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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: iSCSI: Wrapping up SendTargetsI agree with Mark's statements: " Now - Keep SendTargets, document it in the iSCSI spec, and declare its limitation to just what is needed to connect to a target (name, address, aggregation). Define ReportPortalGroups functionality as a subset of SendTargets. Future - Pursue SLP as the "standard discovery", allowing for other solutions such as iSNS as appropriate." especially since most folks that bothered to respond did not like my compromise of an Annex. The only important point, from my standpoint is: if SendTargets goes away for any reason, we still need the ReportPortalGroups function. So if we use the suggested syntax of "SendTargets <iscsi-target-name>" instead of ReportPortalGroups, we need to find a way to protect the subset function that is "ReportPortalGroups", so it never goes away even if SendTargets does. . . . John L. Hufferd Senior Technical Staff Member (STSM) IBM/SSG San Jose Ca (408) 256-0403, Tie: 276-0403, eFax: (408) 904-4688 Internet address: hufferd@us.ibm.com Mark Bakke <mbakke@cisco.com>@ece.cmu.edu on 06/08/2001 01:31:16 PM Sent by: owner-ips@ece.cmu.edu To: IPS <ips@ece.cmu.edu> cc: Subject: iSCSI: Wrapping up SendTargets Dear Discovery Enthusiasts- The SendTargets threads are winding down, so I would like to see if we have a rough consensus on a few things. I've read through all of the threads on whether to keep SendTargets in iSCSI, and I believe there is a rough concensus that we should keep it in, carefully limit its growth, and recommend that functionality beyond the basic reporting of the targets and addresses available be implemented using standard discovery protocols instead. On looking through responses from Josh, Steph, Larry, Paul, Julian, Mallikarjun, John, Kaladhar, Jim, and Marjorie, I have seen 7 (I include myself in this count) in favor of keeping SendTargets but limiting its growth, one in favor of dropping SendTargets, and three with no comment on SendTargets. For adding discovery functionality beyond basic reporting of available targets and addresses, I have seen 5 (again, including myself) in favor of using SLP for future discovery, one in favor of using iSNS for future discovery, two in favor of either SLP or iSNS, and three with no comment. I realize that this doesn't constitute calling consensus, and I'm not the person to do it, but I wanted to point out where most people who have responded seem to be headed, so that others who wish to be heard are motivated to comment. Anyway, that said, I would like to see SendTargets stay in the draft, mainly for the same reasons that several others already stated: SendTargets shares the same authentication as iSCSI. SendTargets provides a simple, low-risk path to building interoperable, minimal-configuration iSCSI implementations. SendTargets builds on the existing iSCSI login and text commands, and will be the smallest-footprint and -effort way to implement this basic functionality. The first reason given above is the most important. I believe that we should limit extensions to it as much as possible, for instance, we should not attempt to return certificates and other information. Implementations that wish to do fancier things like these would implement one of the other discovery mechanisms. We could go as far as atrophying SendTargets later, but I think that John is right, that it would be a decision to be made later (iSCSIv2). That said, I do agree that Julian is correct from a philosophical point of view; discovery really belongs outside the protocol. This is a direction we need to pursue. I absolutely agree with Julian that we have to be careful not to let something like SendTargets turn into a management protocol. It would be "easy to do" :-). I see a mild consensus toward SLP as a good direction for moving forward with discovery beyond simple target reporting. The SLP folks themselves intended for hosts to be able to behave in the Unicast manner we are trying, and are interested in updating the SLP API to handle this. However, I think that it would be best to use SendTargets for now, while we both make sure that the right SLP API is developed, and that we can solve the problem of authentication schemes. On ReportPortalGroups I did not hear anyone say we didn't need this functionality; most seemed to say the we either "at least" need ReportPortalGroups if we don't have SendTargets, or that SendTargets was assumed, and ReportPortalGroups is a subset. I agree that this is necessary functionality, but that if we can assume that we still have SendTargets, ReportPortalGroups is really a subset. Paul mentioned just using: SendTargets <iscsi-target-name> would be the same as ReportPortalGroups. This might help avoid the feature creep that some of the responders feared. Anyway, either way of doing ReportPortalGroups (making it its own command or making it part of SendTargets) is fine with me. I think that the consensus was that as long as we have SendTargets, we should use it for the ReportPortalGroups functionality. On the Growth of SendTargets A few people mentioned concern about TargetAlias and digital certificates. TargetAlias is returned by the target upon login anyway, so I could live with removing it from SendTargets, and letting the higher-level discovery/management mechanisms deal with it. I think that the same goes for certificates. As we figure out how our customers really want to do security for iSCSI, we may have other mechanisms in place for handling these. This should help keep SendTargets from growing. Stating that it is limited to name, address, and aggregation information (just what is required to connect) should keep it right where it is, and the future discovery mechanisms can take over from there. So here's what I think we have: Now - Keep SendTargets, document it in the iSCSI spec, and declare its limitation to just what is needed to connect to a target (name, address, aggregation). Define ReportPortalGroups functionality as a subset of SendTargets. Future - Pursue SLP as the "standard discovery", allowing for other solutions such as iSNS as appropriate. Do we have rough consensus on either of the above, at least on the "Now" part? Once we have consensus on that, we can continue the threads on aggregation tags, which targets should provide SendTargets, and whether or not we need iterators. Anyway, I have to apologize in advance; I will be out of the office until the 18th, so I am sort of throwing this out on the list and running away. Regards, -- Mark A. Bakke Cisco Systems mbakke@cisco.com 763.398.1054
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