[MLB-WIRELESS] [TIB] A new offer has been added to TIB-23/01/2003

[James Healy]

> My brief research since this was posted suggest that this is pretty
> critical. As I understand it, this means a wireless mesh can only be
> built using nodes in ad-hoc mode, or perhaps using AP's that support
> point-to-multi-point bridging. You cannot build a mesh
> using a mixture
> of these, as they can't talk to each other.

I'd probably disagree.

If we were aiming for a 'true' mesh, then this would be true. (ie.
where everyone has one radio, operating on the same channel, same
SSID, probably with an omni). But for many reasons this isn't
practical, including (but not limited to!)

- creates unneeded polution
- much more susectible to polution created by others
- bandwidth issues (see
http://melbourne.wireless.org.au/~yob/the_bandwidth_problem.html)

We're aiming for a huge network of interconnected nodes. Meaning, for
example

	a <-----> b <-----> c

node a and b can talk via IBSS, and b and c can talk via BSS, laser,
carrier pidgeon, smoke signals, whatever, and a and c can talk to
eachother as node b is routing.

One problem that will hopefully resolve as the network is developed is
that with this method, you can't open your laptop on the other side of
town and just expect a connection. You need to know what nodes are
nearby, and what channel/protocol/SSID they're running etc.

I think it was Simon Butcher that proposed on the list a month or two
back that maybe we can standadise a "public access channel". ie. once
nodes are interconnected with whatever method they want, they offer an
omni on channel 1 with the same SSID as everyone else to standadise
how people can connect.

Hmm.. does all that make sense? mebbe not :)

<snip>

> This makes it pretty critical that melb-wireless should
> recommend IBSS,
> and hence discorage AP's, for nodes that want to become
> part of a mesh.

or not... see above reasons.

> Can someone please correct me if I've missed something.
> Putting a $125
> AP up a pole is cheaper and more convenient than $60 WNIC +
> $88 PCMCIA
> cradle + $40 486PC in the roof.

True. I'd go for this option wherever possible. Maybe use an AP that
is capable of bridging to another AP to connect to a nearby node, and
run an AP in BSS mode for public access.

James


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