FCP Public Review Comment

Kurt Chan kc at core.rose.hp.com
Fri Mar 10 08:21:27 PST 1995

From: Kurt Chan
To:   X3T10
Subj: FCP Rev 10 Public Review Comment - Task Management Function Response
Date: 3/10/95

The following change proposal to add a mandatory Task Management
Function Response to FCP Rev 10 has been reviewed at great length by
the FC-AL adhoc working group in conjunction with Bob Snively.  Here
are the words we've agreed on:


In the description of Task Management Functions on page 60 of the
SCSI-3 Architecture Model (SAM), service responses are required which
indicate the status of the function:

- Function Complete
- Function Rejected
- Service Delivery or Target Failure

SAM requires that one of the above service responses be returned for
every task management function.  However, FCP provides no means of
providing that response.  There are valid reasons why such as response
is needed for multi-initiator, class 3 environments in Fibre Channel
(examples provided upon request).  It is inappropriate to rely link
layer acknowledgements (such as class 1 or class 2 ACKs) to provide
this service.

Therefore we suggest the following changes be made to FCP to make it
compliant with SAM, and to provide a reliable, service
class-independent FC-4:

Table 5, Page 10
- Change T1 to:  Command or Task Management Function Request
- Delete T5. (May want to add explanatory note regarding its absence).

Table 6, Page 11
- Change I4 to: Command or Task Management Function Response

7.4.5, page 33
Modify RSP_CODE = 00 and add codes 04 and 05 to table 20:

            RSP_CODE               Definition
               00        No Failure or Task Management Function Complete
               04        Task Management Function Not Supported
               05        Task Management Function Failed

The task management function may or may not have been performed by the
target if RSP_CODE = 05 is returned, or if no FCP_RSP is returned.
Values 04 and 05 are not valid responses to SCSI Commands.

B.1.9, page 53
Change the example to T1 instead of T5, and add the I4 response.
Delete the last sentence of the first paragraph.

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