iSCSI: CRC-64 a "MUST"?

[Venkat Rangan <venkat@rhapsodynetworks.com>]

All,

I know this was discussed at length, but I tried locating an email stating a
consensus position that supports the following paragraph on page 93.

   "The following table lists cyclic integrity checksums that can be 
   negotiated for the digests and MUST be implemented by every iSCSI 
   initiator and target. Note that these digest options have only error 
   detection significance."

And CRC-64 is listed in the table as a "MUST" for implementation, with a TBD
on the polynomial. Is CRC-64 required if an iSCSI session never negotiates a
PDU size larger than 8K? Why is this requirement being imposed when it is
known to be not very useful at shorter lengths?

The draft-cavanna-iscsi-crc-vs-cksum-01.txt states that "CRC-64 is overkill"
in Section 5.

Can we therefore not be required to implement CRC-64? Also, even if a
particular instance implements it, and always negotiates it down to CRC-32Q
(or its equivalent), what is the purpose of carrying the implementation
burden of a never-used option?

Venkat Rangan
Rhapsody Networks Inc.
http://www.rhapsodynetworks.com