HELP! Adding Wireless to School LAN

Hello,

I've been asked to develop a plan to add wireless to a school's wired
LAN. There are two floors and each with two wings about 30 meters long
with classrooms on both sides and then a foyer/library connecting the
two wings. I was going to have a router for each wing as well as one
for the office/foyer, library and gym. They want the wireless system to
be seamless. So if a teacher picked up her laptop and went from a wing
to the library the change from the original AP to the new AP would
happen promptly and the laptop would not hold on to a weak AP signal
when it could use a stronger one (I understand that this could be the
laptops problem but I want to know if there are solutions that don't
rely on the client to jump between APs).

I was thinking of going with the WRT600N because it has dual-radio and
the school has more microwaves (1-2) per classroom then it will APs and
these are used constantly throughout the day.

My question is I've looked into WDS which looks promising but the
WRT600N does not support it and I'm thinking that if I flash it with
DD-WRT that I will lose Dual-Radio abilities. Also WDS splits the
wireless bandwidth and I think that client connections to the local
server would slow right down.

Any recommendations? I'm wondering if it's worth running Ethernet to
each Wireless AP or not? And how would I make it seamless if each
Wireless router has an individual connection to the switch.


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You definitely need help from some of the professionals here, but I
can comment that yes, it does seem best to plan on distributing your
signal via ethernet cable to various points in the buildings, and then
attaching APs there.

Antenna strategy is always the big question. Right off, I imagine
that you can go with a grid of Omnis that are centered in the areas to
be covered or mix directionals set at ends of coverage areas with
perhaps omnis in the middle.

I might be thinking about commercial grade units (not the linksys)
that are all-in-one antenna POE boxes. Mounted in the ceiling (out of
reach) perhaps.

I wonder if the best way to combat microwave interference is to simply
have the units as close to the microwave ovens as possible. Or accept
that there will be periodic interference problems.

Or shield the ovens? Not likely, but it's an idea.

I also wonder if it's a good idea to go with A or N if you don't have
control over the various clients that are connecting. G is nearly
universal now, A and N are not. But then, maybe you do have control.

WDS seems kind of flaky, especially if you want a secure connection
with WPA.

Theoretically, I understand that you can get functional roaming by
giving all APs the same SSID and security key, but varying channels in
overlapping areas. Don't know for sure how it tends to work in
practice.

Hopefully Jeff or one of the other pros here can jump in on this.

Cheers,
Steve

On Fri, 1 Feb 2008 17:08:01 -0500, taekat
<(E-Mail Removed)> wrote in
<(E-Mail Removed)>:

>I've been asked to develop a plan to add wireless to a school's wired
>LAN.

This is a job for real experts. There are huge potential problems in
coverage, interference, security, configuration, and the like. Since
you're obviously not a real expert, do the school a favor and tell it to
bring in real pros. It's penny wise and pound foolish to try to do it
on the cheap.

>There are two floors and each with two wings about 30 meters long
>with classrooms on both sides and then a foyer/library connecting the
>two wings. I was going to have a router for each wing as well as one
>for the office/foyer, library and gym.

Almost certainly won't work well, if at all. A serious site survey
needs to be done.

>They want the wireless system to
>be seamless. So if a teacher picked up her laptop and went from a wing
>to the library the change from the original AP to the new AP would
>happen promptly and the laptop would not hold on to a weak AP signal
>when it could use a stronger one (I understand that this could be the
>laptops problem but I want to know if there are solutions that don't
>rely on the client to jump between APs).

That won't work with low-end commodity products.

>I was thinking of going with the WRT600N because it has dual-radio and
>the school has more microwaves (1-2) per classroom then it will APs and
>these are used constantly throughout the day.

That's likely a major problem far beyond the WRT600N.

>My question is I've looked into WDS which looks promising but the
>WRT600N does not support it and I'm thinking that if I flash it with
>DD-WRT that I will lose Dual-Radio abilities. Also WDS splits the
>wireless bandwidth and I think that client connections to the local
>server would slow right down.

Really bad idea. Run Ethernet.

>Any recommendations? I'm wondering if it's worth running Ethernet to
>each Wireless AP or not? And how would I make it seamless if each
>Wireless router has an individual connection to the switch.

Turn the job over to real pros. Seriously.

--
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> You definitely need help from some of the professionals here, but I
> can comment that yes, it does seem best to plan on distributing your
> signal via ethernet cable to various points in the buildings, and then
> attaching APs there.

seaweedsteve: That's what I said when I was asked. But somehow that
have it in their minds that a shortcut is feasible. I firmly believe
that shortcuts will cost them in performance and IT support.
Regardless, they want to know how they will save if they go the consumer
route instead of the industrial/commercial route.

