"Lower overhead" iSCSI

[Dan_McConnell@Dell.com]

Let me start off by saying that I am interested in doing "iSCSI" protocol
over UDP.  Now I realize that this is an old issue and will probably start
some "religious" battles, but let me state the scenarios before I receive
death threats.  The planned environment that this will go into is a small
one with say 10 servers connected through a "non-blocking" switch to the
storage device (ie no routers, gateways, etc...just direct point-to-point
connections).  This is assuming that the switch is really non-blocking and
hopefully implements flow control or pause frames.  So technically all you
should have to worry about is port/device contention.  However, when you
think about it...this is similar to FC.  FCP runs on class 3 FC which is a
non-reliable transport protocol such as UDP and handles contention, also
some of the early "SAN interconnect" guys are doing this today with
relatively good performance and few issues.
	The attempt here is to maintain low CPU utilization at high
performance rates.  While I realize that these TOE devices are moving along
rapidly, there are some situations where they are not feasible, such as a
blade server environment (no PCI slots, and no real estate/power available
for onboard TOE).  Worst case scenario is that a packet is dropped or
received out of order and the ULP (SCSI) must resend the cmd/data sequence -
still no data lost, just a temporary performance hit.
	So my question is:  is this feasible?, and why not implement an
"iSCSI" protocol layer that can run over TCP or UDP(though I realize it
won't be considered "standards compliant")?

Thanks,
Dan