RE: ips : Is FirstBurstSize valid when InitialR2T=yes ?

["THALER,PAT (A-Roseville,ex1)" <pat_thaler@agilent.com>]

Michael, 

It doesn't matter that FirstBurstSize was negotiated but is now not used. It doesn't hurt anything for it to be sitting around with a value in it. Also, the initiator declaring that it is ready to go to Full phase does not mean that the target has to go to full feature phase. The target can still continue to negotiate and, if the target does continue (by sending T=0), the initiator can change back to T=0 in its Login Request. What would happen is:

I->T	FirstBurstSize=512; T=0; NSG=CSG;
T->I	FirstBurstSize=512; T=0; NSG=CSG;
I->T	InitialR2T=no, ImmediateData=no; T=1; NSG=FULL
T->I  InitialR2T=yes, ImmediateData=no; <declarative keys>; T=1; NSG=FULL
 or if the target still has other keys it wants to send in further PDUs or the target also originates a key this line would be
T->I InitialR2T=yes, ImmediateData=no; <declarative and originated keys>; T=0; NSG=FULL

In this latter case, the initiator might respond with T=1 if it is still ready to go to full feature phase or it might respond with T=0 if to continue the negotiation in response to the new keys it received.

When the Initiator originates keys while setting T=1; it is allowing the target to respond and is willing to go to the next phase regardless of the response.

Regards,
Pat

-----Original Message-----
From: Fischer, Michael [mailto:Michael_Fischer@adaptec.com]
Sent: Wednesday, February 06, 2002 11:39 AM
To: 'Eddy Quicksall'; Santosh Rao; IPS Reflector
Subject: RE: ips : Is FirstBurstSize valid when InitialR2T=yes ?



What if the sequence is as follows:

I->T	FirstBurstSize=512; T=0; NSG=CSG;
T->I	FirstBurstSize=512; T=0; NSG=CSG;
I->T	InitialR2T=no, ImmediateData=no; T=1; NSG=FULL

If the target does not support InitialR2T=no..  Does login now fail?  There
does not seem to be a way for the target to say that it requires R2T.  Why
did the Initiator send FirstBurstSize if it was setting InitialR2T to no?
There is no negotiation with an AND function.   

Michael Fischer

-----Original Message-----
From: Eddy Quicksall [mailto:Eddy_Quicksall@ivivity.com]
Sent: Wednesday, February 06, 2002 9:47 AM
To: Santosh Rao; IPS Reflector
Subject: RE: ips : Is FirstBurstSize valid when InitialR2T=yes ?


That is how I am interpreting it.

BTW: How about this one ...

I->T FirstBurstSize=512, InitialR2T=no, ImmediateData=no

If the target does not support InitialR2T=no, how should it respond to
FirstBurstSize?

Should the target do this (for draft >= 9)?

T->I FirstBurstSize=irrelevant, InitialR2T=yes, ImmediateData=no


Eddy

-----Original Message-----
From: Santosh Rao [mailto:santoshr@cup.hp.com]
Sent: Tuesday, February 05, 2002 2:56 PM
To: IPS Reflector
Subject: ips : Is FirstBurstSize valid when InitialR2T=yes ?

Hello,

Can someone clarify if the login key FirstBurstSize is valid when :
InitialR2T=yes  and ImmediateData=yes ?

i.e. if immediate data is enabled and un-solicited data is disabled
during login negotiation, is the value of FirstBurstSize received in the
login response to be interpreted ?

My current understanding is that FirstBurstSize is inclusive of the
immediate data portion, and so, if immediate data is enabled, but
un-solicited data is disabled, then, FirstBurstSize *must* be valid and
must be <= DataPDULength. (after rev 09, it would be <=
(MaxRecvPDULength - the header components size)).

For example, a target implementation may offer a FirstBurstSize <
DataPDULength, in which case, the immediate data size is the
MIN(DataPDULength, FirstBurstSize, bytes_to_send).

Can someone clarify if this is a correct interpretation or set me right
on this ?

Thanks,
Santosh


--
##################################
Santosh Rao
Software Design Engineer,
HP-UX iSCSI Driver Team,
Hewlett Packard, Cupertino.
email : santoshr@cup.hp.com
Phone : 408-447-3751
##################################