Summary: One issue needs resolution. First, let me start by saying that -09, which was put out for Last Call, was a substantial improvement over the -08. I normally read Last Call documents using a diff tool, and the number of really solid additions in this update was quite high. I was a bit surprised, given the extent of the new text, that there was no WG last call, but I assume that the WG is reviewing the changes in parallel. I assume that the issuance of -10, which came out during the last call, was a response to one or more reviews from the WG or solicited experts. To call out one particular improvement, I found the update's language around multi-homing much clearer, and I believe the risk of assignment of the same address to multiple interfaces is much reduced in this version. Given the potential consequences (watching your stack scream "I'm melting! I'm melting!" as someone entertainingly put it), that's a really good thing. There are still some opportunities for editorial update, and I hope that as the IESG enters its discussions that some of those are targets for resolution. I'd particularly like to see even more clear light on the description in bullet 4 of Section 6.9.1.1, as "predictably knows" is not as clean as it might be. (The current sentence is: "The Handoff Indicator field MUST be set to value 1 (Attachment over a new interface), if the mobile access gateway predictably knows that the mobile node's current attachment to the network over this interface is not as a result of an handoff of an existing mobility session (over the same interface or through a different interface), but as a result of an attachment over a new interface. "). But that is really a language clarity problem, at least I hope, at this point. The big issue that remains is actually one that starts from the scope creep. I was on the IESG during the period when this charter was approved, and it was clear at the time that some of the limitations being put in were intended to focus NETLMM on cases where nodes were re-associating at layer 2 with the same network. The charter says, for example: "The protocol will not attempt to hide handover between two separate interfaces on the mobile node.". This document (and, as I understand it, the working group discussion for some time) has gone beyond that initial scope. A good portion of this document's complexity is because it does handle the multi-interface case. While it would have been nice to have the charter updated to state the new scope, I don't personally have a problem with the scope. I am concerned, however, that the design constraints changed with that new scope and that other parts of the charter are limiting folks' understandings of what can be done here, when those restraints are really salient for the single layer 2 initial scope. To put it simply, given the inter-technology handoff, signalling from the mobile node to the network is one of the clearest and most likely to be interoperable ways to achieve the correct behavior in some of the base cases. At the moment, because the mechanisms for setting the handoff indicator do not necessarily involve the mobile node (and are appear to be below IP where between the mobile node and the networ), a mobile node with multiple interfaces will not always be able to signal that it desires handoff or prefers multihoming. The document is now clear that in that case it gets multihoming. That's a tremendous advance over the previous state. But the really big win here would be to enable the signaling . As it stands, the operations are based on the handoff indicator provided by the MAG, but the document does not provide any information on how the MAG will know this information. There certainly will be cases where a network architecture will allow the MAG to use layer 2 indicators or other mechanisms, but there will also be cases where that set of mechanisms is inconsistently available. Adding the higher-layer signalling makes this a complete solution. I'm concerned that sending the document out in its current state will either require a quick re-spin at PS to enable this once the issues arise in deployment or that some of the contexts in which this is intended to be used will work around the problem in ways which will hinder an interoperable, long-term deployment. I am very conscious, however, that there is considerable time pressure on this document. I propose the following as a way forward which should not add any significant delay. 1) Add an explicit, normative reference to draft-netlmm-mn-ar (which would need to be revived) as the basis for a forthcoming above-IP signalling mechanism, using an RFC-Editor's note. 2) Put draft-netlmm-mn-ar on the standards track, but make an explicit downref statement for this document to the internet-draft. This would allow this document to progress without delay, but provide a reference for those who will be deploying this in contexts which do not have the same highly-structured network management of the networks for which this is urgent. When draft-netlmm-mn-ar is published, it would be available, of course, to both network types. 3) Go ahead with IESG processing on this document on the basis of the existing Last Call date, with the understand that the IESG would reconsider only if the second Last Call with the explicit downref raised new issues. IESG consideration prior to the end of a Last Call already occurs in some cases, and it certainly could be used in this case to meet the time pressures. I'm aware that the charter states that there should be no signalling required between the mobile and the network. In the context of the original design scope, that should have been read quite strictly. In the context of the current design scope, I believe we have to distinguish between making something required and setting a standard way of handling something in the inter-technology case. I do not believe that adding this normative reference would make it required. It would simply show how the IETF intended to meet the need for an interoperable mechanism for signalling where the mobile node had the capability and interest. Where it did not, the basic mechanisms in this draft would suffice. I understand that this has been an active, and at times contentious, area of discussion, and I do not want this last call comment to fan any old flames. As an APPs guy, trust that I'm in favor of pretty much anything that reduces the need for updated IP addresses and all the concomitant pain. I also see us about to miss an opportunity here, by setting out a toolkit that is missing a critical tool. I don't believe the time pressures here should or need to stop us from building the full toolkit, even if the first shipment of toolboxes goes out simply with the right shape cut out, to be filled later. regards, Ted Hardie _______________________________________________ Ietf@xxxxxxxx http://www.ietf.org/mailman/listinfo/ietf