Wireless Issue

[tomscaper]

We have just bought some laptop trolley that will hold 30 laptops in each, and got a 3com 7760 AP for each, the laptops connect to the AP fine but for some reason every now and again, they will come up with limited connection, i restart them and they they connect again. Other times i have to turn them all on and then reboot the AP.

But even doing that does not guarantee that the next day when they turn them on they will connect again.

 

I hate laptops trolleys and Wireless!

[chilbs]

The joys of wireless!!!

 

Think you will find that you are running out of bandwidth with 30 laptops on one access point.

 

I am aware of a certain model of access points that fall over at 7 connections and the supplier of the access point has had the manufacturer test and confirm this.

 

Be aware that actual through put on a 54MB connection is actually about 22MB and this is being devided between 30 laptops.

 

Even if the the laptops are idle they still maintain a connection with the access point.

 

I would suggest that a maximum of 15 laptops per access point would be more ideal or a managed solution with fixed access points.

 

Chilbs

[tomscaper]

well we have only bought 1 for each trolley as they said they could handle up to 64 i never believed it. Looked at managed solution but it was like 19k. They eventually get on but it takes a few reboots of the access point.

[kmount]

We have 3 trolleys each of 15 and a cheap D-Link DWL-7100AP on each and have no problems at all as we use the 802.11a band which makes sense with our site being blanket covered on 802.11g.

 

What Chilbs said about the bandwidth is also true but this shouldn't stop you getting IP addresses really unless there's a device using all the juice up whilst the others are trying.

 

For example, if you laid all 30 out on a table and booted them all up and left them at a login screen, would all of them get an IP?

 

Do you have any other wireless in the area? Have you looked at interference on the channel? Are your IP's being handed out from a server via the AP?

[NightShade01]

What are you using to allow the laptops to connect....windows wireless? I only ask because we have a similar situation and we use a third party utility that starts on boot which connects to the APs. This utility reports alot more information including what AP it is connected to including signal strength, etc...

 

I don't think 15 or even 30 laptops should saturate an AP by just trying to connect

[mullet_man]

We find static IP for laptops works so much better than DHCP.

 

Would suggest you try to see if it helps.

[tomscaper]

We use windows wireless to connect them, for some reason some computers connect straight away some come up with limited or no connection, i then either change the channel on the AP and it sorts it out or reboot it and it sorts it out.

If i put them all on the tables and connected them, no they wouldnt pick up an IP if i logged on as a local admin and then rebooted the AP they would all then get an IP.

We have other wireless AP around school, no idea how far they cover, i would bet they are the problem but if i turn them off you can bet someone will need the other trolley that uses them.

 

I hate the trolleys so much, just had the head asking about them, explained again and again but when they hear the cost they stop asking.

[MarkPower]

We use windows wireless to connect them, for some reason some computers connect straight away some come up with limited or no connection, i then either change the channel on the AP and it sorts it out or reboot it and it sorts it out.

If i put them all on the tables and connected them, no they wouldnt pick up an IP if i logged on as a local admin and then rebooted the AP they would all then get an IP.

We have other wireless AP around school, no idea how far they cover, i would bet they are the problem but if i turn them off you can bet someone will need the other trolley that uses them.

 

I hate the trolleys so much, just had the head asking about them, explained again and again but when they hear the cost they stop asking.

 

Hi tomscaper

 

It sounds like you have had enough and if the cost is sensible then you may be able to get a manged wireless soloution in the school, or even some fat access points that work well with a large number of users.

 

I can gurantee both with Ruckus Wireless and would be more than happy to discuss this with you when you have the chance.

 

It sounds like you have looked at solutions that cost a fortune already which is something that Ruckus addresses by being very cost effective.

 

If the complete solution is not needed then the fat access point method would certainly get you out of a hole for now and for very little cost.

 

PM, email or call me I am happy to help

 

Also check out what other people say about Ruckus on Edugeek to see for yourself.

 

This is not going to cost you anything to chat about it and see if this is an option for you, if it's not then no problem.

 

I look forward to hearing from you.

 

Cheers

 

Mark Power

01473 281211

[email protected]

[plexer]

NightShade01: What client program are you using?

 

Ben

[tomscaper]

Hi tomscaper

 

It sounds like you have had enough and if the cost is sensible then you may be able to get a manged wireless soloution in the school, or even some fat access points that work well with a large number of users.

 

I can gurantee both with Ruckus Wireless and would be more than happy to discuss this with you when you have the chance.

 

It sounds like you have looked at solutions that cost a fortune already which is something that Ruckus addresses by being very cost effective.

 

If the complete solution is not needed then the fat access point method would certainly get you out of a hole for now and for very little cost.

 

PM, email or call me I am happy to help

 

Also check out what other people say about Ruckus on Edugeek to see for yourself.

 

This is not going to cost you anything to chat about it and see if this is an option for you, if it's not then no problem.

 

I look forward to hearing from you.

 

Cheers

 

Mark Power

01473 281211

[email protected]

 

 

Hi Mark

 

I have actually spoken to you and you emailed me a few quotes to pass up, but i dont think there is any budget to go ahead with anything, currently just waiting still.

