vishal, point A has been clarified on the list (and i think that the suggestion that was made/received on the list makes perfectly sense) point B (note: in your e-mail neither i) or ii) translates exactly the terms of the terminology draft, and none of your inferences are entirely correct, i have explain it to you already) in particular after the clarification on point A has been given, the term "1:1 re-routing without extra-traffic" (ref. also in the terminology i-d) should have been also understood that it meant that *this recovery lsp* (+) is not able to carry any traffic referred (per the terminology i-d) as "extra-traffic" (if this lsp would have been fully provisioned) what you call circular is just consistence. (+) from the early beginning you refer to other lsp's (ie the lower priority ones - see point A) than the one the sig i-d refers to for this recovery type thanks, - dimitri. Vishal Sharma wrote:
Dimitri,
(A) I see your point about reusing the priority mechanism to setup
low-priority pre-emptible LSPs over the resources reserved for
restoration. However, there is still the issue that such LSPs
ought not to be pre-empted by anything other than working LSPs
that need to use those recovery resources. They should not, for example,
be pre-empted by other higher priority LSPs (whether working or
protection LSPs).
So, it appears there does need to be some thought given to how
this will be achieved, and how the resources reserved for
restoration will be advertised.
Perhaps it is matter of sitting down and working through a priority allocation scheme to these
different types of LSPs that will achieve such consistent behavior.
The point being that some thinking along those lines is needed, which is what the extra-class LSP draft, I guess, tries to initiate.
(B) Now a question about the definition of "extra traffic"
Are _both_ of the following "extra traffic" per the terminology draft?
i) Traffic that uses resources reserved and cross-connected for
a protection path, and travels between the same source-destination pair
as the protection path.
ii) Traffic that uses resources reserved (but not cross-connected)
for recovery. This traffic is sent by setting up low-priority
pre-emptible LSPs on those reserved resources.
From your initial reply to Shiomoto-san (repeated below so people
can follow the context) and some of your subsequent
explanation it appears that this is the case (since you said that
this definition is designed to "cover any cases of extra-traffic
that we may encounter").
"in the case of pre-planned re-routing without extra-traffic
the unallocated protecting resource can be used by other
(lower priority LSPs) at the condition that the resources
are preempted when the working LSP fails (hint: i wanted
to point out also that this should be obvious otherwise
there is no reason for having this "path protection only")"
If so, the term "pre-planned re-routing without extra traffic" is circular,
since the type of traffic that can used those pre-planned (but
not cross-connected) resources is "extra traffic."
If not, then it appears that "extra-traffic" only covers traffic
of type (i) above, and the definition should make that clear.
Or else, the term "pre-planned re-routing without extra traffic"
should be changed to be consistent with the terminology doc.
-Vishal
-----Original Message----- From: Dimitri.Papadimitriou@alcatel.be [mailto:Dimitri.Papadimitriou@alcatel.be] Sent: Saturday, July 05, 2003 5:01 AM To: v.sharma@ieee.org Cc: Kohei Shiomoto; Adrian Farrel; ccamp@ops.ietf.org Subject: Re: New draft on Extra class LSP vishal, [snip]In the latter case, however, the only way any traffic could use the
reserved resources would be for one to setup a low-priority,pre-emptibleLSP using those resources, with the distinction that these particular low-priority LSPs are not subject to pre-emption unless a working LSP that needs to use those reserved resources fails (This what Shiomoto-san more accurately calls "extra-LSP".)the point is to have a network wide homogeneous allocation of resources, starting to have allocation based on the reason why the lower priority lsp can be preempted leads you to the issue of how many of such conditions can we have in a network ? or do you plan to start defining one class of lsp and priority per such event ? the idea behind the "re-use" of these preemptible resources is to abstract its complexity not to spread it network wide - this while what we have today works perfectly -So let's call an "extra-traffic LSP" an "extra-traffic LSP" :-)and let'sclearly define "extra traffic" in the terminology doc., because I don't think the definition, as it stands, in precise enough, unfortunately.the proposed definition (in the terminology i-d) is generic enough to cover any cases of extra-traffic that we may encounter, as said before in the "e2e" signaling i-d this definition is applied in this "e2e" context, there is here absolutely no reason (for the time being) to change the definition in the terminology document due to its usage in the signaling i-d - the only reason to change a def. in the terminology i-d would be that it doesn't cover the case of a concept developed in one of the subsequent i-d's not the other way around thanks, - dimitri.
-- Papadimitriou Dimitri E-mail : dimitri.papadimitriou@alcatel.be Private: http://www.rc.bel.alcatel.be/~papadimd/index.html E-mail : dpapadimitriou@psg.com Public : http://psg.com/~dpapadimitriou/ Address: Fr. Wellesplein 1, B-2018 Antwerpen, Belgium Phone : +32 3 240-8491