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Access ZM server over cellular link

Posted: Sun May 22, 2011 4:35 pm
by kp4djt
Normally in this case you would be connecting to the ZM host from a
display device with cellular data ability. But in this case the ZM host
is in a portable environment and as the system is moved around from
location to location (all over the country) they want to be able to just
install the facilities place the cameras (3-4 wireless cameras monitor-
ing job site locations) and access the ZM box over a cellular link. Of
course I assume that most all of us have gone the other way accessing
a ZM host on the wired network from a wireless device, now in this
case it would be the opposite. The big thing as I see it is if I try to use
some form of dyndns, the network is probably going to not like it as
most of them are not built on the idea of the server side being accessed
on the wireless side of the network.

Have any of you tried this and what were the results. I have considered
a VPN but my experience with VPN's over wireless links has not been
good because most VPN security and timing does not like the hit/miss
operation of a wireless link. And if you go in and modify the timers
on the VPN to deal with the idiosyncracies of a radio link then at times
when the link does die, the VPN takes a while to figure it out.

TAKE NOTE:
Due to the nature if the operation, they do not want to have to obtain
a DSL or cable line, they have tried this route and advise me that many
times they have the work almost done by the time they can get the
service requested.

WiFi is not a solution most places will not have it available and if they
do usually servers on the client side are a no-no.

Due to the transitory nature of the operation (construction) obtaining
a wired server at another location and using WiFi to bridge is also not
a solution, again time is the factor and finding a willing person to allow
a wifi device with external antenna is not that easy either.

So the obvious solution is cellular data but the normal data flow is
reversed and there needs to be a way to resolve the address of the
ZM server at the far end of the wireless connection.

Re: Access ZM server over cellular link

Posted: Sun Jun 05, 2011 2:59 am
by kingofkya
Might check out clear http://internet.clear.com/?gclid=CL_ela ... bAodjSPjuw they have a 4g / 3g modem that might work for this. Clear gives you a real ip unlike a normal 3g isp. Most 3g ones seam to be behind a nat now a days. The vpn may also work but you have to use a UDP vpn link as tcp will be painfully slow. You might have to check if there 3g modules are linux compatible they were not when clear launched a few years ago.

Re: Access ZM server over cellular link

Posted: Sun Jun 05, 2011 12:52 pm
by kp4djt
I should have posted what I found out, sorry folks, I will
try to remember and not leave people hanging.

After some digging I found that all of the providers will
offer for some cost public DHCP addresses, you can use
ddns to get to those, or static addresses, of course the
static addresses are more costly but no need for ddns.

Actually some of them offer the DHCP for the same pri-
ce as regular service, it is just not published until you go
into the business offerings, there is usually a set up ch-
arge on the order of $500 with some of them. Then if
you use static there is a small additional monthly charge
for the static addresses.

You also have the option of using your own address block
if you have one. Again there is the set up charge, but
no additional charges. You do have to dig to find it
though. AT&T has the best all around in terms of what
I was able to find.