RE: iSCSI:flow control, acknowledgement, and a deterministic reco very

[julian_satran@il.ibm.com]

The main reason for selecting 0 and not a flag for immediate delivery was
to enable immediate delivery even when the command window is closed.

However we can achieve the same effect by using an immediate flag and
ausing the current CmdSN without advancing it.  With this we get a
reference to where in the stream the command where supposed to act if the
stream order is important. All commands that reached the target having
CmdSN less than the immediate CmdSN where sent before our command and all
those with a number equal or higher where sent after. Immediate commands
are the only ones that can have a CmdSN higher (by 1) that the allowed
window.

Julo