Here is my logic behind the dual-radio. The school just installed
brand new iMacs for the teachers that have the intel 802.11n wireless
chip. These are the only computers that connect to the server and
require a higher bandwidth. I figured with dual-radio APs we could set
one radio to 5ghz for the iMacs and the other radio to 2.4ghz mixed (b,
g, n) for any guests systems that may require connections.

Does this make sense? Would this setup help with the interference
problem or is it not with the extra cash for the dual-radio capable
APs?

>
> Theoretically, I understand that you can get functional roaming by
> giving all APs the same SSID and security key, but varying channels in
> overlapping areas. Don't know for sure how it tends to work in
> practice.

Originally the school was quoted for a Colubris and they found it to be
too expensive. I did some investigation and found out that this was
what they recommended to do in their quote. There are already ethernet
lines run throughout the school that can be used and I understand the
whole setup with same SSID and security key but different channels.

I also found out that in order to run POE they would have to upgrade
the main switch which was in addition to already high quote for the
Colubris system. I did some research and the only dual-radio AP that
can run on POE is the Cisco Aironet 1250 but it requires a Cisco Switch
but this school deals with Nortel switches and the 470 is the one that
they would need for POE which is not compatible with the Aironet 1250.
So basically if they were to go with POE they would be forced to use
single-radio APs.

So this is the big crossroad that I have to present to school:

POE or Dual-radio or neither. Will dual-radio circumvent the microwave
problem (2 microwaves per classroom that are used constantly thus
jamming the 2.4ghz band)? If not then the option is clearly POE or no
POE. Anyone have an opinion on this. If it were not for the fact that
the teacher computers need to access the server for files and log-ons
then this would not be a problem.


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On Sun, 3 Feb 2008 15:42:51 -0500, taekat
<(E-Mail Removed)> wrote in
<(E-Mail Removed)>:

>> You definitely need help from some of the professionals here, but I
>> can comment that yes, it does seem best to plan on distributing your
>> signal via ethernet cable to various points in the buildings, and then
>> attaching APs there.
>
>seaweedsteve: That's what I said when I was asked. But somehow that
>have it in their minds that a shortcut is feasible. I firmly believe
>that shortcuts will cost them in performance and IT support.
>Regardless, they want to know how they will save if they go the consumer
>route instead of the industrial/commercial route.

They won't save. They absolutely positively will pay more, probably a
lot more, in the long run. It's called "total cost of ownership", a
fact of life that all too many schools ignore. Businesses aren't stupid
-- they buy commercial gear because it costs less in the long run.

My own district spend a bunch of bond money on computers, many of which
are now broken and useless because it can't afford to maintain them
properly. The assumption was that teachers could fix them in their
spare time.

I know of another district where the network got hacked and the servers
compromised. Records were lost, and only deity knows how much personal
information fell into the wrong hands.

>Here is my logic behind the dual-radio.

In the great scheme of things this kind of thing should be way down the
list of priorities. It just isn't that important.

>The school just installed
>brand new iMacs for the teachers that have the intel 802.11n wireless
>chip. These are the only computers that connect to the server and
>require a higher bandwidth. I figured with dual-radio APs we could set
>one radio to 5ghz for the iMacs and the other radio to 2.4ghz mixed (b,
>g, n) for any guests systems that may require connections.
>
>Does this make sense?

No way of knowing. Without a serious site survey it's just speculation,
a bit like wandering around blindfolded.

>Would this setup help with the interference
>problem or is it not with the extra cash for the dual-radio capable
>APs?

You need to know what problems you have *before* trying to solve them.

>> Theoretically, I understand that you can get functional roaming by
>> giving all APs the same SSID and security key, but varying channels in
>> overlapping areas. Don't know for sure how it tends to work in
>> practice.
>
>Originally the school was quoted for a Colubris and they found it to be
>too expensive.

So the school can't really afford it, and now wants to try doing it on
the cheap.

Remember: fast ... cheap ... good -- pick (at most) two.

So do they want fast and not good, or good and not fast?

>I also found out that in order to run POE they would have to upgrade
>the main switch which was in addition to already high quote for the
>Colubris system. I did some research and the only dual-radio AP that
>can run on POE is the Cisco Aironet 1250 but it requires a Cisco Switch
>but this school deals with Nortel switches and the 470 is the one that
>they would need for POE which is not compatible with the Aironet 1250.
>So basically if they were to go with POE they would be forced to use
>single-radio APs.

Real experts can easily power pretty much anything over Ethernet.

>So this is the big crossroad that I have to present to school:
>
>POE or Dual-radio or neither. Will dual-radio circumvent the microwave
>problem (2 microwaves per classroom that are used constantly thus
>jamming the 2.4ghz band)? If not then the option is clearly POE or no
>POE. Anyone have an opinion on this. If it were not for the fact that
>the teacher computers need to access the server for files and log-ons
>then this would not be a problem.

