wndap360 and wc7520 speed issues and correct setup

[MrBarnett]

Hi, 

I am having issue with the speeds of the wndap360's. we have 18 of these setup so far, i have 2 more to setup up, we have had them for quite a while now and I havn't had any issues. Recently the wireless speeds are seeming to be very slow, I was looking to find out what speeds should I be expecting.

looking at the usage graph in the wc7520 is suggesting that the peak network usage is 3.20Mbps, that seems very slow to me.

i have run some tests using iperf to a wired device and to a wireless device and the speeds arnt much better.

Wireless reports at 25.9Mbps

Wired reports at 847Mbps

I know that obviously wired is going to be  much quicker but that difference seems like something may be wrong on the wireless side.

I am happy to scrap all the settings i have and start aginif need be, but i would like to know if its posible to sve the curent settings to revert back to if need be.

Thanks

Rich 

[LaxmankumarG · Accepted solution]

Hi,

The maximum speed depends on the channel width, guard interval, the channel congestion and the distance of the client from the AP.

In general 2.4Ghz wireless is more congested, so as and when the congestion increases the data rates will go down to increase the reliability.

When the channel width is set to dynamic 20/40Mhz and if the AP can operate at 40 Mhz, then the maximum speed will reach to 270Mbps, if it cant operate at 40Mhz then the data rate will fall down to 130Mbps maximum. But if we configure the channel width to static 20Mhz the maxmium speed the AP can operate is 130Mbps, and it will never be more than that. That is the reason you are seeing the data rate at 130Mbps. 

[MrBarnett]

I have found the back up settings on the controller now so dont worry about that please

[JohnRo]

Hello MrBarnett, 

Welcome to the community! 

I'd like to know how the AP's are configured are they running on all 5Ghz and 2.4Ghz? What firmware version is the controller using? Before you noticed the issue, were there any changes made on your network? 

Thanks, 

[MrBarnett]

Hi John, 

Thanks for the reply.

The AP's are configured with both 5Ghz and 2.4 Ghz, the firmware is the most recent I believe: 2.5.0.43.

I do not recall having any recent changes to the network, I couldnt tell you how long the issue has been going on for but the last major change to the network was possibly 18 months ago when we changed all the switches to gigabit switches, i dont think the issue has been around for this long.

Rich 

[LaxmankumarG]

Hi,

From your previous post it is clear that you are using both the radios 2.4 & 5 Ghz. When you see the slowness in the network do you know to which radio your client is connected (2.4/5)? and to which AP?. at is the operating channel of that AP?

Over a period of time the wireless environment may change which can effect the overall performance of the network. Because wireless is a single broadcast domain any new AP addition in your neighborhood can effect the performance. Can you answer the above questions? 

[MrBarnett]

Hi, 

The slowness occurs regardless of the radio used, both 2.4hz and 5Ghz. The slowness is constant.

I have just done 5 tests on both 2.4 and 5.

The average speed of 2.4 was 20.82Mbps

The average speed of 5 was 21.04Mbps

The laptop is running windows 7

The laptop is connected to the AP in my office and the channel of the AP is

8 / 2.447Ghz

128 / 5.640Ghz

From my office I am unable to see any neighbouring wireless on the PC. However using an app on an android phone I am able to see some neighbouring wireless but their signal levels are very low, around -90 db

In another area of the school, so using a different AP on channels

10 / 2.457Ghz

44 / 5.220Ghz

There were a couple of neighbouring signals, again at the around -90db this time the laptop could see the wireless

The Average speed of the 2.4 is 21.96Mbps

The average speed of the 5 is 22.76Mbps

I am going to perform the same tests on another laptop, running windows 7 and also on another laptop running Linux to see if there is any differences.

Thanks

Rich

[LaxmankumarG]

Hi,

Thanks for quick reply, based on the data you have provided. I suspect the wireless mode. Can you tell me what is the wireless mode set to by going to the following page.

Configuration->Wireless->Wireless->Wireless Mode.

[MrBarnett]

Hi, 

I have looked at the wireles mode and for the 2.4Ghz it is on 802.11ng and for the 5Ghz it is on 802.11na. 

There is an arrow next to these which suggests a dropdown list to change this mode, however on both the 2.4 and the 5 the drop down does not drop down

Rich

[LaxmankumarG]

Hi,

How many number of APs are currently managed by the controller. And in what group they are in. In the recent past have you ever touched the Channel allocation configuration which is present in Configuration->Wireless->Channel Allocation page. It looks like somhow the APs are operating in 11g, 11a modes.

What is the link speed shown when you right click on the wireless network ssid, and select status?.

[MrBarnett]

Hi, 

There are currently 18 APs, and im not sure that tey are in any group. the only gropups i can recall in the software are the basic and group 1 and group but im sure i have only ever used basic. looking at the channels, all of the channels for both 2.4 and 5 are ticked, last time i remember looking at this only 1,6 and 11 were ticked, i dont remember doing this.

the link speed has been 54Mbps untill a couple of hours ago i enabled Wifi multimedia, this has made the link speed up to 270Mbps on the 5 and 130 on 2.4 but im not sure if i need or want the QOS WMM on or not. we had a couple of issues with irratic pings since then, but on the same hand we have had some instances where the ping is a very stable 1ms.

Rich

[LaxmankumarG]

Hi,

Yes Wi-Fi Multimedia (WMM) feature plays a major role in getting the higher throughput values. When we disable this feature, it disabled the 11n rates, and the device will start transmiting the packets at legacy rates that is 54Mbps or less, because of this you are seeing the low throughput values. Once you have enabled  this feature, the 11n transmit rates will be enabled internally and the AP can transmit at higher data rates, that is whay now you are getting good throughput.

with this setting change your concers are resolved, so do you need any help from our side?. 

[MrBarnett]

I did think it was sorted and the speeds have gone up considerably, however the only real stable wireless is the 5Ghz. The 2.4Ghz is sometimes as high as 270Mbps and currently it has dropped to as low as 1Mbps i havent changed anything for this to happen.

i have changed on the laptop within the drivers 802.11n chsnnel width for band 2.4Ghz form auto to 20MHz only and the speeds went up to 130Mbps i have changed it back to auto and the speed stayed up around 130Mbps. this happened on 3 identical laptops at the same time. any ideas?

Thanks

[LaxmankumarG · Accepted solution]

Hi,

The maximum speed depends on the channel width, guard interval, the channel congestion and the distance of the client from the AP.

In general 2.4Ghz wireless is more congested, so as and when the congestion increases the data rates will go down to increase the reliability.

When the channel width is set to dynamic 20/40Mhz and if the AP can operate at 40 Mhz, then the maximum speed will reach to 270Mbps, if it cant operate at 40Mhz then the data rate will fall down to 130Mbps maximum. But if we configure the channel width to static 20Mhz the maxmium speed the AP can operate is 130Mbps, and it will never be more than that. That is the reason you are seeing the data rate at 130Mbps. 

[LaxmankumarG]

Hi,

Do you need any help or more understanding regarding the data rate and throughput?

[MrBarnett]

That explains quite a bit, i think that is what is happening on our network.

thank you for clarifying this for me

[MrBarnett]

thats all i think 

thank you all for your help