Re: [storm] iSCSI version descriptors

[<[e-mail]>]

> Due to RFC4850, the consolidated draft is different than just 3720+5048 (4850 created the
> "X#NodeArchitecture" key).

That's an X extension format key, for which a NotUnderstood response is possible (RFC 4850 explicitly says so), and the key is only announced, not negotiated.

> How should we handle this?  Do we need:
> 	0 = no version claimed
> 	1 = 3720/5048
> 	2 = 3720/4850/5048 or new consolidated draft
> 	3 = (3720/4850/5048 or new consolidated draft) + SAM 4/5 features from the SAM draft.

I don't think 4850's presence/absence makes a sufficient difference, so I'd combine 1 and 2 above, plus rephrase the description of 3 (which would then become the new 2).

Thanks,
--David

> -----Original Message-----
> From: Knight, Frederick [mailto:[e-mail]]
> Sent: Friday, October 22, 2010 3:02 PM
> To: Black, David; [e-mail]
> Subject: RE: [storm] iSCSI version descriptors
> 
> The consolidated draft incorporates:
> 
> Updates: RFC 3720, 3721, 3980, 4850, 5048
> 
> Due to RFC4850, the consolidated draft is different than just 3720+5048 (4850 created the
> "X#NodeArchitecture" key).
> 
> How should we handle this?  Do we need:
> 	0 = no version claimed
> 	1 = 3720/5048
> 	2 = 3720/4850/5048 or new consolidated draft
> 	3 = (3720/4850/5048 or new consolidated draft) + SAM 4/5 features from the SAM draft.
> 
> 	Fred Knight
> 
> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]]
> Sent: Friday, October 22, 2010 1:15 AM
> To: [e-mail]
> Subject: [storm] iSCSI version descriptors
> 
> One more time on this issue.  This is for discussion - it's not an announcement of a decision.  This
> is the only real issue that needs to be resolved to complete the new (SAM) features draft for iSCSI.
> 
> Reminder: we need to define a set of small positive integer values to describe the iSCSI version
> starting with 0 = "no version claimed".  After some private discussions, it appears that we need two
> additional version values beyond 0.
> 
> The first observation is that the baseline should be at least RFC 3720 (original iSCSI) + RFC 5048
> (Corrections and Clarifications).  That would be version value 1.
> 
> The next observation is that taking features out of the consolidated iSCSI draft may allow a visible
> behavior change.  RFC 3720 has this to say about text keys for negotiation:
> 
>    All keys in this document, except for the X extension formats, MUST
>    be supported by iSCSI initiators and targets when used as specified
>    here.  If used as specified, these keys MUST NOT be answered with
>    NotUnderstood.
> 
> When we take out a feature in the new iSCSI consolidated draft, the easiest thing to do is allow a
> NotUnderstood response to the keys that negotiate that feature.  This should not pose a problem for
> unimplemented features, but it would be a behavior change.  The completely backwards-compatible
> alternative is have the consolidated iSCSI draft list the keys used for removed features and
> prohibit  a NotUnderstood response to those keys (Reject would be an acceptable alternative
> response).
> 
> If we're careful about this, the same version value can apply to 3720/5048 and the consolidated
> iSCSI draft.  I'd suggest that we be careful, and the details of how can be worked out as we
> finalize the consolidated draft - I think we should have at least one more round of looking at
> features to remove.
> 
> After that, we'll need a version value for the new (SAM) features draft additions.  The result would
> be 3 version values:
> 	0 = no version claimed
> 	1 = 3720/5048 or new consolidated draft
> 	2 = (3720/5048 or new consolidated draft) + SAM 4/5 features from the SAM draft.
> 
> Comments?
> 
> The SAM 4/5 features draft will expire while draft submission is closed for the Beijing meeting - if
> we can resolve this issue, the next version of that draft could be submitted shortly after draft
> submission opens again, and would probably go to WG Last Call shortly thereafter.
> 
> Thanks,
> --David
> ----------------------------------------------------
> David L. Black, Distinguished Engineer
> EMC Corporation, 176 South St., Hopkinton, MA  01748
> [phone]             FAX: [phone]
> [e-mail]        Mobile: [phone]
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