Wireless Signal Strength going up and down

[lzakariya]

Hi...

I am using Cisco WLC 4404 and Ciso Aironet 1200 series. I have configure many SSIDs various security policies like

[WPA2][Auth(802.1X)],

[WPA + WPA2][Auth(PSK)]

Web-Auth

WEP

MAC Filtering

I can connect to any of the SSID. But after I connected, I can see the signal strenth is getting up and down. Sometimes its excellent, sometimes fair, sometimes low. Even if I am sitting very near to my Access point range, its happening.

Please help me.. this started since one week

[Leo Laohoo]

Is this happening to ALL your APs or just one?

[lzakariya]

To all APs this is happening

[Leo Laohoo]

And you are seeing signals fluctuating from all clients?

[lzakariya]

I tested already with 3 clients, all of them facing this issues.... I have to test more

[Leo Laohoo]

Do you have DCA and TPC enabled?

[lzakariya]

For 802.11a/n

TPC :

Power Level Assignment Method -Automatic

DCA:

Channel Assignment Method - Automatic

DCA Channels - 36, 40, 44, 48, 52, 56, 60, 64

For 802.11b/g/n

TPC :

Power Level Assignment Method -Automatic

DCA:

Channel Assignment Method - Automatic

DCA Channels - 1, 6, 11

[Jaca]

We are having the same issues as well.

Our Hardware is different than yours though.

5508 WLC (7.0.235.3) and 3500i AP's.

For our DCA and TPC readings:

802.11 a/n

TPC:

Power Level Assignment Method: Automatic Every 600 secs

DCA:

Channel Assignment Method: Automatic Every 8 hours

DHC Channels: 36, 40, 44, 48, 149, 153, 157, 161

802.11 b/g/n

TPC:

Power Level Assignment Method: Automatic Every 600 secs

DCA:

Channel Assignment Method: Automatic Every 10 Minutes

DCA Channels: 1, 6, 11

It was noticed by an end user on 06/24/2013.

It effects both multiple variants of HP Laptops and 6120 Avaya wireless phones. They will go from 0 to 5 bars when standing underneath an AP and when connecting to different SSIDs. The Avaya's work off 802.11b only and all other equipment works of 802.11a/g/n. Cisco phones work off 802.11a only.

Our Cisco 7925 phones do not show any loss of signal strength as the Avayas do.

[it dude man]

We are also seeing this type of behavior on our systems too. Actually, I have noticed this issue in a ton of businesses i've been at lately too (ie my BMW dealership, several other dealerships) and also at our law firm that has a 5508 WLC based wifi system.

We are running WLC 5508 code of: 7.4.100.60

DCA settings for both 802.11a/n and 802.11b/g/n APs are set as the following:

Settings enabled:

DCA - Channel Assignment method: automatic - 12hrs, anchortime - 0

Avoid Foreign AP interference - Enabled

Avoid non-802.11a noise - Enabled

DCA Channel Sensitivity - medium (15 dB)

Channel Width = 20 Mhz

TPC = Coverage optimal mode (TPCv1)

Power level assignment = Automatic (every 600 secs)
Max power level assignment = 30 dBm

Min power level assignment = -10 dBm

Power threshold = -70

I plan to put in a TAC on this issue since i've been seeing this issue for well over 6 months now.

[Scott Fella]

Well you really need to look at the environment and what are you really seeing and what might or might not be the issue.  The 2.4ghz and the 5ghz are two different frequencies and can have various affects depending on the client.  Having high density to not having enough density is another issue you can have.  With just the information you provided, I would have to say you need to tweak your power level addignment:

Max power level assignment = 30 dBm

Min power level assignment = -10 dBm

To

Max power level assignment = 20 dBm

Min power level assignment = 14 dBm

Aslo make sure you don't have unii-2 extended channel enabled on the 5ghz.

Thanks,

Scott

Help out other by using the rating system and marking answered questions as "Answered"

[rniu]

Hi Scott Fella,

I am really interested in this "Having high density to not having enough density is another issue you can have", I found this  phenomenon in our meeting room,there are 4 APs and the RSSI always up and down, could you please explain it ? thakns a lot!

One more request, could you please tell me is there any book talk about wireless trouble shooting? thanks!

[Ravi Singh]

There is possibility of  interference from other devices. If you have 802.11b or 802.11g  network  hardware, it uses the 2.4 gigahertz (GHz) frequency. Other devices that  use this frequency include microwave ovens and cordless phones. If you  have 802.11a  network hardware, it uses the 5 GHz frequency. Some  cordless phones also use this frequency.  These devices can cause  interference between your computer and the network.

There are two things you can try in this situation:

• If any devices like these are near your computer, turn them off temporarily or move them farther away.

• Change the router or access point settings  to use a different wireless channel, or set the channel to be selected  automatically if it's set to a fixed channel number. Sometimes one  wireless channel is clearer than others. In the United States and  Canada, you can use channels 1, 6, and 11. Check the information that  came with  your access point or router for instructions about setting  the wireless signal channel.