Andre: I'm attaching specific comments on LMP-WDM. Top level issues are as follows: 1. Layer mix-up: In some places, the WDM system is required to send information which is not native to OLS to the OXCs. In fact, this is very strange, because this information must originate from the OXC domain, get configured in WDM, and then go back to OXCs. This is a problem with OLI definition, not LMP-WDM itself. This requires some discussion and clean up. 2. Rather than tailoring the procedures for the particular requirements (OLI), the draft seems to be written with the goal of maximal reuse of LMP. This sometimes adds to the complexity of the proposal. Specifically, LMP-WDM has many "extensions" to LMP, giving the impression that LMP-WDM is a superset of LMP. I think there are differences in the situations where LMP is applied as compared to LMP-WDM and these aspects are not discussed sufficiently. I think a meticulous examination of the OLI requirements and LMP procedures is necessary to just carve out a set of procedures for OLI, rather than the superset approach. The maximal "re-use" argument doesn't make any sense on the WDM side where there is no LMP. Or, for that matter, where OXCs don't implement LMP. (This is where NTIP makes a good point). 3. I'm afraid the current LMP link verification definition (and as a corollary, LMP-WDM link verification) has only a marginal value considering the investment on hardware and protocol implementation. This is an area that requires more work. 4. Some of the procedures in the draft must be more explicitly described rather than saying that they are same as LMP's. As you noted, a more careful examination of LMP itself is in order. Regards, Bala Bala Rajagopalan Tellium, Inc. 2 Crescent Place P.O. Box 901 Oceanport, NJ 07757-0901 Tel: (732) 923-4237 Fax: (732) 923-9804 Email: braja@tellium.com > -----Original Message----- > From: Andre Fredette [mailto:fredette@photonex.com] > Sent: Friday, July 27, 2001 11:02 AM > To: Bala Rajagopalan > Cc: 'ccamp@ops.ietf.org' > Subject: RE: Optical Link Interface - Correction > > > Bala, > > Yes, I counted you as "agnostic" in the LMP-WDM vs. NTIP > debate, though I > do know that you think the OLI is important and you care that > the solution > is a good one. I also agree (as I've stated before) that > either LMP-WDM or > NTIP could be made to work. I just believe that having the > group focus on > one protocol rather than two will have a better end result > and aid in wider > deployment. > > I'd also be glad to work on streamlining LMP-WDM. > > As I see it, the basic requirements are the same for both LMP > and OLI for > the following: > 1. Control Channel Maintenance (A.K.A. a light weight hello protocol). > 2. The ability to exchange information on links (link > summary, perhaps with > a few different TLVs) > 3. Discovery/Test. (Note: The main purpose here is for two > devices to agree > on ID's for each link so information exchange regarding > the links is > possible. The only reasonable way it is possible to > automate this, is to > send some type of test messages on the physical links). > To do this, > you need to be able > to terminate the links. > 4. Fault Notification (By the way, I think the ChannelStatus Message > defined in LMP-WDM > could replace the current ChannelFail Message in LMP) > 5. Notification whether a link is in use (ChannelActive Message). > > Because of this we have proposed basing the OLI on LMP. > > If these features need streamlining for LMP-WDM, they > probably also need > streamlining for LMP, so let's fix them once. > > If there are other LMP-WDM-specific procedures that need to > be streamlined, > I'm all ears. > > The major difference I see is that LMP needs is the ability > to manage link > bundles for the purpose of routing advertisements, but the > OLI doesn't. In > the LMP-WDM case, I was expecting we'd usually have a single > link bundle > (effectively ignoring this feature of LMP). > > Regarding the discovery portion of LMP (i.e., "link connectivity > verification"), from a protocol standpoint, it should work. It does > require that the PXC be able to terminate each port with an > appropriate > interface (from LMP: "For the LMP Test procedure, the free > (unallocated) > data-bearing links MUST be opaque (i.e., able to be > terminated)"). The PXC > would need to support termination of the various types of > ports that could > be used (e.g., SONET, SDH). But, this is more of a hardware > requirement > than a protocol requirement. > > Andre > > At 09:36 AM 7/27/2001 -0400, Bala Rajagopalan wrote: > > >Forgot to attach the new NTIP draft. > >Also, I meant "working on (4)", not (3). > > > > > >Bala Rajagopalan > >Tellium, Inc. > >2 Crescent Place > >P.O. Box 901 > >Oceanport, NJ 07757-0901 > >Tel: (732) 923-4237 > >Fax: (732) 923-9804 > >Email: braja@tellium.com > > > > > -----Original Message----- > > > From: Bala Rajagopalan > > > Sent: Friday, July 27, 2001 9:28 AM > > > To: 'Andre Fredette'; ccamp@ops.ietf.org > > > Subject: RE: Optical Link Interface > > > > > > > > > Andre: > > > > > > I believe you're counting me in the "agnostic" category. > > > I hope this is not taken as "don't care", since I > > > do have an interest in making a choice quickly. > > > > > > I have looked at the LMP-WDM draft (again) and the new > > > NTIP draft sent by Osama (attached). I see the following: > > > > > > 1. Both these solutions gloss over the details of > > > auto-discovery between OXCs and WDM. (Note: the > > > issues are the same regardless of the protocol used > > > and neither provides full details. Furthermore, > > > the hardware requirements and actions under both > > > are the same). > > > > > > 2. If we leave out (1), then the other functions are > > > based on messaging over the control channel > > > between the OXC and the WDM. This messaging > > > can be done one way or the other. > > > > > > 3. Both require control channel maintenance using > > > (simple) keepalive. > > > > > > 4. It seems LMP-WDM can be streamlined to make it > > > more lean and mean. > > > > > > Unless there is a significant technical issue > > > of one choice over the other, we have to consider > > > the fact that LMP-WDM has the first mover advantage. > > > Is it possible for > > > the NTIP proponents to seriously consider working on > > > (3)? Specifically, focus LMP-WDM on OLI requirements > > > only and not carry any unrelated LMP concepts into > > > LMP-WDM. Would this satisfy the design motivation for NTIP? > > > > > > Regards, > > > > > > Bala > > > > > > > > > Bala Rajagopalan > > > Tellium, Inc. > > > 2 Crescent Place > > > P.O. Box 901 > > > Oceanport, NJ 07757-0901 > > > Tel: (732) 923-4237 > > > Fax: (732) 923-9804 > > > Email: braja@tellium.com > > > > > > > -----Original Message----- > > > > From: Andre Fredette [mailto:fredette@photonex.com] > > > > Sent: Thursday, July 26, 2001 2:52 PM > > > > To: ccamp@ops.ietf.org > > > > Subject: RE: Optical Link Interface > > > > > > > > > > > > From my count on the mailing list we have the following > > > > results so far: > > > > > > > > LMP-WDM: 8 > > > > NTIP: 3 (All from Nortel) > > > > Agnostic: 1 > > > > > > > > And then there are the other 16 co-authors of LMP-WDM who > > > > haven't posted > > > > (perhaps because they don't think they have any new > points to add). > > > > > > > > Andre > > > > > > > > At 02:00 PM 7/26/2001 -0400, Martin Dubuc wrote: > > > > >Kireeti, > > > > > > > > > >I have been following this thread with great interest. I > > > > agree with your > > > > >conclusion that we should pick one protocol and move forward. > > > > > > > > > >You are talking about WG reaching a consensus. I cannot see > > > > how this is > > > > >possible given the two very different views I see in the > > > latest email > > > > >exchanges. > > > > > > > > > >How can we resolve the current dispute? What forum should we > > > > use to make > > > > >a final decision on this? > > > > > > > > > >Martin > > > > > > > > > >-----Original Message----- > > > > >From: Kireeti Kompella [mailto:kireeti@juniper.net] > > > > >Sent: Wednesday, July 25, 2001 9:57 PM > > > > >To: jamoussi@nortelnetworks.com; kireeti@juniper.net; > > > > >osama@nortelnetworks.com > > > > >Cc: bon@nortelnetworks.com; ccamp@ops.ietf.org; > > > > >vasants@nortelnetworks.com > > > > >Subject: RE: Optical Link Interface > > > > > > > > > > > > > > >Hi Osama, > > > > > > > > > > > Even though I don't think reviving CR-LDP and RSVP-TE > > > > history will get > > > > >us > > > > > > anywhere > > > > > > > > > >"Those who forget (ignore) history are doomed to repeat it." > > > > > > > > > >Yes, it makes for painful recollections. We're living with the > > > > >consequences now, though, and I don't want to again. > > > > > > > > > > > the existence of two protocols here have proven to > be useful. > > > > > > > > > >That's not what I'm hearing, either from customers, or from the > > > > >WG (admittedly, the sample is small). > > > > > > > > > >Listen carefully: I don't want LMP-WDM and NTIP moving forward. > > > > >Just NTIP (or NTIP and LMP) is OKAY if that is what the WG > > > > >consensus is. LMP-WDM and LMP works too. > > > > > > > > > >So: you've got the WG chairs (scarred and grumpy), the ADs > > > > >and TA (speak up if I'm misrepresenting you), and customers > > > > >saying, Pick one protocol and move forward. Let's do that. > > > > >And, please, as Vijay says, let's resolve this already. > > > > > > > > > >Kireeti. > > > > > > > > > > > >
draft-fredette-lmp-wdm-01-comments.doc