SBP2 clarification

Stephen_Finch at Stephen_Finch at
Tue Sep 16 09:10:31 PDT 1997

* From the T10 (formerly SCSI) Reflector (t10 at, posted by:
* Stephen_Finch at

First, this message should have been sent to the T10 reflector, I have
enclosed it and copied my answer to both reflectors to make sure all have
seen my response.  In the future, let's do SBP-2 only on the T10 reflector.

Now, my answer:

Whether the target uses different CSR addresses for different initiators is
definitely an implementation issue.  The combination of source_ID,
destination_ID, and CSR address must provide the information necessary for
the target to determine what initiator's are allowed to talk to which
units/logical_units and which aren't, and to make sure that it can't make a
mistake in doing so.  Reuse of CSR addresses is possible, using different
CSR addresses is a little more obvious.  Even using a single CSR address to
to allow initiator 1 to talk to unit 1, and allow initiator 2 to talk to
unit 2.  I don't think I'd choose to do it that way, but there is no

The fetch agent for each initiator/lun pair is unique.

steve finch

srao at on 09/15/97 10:38:18 AM

To:   p1394 at Sun.COM
cc:    (bcc: Stephen Finch/SSI1)
Subject:  SBP2 clarification

I was going through SBP-2 document. I have following
observations and questions.

If target supports mutilple units
  Each unit will have its own Management CSR.
  Each unit can have one or more logical units.
  Each logical unit can support single initiator or multiple

If the target allows multiple initiators ( for same LUN ),
 will the target give
different fetch agent CSR space for each initiator, Or does it
give single fetch agent CSR space for all initiators in the logical
unit? Or Is it implementation dependent?

It seems to me that having different fetch agent CSR space for
each initiator is logical to me. Is it?

Is there are different fetch agents for same LUN ( if above
assumption is OK ), then they run independently. If so, in
which order the command ORBs are executed? Does SBp-2 specify this
or Is it completely implmentation dependent?

Thanks in advance
SRINIVASA ADDEPALLI                             408-566-0280 x309
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