Wireless Access

Hello,

I have a wireless network consisting of 6 Aruba AP-305 access points.

Performance of the network is generally good, but the clients connecting to just 1 of the access points regularly have very poor connection speeds. The connection speeds on all the other access points are fine.

The configuration across all the access points is consistent, so the variables as I see them are the AP location and the physical route back to the switch.

I have tried moving the AP a little closer to the clients (a matter of 0.5 metres maybe, but from the "wrong" side of a glass partition), and have verified that the ethernet connection for the access point is operating at 1gbps on the switch. Although, I wouldn't expect that to affect the connection speed between the clients and the access point.

As I type, the speeds for the 18 clients connected range from 39mbps to 243mbps. However, only 4 clients have connection speeds above 108mbps. Contrast this with another of our access points, whose 21 clients range from 58mbps to 600mbps, where only 5 of the clients have a speed of 150mbps or lower. Put simply, the problem access point features mainly amber coloured speeds, the healthy ones are mainly green speeds.

All users/clients in the area have line of sight to the access point, and the furthest away user sits perhaps 10-12 metres away from the access point. So I would expect performance to be good, and can't see a reason for the performance to lag so far behind the other access points.

Could someone recommend what I should be looking at to try and improve the connection speeds for this 1 access point, or what the cause might be?

Many thanks!

Are you running 20, 40 o4 80mhz channels?

I can see that 80mhz is disabled. So, 40mhz. Could you offer guidance on how I can confirm this for certain please? Thank you.

You can confirm what channel width you are running by logging into the CLI and issuing "show ap radio-summary" and check the channel assignment. Ignore "HT" or "VHT" as that can be enabled without using 40Mhz or 80Mhz channel widths. If you see a "+" or "-" that means 40Mhz, if you see "E" then it's running 80Mhz widths. If you just see the channel number, it's 20Mhz. 

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@ewangibb wrote:

I can see that 80mhz is disabled. So, 40mhz. Could you offer guidance on how I can confirm this for certain please? Thank you.

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Does the glass partition have foil or metal in it?  If the glass partition is the only difference, that might be your problem.

Thank you both for your responses, and apologies for not responding sooner.

Responding to each in order:

1 - I have enabled access to the CLI and logged in. Unfortunately, the "show ap radio-summary" command returns a parse error. I have used "?" to tell me what commands are available, and "radio-summary" isn't among them. My APs have version 6.5.4.3 on them.

See below for the available commands.

Is there another way to confirm this information on 6.5.4.3? I have run "show arm" and "show arm-channels", and can see many enabled channels under both 2.4GHz and 5.0GHz with a "+", an "E", and also "S". Is this relevant information? As mentioned before, "80Mhz Support" is explicitly disabled in the ARM configuration.


2 - I have done a test using 2 laptops. The signal strength figures come from the Aruba virtual controller. Let me know if this is not what you were suggesting, and I'll look at it again.

A) when connected to the problem AP:

Laptop 1, signal strength 55, speed 121mbps.
Laptop 2, signal strength 43, speed 108mbps.

B) when connected to another AP:

Laptop 1, signal strength 52, speed 600mbps.
Laptop 2, signal strength 47, speed 400mbps.

I can confirm that the problem AP is nowhere near a microwave.


3 -There's no metal or foil in the glass partition. The glass partition I referred to is no longer between the AP and its nearest clients. This change had been made prior to raising the original post.

Many thanks for your input!

# Available commands:

AP01 - MACADDRESS# show ap?
ap                Access Point
ap-alert          Access Point alerts
ap-env
ap-env-backup
ap1x
ap1xcert
app-services
aps

AP01 - MACADDRESS# show ap ?
allowed-channels            Legal channels
allowed-max-EIRP
arm                         Adaptive Radio Management
association                 Association table
bss-stats                   BSSID statistics
bss-table                   BSSID information
cacert
checksum                    enable/disable UDP checksum
client-match-actions
client-match-history        Show history Client Match Actions
client-match-live           Show current Client Match Actions
client-match-refused        Show latest 8 clients refused due to CM
client-match-ssid-table     Show SSID table stored in Client Match
client-match-triggers
client-probe-report         Show current Client Probe reports
client-view                 Show SLB neighbor information
commands
debug                       Debugging information
dot11k-beacon-report
dot11k-nbrs
dot11k-stat
feature-map
flash-operation
ids
mesh
monitor                     Monitoring Information
pmkcache                    Show PMK cache
port                        Port
regulatory                  DRT details
spectrum
tpm-info
virtual-beacon-report       Show Client Match Database

Not saying this is your issue but I ran into this same problem a few months ago with a single IAP connected to a VC.  It had much slower speeds then the rest of the IAP's in the cluster (~50).  We first factory reset the AP but still encountered slow speeds.  Next I took an existing AP and swapped it out with the "slow" AP and we confirmed speeds were fast so we knew it had something to do with the AP itself, not cabling etc.  We ended up having Aruba support replace it and the replacement one resolved the issue.

Thanks for the suggestion.

I have swapped the AP for another. I will monitor the performance over the coming days, and feed back how we get on.

An update.

It really looked like swapping the access point had done the job, and had identified an issue with the original access point.

The swap was performed on 28th August, and I've been checking performance regularly since then and been satisfied that there was a clear improvement in performance with the replacement AP.

However, this morning (5th September) I've checked prior to beginning the process of arranging a replacement for the apparent problem AP, and the performance has dropped again. Monitoring over the last week had been so promising too.

As it stands, we're back to square one, and even the AP we put in place for testing is experiencing poor speeds.

Does anyone have any more suggestions at this point?

Thanks.

For the benefit of anyone who has been keeping tabs on this thread, and for anyone who happens across it in future having had a similar issue, I can report that we have managed to get to a state where performance seems reliably strong.

I've been very cautious about declaring this as resolved, as throughout this process I've had false dawns and wanted to make sure the APs were monitored thoroughly for a long period to ensure they were behaving as required.

The solution for us was to tweak the 'Min transmit power' and 'Max transmit power' of our VC's ARM settings. These are now set to 3 and 18 respectively. Previously they were set to 18 and Max. Our networking provider recommended lowering the settings, and through some trial and error, we came to the current settings, which are now working for us.

Again, thank you to everyone who offered help and advice above!

Have you tried monitoring the RSSI from the same client device while connected to the problematic AP and to a good AP? Also monitoring the noise/interference could be helpful.

If that AP is next to a microwave or some other source of interference, could result in packet loss or lower data rates.