RE: iscsi : DataPDULength can differ in each direction.

["Rod Harrison" <rod.harrison@windriver.com>]

	Can someone give a tangible benefit to this that can outweigh the
spec and implementation churn at this late stage of the game?

	From my point of view the benefit of asymmetric PDU sizes would have
to be very large to make it worth the extra complexity in buffer
management code alone.

	- Rod

-----Original Message-----
From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
Ayman Ghanem
Sent: Wednesday, October 03, 2001 8:29 PM
To: ips@ece.cmu.edu
Subject: RE: iscsi : DataPDULength can differ in each direction.


Well, the proposal says:

	Each side should be allowed to specify the DataPDULength it will be
	using and there should be no attempt to negotiate this value. Rather,
	the key is exchanged in either direction to inform the other side as
to
	what sized PDUs it should expect.

So, I understand that as if the initiator sends
DataPDULength=reallyBigNumber, then it is informing the target that
this is
what it will be using, but the target should not attempt to negotiate
it.

-Ayman

> -----Original Message-----
> From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf
Of
> Buck Landry
> Sent: Wednesday, October 03, 2001 2:13 PM
> To: ips@ece.cmu.edu
> Subject: RE: iscsi : DataPDULength can differ in each direction.
>
>
> It may add complexity, but, since DataPDULength is only a boundary
on
> the maximum number of bytes transmitted in a Data PDU (not the
minimum),
> "the first" *does* have a say about it.  Right?
>
> -----Original Message-----
> From: Ayman Ghanem [mailto:aghanem@cisco.com]
> Sent: Wednesday, October 03, 2001 1:38 PM
> To: ips@ece.cmu.edu
> Subject: RE: iscsi : DataPDULength can differ in each direction.
>
>
> I think this will add unnecessary complexity, specially for data
CRCs
> having
> to be calculated based on two different PDU sizes for Reads and
Writes.
> Also, one end may choose to do data digests in software. If the
other
> end
> decides to use a really large PDU length (and the first doesn't have
a
> say
> about it), this could be a problem.
>
> -Ayman
>
> <snip>
>