Devices disconnecting when moving to closer WAP

[Henry O'Reilly]

Hi all,

I've inherited a site, this is a warehouse setting with various WAPs:

AIR-CAP2702E-E-K9

AIR-AP1562I-E-K9

= x15 WAPs

Running from WLC: AIR-CT2504-K9

= x2 WLCs

The warehouse mainly uses wireless ATEX mobile phones and wireless bar code scanners.

The current issue is when an operative is using a bar code scanner then moves to another location, the scanner disconnects. Signing out of the app, needing to sign back in.

There was an issue around 2 years ago that was resolved (an email thread) by having a wireless signal survey and adding additional WAPs to black spot areas (believed this fixed the issue, was before my time). Now the same issue has appeared within the last month. The ATEX phones have also had interment connection issues.

I've tested with my own mobile phone where I had signal, moved to a different WAP and stood next to it. The phone went to 1 bar of reception then disconnected completely. By then, I walked off for a bit and came back, to see the mobile phone had connected with full signal.

We had an operative use a bar code scanner, leave it in the same position for around 10-15mins = was fine. Until they moved it dropped connection.

From my limited access to the infrastructure. I can see from the WLC that some of the WAP's are configured by DHCP, others by Static. To me this doesn't seem right. I've not seen this type of mash up set up before, would this cause issues when moving from WAPs? i.e. x8 = DHCP, x7 = Static

My suggestion would be to put all WAPs on DHCP on the WLC, as other sites have this set up.

Any opinions are welcome!

Henry

[Scott Fella]

I think it is more than that.  When you have a site survey done, you should be able to see the signal of a given ap from various locations in the site.  If ap's are too high, you need to get the right antennas to get the down tilt to provide better coverage below.  AP's with internal antennas and or some external antennas are not made to be mounted over a certain height.  So keep that in mind, also keep in mind that you want to have overlapping coverage and in a warehouse environment, that can be tricky.  Seem's like the ap's and or antennas are pretty high and you don't have enough to provide adequate overlap.  The survey can also show your SNR which you want to be at least 20dbm or better.  Metal and or products around the area can attenuate the signal and or cause reflection that would decrease the signal quality you might be requiring.

This is not easy to explain on a forum with out data.  You should reach out to your Cisco SE or Cisco VAR for help.

[Rich R]

No harm in switching all APs to DHCP but very unlikely that has anything to do with the observed problems.

The question you need to be asking is what changed?

- New shelves or structures?

- New equipment (common culprits motion detectors for lighting or security)

- What band are those devices using - 2.4 or 5GHz?  And is there anything new (non WiFi) using the same band?

- What version of code are you running? Has it changed recently?  Has the WLC config changed at all?  If you're on old code consider upgrading to latest. https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/200046-tac-recommended-aireos.html#anc3

- Did the client problems start after device OS updates?

- Some problems (usually bug related) magically disappear for a while after the APs are reloaded - worth a try.

Run a debug on your client MAC on the WLC while you test and observe the problem. Look for obvious problems and run it through https://cway.cisco.com/wireless-debug-analyzer/

And like Scott said maybe you need a new site survey.