Re: [storm] iSCSI Level and Version
Mallikarjun Chadalapaka <cbm@chadalapaka.com> Fri, 19 August 2011 00:39 UTC
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From: Mallikarjun Chadalapaka <cbm@chadalapaka.com>
To: "'Knight, Frederick'" <Frederick.Knight@netapp.com>, storm@ietf.org
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Date: Thu, 18 Aug 2011 17:39:36 -0700
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Subject: Re: [storm] iSCSI Level and Version
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I agree with Fred. I think we should mark the key as IO (Initialize-Only) in terms of when it can be used. As far as what the iSCSIProtocolLevel indicates though, it may communicate changes in PDU format and/or end node semantics. IOW, there is no reason to limit this exclusively to signal PDU format changes. Hope that makes sense. Changing the format of the Login-related PDUs is an interesting question. I would think that Version number should be bumped up to cover that scenario. Thanks. Mallikarjun -----Original Message----- From: Knight, Frederick [mailto:Frederick.Knight@netapp.com] Sent: Tuesday, August 16, 2011 10:14 PM To: Mallikarjun Chadalapaka; storm@ietf.org Subject: RE: [storm] iSCSI Level and Version The new SAM features draft changes the format of some PDUs. The current Version-max/min/active are fields within a PDU. The iSCSIProtocolLevel tells the end points which format to use for the PDUs, so the end point can find the fields within the PDU. This lets us have different format PDUs AFTER the negotiation of this key. The creation of the iSCSIProtocolLevel key allows us to write future drafts that make changes more radical than what the new SAM features draft contains. You need to know the iSCSIProtocolLevel to know which PDU format to use. So this makes me wonder, if we should move the negotiation of iSCSIProtocolLevel from the full feature phase to the login phase (should the negotiation of iSCSIProtocolLevel come earlier)? Might we ever want to change the format of any of the PDUs used during login? Fred -----Original Message----- From: Mallikarjun Chadalapaka [mailto:cbm@chadalapaka.com] Sent: Tuesday, August 16, 2011 11:14 PM To: storm@ietf.org Subject: [storm] iSCSI Level and Version In doing an internal review of the iSCSI Last Call drafts, someone asked me this. I want to run this response by the larger WG to see if we're all in agreement. Question: What is the difference between Version-max/Version- min/Version-active values exchanged during the iSCSI Login phase, and the negotiated value of iSCSIProtocolLevel key? Answer: The V-* values agreed to during the Login process determine the operating version of the iSCSI protocol, and announce if any other versions can be supported by either side. The operational iSCSIProtocolLevel key on the other hand determines the specific protocol features that may be used on an iSCSI session, within the "Version-active" versioned iSCSI protocol. If this sounds reasonable, it is worth capturing this clarification in the SAM-4 draft where this key is defined. Thanks. Mallikarjun _______________________________________________ storm mailing list storm@ietf.org https://www.ietf.org/mailman/listinfo/storm
- [storm] iSCSI Level and Version Mallikarjun Chadalapaka
- Re: [storm] iSCSI Level and Version Knight, Frederick
- Re: [storm] iSCSI Level and Version Mallikarjun Chadalapaka
- Re: [storm] iSCSI Level and Version Knight, Frederick