Subject: iSCSI: Clarification requested

From: "Prasenjit Sarkar" <[email-masked]>
Date: Tue, 19 Jun 2001 15:09:55 -0700

Can multiple iSCSI sessions share a TCP/IP connection? (We came across an
implementation that does this).

If I've missed text which disallows this, apologies in advance,

Regards,
Prasenjit

   Prasenjit Sarkar
   Research Staff Member
   IBM Almaden Research
   San Jose

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From: Stephen Bailey <[email-masked]>
Date: Wed, 20 Jun 2001 11:45:12 -0400

Prasenjit,

> Can multiple iSCSI sessions share a TCP/IP connection?

Huh?  My knee jerk is, absolutely not!  How could that work?  How are
the PDUs for different sessions distinguished?

Independently of that, the login process doesn't allow it.  There's
only one SID pair exchanged, with a Login/Login Response and then the
connection is in full feature mode (at which point, you couldn't
exchange more SIDs).

> (We came across an implementation that does this).

So, I'll bite, how DOES said implementation do this?

Wow.

Thanks,
  Steph

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From: Mark Bakke <[email-masked]>
Date: Wed, 20 Jun 2001 16:24:17 -0500

We implemented a similar thing early last year, which allowed
multiple targets to be accessed on a session, but only one session
on the connection.  There's no session ID in the PDU headers, so
multiple sessions on a connection could probably not be done
anyway.  We later decided that multiplexing targets on a session
was just not worth doing.

I think that if it hasn't been clearly stated already, the iSCSI
spec should say:

  1 initiator-target pair per session
  1 session per connection

The MIB reflects this model.

--
Mark

-- 
Mark A. Bakke
Cisco Systems
[email-masked]
763.398.1054