Because
of what Chuck pointed out, my feeling is that the TTT should be provided when
the A bit is set. It also makes the association faster since the ITT would
require a search by the target.
Eddy
-----Original
Message-----
From: Julian
Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Saturday, February 16, 2002 2:52
AM
To: Chuck
Micalizzi
Cc:
ips@ece.cmu.edu
Subject: RE:
iSCSI: DataACK SNACK
Chuck,
The Initiator
Task Tag is thhe only reliable indicator the protocol provides
today.
If nobody
shouts against it we might let the target provide a Target Transfer Task for
Data-In PDUs that have the A bit set
to
be returned with the ACK for target convenience.
Julo
|
|
"Chuck
Micalizzi" <chuck.micalizzi@qlogic.com>
15-02-02
23:14
|
To: Julian
Satran/Haifa/IBM@IBMIL
cc:
<ips@ece.cmu.edu>
Subject: RE: iSCSI:
DataACK SNACK
|
Julian,
Thank
you for the response.
Let me try to be more direct. If a target has been issued
multiple
read
commands, with transfer counts that exceed the negotiated
maxBurstSize. After the target sends a data sequence for one of
these
commands must it wait for a DataACK before sending a data
sequence
for
another command. Or is it free to send a data sequence for each
outstanding
command?
If the target can
have a data sequence in flight for each active command then
it must
expect a DataACK for each sequence sent with the
Acknowledge
bit set. If the
DataACK SNACK doesn't include a task Tag the target can't
be
certain
as to which data sequence the initiator is acknowledging. So how
can
the target determine
which resources to free or which sequence to send next?
chuck
-----Original
Message-----
From: Julian
Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Friday, February 15, 2002 9:30
AM
To: Chuck
Micalizzi
Cc:
ips@ece.cmu.edu; owner-ips@ece.cmu.edu
Subject: Re: iSCSI: DataACK
SNACK
DataACK is
a "bulk ack". Answering the last (in case of several) is good
enough.
I fail to
see your point.
Julo
|
|
"Chuck
Micalizzi" <chuck.micalizzi@qlogic.com>
Sent
by: owner-ips@ece.cmu.edu
14-02-02
21:02
|
To:
<ips@ece.cmu.edu>
cc:
Subject: iSCSI: DataACK
SNACK
|
All,
I have a question regarding DataACK.
Rev. 10 section
10.16.1 states:
For a Data/R2T SNACK, the Initiator Task Tag
MUST be set
to the Initiator Task Tag of the referenced
Command.
Otherwise, it is reserved.
it also
states:
The DataACK is used to free resources at the target and
not to request or imply data retransmission.
Is the
target allowed to have more than one DataACK
outstanding on a
connection?
If multiple outstanding DataACKs are
allowed per connection
then in my opinion the DataACK must have a
valid task tag
inorder for the target to associate the DataACK with
the
appropriate resources to be freed.
chuck
micalizzi
Qlogic Corp.
