FCIP: Comment 109

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

Ralph,

> http://www.ietf.org/internet-drafts/draft-ietf-ips-fcip-wglc-01.pdf
....
> Please review these comments resolutions to ensure that
> the desired changes are described.


Sorry for the delayed review, I have additional comments on wglc-01
for Comment 109.

Regards.
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
Hewlett-Packard MS 5668 
Roseville CA 95747
cbm@rose.hp.com


>>Comment 109 Technical
>> 6.6.1 FCIP Encapsulation of FC Frames
>....
>> The CRCV (CRC Valid) Flag SHALL be set to 0.
>>
>> The CRC field SHALL be set to 0.
>I am surprised that the FCIP encapsulated header is never protected
>by a CRC. The error detection section clearly acknowledges the
>possibility that TCP checksum could be inadequate for certain
>deployments - and even suggests checking the FC frame CRC (sort
>of like a data digest) on reception at the Encapsulated Frame
>Receiver Portal.
>My recommendation is to require an FCIP Entity to employ the header
>CRC if the SF that it receives asks for CRC - IOW, similar to iSCSI's
>approach. So, I guess I am also advocating a new bit in the pFlags
>field to announce this. When this CRC expectation is announced, the
>FC CRC checking test in 6.6.2.2 should also be a mandatory test -from
>the "semi-optional" list it is currently in.
>Accepted with the following result
>Add the following to the new section created in response to comment
>44: "Note: Owing to the limited manner in which the FSF is used and
>the requirement that the FSF be echoed without changes before a TCP
>connection is allowed to carry user data, no error checking beyond
>that provided by TCP is deemed necessary."

Sorry, I missed the earlier discussion on this comment.

My comment was for __all__ FCIP encapsulated headers on all FCIP 
Frames - not just for FSF.  The reference to FSF in my comment was
to suggest how an "I want CRC" demand be communicated at the FCIP
Link establishment time - i.e. the reference was a solution strawman.

I probably missed something critical - could you please comment on
whether or not CRC protection is available on FCIP headers and
help me with a reference if so?