Re: From Andy:

>> I can't find any documentation on it at all. Has anyone found any? If it
>> does what it says it does on the side of the tin, it might be useful.
>
> That's the conclusion I drew.  I don't know if you follow the main
> Consume  mailing list, but the creator has been answering questions
> there.   Allegedly there's a 6000 user trial going ahead!  That should
> prove/disprove the theory.

I've downloaded the ISO, and had a prod at it.  Basically, it's derived 
from a slackware distro, hence the size.  I haven't actually tied using it 
(for lack of suitable laptop and prism card) but from looking at it I'd be 
surprised if it does do what it says on the tin. From a 15 minute 
inspection of the ISO image, this is what I've discovered.

A node either operates in gateway or cell/repeater mode.  The node decides 
it's the gateway if it recieves a response to a ping from a hard-wired 
address (an upstream IP router, ie. your ADSL router).

If it decides to become a gateway, it starts up a vtund daemon (vtun is 
quite a nice a VPN protocol), and waits for cells to join.

If a node doesn't recieve a response to said ping, it decides to become a 
cell/repeater.  If it associates with a gateway, it starts up a vtund 
session with it.

Nodes randomly select a /24 network from RFC1918 space, and use allocate 
addresses from this address space to clients.  The default IP gateway is 
the gateway node, hence all traffic is routed via the gateway.

My opinion is that this is a brave effort, but I will happily bet any part 
of my anatomy that this won't scale to 6000 nodes.  There are so many 
things wrong with this approach it's difficult to know where to start, but 
here goes:

1) This ain't a mesh network.  Repeaters must associate directly with the 
gateway node, and can't associate with each other.  Repeaters can't pass 
data between themselves, and can't "chain" at all.  This limits the size of 
the wireless "footprint", and increases the density of ISP connections that 
you require.

2) There's no attempt (that I can see) to ensure that IP address space is 
non-overlapping.  Hence, it's possible for two nodes to randomly select the 
same /24 network.  The larger the network becomes, the more likely a 
"collision" will occur (1 in 256 for the second node, with the probability 
doubling whenever a new node associates).  Guess what this will do to the 
routing.  Peer to peer communication will be flaky and will get 
progressively worse as the network grows.

3) You can't even roam between *repeater cells* without being allocated a 
completely different IP address.  Which may or may not be conflicting with 
someone else, d'oh.

4) No authentication/encryption.  Yes it says encryption on the website, 
but the keys on the tunnels are like this:
	YesAtTheMomentAllEncryptionKeysAreTheSame0
	YesAtTheMomentAllEncryptionKeysAreTheSame1
	YesAtTheMomentAllEncryptionKeysAreTheSame2
	etc...

IMHO, this is really just a very complicated and broken system for NATing 
an internet connection over wireless.

cheers, josh.

Josh Howlett, Networking and Digital Communications Group,
Information Systems & Computing, University of Bristol.
email: [email protected] | phone: +44 (0)117 928 7850

Bristol Consume Website: http://consume.andylaurence.co.uk/
Bristol Consume Discussion: http://consume.cyberprog.net/
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