RE: Problem with use of NotUnderstood in negotiations

["THALER,PAT (A-Roseville,ex1)" <pat_thaler@agilent.com>]

Julian,

In the scenario, each device does use Notunderstood in a response. 

A sends keyxxx
Silent data corruption occurs that changes keyxxx to keyxxy
B gets keyxxy and doesn't recognize it so it responds
keyxxy=Notunderstood
A gets that and thinks it is an offer of a key it doesn't understand because it never sent keyxxy.
A therefore sends
keyxxy=Notunderstood
B gets keyxxy and doesn't recognize it so it responds
keyxxy=Notunderstood
.....

Regards,
Pat

-----Original Message-----
From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Friday, August 09, 2002 9:24 PM
To: ips@ece.cmu.edu
Subject: RE: Problem with use of NotUnderstood in negotiations



Bill,

Perhaps the text is unabiguos but you just ignored the text that forbids
it.
The use of Notunderstood is limited to responses. Using it as you suggest
is a protocol error.
A repeated use will also violate the "no renegotiation rule".

Julo




                                                                                                                                    
                      Bill Studenmund                                                                                               
                      <wrstuden@wasabis        To:       Bart Crane <bcrane@iready.com>                                             
                      ystems.com>              cc:       <ips@ece.cmu.edu>                                                          
                      Sent by:                 Subject:  RE: Problem with use of NotUnderstood in negotiations                      
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                      08/10/2002 02:22                                                                                              
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On Fri, 9 Aug 2002, Bart Crane wrote:

?? In the scenario I describe, neither side believes it offered the key.

> Thus, there is no need to add another rule regarding not-responding to
> keys with NotUnderstood as a value, because a key with that value is
> a protocol error.
>
> This could be made more explicit, but there does not seem to be any
> ambiguity.

There obviously is ambiguity. The fact we're having this discussion is
proof. :-)

I'd support saying this case is a protocol error, since it means something
neither side understands got into the stream (and chances are an offer got
removed). But I think adding an explicit direction as to what to do is
needed.

Take care,

Bill