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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: iSCSI : target session login behaviour"Mudaliar, Hari" wrote: > 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. Hari, You may want to take a second look at my mail. It specifically refers to the problem in the context of a given (Initiator Name, ISID). Your example above does not fall under that category. A 2nd initiator using the same ISID would have a different Initiator Name. (a.k.a initiator WWUI). The problem raised is in the context of an existing session for a given (Initiator Name, ISID). How does a target deal with a second session login received for the same (Initiator Name, ISID) with a NULL TSID ? > 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. Then again, it may not. There's 2 aspects to this issue : 1) Successful session re-logins from the rebooted host. 2) Garbage collection and cleanup of the old session resources. (1) is a more serious issue, since the target MUST NOT reject the login based on a pre-existing active session for a given (Initiator Name, ISID). (2) is handled through garbage collection algorithms, but implementation of the proposal would help accelerate the release of stale session resources. - Santosh > > -----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 begin:vcard n:Rao;Santosh tel;work:408-447-3751 x-mozilla-html:FALSE org:Hewlett Packard, Cupertino.;SISL adr:;;19420, Homestead Road, M\S 43LN, ;Cupertino.;CA.;95014.;USA. version:2.1 email;internet:santoshr@cup.hp.com title:Software Design Engineer x-mozilla-cpt:;21088 fn:Santosh Rao end:vcard
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