RE: Question

["Sukanta Ganguly" <sganguly@opulentsystems.com>]

Well TCP's congestion control will still be functional but the the iSCSI cannot make much use of it as it sits at a higher layer than TCP. What really is required is a congestion control within the iSCSI layer and run it over plain IP, that would be the most efficient way of doing it. I agree to that some amount of TCP like congestion control will be built into iSCSI but will be much less than the overheads of the TCP layer (their are multiple ways of achieving reliability and congestion avoidance on UDP), and also will make useful sense for the iSCSI layer.
  I don't know whether it is too late of not, cause I see many companies spending a huge amount of money doing TCP offloads. According to them iSCSI is going to benefit out of it. Yeah it make the un-optimal way of doing SCSI over IP a little more fast by having a dedicated processor, but is it the most optimal way of doing the work ????
  I have nothing against TCP offload. but lets have a good iSCSI solution rather than patching up a unoptimal one.

SG


*********** REPLY SEPARATOR  ***********

On 10/24/2001 at 2:25 PM Somesh Gupta wrote:

>The question is not crazy at all (the answer
>might be :-)). New protocols are required (and
>really should for everyone's benefit) implement
>some congestion avoidance mechanism.
>
>Currently the easiest way to achieve this is to
>use TCP. Unfortunately we do not depend enough
>on it, leading to significant complexity
>in the protocol.
>
>Somesh
>
>> -----Original Message-----
>> From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
>> shesha bhushan
>> Sent: Wednesday, October 24, 2001 6:39 PM
>> To: ips@ece.cmu.edu
>> Subject: Question
>>
>>
>> Hi,
>>   I am doing a research project at Arizona State University on SCSI and
>> iSCSI. I was going through both the protocols. I have a crazy question.
>> iSCSI = SCSI/(TCP/IP). But SCSI is a reliable protocol so is TCP.
>> so can't
>> we just try to send SCSI packets on IP or SCSI/UDP. Any & All
>> comments are
>> welcome.
>>
>> Thanks
>> Shesha Bhushan S
>> Research Assistant
>> Arizona State University
>>
>>
>> _________________________________________________________________
>> Get your FREE download of MSN Explorer at
>http://explorer.msn.com/intl.asp
>>
>>