 

For now i have decided to forget about the 3Com ones and have put two older ones in the room and they seem to be coping with the laptops far better.

 

I know it will still run slow but its all i have to work with right now.

[MarkPower]

Hi Mark

 

I have actually spoken to you and you emailed me a few quotes to pass up, but i dont think there is any budget to go ahead with anything, currently just waiting still.

 

For now i have decided to forget about the 3Com ones and have put two older ones in the room and they seem to be coping with the laptops far better.

 

I know it will still run slow but its all i have to work with right now.

 

Hi Tom

 

I think I recal the conversation and understand that it may not be possible at the moment.

 

If I can help further in the future please let me know.

 

Cheers

 

Mark

[NightShade01]

We have an IBM only school district so we use their built in client Acess Connections. I HATE IT! There are so many problems with it...but that is another story. When it actually works I can tell you basically anything about APs in or close to the area of the laptop on. There are other open source tools (the names are escaping me at the moment) that work in a similar fashion. I seriously would consider testing some of these out because if it is just a matter of reconfiguring the APs because they aren't working right that could save you alot of money and/or time if you can pinpoint it to that. Trust me I know what you are going through we have a huge district with about 30 of the trolley's and over 60 APs. Wireless is always an issue.....

[tomscaper]

I have wandered around the school many times using netstumbler, i know the channels are all conflicting with each other. I wish i could just turn them all off. but i would just end up with student after student coming asking "why isn't the domain available"

[tonyd]

Tom, have you made sure that the APs are only operating on channels 1, 6 & 11 (13?). It is important that you use these, and only these, since chosing others will cause greater interferance. It is better to have APs that operate on the same channels, since the can then 'see' each other, and allow for each others traffic better. Using the middle channels will only slow things donw even more. All of the managed WiFi systems I've used use only these 3 channels.

[MarkPower]

Tom, have you made sure that the APs are only operating on channels 1, 6 & 11 (13?). It is important that you use these, and only these, since chosing others will cause greater interferance. It is better to have APs that operate on the same channels, since the can then 'see' each other, and allow for each others traffic better. Using the middle channels will only slow things donw even more. All of the managed WiFi systems I've used use only these 3 channels.

 

Tom the above is a very true and vital for good wireless.

 

13 will work but will overlap with 11 quite a bit in standard omni directional antennas due to how close it is.

[HodgeHi]

apparently 802.11n APs can hold more connections since it has more bandwidth available. We currently have a mobile trolley of 15 apple macbooks and an airport extreme. All connect wirelessly and use garageband. They also boot into windows. So far very few issues with the trolley.

 

Even that said though i am still in the same thought as yourself when it comes to wireless. I don't like wifi networks. It's not as easy as people make out to set up. It's easy to get going but when there's problems, they can be very difficult to resolve.

 

It's gonna be murder when the laptop per child scheme really gets underway.

[tomscaper]

I have tried to plan each AP and set them on either channel 1 6 or 11 around school, to be honest i think they all overlap each other anyway, i can't figure out away to get them to not conflict with each other.

 

The only thing i have noticed is for the laptop trolleys to work i had to set the AP to channel 2, any other channel and they drop all the time.

 

Might have another go at mapping out the channels around school again and reduce signal strength, to see if the performance improves.

[chilbs]

Some overlap is ok as long as its minimal. Try to obtain a Wi-Spy as this will show frequencys that are in use around your school that don't show up using netstumbler because they are not wi-fi devices. Typically they are the monitoring systems for items such as fire and burglar alarms. I have found channel 8 is popular which wipes out channel 6 and 11 because of the frequency spread actually in use. When you set a channel the devices actually use about 3 channels either side as well.

[NightShade01]

you might also consider using airodump-ng (the backtrack cd has it). It will show every AP by MAC address, the signal strength, and an approx amount of data vs beacons being sent out. I use it frequently to test if the APs are being overloaded or aren't available for connection.

[tomscaper]

you might also consider using airodump-ng (the backtrack cd has it). It will show every AP by MAC address, the signal strength, and an approx amount of data vs beacons being sent out. I use it frequently to test if the APs are being overloaded or aren't available for connection.

 

Good idea might have a play see what i can find, i am past caring about it right now, mabye on monday i will be bothered to sort this out, i am the right mind of put them all on channel 1 let hell break loose and wait for them to either, scrap laptops altogether or get managed system in.

Either way i will get the blame for it not working.

[MarkPower]

The Wi-Spy device we use on all site visits and surveys is cracking, it really helps to show the problem noise, we found that motion sensors and projectors a real pain and always interfer with omni directional access points.

 

I purchased mine from MetaGeek | Makers of the Wi-Spy Spectrum Analyzer only problem is they are US and some schools wont purchase from the US.

 

Cheers

 

Mark

[Oops_my_bad]

I purchased mine from MetaGeek | Makers of the Wi-Spy Spectrum Analyzer only problem is they are US and some schools wont purchase from the US.

 

Same here... but only because the bursar cant be bothered to do the currency conversion. Just get it on your credit card and claim it back