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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)"

Thanks in advance for you help.

Balu




-----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







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