Possible Wifi issues - what steps to take to locate the issue

[Ditto]

Had a teacher complain a new laptop is performing badly. Initially it was thought that this was because the device has been off for a while and started to d/l a bunch of updates before settling down. Having completed a full update, the laptop behaved well in my location and it was handed back to teacher. The teacher then used he device for a couple of hours and then gave up. It suffered dropped connections repeatedly. I'm thinking it's a Wifi issue and not the PC as it worked well in another location.

 

As this sort of thing is all new to me, I'm looking for basic trouble shooting advice to investigate. One thing I'm considering is hooking the laptop to a wired connection temporarily just to eliminate some possibilities.

[pete]

• Check if there are newer drivers for the wireless card
  
• ..and BIOS, just in case it's doing something dumb
  
• Is power-saving turned on in the Wireless. How aggressively does it kick in?
  
• What do the logs on your wireless system say? Lots of odd traffic from that laptop in a particular location?
  
• Is the nearest AP to them in good shape? Do other people in that area get on fine.
  
• If they teach in multiple classrooms, are there places where it's always a good connection?
  
• If you're using RADIUS for machine auth, is there anything strange in the logs there?
  

 

You will find certain wireless card + AP combos can be problematic, but it's usually older cards having issues with newer APs.

[AlanD]

I'd swap the laptop to eliminate that as a possibility.

[njc235]

Could be a sticky client scenario. Check which AP it's associating with via the controller. Which Wifi is it?

[mikeprice]

silly idea but I had this once - the laptop was set to worldwide wifi settings - which only uses channels 1-11 - but the wifi system was set to UK - which uses channels 1-13

 

the nearest AP was on channel 13 ( a while ago - the accepted best practice was to use channels 1 3 5 7 9 11 13) so the laptop only connected to the next best AP - which had a very weak signal

 

so check which ap it is connecting to and which one is nearest - if they differ check channel numbers

 

for reference - nowadays they are supposed to use channels 1 6 and 11

[Ditto]

• Check if there are newer drivers for the wireless card
  
• ..and BIOS, just in case it's doing something dumb
  
• Is power-saving turned on in the Wireless. How aggressively does it kick in?
  
• What do the logs on your wireless system say? Lots of odd traffic from that laptop in a particular location?
  
• Is the nearest AP to them in good shape? Do other people in that area get on fine.
  
• If they teach in multiple classrooms, are there places where it's always a good connection?
  
• If you're using RADIUS for machine auth, is there anything strange in the logs there?
  

You will find certain wireless card + AP combos can be problematic, but it's usually older cards having issues with newer APs.

In bullet order:

 

• I will check but this is a very new Dell laptop so I suspect unlikely
  
• As above
  
• I will check but lost connections were within minutes of each other. What's a typical time. Are the settings for this going to be found via the device driver?
  
• Good question! It's so early at the school, that I've no idea how to access those but will make enquiries on Monday. Handover hasn't been great!
  
• It's within a few metres. I'll be checking with my laptop on Monday. I don't think it's a location that's used much. Also, going check the AP is powered!
  
• Generally in just one room. Teacher will be trying the same location with a cable connection and then with wifi in another location, ideally my location I know that works reliably.
  
• We're not.
  

[round2it]

I had issues with some dell laptops because we have a mixture of old aps bg and bgn in this one location the laptops were connecting to the fastest not strongest signal.

 

So in the driver settings you should have an option for preferred band.

I set it to bg first and the laptops work fine now

[Ditto]

I'd swap the laptop to eliminate that as a possibility.

I'll be trying mine in same location as part of a process of elimination. Any replacement is likely to be old and Win 7, so I'm going to avoid that complication if possible.