My opinion is that you should take out a big errors and omission
insurance policy.

Download <http://802.11junk.com/jeffl/crud/Intel%20HotSpot%20Guide.pdf>
and read it from cover to cover. If you don't fully understand
everything (and I mean *everything*) in there, then you have no business
doing this, any more than you would have doing a back street abortion
for someone that couldn't afford a real doctor.

Do the school (and yourself) a real favor, and just say "no".

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
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taekat wrote:
> Regardless, they want to know how they will save if they go the consumer
> route instead of the industrial/commercial route.

They will save over twice as much going the commercial grade radios.
Lower failure rate, better preformance, etc. will mean less service
calls which cost money.

> Here is my logic behind the dual-radio. The school just installed
> brand new iMacs for the teachers that have the intel 802.11n wireless
> chip. These are the only computers that connect to the server and
> require a higher bandwidth. I figured with dual-radio APs we could set
> one radio to 5ghz for the iMacs and the other radio to 2.4ghz mixed (b,
> g, n) for any guests systems that may require connections.

Back in '05, a Netgear engineer told me they are not going to pursue
5.8 GHz products because the short range was too problematic. However
their new product line has some 5.8 gear, no doubt to address the
2.4 GHz interference issues. Personally I'd stay away from 5.8 GHz for
in building deployment unless you have compelling reasons.

> Does this make sense? Would this setup help with the interference
> problem or is it not with the extra cash for the dual-radio capable
> APs?

Depends what you are expecting. Using dual radios on 5.8 and 2.4 isn't
going to solve the 2.4 GHz interference problems.

> So basically if they were to go with POE they would be forced to use
> single-radio APs.

Not necessarily so. Those PoE compatible switches simply mean they have
the spare ethernet cable pairs are wired up internally for a external
power supply (some have their own internal power supply).

Simply add some external PoE injectors and you'll accomplish the same
thing. The advantage of PoE is that you don't have to run separate power
cables, but that is offset by the PoE costs.

> So this is the big crossroad that I have to present to school:
>
> POE or Dual-radio or neither. Will dual-radio circumvent the microwave
> problem.

If one of the dual radios is on 5.8 GHz, then yes...it will circumvent
the interference issue ONLY for the 5.8 GHz users, not the 2.4 GHz
users.

> (2 microwaves per classroom that are used constantly thus
> jamming the 2.4ghz band)?

EVEN if ALL the classroom were ALL teaching Home Economics AND
teaching ONLY how to cook with microwaves ovens, you STILL wouldn't
have the ovens running CONSTANTLY. I'd rethink this.

> If not then the option is clearly POE or no PoE.

Since PoE can be implemented just about anywhere, that should not be
a compelling reason or restriction of specific manufactures' models
of equipment.

> Anyone have an opinion on this. If it were not for the fact that
> the teacher computers need to access the server for files and log-ons
> then this would not be a problem.

Not sure what you mean. WHAT would not be a problem if you didn't need
anyone to transfer files or log-in. Anything you do with a server should
require a log in. Is there something special about transferring files
as to casual general office/classroom work (are the files THAT big?).

Bottom line...get their expectations on paper, have upper management
sign off on it. Get a professional company to do the work. Get yourself
out of the loop.

On Feb 4, 11:42 pm, DTC <m...@nothingtoseehere.zzx> wrote:

> Bottom line...get their expectations on paper, have upper management
> sign off on it. Get a professional company to do the work. Get yourself
> out of the loop.


Reminds me of when I worked in the media dept at the university. We
solved the daily stuff, but when we had complicated engineering
problems , we hired the experienced pros. Then, when it didn't work
exactly right (many problems were not completely solvable), we were
out of the loop and could be sure that we at least had the best tech
available and had not made foolish amateur decisions.

If you can't convince them, then write up a proposal for a provisional
solution doing something that is very clearly a stop-gap that does not
displace a real solution. Point out many possible shortcomings of the
stop-gap solution if they insist on it and then implement it in a way
that makes it clear that's what it is.

Rolling carts were always good. When they inisist on WiFi for a
special event, roll out a cart with an AP and plug it in for their
instant hotspot !

Can you get somebody out there to do a site survey and a proposal?
Then submit it along with your temporary plan B.

In my experience management studies their options more seriously when
the choice of cheap or good is right there on paper in front of them
and they realize that they will be held accountable for the decision.


P.S. Sorry, I missed before that your teachers have N already.

> Since PoE can be implemented just about anywhere, that should not be
> a compelling reason or restriction of specific manufactures' models
> of equipment.

