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
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