iSCSI: statement on mandatory/optional

["Mallikarjun C." <cbm@rose.hp.com>]

Julian,

I suggest the following explanatory text to be added to
the iSCSI main draft (possibly as section 1.2.1).  I really
think this (in an abstract sense) helps readers to understand 
the optionality or otherwise of iSCSI features.

Mandatory and optional features

  - All the features that are specified in this draft are
    mandatory to implement and mandatory to use, unless otherwise
    stated.
  - Features that are identified as "mandatory to implement
    but optional to use" (like the digests) MUST be implemented
    and MUST be honored by one side when the other side uses
    them (as in a PDU type), or wants to use them (as in negotiation).
  - Features that are identified as "optional to implement" 
    (like the synch and steering layer) imply that implementations
    that support the features MUST interoperate with other 
    implementations that do not support these features (i.e.
    implementations are guaranteed to be interoperable regardless
    of the feature support).

Regards.
--
Mallikarjun 


Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
MS 5668	Hewlett-Packard, Roseville.
cbm@rose.hp.com