Re: [SLUG] Wireless broadband

From: Chuck Hast (wchast@gmail.com)
Date: Fri Oct 22 2004 - 11:42:04 EDT


On Fri, 22 Oct 2004 05:42:42 -0700, Chuck Hast <wchast@gmail.com> wrote:
> On Fri, 22 Oct 2004 03:40:23 -0400, Pete Theisen <petet@acun.com> 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,
>
> I do "can you hear me now?" and find that the toss is between Verizon and
> AT&T. Verizon uses CDMA and is running X1RTT which will give you on the
> order of about 120kb on a good day.
> AT&T uses GPRS and is introducing EDGE on all of it's sites. GPRS will give
> you about 40-60 kb and EDGE will boost that to about 160 to 200 something.
>
> They all leapfrog on another, Verizon had the 'edge' for a while, but now with
> AT&T rolling out EDGE they will have greater speed.
>
> Now here is the intereting part.
> CDMA still retains certain "land line legacies" one of which is the
> fact that when
> you use it you have to use a 'dialer' in order to get a path, now once you have
> established your 'connection' the radio side if it is idle to long
> will hang up, as
> soon as you do some activity that causes it to need to send data to the network
> in the background the dialer 'redials' the link and brings up the
> path. This usually
> only takes 4-8 seconds so you may or may not perceive a delay when you start
> doing what you are doing. BUT if the network is busy and there is not
> a available
> resource you may get a 'busy' When we do CDMA testing we use two computers,
> one gathers RF environmental data, and at the same tiime pings a remote server
> and gathers round trip time data, and the second one does nothing but set there
> and ever 45 seconds (that is the industry standard for this test) attempt to get
> 'dialtone' which is just a digital confirmation that the path is
> there, if we get it
> we log the 6 different code returns calculate the time it took to get
> DT and then
> hang up. If after 45 seconds we get no DT we capture all of the error codes
> and hang up and start again.
>
> They appear to do this in order to conserve RF facilities, I see no other reason
> to do so.
>
> GPRS/EDGE on the other hand looks like a NIC card, when you turn the device
> on it sticks up it's hand and registers with the network, the network checks the
> registration (are you a paid subscriber and are you up to date?) and if all is
> OK registers you, there is no dialer, no delays unless you have moved into a
> poor coverage area then you may see delays due to retries or deep FEC for
> error recovery, but if there is a reasonable path there will not be any delays
> trying to establish a new circuit.
>
> If the site is loaded you may see delays due to high traffic loading and retries
> but I have yet to see that on a GPRS site, not saying that it does not happen.
> The disconnected mode of GPRS/EDGE seems to facilitate getting a packet
> through here and there on a loaded network much better than the 'dialer'
> concept of checking if the full resource is available.
>
> You need to compare them in terms of where you are going to be traveling,
> if you do international then GPRS/EDGE is what you need as that is what is
> used in much of the rest of the world.
>
> Verizon has very good coverage in much of the country and if you keep the
> machine busy you will not notice the 'hangups' much.
>
> Will be interesting to see what happens after Cingular and ATT WS merge,
> both of them are rolling out EDGE and will have a even larger combined
> network.
>
> Both Verizon and AT&T provide you with a "all you can push down the pipe"
> price of right around $75/mo. You need to check out the different plans and
> see which one works.
>
> We use the Sierra Wireless cards exclusivly at work, and indeed I think they
> are the only product has Linux support though it is third party and they do not
> support it directly.
>
> Here is a SW555 card (the card that Verizon uses) page
> ttp://centerclick.org/aircard555/
>
> Here is a page for the 7x0 series cards (GPRS)
> http://www.sierrawireless.com/SupportDownload/ac7x0_linux.asp
>
> A google will turn up a lot of data.
>

Forgot to toss in Sprint, we also do them but if you get off of the main
highways and you will find that they are not quite so prevalent as ATT
and Verizon are. As long as you are in metro areas and on the main
highways you will be just fine with Sprint, again they are CDMA and
so the card will only work in this country.

-- 
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."
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