Wireless Access

Hi,

We have 6 story building office. Total 14 AP deployed in the building. At 4th floor we hv deployed 3 AP

Since last 1 year setup is working fine. But suddenly we are facing signal fluction onthe 4th floor.

All other location AP working fine. No change at 4th floor i.e. Oven, high frequency cable or element.

Raise the case with TAC. TAC suggested do the site survey.

Can anybody suggest me site survey tool and procedure or any solution to fix the signal fluction?

Thanks in advance....

First of all we need to ask many question:

What type of access point you are using?

What is the mounting type celling or wall?

Is there is any new place environment changes like furniture and so on?

If you are using a celling mount did you mounted on the 6 floors as the same each AP above the other and what is the height of celling?

In the specified floor did you saw any neighbor wireless networks?

Do you face this problem with a specific device or on all devices?

Do you see a high channel utilization in dashboard?

Is there is a new PoE devices connected to the switch where the problem happens?

Thanks for your reply....

I am attaching tac observation txt that will helpful you to figure out the issue.

Please find below answer of your question.

What type of access point you are using?   --> AP 105
What is the mounting type celling or wall?  --> Celling
Is there is any new place environment changes like furniture and so on?   --> No
If you are using a celling mount did you mounted on the 6 floors as the same each AP above the other and what is the height of celling?
--> AP deployed on 1st, 4th,5th & 6th floor.
In the specified floor did you saw any neighbor wireless networks? --> Yes
Do you face this problem with a specific device or on all devices? --> Only on 4th floor.
Do you see a high channel utilization in dashboard? --> Plz find in attach txt file.
Is there is a new PoE devices connected to the switch where the problem happens? --> No

Controller OS : --> 6.3.1

Please feel free to ask any doughts or query.

Thank You...

Attachment(s)

Signal fluctuation.txt   1 KB 1 version

What are you using to measure signal strength?  Depending on the device you are using to measure signal strength, you will see fluctuations due to collisions.  The most reliable measure is to do a packet capture filtering on a single BSSID.  if you are seeing 14 access points, you could have too much coverage.

So, to recap:

Not all devices that measure signal strength are reliable.

Collisions and interference could make the signal strength seem like it is fluctuating

Signal strength fluctuating a certain amount can be normal, depending on what the signal has to pass through to get to you

Doing a packet capture and filtering on a single BSSID will tell you if the signal strength is really fluctuating.

If you can see 14 access points, you need to either (1) turn some access points into air monitors (2) turn down the power of some access points (3) reposition access points

Collisions and interference could be your primary issue.

Edit:

There must be some other complaint besides signal fluctuation.  Are there client disconnects, etc?  Those are easier to deal with than possible signal fluctuation.

Client are not disconnecting.

But wireless tower(indicator) decrease & increase frequently on wireless devices.

Cabin user are complaining to getting low signal strength. One moth before they were able to get stable & full range.

Regards,

Nikhil.

Nikhil,

Did YOU personally witness or investigate the signal fluctuating?

Do you know what OS this was witnessed on?

Different operating systems can report signals differently.

Some OS report signal fluctuation, when others do not.

We need to know from you or the network administrator, NOT the users what is going on and what has changed in the environment to cause this.

What users report and what is fact can be two different things.  We need you to report detail about what is going on, so that we can guess what could be wrong.  Users reporting an incident is only a small piece of what we can use to figure out what is going on, and in many cases is unreliable.   What an administrator reports, and the detail reported after users complain is much more important.

Hi Joseph,

Thanks for your reply..

I have personaly observed signal fluction on multiple user Windows & Android OS. 

I asked the network administrator about network change or any enviorment change in setup but he said no.

Wireless setup is managed by me only.

Before we was using AOS 6.2.0 at that time we had faced this issue first time.

Then i had statically assigned channals to AP and issue was resolved. But after some days again we observed the same issue.

So i had upgraded the AOS 6.3.7 & log the case with TAC. TAC said configuration is all right. But issue was not resolved.

Finally TAC suggested do the site survey so we will get some clearity.

I haven't done any site survey yet.

If you require any log or details, plz ask me.

Regards,

Nik..

Nik,

Android, especially with wifianalyzer will show signal fluctuation when there is alot of co-channel interference.  If you see it with Windows, that could mean that you have too much RF in an area.  You would normally do a site survey with Airmagnet Survey Pro or Eckahau survey Pro.  If you do not have that, you would use inssider to determine how many access points can be seen in an area.

Some areas that are good, and then are bad, become bad because many more people are using wireless than before.  If this is a controller-based system, do you have "Drop Broadcast and Multicast" enabled in all of your Virtual AP profiles?  Many times, broadcast and multicast increases significantly when there are more people on the network.