[afnog] need to identify low priced but good wi-fi bridge set

[Brian Candler]

On Tue, May 17, 2005 at 02:58:02PM +0200, Dr Paulos Nyirenda wrote:
> We are searching for a good but low- priced wi-fi set that can be used at an end 
> user to connect a large number of end-users, locations or networks VIA one Cisco 
> Aironet 350 central or root bridge covering a cell radius of about 3km. 

Are the local users to be connected to their wi-fi set via ethernet, or do
you want to create a second wireless cell within the customer premises?

And, how cheap do you want to go? :-)

There is commodity consumer hardware which can bridge ethernet to 802.11b/g
e.g.
http://www.dabs.com/uk/productview?quicklinx=30HT
http://www.dabs.com/uk/productview?quicklinx=3KN7
http://www.dabs.com/uk/productview?quicklinx=2X37

(search for "ethernet wireless" at this site and you'll find several others
from other manufacturers, at similar price point of around £50-£60)

These *are* just bridges. If you have lots of client PCs at a remote site,
you'll need to check that the bridge can remember enough MAC addresses,
including both the local site and all the other sites. And in any case, if
there are lots of clients at a site, you'd probably be better separating
them with a router (so that broadcast traffic from their site doesn't
propagate into the wireless backbone, and vice versa)

You can get broadband routers with built-in wireless, but I suspect that
they all require the wireless part to act as an access point, rather than a
client to another wireless network. However if someone knows of a device
which can work the other way round, please let us know...

It is possible to build your own. Something like a Soekris PC
(www.soekris.com) with a wireless PC card, running FreeBSD or Linux or
something commercial (e.g. Microtix). That would give you a lot of
flexibility, at the cost of complexity.

Or else just combine two devices to do the job you need:

      < - - - - -  \|/
                    |
                 wireless
                  bridge                 \|/ - - - - - more
                    |                     |         customer PCs
                    +----------------- router/AP
                       ethernet         | | | |
                                     customer PCs

Both are cheap items: e.g. Linksys WET54G (bridge) and WRT54G (router/AP)
would cost around $200 together. The wireless bridge can then be situated
close to the antenna, with a single CAT5 run to the in-building router/AP.
If you invest in a pair of CAT5-to-fibre adaptors and run fibre instead,
then a lightening strike will damage only the wireless bridge (and more
importantly, not the client's PCs!) However this adds to the expense: e.g.
http://www.dabs.com/uk/productview?quicklinx=36V2

This arrangement also lets you give their router one real IP address, while
the customer PCs use NAT. This is sufficiently flexible with port forwarding
that customers can run their own servers if they wish.

You can get router/AP combos that include a couple of phone ports, for doing
voice over IP, or VPN tunnelling software (which would secure your
customers' traffic over the air).

I haven't tested any of this... just suggesting some ideas.

> b)	antenna, yagi or patch, 
> c)	cable from bridge to antenna 
> d)	lightning protector 

Those would be extra, so if you go the 'cheap' route you'll need to assemble
your own kit of those. I guess you must be using something on the Aironet
350 already.

Regards,

Brian.