
> >
> > hope this clarifies (note: an update is being prepared to further
> > clarify some of the comments made on the list)
> >
> > thanks,
> > - dimitri
> >
> >>Thanks for you time
> >>
> >>Balu
> >>
> >>
> >>
> >>
> >
> >
>
> --
> Papadimitriou Dimitri
> E-mail : dimitri.papadimitriou@alcatel.be
> E-mail : dpapadimitriou@psg.com
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>