HELP! Adding Wireless to School LAN

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 wrote in :

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.

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

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

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

Really bad idea. Run Ethernet.

Turn the job over to real pros. Seriously.

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?

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 wrote in :

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.

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

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

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

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?

Real experts can easily power pretty much anything over Ethernet.

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

Download 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".

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

Plus, some consumer rated equipment doesn't not have upgradeable antennas.

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

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.

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

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.

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%.

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.

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 wrote in :

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

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

Change "wiser" to "essential".

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

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

Instead of a "dual-radio" box, just use two CAT5 runs and two radios.

There are a lot of ad hoc "non-standard" ways to implement POE. 1) Cut the end of your power cable and splice into the CAT5 using modular jacks. 2) PoE injector from the manufacture that are little more than above. 3) Injectors that use the more standard 48 volt methond. 4) Full PoE specification adherence.

Ok, that makes more sense..but still I would expect it to be running perhaps 80% duty cycle only at lunch time.

Or they are lying to cover up their failures. On the other hand, it might work for them...until failures start arriving.

Don't be surprised if you have to end up putting a 5.8 AP in every classroom. You could try just one AP mounted in several test locations. It doesn't have to be connected to anything, simply set your laptops to look for the SSID of the AP and check the signal reliability or link quality.

They might be realizing how hard it will be to implement.

Its "cutting edge" because its somewhat of a near term solution to

2.4 pollution and still be backwards compatible.

Deliberant's LigoWave is what we use.

The LGO2AGN has two radios (and two coax connectors) and can run BOTH 2.4 and 5.8, and is PoE (48 volt/ .4 amp).

DTC:

The LGO2AGN is two radios but not for 802.11n. It looks good. Here's my question. If I have one radio on the 5.8ghz bandwidth and one on the

2.4ghz bandwidth which one will the 802.11n client with the Intel Chipset connect to. I would like to think that 802.11n can operate on the 802.11a channel but I'm not entirely sure.

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