Subject: RE: [rddp] Optional CRC: Proposed Compromise

From: "Williams, Jim" <[email-masked]>
Date: Wed, 7 May 2003 14:47:18 -0400

> -----Original Message-----
> From: Barron, Dwight [mailto:[email-masked]]
> Sent: Wednesday, May 07, 2003 2:03 PM
> To: Williams, Jim; [email-masked]
> Subject: RE: [rddp] Optional CRC: Proposed Compromise
> 
> 
> Jim, would provide comments on the acceptability of the 
> following clarification points (aka fine print)?
> 
> - The CRC option always applies to both directions of a connection

That's what I intended.  Sorry if that was not clear.

> - The CRC field is always present, but sometimes may not be valid

This drops down to a lower level of detail.
However, that approach sounds right to me.

> - The disposition of the CRC option is never made available to the ULP

Likewise the request to opt out of CRC use
should not come from the ULP, or be visible to the ULP.

This doesn't sound like a problem in principle.  TCP typically
doesn't notify the application of what options are negotiated
at the TCP layer.  I don't know, however, what a reasonable
wording of this requirement would be.  It seems a bit strong
to require RDDP to insure that the ULP cannot, by any means, 
determine this.  Certainly vendors providing management
interfaces would want to make this type of information 
available.  Any reasonable wording should be OK, though,
as long as it's not too extreme, and clear on the spirit.

> I believe that one of the reasons you want CRCs 
> optional is that you deem link CRC+TCP checksum "sufficient." 

Sufficient in some cases.  That's the only reason.

> In both cases, I don't believe either of us are proposing 
> that the ULP take additional measures. 

I agree.

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---

From: "John A. Thodiyil" <[email-masked]>
Date: Wed, 7 May 2003 12:14:49 -0700

Hi RDDP Group
I have been following the Emails on this forum for a while.
I have some ideas. But i would like to get a detailed picture
of whats going on. As, i started following this later in the
process.
Any suggestions for me to get to the level of speaking and
making sense will be appreciated.

I however would like to make the comment that CRC at the RDDP
level has positives and negatives. By making the CRC optional
we do not forgo the positives and have the option to prevent
the negatives. 
This CRC negotiation can happen at the RDDP level since at STCP/TCP
does not look like a good place to do this and there are no hooks at
this point of life of TCP.

-John

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Williams, Jim
Sent: Wednesday, May 07, 2003 11:47 AM
To: [email-masked]
Subject: RE: [rddp] Optional CRC: Proposed Compromise

I agree.