From what I read, Dual-radio APs require 16.5kwh which is above the POE
standard but Cisco has worked some special formula for their high end
switches. Regardless, I do believe that POE is the way to go because it
gives you flexibily in where you place your APs and if you ever need to
move them.

>
> They will save over twice as much going the commercial grade radios.
> Lower failure rate, better preformance, etc. will mean less service
> calls which cost money.

Plus, some consumer rated equipment doesn't not have upgradeable
antennas.
>
> EVEN if ALL the classroom were ALL teaching Home Economics AND
> teaching ONLY how to cook with microwaves ovens, you STILL wouldn't
> have the ovens running CONSTANTLY. I'd rethink this.

I guess what I meant was there was always at least one microwave
running in the school.

> They won't save. They absolutely positively will pay more, probably a
> lot more, in the long run. It's called "total cost of ownership", a
> fact of life that all too many schools ignore. Businesses aren't
> stupid
> -- they buy commercial gear because it costs less in the long run.

They already understand this. I've been asked to develop a plan for a
low cost system that they could support in-house. I've already told
them that it would be wiser to wait until they did have the money for a
professional setup but all they want to do is throughly investigate all
the options. The hardest part is that this "low cost option" came by
word of mouth from other schools which have gone this route and have
professed to be happy ... so either the expectations are really low or
these other schools are lying.

> If you can't convince them, then write up a proposal for a provisional
> solution doing something that is very clearly a stop-gap that does not
> displace a real solution. Point out many possible shortcomings of the
> stop-gap solution if they insist on it and then implement it in a way
> that makes it clear that's what it is.

Good point. That will be my intro on the proposal.

> Depends what you are expecting. Using dual radios on 5.8 and 2.4 isn't
> going to solve the 2.4 GHz interference problems.

The only computers that need high bandwidth will be operating on the
5.8ghz frequency so I'm not worried about the computers that are hooked
up through the 2.4ghz.

> Rolling carts were always good. When they inisist on WiFi for a
> special event, roll out a cart with an AP and plug it in for their
> instant hotspot !
>
> Can you get somebody out there to do a site survey and a proposal?
> Then submit it along with your temporary plan B.

The rolling cars is a good idea. I was also thinking of something that
was really inexpensive and could maybe hold them off until they could
afford the bigger system. In terms of site survey. It's already been
done and revised twice by the company and each time it was revised the
price went up about 10%.

> Back in '05, a Netgear engineer told me they are not going to pursue
> 5.8 GHz products because the short range was too problematic. However
> their new product line has some 5.8 gear, no doubt to address the
> 2.4 GHz interference issues. Personally I'd stay away from 5.8 GHz for
> in building deployment unless you have compelling reasons.

It does seem that dual-radio is cutting edge and when your on that edge
you will be cut. I know Colubris and Cisco are shipping their
Dual-radio 802.11n APs in February. It seems best to stick with
single-radio 2.4ghz. There are more antenna options for APs within that
frequency as well.

My opinion is that you should take out a big errors and omission
insurance policy.

> Download <http://802.11junk.com/jeffl/crud/Intel%20HotSpot%20Guide.pdf>
> and read it from cover to cover. If you don't fully understand
> everything (and I mean *everything*) in there, then you have no
> business
> doing this, any more than you would have doing a back street abortion
> for someone that couldn't afford a real doctor.

Thanks John I'll read it and then try to get the IT guy at the school
to read it just so they know what they are getting into!


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Can any of you guys recommend an AP model or manufacturer to use for
this setup? As well, can you recommend a certain antenna model or
manufacturer for the omnis and mix directionals?


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On Tue, 5 Feb 2008 19:20:59 -0500, taekat
<(E-Mail Removed)> wrote in
<(E-Mail Removed)>:

>> They won't save. They absolutely positively will pay more, probably a
>> lot more, in the long run. It's called "total cost of ownership", a
>> fact of life that all too many schools ignore. Businesses aren't
>> stupid
>> -- they buy commercial gear because it costs less in the long run.
>
>They already understand this.

Apparently not, because they're trying to go down the wrong path.

>I've been asked to develop a plan for a
>low cost system that they could support in-house.

They don't have the skills, or they wouldn't be asking you to develop
the plan.

>I've already told
>them that it would be wiser to wait until they did have the money for a
>professional setup but all they want to do is throughly investigate all
>the options.

Change "wiser" to "essential".

>The hardest part is that this "low cost option" came by
>word of mouth from other schools which have gone this route and have
>professed to be happy ... so either the expectations are really low or
>these other schools are lying.

More likely they are very naive. Optimism can come from early success,
not knowing what problems lie down the road.

>In terms of site survey. It's already been
>done and revised twice by the company and each time it was revised the
>price went up about 10%.

What does it say? Why aren't you using it?

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
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