Laptops wirelessly

[Katy]

Keep getting reports that the laptop trolleys are "useless" / "not fit for purpose" etc etc, actually frequently since they were put in place 3 years ago. We have done the following to try and fix the problems:

 

- Swap all HDDs for SSD

- Shut down when lid is closed

- No switch user

- Increase backbone to PoE switch to 4Gbps, and backbone to the building to 10Gbps

 

Whenever we go over and test them, they work fine. Then the next day we get told "they took 15 minutes to log on, half of them are only showing search and customer support on the start menu". Which sounds like something to do with the network as it's failing to load the redirected start menu.

 

We use a HP MSM460 based wireless network (with one of the 765zl controllers), all traffic comes out of the AP onto the VLAN (it is not tunneled back to the controller). There is one AP for every 2 rooms, the building is 3 years old.

 

Does anybody have any ideas? All I can think is it's the fact they are attempting to log 16 on simultaneously and the wireless can't cope - when we test them we can only do 2 at a time (due to there only being 2 of us) and the only issues we get when testing were too many people logged on at once (solved by disabling switch user), not rebooted for ages (solved by shutting down with lid close) and no network (no permanent fix for this, it's when the children press the button to turn off the wifi, but it's a rare one).

 

Getting sick of being moaned at really, I didn't pick the laptops and I didn't design the wireless network. In fact I proposed replacing the wireless with one Ubiquiti AP per room last year and was turned down (HP discontinued the APs we use so we can't just add more to the existing system)

[bwestlake]

I would suggest finding out when they are going to use them next and going down to see what they are doing, it might be that they are expecting them to load instantly or they are doing something silly.

[tmoon-mint]

I would suggest starting a log for staff. Stating what the problem is, what time it happened, how many laptops were in use at the same time, location in school etc. Very difficult to troubleshoot without help from the end users unfortunately.

[Katy]

I would suggest starting a log for staff. Stating what the problem is, what time it happened, how many laptops were in use at the same time, location in school etc. Very difficult to troubleshoot without help from the end users unfortunately.

We tried that, didn't get filled in. Forgot to mention it's in the junior school and we aren't based down there, so it's about 5-10 minutes to walk down there.

 

I've asked them when they are next being used so we can go and watch, although when we have done this in the past it has worked fine (maybe the laptops can sense our presence and are scared of misbehaving)

[tmoon-mint]

Argh very frustrating! I often find that giving computers a menacing look while the user is trying to describe their problem does the trick! Definitely observe a lesson then if you have the time to spend on it.

[GuyJD]

you could look at doing a gradual roll out of new AP's I had to do that here as we had a Netgear managed system in place already that wasn't coping with having all of the laptops logging on at the same time, so I put Ubiquiti AP's in every other classroom and configured the load balancing on the Netgear controller to only allow 10 connections per AP before denying access at which point the laptops would then start connecting to the nearest Ubiquiti AP.

[andydis]

Katy, out of interest have you tried this test:

 

get 5 laptops put them very close to each other and boot/ log them all in at the same time, note the time it takes to login,,

repeat the test with just 1 laptop and note the time to login.

repeat test with 10 laptops ,

 

I had a very similar issue a few years ago.

[Katy]

It is starting to become more clear, they have finally told me their room number and turns out they moved over the summer from a room with AP to a room with no AP.

 

Going to look for an AP that barely gets used over in the seniors and nick that, then go and observe once it's fitted down there.

Edited February 3, 2017 by Katy

[Meldrew]

Do you know if the laptops are connecting via 2.4 or 5Ghz? We had this type of issue and had to manually configure laptops to 'prefer 5Ghz'. Also you could setup (if you haven't already) enough test user accounts for 1 per laptop, so 16 for example and type in the credentials into each laptop ready, then go around and hit enter on all of them as quickly as possible. This very easily simulates a whole class at once.

 

HTH,

 

Meldrew

[Katy]

Do you know if the laptops are connecting via 2.4 or 5Ghz? We had this type of issue and had to manually configure laptops to 'prefer 5Ghz'.

Not sure... where abouts do you tell them which to use? Is it just in the wireless adapter properties in device manager?

[pcstru]

Whenever we go over and test them, they work fine. Then the next day we get told "they took 15 minutes to log on, half of them are only showing search and customer support on the start menu". Which sounds like something to do with the network as it's failing to load the redirected start menu.

 

Does anybody have any ideas? All I can think is it's the fact they are attempting to log 16 on simultaneously and the wireless can't cope - when we test them we can only do 2 at a time (due to there only being 2 of us) and the only issues we get when testing were too many people logged on at once (solved by disabling switch user), not rebooted for ages (solved by shutting down with lid close) and no network (no permanent fix for this, it's when the children press the button to turn off the wifi, but it's a rare one).

If you are only testing 2 at a time then your test is very likely not replicating what is going on. I'd invite myself to a class to see what is happening or run tests which replicate the actual conditions (i.e. however many simultaneous logins are happening together).

