[Preston] Network Newbie need help with WiFi

[Richard Revis]

On Wednesday 20 Nov 2002 9:52 pm, Ken Wolstencroft wrote:

> St Annes is not a problem, the idea is to build a number of nodes and t=
hen
> fill in the gaps.

Well, I *might* be able to nick a 24dbi directional antenna from work, to=
=20
point at a tower block in Preston ;o)

> I was considering using zebra, but I will have a look at mobile mesh.

Zebra/OSPF has a number of issues, the worst being the application of rou=
tes=20
to the kernel routing table on backup routers. OSPF is also not designed =
for=20
a wireless environment and as such the metrics are not the best. You may =
have=20
seen my posts to $mailing_lists about my issues with Zebra recently.

On the plus side you do not need to run the routing software on every nod=
e - I=20
have a perl script which uses a broadcast ping to detect clients, which t=
hen=20
adds them to the kernel routing table and this is distributed via OSPF.

Grid (http://www.pdos.lcs.mit.edu/grid/) *does* take account of link=20
congestion as well as hop count but is even worse to configure than Zebra=
=20
IME, and is not ideal for large scale WLANs, especially since it seems ve=
ry=20
prone to partitioning for no reason I can determine.

Mobile mesh (http://www.mitre.org/tech_transfer/mobilemesh/) is a happy=20
medium. You *do* need to run it on every node, but it is very very easy t=
o=20
run (even on a zaurus). It can be configured with multiple internet=20
connection points accross the WLAN if required, and can use these to rout=
e=20
WLAN traffic via wired routes if it determines that this would be faster.=
=20
This also allows it to mostly stop BSSID partitioning, a serious problem =
in=20
very large WLANs. The metric system is not the best but in IME works fine=
 in=20
99% of cases.

Where hotspots are not linked of course you can then route your authentic=
ation=20
information over the global internet to the radius server(s).

=2E..this all assumes that you were planning to run the thing as a large =
ad-hoc=20
cloud of course.

> At present I have been building a central user database for radius
> authentication. This will allow users to access any of our groups nodes
> from a single user account, the idea is to connect users via vpn.

IPSEC or CIPE? Be wary of tcp over SSH where link quality is bad -=20
http://sites.inka.de/bigred/devel/tcp-tcp.html

> I would like to build a list of potential nodes for the group, so if an=
yone
> is interested either e-mail me direct or to the list. The group website
> will be launched at the end of the week, so if you would like to join t=
he
> fun I will add you to the list of nodes.

As you may have gathered I did do some of this for profit as well as fun =
;o)=20
Hope some of this information helps you, after all I got paid to bang my =
head=20
against a brick wall, no reason why you should have to do it again for fr=
ee!

--=20
Richard Revis
Outgoing e-mail is signed with my public PGP key
You may obtain a copy of my key at http://key.revis.org