Re: iSCSI sessions: Let's try again

[Matt Wakeley <matt_wakeley@agilent.com>]

Black_David@emc.com wrote:

<snip>

> Summarizing the above discussion:
>
> [Consensus Attempt 1]  I don't see anything that REQUIRES
> two TCP connections in all iSCSI sessions, because I haven't
> seen any TCP window closure scenarios [3] that aren't avoidable
> by reasonable design/engineering of the target.  I therefore
> propose to re-establish the WG consensus that multiple TCP
> connections per iSCSI session is OPTIONAL.

Reasons requiring 2 tcp connections per iSCSI session (one for commands the
other for data):

1- It allows a target to temporarily flow control commands from the initiator
while still allowing data to continue on the "data" connection (allowing
commands to complete so that the flow control can be opened again).

2- It allows commands to be received without being stuck behind a large data
transfer, allowing the target to begin command execution sooner.

3- if "Consensus Attempt 2" is allowed, it provides a single "model" of iSCSI
while allowing more than one data connection.  It also simplifies the "command
ordering" issues of the symetric model (sending commands on any connection).

-Matt Wakeley
Agilent Technologies