Re: Potential data corruption in DDP with MSN protocol violation

On Apr 27, 2004, at 1:06 AM, [email protected] wrote:

> Tom,
>
> I think at a minimum there should also be something added to say that 
> if such a case occurs the receiver MUST not deliver whatever junk is 
> lying around as message 2.
>
> I don't mind the case where the connection grinds to a halt because it 
> has message 3 complete and no message 2. Something somewhere will time 
> out eventually and while it may not be as graceful as detecting the 
> error it is not disastrous.
>
> The case that worries me is a designer who did not think about 
> protecting against this error in the received stream. An 
> implementation may be built that assumes when the stream receives the 
> completion of MSN 3 and the stream has no gaps up to that point that 
> the prior messages are also complete. If we don't want to allow that, 
> then we need to says something explicit about it.
>
> Once we do that, we might as well add the error and at least allow an 
> implementation the choice of reporting it instead of silently 
> freezing.
>
> Pat
>

Do you agree that such text would be merely informative?

My reading is that the existing rules already forbid delivery
of message 3 when message 2 has not been delivered,
and message 2 can only be delivered when its L segment
is deliverable -- which it can never be if it does not exist.



--
Caitlin Bestler
http://asomi.com/