Doug Crompton on 29 Jan 2011 19:39:22 -0800

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: [PLUG] Can wifi mesh networks make up for Internet Service non-Providers

>Most mesh network technology is also not built with intentional
>jamming in mind.  The dinky transmitters in your Linksys router aren't
>going to stand up when somebody just dumps 10MW of RF in the 2.4GHz
>range.  A jammer could take out nodes for miles around.  You need a
>lot more nodes than jammers, and jammers aren't that expensive to
>build.  Because of natural corridors the jammers need not have
>ubiquitous coverage either.

This is true of most all commercial wireless. Several watts (wireless
routers and cellphones are 10's of milliwatts) of wideband noise close to
a tower or directed at a wireless antenna would wipe them out. If a
country has control of the communications network and is intent on taking
it down there is not much you can do. You cannot compare the US and a
country like Egypt where the very existence of some alternative means of
communications could be prohibited. In the US you can put a high gain
point-to-point antenna on your wireless router and talk across a city. In
many countries that might put you in jail for trying such a thing.

Mesh networks are used extensively in Africa to bring Internet to the most
remote areas. In those systems there is often only one route to the
Internet out of the mesh but many ways to get to that point with lots of
stations up. You still depend on that one connection to an adjacent mesh
or wire or satelite connection to the Internet. In a truely redundant mesh
here could be more than one "gateway" to the Internet but you sill have to
get thru the mesh to that gateway and then to the Internet. Nothing is
fool proof!

Virtually every wireless sites in the US depends on wire (Fibre) lines to
connect them. I would suspect that a few commands at a Verizon, ATT, etc.
command center could bring the whole thing down. Hopefully it is not that
simple but who knows. We have the perception of being more robust today
than 60 years ago when it was all copper, batteries, and relays but that
may not be the case. If you have FIOS and the power is down your Internet
and TV will fail and if it is down for more than 6 hours your phone will
probably fail also. Most cell sites don't have backup power. So if we
really have a serious power outage that lasts days I will be glad I have
my solar panel and ham radio. Beyond that there is smoke signals! I wonder
how many kids will go into convulsions from text withdraw when that

Philadelphia Linux Users Group         --
Announcements -
General Discussion  --