Wireless Access

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Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Clients drop off of wireless network

I've been working on an issue with a group of wireless clients that are having issues with excessive drops in network connectivity. These are Windows machines (4 of them)  running a POS application in a high school environment.

 

These machines attach to a dedicated SSID (WPA2/PSK) on a dedicated AP 105 (e.g. this AP serves up only this SSID for only these 4 machines).

 

There are another 4 APs in the area that service about 220 clients on another SSID (802.1x).

 

When the lunch bell rings these POS machines will lose their network connection. The laptop (connected to the same AP/SSID) I've been using to troubleshoot this drops about 20% of its pings while doing a continuous ping during the same time period.

 

Any thoughts on what I can do to resolve this?

 

Thanks

 

Matt

MVP
Posts: 3,009
Registered: ‎10-25-2011

Re: Clients drop off of wireless network

Does this PODS does just work on 2.4ghz?

 

Can you run

show ap active ip-addr <ap ip address>

 

Check to make sure:
• Channel Frame Retry Rate % is below 30%. If higher then too much
interference.
• Channel Noise Floor is above 80. If Noise Floor is lower then too much
non-802.11 interference

 

Check this on 2.4ghz and also on the 5ghz if you got dual band to see

 

 

Besides this

Does this WLAN  got a vlan deditcated just to that? mean this vlan is not used for nothing else rather than that?

 

----------------------------------------------------
Product Manager - Aruba Networks
Alternetworks Corp
Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Re: Clients drop off of wireless network

The POS machines have draft-n NICs in them. They connect at 65Mbps which seems a bit odd.. Originally they where attached to an AP61 - but I swapped that for a 105 thinking/hoping they had 5Ghz NICs in the clients..

 

I'll check the ap stats on Monday when they're having problems.

 

Yeah - or WLAN is on its own VLANs.

 

I suspect this is some sort of noise/interference issue.

 

Thanks

Guru Elite
Posts: 21,272
Registered: ‎03-29-2007

Re: Clients drop off of wireless network


mcolwell wrote:

The POS machines have draft-n NICs in them. They connect at 65Mbps which seems a bit odd.. Originally they where attached to an AP61 - but I swapped that for a 105 thinking/hoping they had 5Ghz NICs in the clients..

 

I'll check the ap stats on Monday when they're having problems.

 

Yeah - or WLAN is on its own VLANs.

 

I suspect this is some sort of noise/interference issue.

 

Thanks


If they are draft-N, they will potentially have trouble with an "N" preamble.  65Mbps is a single stream device.  Most cellphones with "N" connect at this.  I would turn off High Throughput in the HT SSID profile that these devices connect to and see if that stabilizes the connection.

 



Colin Joseph
Aruba Customer Engineering

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MVP
Posts: 3,009
Registered: ‎10-25-2011

Re: Clients drop off of wireless network

Did they also had issues with the AP 65?

 

Did yo try connecting a windows client for example, and see if you get this issue? because if you do must be what collin said... would be a issue bettween the AP and the POD which got a draft N card.

 

Cheers

Carlos

----------------------------------------------------
Product Manager - Aruba Networks
Alternetworks Corp
Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Re: Clients drop off of wireless network

I'll go ahead and disable the HT as you suggest, but I fear it will be of little benefit. These machines had issues maintaining a connection to an AP61.

 

Carlos.. a Windows machine connected to the AP has the same issue.

MVP
Posts: 3,009
Registered: ‎10-25-2011

Re: Clients drop off of wireless network

Then i dont think the issue is the draft n cards you got because if the laptop has the same issue which has normal cards and still got the issue then something else is...

We should correct the issue in the normal windows clients first and then on the pos i think

Can you asnwer my other quetistion i asked you in my first message?

----------------------------------------------------
Product Manager - Aruba Networks
Alternetworks Corp
Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Re: Clients drop off of wireless network


NightShade1 wrote:

Can you asnwer my other quetistion i asked you in my first message?


I have to wait untill around 11:30 AM PST to do this.. These machines are only used to serve lunch to our students, so they only operate Monday-Friday around 11:30-12:30(ish).

Occasional Contributor II
Posts: 44
Registered: ‎10-06-2009

Re: Clients drop off of wireless network

Here are some stats:

 

Channel 11
Channel Frame Retry Rate(%) 72
Channel Frame Low Speed Rate(%) 0
Channel Frame Non Unicast Rate(%) 1
Channel Frame Fragmentation Rate(%) 0
Channel Frame Error Rate(%) 25
Channel Bandwidth Rate(kbps) 25
Channel Noise 91
BSS Frame Retry Rate(%) 100
BSS Frame Low Speed Rate(%) 0
BSS Frame Non Unicast Rate(%) 0
BSS Frame Fragmentation Rate(%) 0
BSS Frame Receive Error Rate(%) 0
BSS Bandwidth Rate(kbps) 0
BSS Tx Packets 514009
BSS Rx Packets 228506
BSS Tx Bytes 169438564
BSS Rx Bytes 9570272
BSS SNR 25
BSS Tx Rate 1 mbps
BSS Rx Rate 1 mbps

 

 

Channel 11
Channel Frame Retry Rate(%) 35
Channel Frame Low Speed Rate(%) 0
Channel Frame Non Unicast Rate(%) 3
Channel Frame Fragmentation Rate(%) 28
Channel Frame Error Rate(%) 16
Channel Bandwidth Rate(kbps) 205
Channel Noise 91
BSS Frame Retry Rate(%) 22
BSS Frame Low Speed Rate(%) 0
BSS Frame Non Unicast Rate(%) 0
BSS Frame Fragmentation Rate(%) 45
BSS Frame Receive Error Rate(%) 0
BSS Bandwidth Rate(kbps) 192
BSS Tx Packets 514748
BSS Rx Packets 229736
BSS Tx Bytes 169768933
BSS Rx Bytes 9641278
BSS SNR 25
BSS Tx Rate 1 mbps
BSS Rx Rate 54 mbps

 


Channel 11
Channel Frame Retry Rate(%) 69
Channel Frame Low Speed Rate(%) 0
Channel Frame Non Unicast Rate(%) 3
Channel Frame Fragmentation Rate(%) 1
Channel Frame Error Rate(%) 29
Channel Bandwidth Rate(kbps) 31
Channel Noise 91
BSS Frame Retry Rate(%) 0
BSS Frame Low Speed Rate(%) 0
BSS Frame Non Unicast Rate(%) 0
BSS Frame Fragmentation Rate(%) 13
BSS Frame Receive Error Rate(%) 0
BSS Bandwidth Rate(kbps) 6
BSS Tx Packets 514824
BSS Rx Packets 229825
BSS Tx Bytes 169777488
BSS Rx Bytes 9643746
BSS SNR 25
BSS Tx Rate 1 mbps
BSS Rx Rate 54 mbps

MVP
Posts: 3,009
Registered: ‎10-25-2011

Re: Clients drop off of wireless network

Your problem is that there is too much interference.... look at your channel retry rate...

 

Channel Frame Retry Rate(%) 72

 

Channel Frame Retry Rate(%) 35

 

Channel Frame Retry Rate(%) 69

 

For example here on the office we got Also Aruba a few APs

 

Channel                              161
Channel Frame Retry Rate(%)          0

 

 

Channel                              11
Channel Frame Retry Rate(%)          0

 

 

Question

If its a 105 why you just put the 2.4ghz output? 

 

 

----------------------------------------------------
Product Manager - Aruba Networks
Alternetworks Corp
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