Re: ISCSI: CmdSN in non-leading login

["Julian Satran" <Julian_Satran@il.ibm.com>]

Logins are all immediate. CmdSN is the current one and not advancing by the sender and should not be checked by the receiver.
Nothing special needs to be mentioned.

Julo

"Mark S. Edwards" <marke@muttsnuts.com> Sent by: owner-ips@ece.cmu.edu 05/10/2002 12:51 PM Please respond to "Mark S. Edwards"

To:        ips@ece.cmu.edu         cc:                 Subject:        ISCSI: CmdSN in non-leading login

I am looking for clarification with regard the value that an initiator 
should put in the CmdSN field of a login request for a non-leading connection.

There is a certain ambiguity about 9.12.8.  The text describes how in a 
leading connection, the target takes must accept and use a non-zero CmdSN, 
but it does not explain what should be present for a non-leading connection.

There are a couple of problems here for the target.  At what point is a 
non-leading connection considered to be part of the session ?  Is it the 
moment that the login request is received with a non-zero TSIH ?  Or is it 
only when the non-leading login succeeds and it enters full feature phase ?

So, should an initiator set the CmdSN in the first login request to zero 
and only synchronise with the session command stream after full feature 
phase is established ?  This is my preferred option.

What happens if the initiator tries using the current session command 
sequence number is that whilst the login negotiation occurs, other 
connections within the session can be issuing new commands, so by the time 
that the login is finished the CmdSN exchanged in the initial request is 
invalid anyway.

I would like to see something along the lines that for a non-leading 
connection, the CmdSN field MUST be zero and that the connection can not be 
considered part of the session until full feature phase is entered, at 
which point any commands issued on the connection are now synchronised with 
the session command sequence number as observed by all other existing 
connections on the session.

regards,

Mark.