 

One thought : in fixed classrooms teacher seating plans tend to mean students get the same machine but often laptops are pulled from the trolly randomly so students get different ones each lesson. Depending on the set-up you have, setting up a new profile on a machine may be worth avoiding (as much as possible), so having students use the same laptop from week to week can be worth a little bit of effort.

[Meldrew]

Not sure... where abouts do you tell them which to use? Is it just in the wireless adapter properties in device manager?

 

We had to ensure that the manufacturers drivers were installed, rather than Microsoft ones and once these were installed, there were a load of settings available in device manager for the wireless adapter. One of them was the prefer 5Hgz option. I'm not sure about your wireless network, but ours (Unifi) shows what band devices are connecting at, so we were able to confirm that before they were connecting at 2.4 and afterwards were on 5Ghz. We found the difference was massive.

[sted]

they arnt by any chance all logging on with the same user name (say reception/year1) etc as ive had that cause me issues in the past even though i managed to get 30 or so logged in using random kids accounts fine the staff were just logging them is as the generic user which caused issues

[FN-GM]

Increase backbone to PoE switch to 4Gbps

 

It doesn't work like that, 4 x 1gbs doesn't = 4Ggbs. The ports still run at the same speed ie 1gbs, you just have more than one connection to go down. Think of it like a motorway. When you add a lane more traffic can go down at one time. But the speed limit is still 70mph.

 

If you have mandatory profiles, store these on the local machine and not a network share. This helped us when we used them. I guess when you had 30 laptops logging on via 1 ap it was bottle necking.

[Katy]

It doesn't work like that, 4 x 1gbs doesn't = 4Ggbs. The ports still run at the same speed ie 1gbs, you just have more than one connection to go down. Think of it like a motorway. When you add a lane more traffic can go down at one time. But the speed limit is still 70mph.

It's set as an aggregated link, and there's 15 APs in the building, so that means more chance of the busy APs hitting 1Gbps than when they are all sharing a single 1Gbps uplink.

 

The users don't have profiles (i.e. it makes a local one each time, all restrictions etc are done via group policy)

[Michael]

Two things come to mind -

 

- Either a weak or saturated wireless signal, as confirmed by Katy, no AP directly in said classroom

- I'd say the Profile creation each time doesn't help. OK this isn't directly a wireless issue, but more so a time/processing issue. I'd definitely explore a single/mandatory profile for end users; it makes a huge difference. Windows 10 especially takes forever to create a new profile (by design), brilliant!

 

Link aggregation or trunking does two things - increases overall throughput, as well as adds redundancy, but to be honest I don't think it would make any difference in this scenario, even if it were a 1Gbps link, rather than 4Gbps.

[Katy]

When we tested it (on wired pcs) it was quicker creating a profile for us than downloading the mandatory one, might look at mandatory profiles again at some point though. I also think it is the connection between laptop and AP rather than between AP and network, but we upgraded the backbone links anyway as the APs share a switch with phones and cctv cameras.

[Michael]

I presume the main LAN, your phones and cctv are on separate VLANs?

 

I am surprised you found mandatory was slower, that's definitely not my experience at all. Mandatory profiles literally take seconds, whereas a new profile can take 30 seconds or longer. 'We're happy to see you' I'm sure gets tiresome for end users every time!

[Katy]

Yep all on different VLANs.

 

Can't remember how I did it but it doesn't show any of that "welcome happy to see you" rubbish to them, think I managed to kill it all out of the image somehow.

 

Might not have tested against mandatory and just roaming actually, due to how much of a faff it is making a mandatory profile these days with having to run sysprep, but it was still acceptable login speeds.

[Michael]

You can stop the messages using GPO, but this doesn't speed anything up, it just suppresses any messages.

 

I think an AP per room and mandatory profile, you'll be spot on for sorting this.

[Katy]

I think an AP per room and mandatory profile, you'll be spot on for sorting this.

An AP per room is not gonna happen this year at least, but hopefully the mandatory profile and moving APs to the rooms that they use the most will sort it... thanks

[Foresthippy]

Have you looked for sources of interference? We had a problem in a school which only manifested when 30 kids tried to login at the same time. It turned out to be PIR sensors which used 2.4GHz microwaves - we've since seen them in loads of schools and usually a program of sensor replacement fixes the issue. If you have logs on your access points, you can see the result of interference as a high number of physical network errors. I've attached a photo of one type of offending PIR, although there are probably loads of different models with this issue - we know of at least 3, which all look different.

 

 

This particular type is the Guardall Astra - we identified this problem using a wi-spy.

Edited February 3, 2017 by jdmackay

[Katy]

All the lights in that building are on some sort of sensor... I will look into it, although just looking now there is an AP over there with 13 clients connected all using Radio 1 (which is the 5GHz radio)

[dry]

What's your GPO setting for 'Always wait for the network at computer startup and logon'?

[Katy]

What's your GPO setting for 'Always wait for the network at computer startup and logon'?

Enabled.