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Re: [K12OSN] wifi wireless k12ltsp support status



Wireless has a place when mobility trumps cost. Wireless is not, and
will not in the foreseeable future be a viable transport method for thin
clients. It may become useful in the chubby client (local apps) as they
require less constant bandwidth.

A $70 AP is quite limited in power and connectivity. It still requires a
copper connection. And each client machine requires a $30 NIC instead of
a $10 NIC.

A 54Mbps AP provides 37.8Mbps of usable client bandwidth. Jumbo frames
are not an option in the wireless specs. Since a current thin client
requires a minimum of 7Mbps with no sound or streaming video that puts
the maximum client count per AP at 5. 

With a measured benefit ratio of 3:1 students:clients that puts the max
class size at 15. In Georgia the max size is 24. So that puts the thin
client using wireless into the 4.8:1 ratio which has been shown to be
ineffective. 

So a WAP ($70) plus 5 clients ($30 *5 = 150) requires $220 and is not
expandable and won't provide enough classroom exposure to make a
statistically significant academic benefit.

Most systems ship with an onboard NIC. An 8 port Gig switch is $70 (A
10/100 is $30). A managed 8 port is $110 - retail. So a wire is already
run for the (theoretical) WAP, plug in the switch (save $210 per
classroom - $30 * 7 clients) and get the 3.4:1 back. And at only 49Mbps,
there is expansion room to support streaming video (limited) over a
100Mbps wire for 7 clients or add more clients using a Gbit feed from
the upstream switch.

Yes. Wireless is "sexy". It's mobile. But the reports are in from all
over corporate and college campuses - it's EXPENSIVE to set up and
maintain well.

My money is on the wire.

On Tue, 2008-10-07 at 08:54 -0400, HOWARD DANIEL-GVN674 wrote:
> IMHO, wireless has it's place in schools and will definitely get better
> in many respects over time, as well as cheaper.  I agree with Jim that
> when doing an enterprise server model, where the wireless links to
> classrooms would be between servers and clients, wireless is a very bad
> idea, and likely to stay a bad idea until we get speeds in excess of 400
> Mbps, since real speed over wireless is usually about half of the stated
> PHY layer speed, so 54 Mbps is really about half the Mbps in reality.
> 
> But wireless links to a classroom server are still viable and cheaper if
> they were only more user friendly in Linux (a point to Jim's $$$ labor
> cost), since $70 for an access point and $30 for a wireless NIC is still
> less than half the cost to wire a classroom (usually at least $200), and
> subsequent rooms nearby would be only $30.  But getting wireless to work
> in Linux is not always easy, which is I think Jim's point, due to things
> like chipsets changing rapidly and not being supported in Linux,
> although I suspect it will get easier over time as well.  And for rooms
> with older wiring, or wiring that runs by noisy electronics, that the
> school won't have the budget to rewire anytime soon, wireless is useful
> as a backup and alternative.  And wireless to classroom K12LTSP servers
> doesn't require batteries, of course.  If we could generate a decent
> list of supported wireless NICs for classroom Linux servers (and keep it
> up to date) I think wireless would have a strong place for K12LTSP
> deployments using the classroom server model.  Plus, if I were in a
> school that had a really hostile IT department that said no way to
> K12LTSP on their network, one of the ways to set it up w/o them and
> their network being affected would be a classroom server with a 3G
> broadband wireless access card.  I've seen folks with Linux laptops with
> 3G access, so I know it's at least possible.  Not the best long term
> solution, agreed, but a way to get a foot in the door perhaps.  And if I
> ever had the time/resources to really evangelize this, a Laptop server
> with 3G Internet (as backup to a wireline) connected to a switch and
> thence to a handful of netbooks/UMPCs would be a great roadshow kit to
> cart around to show schools.
> 
> The point about laptops is important: what makes wireless really
> critical is when laptops become cost effective for schools (note when,
> not if).  Already we now have companies breaking the $100 barrier for
> UMPCs, vis a vis, the HiVision Mini Note:
> http://techvideoblog.com/ifa/98-linux-laptop-the-hivision-mininote/
> 
> At less than $100, it is a viable solution for elementary and perhaps
> even middle schools, and given the lack of moving parts, should be much
> more reliable, albeit not as fully reliable as a desktop, but
> approaching it.  Better reliability can be had if it's not a 1:1
> program, rather a 3:1 or 2:1 with them if they stay in the classrooms
> and thus don't get banged around between school and home.
> 
> My company has wireless deployed throughout all corporate locations so
> that anytime I attend a meeting, whether I'm in someone's office or
> small conference room, or board room, I merely boot up my laptop, log
> on, and I'm connected.  Most of my customer locations are likewise, but
> sometimes they lack an unsecured network for guests, although that too
> is changing.  It is not merely a boardroom thing anymore, and I'm sure
> this model will spill over into schools when the cost of the laptop
> (acquisition and support) gets low enough to make them viable, which I'm
> convinced will happen eventually, and I'm guessing in only a few years
> now.
> 
> Best,
> Daniel
> 
> 
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> 
-- 
James P. Kinney III          
CEO & Director of Engineering 
Local Net Solutions,LLC                           
http://www.localnetsolutions.com

GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
<jkinney localnetsolutions com>
Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3 829C 6CA7


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