Re: iSCSI: Flow Control

[David Robinson <David.Robinson@EBay.Sun.COM>]

Matt Wakeley wrote:

> Ok, so now the SCSI processes the first command, and sends an RTT (XFER_RDY in
> FC terms) to the initiator.  Now, the initiator sends the data down the same
> TCP connection, and it gets stuck behind all those 998 commands in the TCP
> receive buffers.  The command can't complete because it can't get the data,
> and the data can't be delivered because there's no room for the commands in
> front of it.  Deadlock.  Do you see the issue now?  (this is a good example of
> why the single TCP connection model, be it synchronous or asynchronous, is
> bad).

As I said in other e-mail I question the use of RTT in a modern
environment with large buffering. Data immediately following the
command makes much better sense to me, but if we must support
this environment then you are right that deadlock can occur.

	-David