Subject: Re: [Simple] Questions regarding MSRP drafts

From: Cullen Jennings <[email-masked]>
Date: Fri, 21 Oct 2005 21:48:22 -0700

You have some great comments - one I wanted to comment on.

On 8/10/05 1:33 PM, "Paul Kyzivat" <[email-masked]> wrote:

>> Buffer overwriting
>> -------------------
>> 
>>   draft-ietf-simple-message-sessions-11 recommends that, in case of
>> chunk retransmit, the end point overwrites already received data with
>> newly received one. While it is only a SHOULD, there does not seem to be
>> any reason for this. It is illegal to receive new data that would not
>> match previously received chunks anyway. Actually, I'd rather consider
>> this as the sign of a hack attempt. So why should clients do that?
> 
> I agree with you on this one. I wanted it to be an error for any
> overlapping data to differ from the original. (Without requiring that
> this error be detected.) But I was outvoted.

This is somewhat an result of that from an overall message point of view,
this is not a store and forward system but more of a streaming systems. It
is ok to use part of the message before the whole thing is received. People
that were outputting to an output device like a speaker, or a brail printer
may not be able to backup over the data that was already output. 

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From: Paul Kyzivat <[email-masked]>
Date: Sat, 22 Oct 2005 18:37:26 -0400

> may not be able to backup over the data that was already output. 

That is why I wanted to declare it an error but not require it to be 
detected. If you are streaming data, then you just don't detect the 
error. But if you are storing data (e.g. if it was a file transfer) you 
could detect the error.

But this isn't a big deal as long as it isn't considered a *feature* to 
retransmit changed data.

	Paul

	Paul