[Ditto]

silly idea but I had this once - the laptop was set to worldwide wifi settings - which only uses channels 1-11 - but the wifi system was set to UK - which uses channels 1-13

the nearest AP was on channel 13 ( a while ago - the accepted best practice was to use channels 1 3 5 7 9 11 13) so the laptop only connected to the next best AP - which had a very weak signal

so check which ap it is connecting to and which one is nearest - if they differ check channel numbers

for reference - nowadays they are supposed to use channels 1 6 and 11

Will check this, but I will help on how to - this is really a completly new area for me! I will try to get some additional info, like make/model of AP etc as I expect it's tricky to guide without!

[Ditto]

Could be a sticky client scenario. Check which AP it's associating with via the controller. Which Wifi is it?

 

I had to look up 'sticky client'! I see that is a possibility.

[mikeprice]

Will check this, but I will help on how to - this is really a completly new area for me! I will try to get some additional info, like make/model of AP etc as I expect it's tricky to guide without!

 

If you have an android phone/tablet there is a wifi analyser app that shows you the channels

 

there used ot be a Windows system called InSSIDer that did the same - can also be useful to wander around the area and check for black spots - some of the apps have a beeping sound that gives an audible indication as well

 

I once stood a group of students in a line and used this as a guilt detector - I just stood the one I had seen do the deed under the AP - it was a minor thing but the teacher watching thought it was hilarious when i told he how I did it - warning - this may be frowned on by 'some teachers'

[HPlum78]

AirMagnet is a good survey tool, and you need to use a separate adapter than the one used by in a laptop/ phone.... to get a real propper heat map of a WiFi network, if you think it's a dead spot issue.

[Ditto]

Thank you all for the input. I now have a bit more info about the setup which I hope will help. The AP is a Netgear WNDAP360. I now have the IP addresses for the APs so can access the logs/settings etc. I'm not really sure what to look for but can see under Monitoring -> Wireless stations it list 4 MAC addresses under 'Available Wireless stations (802.11ng)' and shows channel 11. Under 'Available Wireless stations (802.11na)' it shows many more and lists I'd estimate 30 MAC addresses.

 

On the teachers laptop I have discovered it has a different Network card to mine. I've updated the driver hers. I also turned off the power save mode. I got a strong signal when I was located near to the AP. Surfing was mostly fine, but it did pop up an error at one point briefly. I'm awaiting further info from when the teacher used her laptop. I'm advised to make sure it's not connecting to the next nearest AP, I would need to turn that one off! I'm told there is no inter-connectivity between the devices.

 

On a later occasion, they had a class of 30 iPads access the internet. At least half a dozen ended up with a spinner in Safari. Closing/restarting sometimes resolved.

 

It all feels a bit uncontrolled, but perhaps that's where I can add some value!? I'm just wondering if the whole setup is not able to cope with the surge of minimal activity to 30 pupils jumping on the system in one go. In the ICT room they have about 16 desktops, all cable connected. When a class all log in at once, most are fine but a few at random seem to freeze and the solution of just restarting seems to be the standard expectation. Unfortunately it often works, so the underlying problem goes un-investigated, which isn't my style so I'll keep plugging away. I will look into some apps/tools to do more analyses, but continued suggestions are very much appreciated.

[AlanD]

Are there more distant APs which support 5ghz? Is it possible the newer cardin this lap supports 5ghz? Do you have band steering enabled? A known issue is a laptop connecting at 2.4g, on a busy AP. Deciding it would be better on 5ghz, but the signal is too weak, because 5ghz rarely works well through walls.

 

Another issue I have seen on the edge of our campus next to a church was that neither ch6 nor 11 worked well at times. Discovered these times were whe the church used some non standard wireless mics they imported from China!

[Scan099]

Hi We have this in the school and usually it is down to an AP other locations are fine.- we just restart the AP in their area and that seems to cure the problem.

[PotNoodleTech]

What wireless card is actually in the laptop? We had a problem where laptops with dell 1504 wireless cards were very unreliable and sporadic. Swapping out the wireless card fixed the issue so the supplier gave us different intel AC cards.

 

It could be the actual laptop.