Date   : Tue, 28 Jul 2009 22:16:17 +0100
From   : mfirth@... (Michael Firth)
Subject: Econet <> Ethernet

----- Original Message ----- 
From: "Phil Blundell" <philb@...>
To: "Rob" <robert@...>
Cc: "BBC micro mailing list" <bbc-micro@...>
Sent: Tuesday, July 28, 2009 12:15 PM
Subject: Re: [BBC-Micro] Econet <> Ethernet


> On Tue, 2009-07-28 at 11:38 +0100, Rob wrote:
>> But you don't need to use that because I also support an AUNMap file
>> (copied off the A5000) to link net number to IP range, so to contact a
>> given net.stn, it checks the overrides first, checks map for the
>> network range, then assumes the last octet based on the station
>> number.   (It then remembers all this for next time.)
>>
>> Thus for me, 192.168.0.x is net 128,  192.168.12.x is net 132 and
>> 192,168.13.x is net 133.
>
> Yeah, that works well enough within a site where you can use
> private-network addressing.  But for WAN routing across the Internet it
> isn't quite sufficient because it would still require you to assign a
> globally-routable IP to each station and that isn't likely to be
> feasible for a lot of people.  (I'm not quite sure how RIPE would react
> if you approached them requesting to be allocated a /24 network to use
> with AUN, but I think the chances of success would be slim.)
>
> In order to make it workable for routing between different sites, which
> might only have a single globally-routable IP address each, you'd need
> to add some kind of encapsulation or tunnelling layer on top of the AUN
> protocol.  The easiest way to do that would be RFC2003 IP-in-IP.
>
Is it possible to route RFC2003 through typical DSL firewall / routers?

I thought they were limited to forwarding TCP or UDP ports, RFC2003 seems
to be a seperate IP protocol from TCP and UDP (4 vs 6 and 17)

If this could be done, then it would be possible for up to 254 Enthusiasts 
to set
up an "inter Econet" by building enough tunnels, and suitably adjusting 
their own
local network ranges - most people run as the default of 10.0.0.x or 
192.168.1.x,
but it is usually simple (and more secure) to change this to another range.
There is the issue of whether every person would need one subnet for their 
Ethernet
side, and at least one more for the Econet side, but I doubt there would be 
even the
127 takers that this would limit things to.

Obviously that doesn't cater for the low level interest - it would be cool 
if people could
just download BeebEm and join in.

There is also the security challenge - the Beeb community may be relatively 
honest, but
I don't think I'd be completely happy with creating an open tunnel into my 
home network
to all enthusiasts.

I guess if the Econet<>Ethernet gateway can terminate the IP in IP sessions, 
then it could
also do a firewalling function, blocking anything from going over the 
tunnel(s) apart from
the AUN traffic.

That wouldn't help people whose primary machines are RiscOS though, as 
having AUN
open to an unknown community would still be a risk (no pun intended!)

>> AUN seems to rely on IP routing, rather than the bridge econet uses,
>> so it surprised, and pleased me, that it "just worked" without having
>> to emulate a bridge as well.
>
> Yeah, the Econet bridge is designed to be transparent: aside from asking
> it for the local network number (if they care about that), the endpoints
> never need to be aware of its existence.
>
>> I'm still struggling a little with broadcasts, but I've not had much
>> time to spend on it recently; it's only going to be something simple
>> wrong,  Plus, I really need to find something relibale that uses them
>> to test, lol.
>
> Heh, right.  Something like *SERVERS is probably the easiest way of
> exercising broadcasts.
>
Presumably *STATIONS does something similar? (though I guess though
you typically get more responses, the broadcast initial message is 
presumably
very similar)

>> As soon as I get that sorted, I'll be ready to get the code off to
>> Mike for inclusion in the released version.
>
> Very good.  I'm somewhat ashamed to report that I haven't actually tried
> out the BeebEm AUN bits yet, though I know Mark has had a go with them.
> I guess we should try to find out why it doesn't seem to want to talk to
> our bri^H^H^Hgateway at the moment.
>
Out of interest, how far away do you think the Econet<>Ethernet device is
from being something that other people can buy / use?

I still haven't looked into how !Gateway is configured, but without any 
documentation
it will probably be challenging!

Regards

Michael