Wireless Mobile Laptop Solution

[CHR1S]

I have been asked to quote for a 30 laptop mobile suite that has to be wireless and will be used for infant pupils. We currently have a handfull of APs that support staff laptops in the staff room and IT suite but we dont have coverage across the whole site.

The brief is for internet and document access so it shouldnt be too much traffic. The implementation is whats bothering me tho.
To support the 30 laptops would a ratio of 10 laptops to 1 AP work? Could I have the APs mobile with the trolley and connect them to the network point in the classroom? Would a Fixed solution provide better coverage and stability but at a greater cost? Would a radius server be needed? Is N a good choice over G now?

Thanks

Chris

[kmount]

We have 3 trolleys each with 15 laptops on them.

Each trolley has a miniswitch into which we plug a HP Laserjet, & Wireless AP (in 802.11a mode).

We configure the laptops to primarily use their 'a' band AP called 'RedTrolley' or BlueTrolley with our normal 'global' wireless coverage as second incase someone randomly decides to take one for a walk.

We then uplink this switch in each room which has a network port to effectively give us a mobile working cloud.

I doubt you'd need RADIUS unless you want to perform some extra auth as dumping the WPA/WEP key in should be sufficient.

Seems to work OK for us, albeit a bit loady having 15 laptops over 100mbit network ports but it works.

[linescanner]

OT

Kmount, did you get my PM about a butchers in Northants ?

Andy

[farmerste]

if the laptops are going to be integrated into your school curriculum domain, you will find them very slow with wireless, i have found that you need approx one wireless access point for ten wireless laptops, before they even come close to the performance of 'real' wired computers.
the problem is, if you have three wap's on a trolley, surely you are 'frying' the users with microwave energy, that would exceed the output of a mobile phone mast?, and we know how parents feel about those in schools?

[Michael]

It really depends how you configure the wireless laptops when you image them. The key to minimising traffic is to ensure Windows itself is updated (latest Service Pack), hotfixes and other updates such as IE7 and .NET Framework 1.1, 2.0 and 3.0 prior to imaging.

Secondly, install all applications (as many as possible) locally. I have been to many sites where they try and pull huge applications down from a file server wirelessly. It doesn't work in practice. You should only allow a few exceptions, such as Smart Learning, (for example) which is designed to quickly and efficiently work over any type of network.

Thirdly, use Windows's own Wireless utility. It works perfectly fine in 99% of cases and also means less services running if you use third party software.

If you include all this as part of your image, you'll find that traffic is kept to a minimum. It means at most only profiles, internet traffic and user files are sent/received across the network.

Using the methods I use above, I can successfully run upto 16 laptops per access point with no issues.

[SSFC]

We are looking to implenent the same here, but are limiting the number of laptops to 15 per set. We have found that number works best because when a class arrives and tries to login the demand on bandwith is huge (as we have a 20mb profile!)

Another thing to remember is if your antivirus updates when the laptop is switched on again this can cause things to grind to a hault. we have recommended that teachers switch on each laptop 5 mins before the class comes in and then try to stagger the students logging on.

Doing this gives us the best results.

[Pete10141748]

ah, mobile laptop suites. The baine of any IT tech's day.

We're looking to upgrade our wireless network, as using 25 laptops in a classroom just does not work (TBH, I hate wireless laptops for pupils completely, and see ICT Suites as having so many advantages that there shouldn't even be a debate about it really.....)

We were running 1 AP per classroom, so there was always 2 (usually 3) APs in range for the laptops to use. Staggering the logon to 5 at a time, it would take around 20 minutes to get the whole class in and ready to begin teaching. By this point, half the laptops's batteries were dying anyway!

We are going to get 3Com AP's, upgrade the switches to Managed Gigbit ones, and pray that this helps out.

Even so, you do the math;

1 54Mb/sec AP serving 15 laptops = 3.6Mb/sec per laptop.
Take into account network traffic, noise etc. and you are lucky if you'd get a 2 meg-a-second connection.

even if you could get a 108Mbps AP, you're still only looking at around 5-6mbps per laptop!

Which to me is just stupid, when anyone can walk their class 2 minutes down the corridor and sit them all at a PC in the IT Suite which has a steady 100Mbps cable connection, with no battery worries.

[jamin100]

I have implemented this in our primary school 4 weeks ago and so far its working well.

I have 30 laptops spread over 2 trolleys (15 in each) Ontop of each trolley are 2 access points.

TrolleyA (WAP1 & WAP2)
TrolleyB (WAP3 & WAP4)

7 laptops from trolleyA connect to the network via WAP1. Then the other 8 connect via WAP2. Its the same for TrolleyB apart from they connect via WAP3 & 4.

This works well and we dont need to stagger the logins anyway and use roaming profiles. 90% of the applications are stored on the local machine as are all of our networked PC's.

Staff cannot tell the dirrefence (speed wise) between the laptops and the wired PC's.

[todav]

I have 3 main trolleys of 30 laptops and 2 further trolleys of 10. I'm running a managed wireless network from a Nortel wireless switch with 68 access points. So I've got some hardcore kit, but I've still got a load of problems. Wireless just isn't great for 30 students to try and log on at once. The first 15 to 20 may connect with no problems, but then it can all go wrong.

In addition to this, you have to think about the real cost of laptops:
Purchase price is signicantly higher for equivalent desktops.
Lifespan is shorter than a desktop.
Support can be more difficult.
They are more easily damaged and less readily repaired.
They are less availalbe than fixed PCs, i.e. the amount of teaching and learning time per lesson is reduced.

I'm now looking at replacing my laptops with fixed PCs in rooms with dual purpose desks, where the monitors pop up at the back of them. I can't wait.

Sorry to sound so negative, but I just want you and your leadership team to understand the real cost (financial and educational). I know that laptops in education can be great and I hope your laptops work out that way.

[CHR1S]

Thanks for your replys!

The sole reason we are looking into laptops is space, we simply dont have anywhere to put new PCs and the IT suites are already dual use for teaching too.

Jamin100 you may in the not to distant future have a visit from myself and some SMT to see the wireless in action. As its your fault all this started here can you not hide them everytime our staff come over? hehe

I think it will come down to having a number of laptops to suppliment the numbers in suites instead of a full on mobile classroom.

Thanks again

Chris

[jamin100]

Jamin100 you may in the not to distant future have a visit from myself and some SMT to see the wireless in action. As its your fault all this started here can you not hide them everytime our staff come over? hehe

Chris

lol.. Sorry Chris.... I know that your Head(s) seemed quite impressed with them when they were here.

I've actually just purchased another 30 laptops.. So we will have 2 mobile classrooms split over 4 trolleys.

I currently have 2 AP's ontop of each trolley although i may change this to 3 on each to split the load a little more. The only slow part with the solution is logging on. But to get round that the laptops have all been numbered and each child is going to get the same laptop each week so there will be a local copy of their profile on the machine already and it shouldnt take as long..

Ben

[ozydave]

I’m desperately trying to put the Head off the idea of laptop fro students.
But anyway, how do you guys handle the student logins. I must be missing something.
With staff I get them to login while connected to the wired network. They can them use the wireless network to login using the cached profile. So how do you do it with students do you just setup mandatory profiles on the laptops?

Cheers

[Michael]

So how do you do it with students do you just setup mandatory profiles on the laptops?

Just setup a single mandatory roaming profile for your pupils (on a file server). Typically mine is about 1.1MB in size.