Re: [SLUG] Wireless broadband

From: Chuck Hast (
Date: Fri Nov 12 2004 - 10:53:22 EST

On Fri, 12 Nov 2004 09:37:39 -0500, Caleb <> wrote:
> Pete Theisen wrote:
> > Mike Branda wrote:
> >
> >> On Fri, 2004-10-22 at 03:40, Pete Theisen wrote:
> >>
> >>> Hi Everybody!
> >>>
> >>> Anyone know of a good wireless broadband to use in Florida? I mean
> >>> go from place to place even mobile like a cell phone with a PCMCIA
> >>> card or something stuck into the notebook. Is there anything?
> >>>
> >>> Of course, this *has* to work with Linux as well as Window$.
> >>>
> >>> Regards,
> >>>
> >>> Pete
> >>
> >>
> >>
> >> At the end of last year I sat next to a guy on a plane coming back from
> >> San Diego and he was looking over some reports. I also noticed his neat
> >> little pcmcia card with an antenna and thought hmmm.....CDPD or is it a
> >> new type of data access?? So I listened to the little voice in my head
> >> and decided to ask what that card was. Turns out, he was a pilot market
> >> tester for verizon on a new broadband card. He boasted that some of the
> >> areas he went through gave him report speeds of 800 kbps!! I was
> >> amazed. He said that it would be on the market soon. A few weeks ago I
> >> remembered that flight and went searching for the technology. Below is
> >> what I found on verizon's site.
> >>
> >>
> >>
> >> snip from site
> >>
> >> High Speed
> >> Verizon Wireless BroadbandAccess is one of the fastest, fully mobile
> >> wireless Internet data solutions available. Quickly download complex
> >> files and view email attachments at typical speeds of 300-500 kbps,
> >> capable of reaching speeds up to 2 Mbps^. Access your mission-critical
> >> data and applications behind the corporate firewall and get the answers
> >> you need with customers in the field right there. ***
> >>
> >> You'll need the data-only Verizon Wireless PC 5220 card* installed in
> >> your laptop
> >>
> >> * $79.99 monthly access gets you unlimited Verizon Wireless
> >> NationalAccess and BroadbandAccess service**
> >>
> >>
> >> Mike Branda Jr.
> >>
> >
> > Hi Mike!
> >
> > Interesting, thanks.
> >
> > Regards,
> >
> > Pete
> >
> > -----------------------------------------------------------------------
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> > posted are those of the author and do not necessarily reflect the
> > official policy or position of NKS or any of its employees.
> >
> Hey Guys just an FYI. When I did get the 5220 Sierra card working with
> linux it would time out every few minutes. I found a few work arounds.
> It seems that Verizon is using a software called Veritas to do the
> compression to increase the speed. The bad news is so far I have not
> been able to find that software for linux. It would make a difference
> in speed.
> Just wanted to let you know.

There are some things that the CDMA providers do not tell you. One
of them is that they still have vestiges of the old dialup system in them
If you will notice that you have to use DUN in order to access the card.
Your system does a boggus dialup in order to get access to the network

When we do a "can you hear me now " on a CDMA network we have
two computers running, one gathers RF environment data and round trips
(pings ) to a machine on the base station side of the network, usually it
does a RTT to the customers gateway. The second machine does nothing
more than "go off hook" and measure the time it takes from when the machine
goes "off hook" (that is what you do when you pick up your phone to get
dialtone) until it gets notified that it has a data path into the network.
The reason for this is what you have noticed above. If you let your machine
set idle for a while after you have logged in on a CDMA network, your RF link
(NOT your upper layers just the RF connection) will be dropped, DUN is supposed
to automagicly jump in and bring it back up for you, but that delay can take
up to several seconds (45 seconds max is what the industry test standard is)
Now here is the scenario that is not pretty. Say you are a law enforcment
officer and you run a tag. You get your information back and get out of your
vehicle to pay the tag owner a visit, now you get a license or some other data
you need to check walk back to your vehicle to run it and when you run it you
find this "delay" while the DUN is trying to get a new RF path. So far you may
or may not notice the delay depending on how long it takes to get the new
path, but ere is the really ugly part, what happens if at that time
all of the RF
resources are exausted, you just got dumped (it will retry in the background
but you maybe several minutes getting a new resource) this is what I have to
test when I do coverage studies on CDMA networks. You can have excellent
signal levels but if there is not enough resources to go around you are hung

GSM/GPRS/EDGE works like a nic card, so it does not demand a channel
resource allocation, all it does is register when it is turned on and like a nic
card (which is exactly what it looked like to the OS) it just sets there and
sends packets, there is always some dead space to ship data it may
be slower if the system is loaded, but you do not have the issue of basicly
a fixed number of virtual circuits being used up. Also you do not have a timer
that knocks you off the network due to not using it.

I do not know why that CDMA has insisted in retaining the dialup network piece,
it is such a kludge, though it makes potential CDMA users set up and take
notice and of course use my services. CDMA has good throuhput and with
the new EVDO it looks like a 300 - 800 kb with up to 2mb burst nic when you
are in a EVDO coverage area, if it is 1xRT it is 40-60 kb with up to 144kb burst

The GSM stuff follows similar speeds on GPRS and EDGE.

Chuck Hast 
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."
This list is provided as an unmoderated internet service by Networked
Knowledge Systems (NKS).  Views and opinions expressed in messages
posted are those of the author and do not necessarily reflect the
official policy or position of NKS or any of its employees.

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