Date   : Wed, 12 Aug 2009 13:50:40 +0100
From   : michael.firth@... (michael.firth@...)
Subject: Econet <> Ethernet

> -----Original Message-----
> From: 
> bbc-micro-bounces+michael.firth=bt.com@... 
> [mailto:bbc-micro-bounces+michael.firth=bt.com@...
> .uk] On Behalf Of Phil Blundell
> Sent: 12 August 2009 12:04
> To: BBC micro mailing list
> Subject: Re: [BBC-Micro] Econet <> Ethernet
> 
> On Tue, 2009-08-11 at 17:28 +0100, Phil Blundell wrote:
> > So, I think the UDP encapsulation is probably the way to go.
> 
> I've written down a proposed packet format for this:
> 
> http://beebwiki.jonripley.com/Routable_AUN
> 
> Comments/suggestions welcome.
> 
> p.
> 
One thought that springs to mind is it would be useful to have some sort
of ID in the 'registration' message, to prevent spoofing of the deregistration
/ accept / reject messages.

Something along the lines of a 32 bit random number that the sender of the
registration message inserts, which has to match in a registration accept
/ reject, and which it (or the other end) will then send in any corresponding
deregistation message.

I guess if you also include this ID in the AUN packets, then it gives a (very
primitive) form of security on the transmission.

You might also want some other form of persistent ID in these messages, 
so that more than one gateway can sit behind the same NAT device (and hence
IP address) - I'm not completely sure why you'd need this, but it seems sensible
to make the protocol capable of supporting it.

Something like that would also help with an accept / reject decision - if
people agreed on an ID range then you could build Econet "VPNs" that would
talk to each other, but reject messages outside the ID range.

Regards

Michael