Date   : Tue, 12 May 2009 00:46:38 +0100
From   : mu.list@... (Mark Usher)
Subject: net monitor - help pls!

Is the frame type byte set correctly? That might explain why it isn't been
recognised.

-Mark 

> -----Original Message-----
> From: bbc-micro-bounces+mu.list=aon.at@... 
> [mailto:bbc-micro-bounces+mu.list=aon.at@...] 
> On Behalf Of Rob
> Sent: 11 May 2009 20:41
> To: BBC micro mailing list
> Subject: Re: [BBC-Micro] net monitor - help pls!
> 
> On 11/05/2009, Chris Johns <chris@...> wrote:
> >> Just need to work out why the **** beeb is trying to resend the 
> >> scout, when I acked it, and how I'm suposed to spot that..
> >
> > Does AUN use 4-way handshake in the same way as Econet? I 
> thought it 
> > just sent the data in a UDP packet, and didn't bother with 
> the scout.
> 
> Nope ... just a two way handshake - the AUN UDP packet has a 
> sequence number in it, and there's an ACK packet containing 
> the same sequence number sent back on receipt, so the 
> transmitter knows it's been received.
> 
> I'm faking the first ack to the beeb in response to the 
> scout, and buffering the scout and it's control byytes so I 
> can add the data packet to it and send the lot as a UDP 
> packet when that arrives.  I then issue the final ack back to 
> the beeb when I get the ack from the remote AUN host.
> 
> (I'm probably leaving myself open to lots of bugs should 
> there be more than one host tring to talk to the emulator at 
> the same time, but I'll worry about that later!  The Beeb 
> being emulated wouldn't be able to deal with that anyway.)
> 
> What I've been seeing so far is
> scout->
> <-ack (faked)
> scout-> which i think is data, so send to the remote host,
>      (get ack from aun host)
> <-ack
> data->  (which fails to be interpreted as a scout ...)
> 
> I'd assume that my first ack is at fault, so the beeb is 
> resending, but not quite sure how it could be - it's only 
> four bytes after all!!
> It might be a timing issue, but I'm using the same timing as 
> the current pseudo-econet code, which does work..
> 
> Not had chance to play with it today, but will have another 
> go later when the kids are settled..
> 
> rob
> 
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