Subject: iSCSI: CmdSN during login : Tabs removed

From: Sanjay Goyal <[email-masked]>
Date: Fri, 10 Aug 2001 10:44:41 -0400

Hi

 Assuming Target and Initiator support multiple connections and the session
is having multiple connections. Assuming out-of-order CmdSN is a possibility
for this session.

 Connection #     1     |    2      |     3
-------------------------------------------------------
Login Cmd  CmdSN=0      |   CmdSN=8	|  CmdSN=9
Txt   Cmd  CmdSN=1      |    	      |   
                        |           |   
                        |   	      |   
Txt   Cmd  CmdSN=7      |  CmdSN=10	|  CmdSN=11
-------------------------------------------------------
Data Cmd   CmdSN=12     | CmdSN=14  | CmdSN=15
Data Cmd   CmdSN=13     |           |
                        |           |

CmdSN=7 is last of the Login sequence and it is acknowledged by the Target
with "accept login" response.

Target would receive the PDUs in this CmdSN order
 0 to 7, 8, 9, 12, 10, 11, 13, 14, 15

Now as Login and Text PDUs are being processed even though you have received
Data Cmd PDUs, you can not pass them to SCSI layer and hence you are adding
latency. 

What I want to convey from this example is why not use CmdSN just during the
FullFeature phase only.

Regards
Sanjay Goyal