RE: iSCSI : target session login behaviour

["Mudaliar, Hari" <Hari_Mudaliar@adaptec.com>]

Santosh,
	I am assuming that you are referring to the creation of a new
session with TSID=0 in your example below. Take the case of an initiator I1
who has established a session with a target with an ISID=ISID1. What if a
second initator I2 tries to login to the same target with ISID1? The target
cannot decide to logout the first initiator (who already has a session
established with ISID1) as suggested by you. It must reject the login.
Initiator I2 perhaps needs to retry with a different ISID.
	Also, depending on implementation, the target may realize that the
TCP connections for a session were lost (using Keep-Alives or iSCSI NOPs
etc.) when the initiator rebooted thus terminating the session. By the time
a new login from the same initiator is received, the old session info may
have been cleared.

- Hari
 

-----Original Message-----
From: Santosh Rao [mailto:santoshr@cup.hp.com]
Sent: Wednesday, April 25, 2001 11:19 AM
To: IPS Reflector
Subject: iSCSI : target session login behaviour


All,

How should a target respond when it receives a session login  [on a new
TCP connection] with the same (ISID, Initiator Name) as a session
already active at the target.

Does such a login request imply :

1) the target should perform implicit logout and re-login of the session
identified by (ISID, initiator name) ? 

2) Or does this result in the target responding to the session login
with :
a login response with status class of non-zero indicating target is
rejecting the login ?

[The draft does not describe target behaviour for this scenario.]

iSCSI session login semantics should explicitly state that the above
scenario will result in case (1) above. i.e. when a target sees a
session login for a given (ISID, initiator name), it MUST treat this as
an implicit logout of any previous session active at the target for that
(ISID, initiator name) and then, establish a new session.

This is required because the above scenario can typically occur when an
initiator reboots without having performed a session logout on all
active sessions.(system did not perform an orderly shutdown).
 
As a side note, the iSCSI draft Status Class/Codes could do with a misc
error category along the lines of the FC "No additional Explantion"
reason explantion. This would help deal with error conditions that don't
come under the listed category.

- Santosh