Re: iSCSI: Flow Control

["Matt Wakeley" <matt_wakeley@agilent.com>]

David Robinson wrote:

> Could someone please clearly state the problem that
> iSCSI "flow control" is attempting to solve.  Given
> the reliable stream nature of TCP with its flow
> control, what problem exists? Also with an iSCSI
> layer flow control will we not also be victim to some
> nasty hysteresis effects due to TCP's flow control as
> well?
>
>         -david

I stated the issue in my earlier message of the same title:


> However, some have wanted to use the sliding window to solve a different
> problem.  They want to enable the target to advertise to the initiator how
> many commands the target is able to receive.  This apparently is not specified
> in SAM-2, and SAM-2 deals with overflowing the command queue in an ugly way -
> throw the commands away and enter an error state.
>
> The question here is whether iSCSI should attempt to solve the command queue
> overflow problem, or allow T10 to deal with it.  Other protocols (fibre
> channel) already deal with it in the "ugly" fashion - perhaps so should
> iSCSI.  What we need consensus on is whether or not iSCSI is going to deal
> with this.
>

There is LOTs of discussion on this topic in earlier postings.

-Matt