Clients not connecting to preferred AP

[James H]

I'll start by saying that I realize that the determination for which AP a client connects to is solely decided by the client's network adapter. But I'm hoping someone can assist me in making changes to the APs to persuade the client devices in this office to connect to the appropriate AP.

We have a Cisco 2504 WLC with 20 AIR-CAP2702I-A-K9 access points and 24 AIR-CAP1532I-B-K9 access points at our site. The 2702 APs are primarily in our office environment where as the 1532 APs are primarily in our manufacturing environment.

We have a small office labeled 'office' below that houses 3 associates. The two red dots below are the nearest APs. They are both AIR-CAP1532I-B-K9 APs in the manufacturing environment. 

I've monitored and witnessed the associates' devices in the 'office' room bouncing between the two access points above Both APs are about equal distance away and have similar signal strength. When using a Wifi Analyzer in their office I observed that both APs were about -75db.

I provisioned a spare AIR-CAP2702I-A-K9 AP and mounted it to the dropped ceiling in their office. Now, one or two of their devices may occasionally connect to this new AP in their office, but not for very long. The devices are still bouncing between the two 1532 APs much further away with worse signal.

We have 5 different 'AP Groups', but the only differences between them are which WLANs they are broadcasting. None of the 'AP Groups' are using 'RF Profiles'. I thought this was worth mentioning as I've seen reference to RF Profile changes to persuade a client to connect to a specific AP.

Here are the results of running 'show ap auto-rf 802.11b AP-44_ControlsOffice' on the WLC CLI:

Number Of Slots.................................. 2
AP Name.......................................... AP-44_ControlsOffice
MAC Address...................................... a0:ec:f9:57:07:94
  Slot ID........................................ 0
  Radio Type..................................... RADIO_TYPE_80211b/g
  Sub-band Type.................................. All
  Noise Information
    Noise Profile................................ PASSED
    Channel 1....................................  -97 dBm
    Channel 2....................................  -95 dBm
    Channel 3....................................  -98 dBm
    Channel 4....................................  -97 dBm
    Channel 5....................................  -95 dBm
    Channel 6....................................  -85 dBm
    Channel 7....................................  -98 dBm
    Channel 8....................................  -96 dBm
    Channel 9....................................  -97 dBm
    Channel 10...................................  -97 dBm
    Channel 11...................................  -85 dBm
  Interference Information
    Interference Profile......................... PASSED

--More-- or (q)uit
    Channel 1.................................... -128 dBm @  0 % busy
    Channel 2.................................... -128 dBm @  0 % busy
    Channel 3.................................... -128 dBm @  0 % busy
    Channel 4.................................... -128 dBm @  0 % busy
    Channel 5....................................  -75 dBm @  2 % busy
    Channel 6....................................  -72 dBm @  8 % busy
    Channel 7....................................  -71 dBm @  1 % busy
    Channel 8.................................... -128 dBm @  0 % busy
    Channel 9.................................... -128 dBm @  0 % busy
    Channel 10................................... -128 dBm @  0 % busy
    Channel 11................................... -128 dBm @  0 % busy
  Load Information
    Load Profile................................. PASSED
    Receive Utilization.......................... 0 %
    Transmit Utilization......................... 0 %
    Channel Utilization.......................... 15 %
    Attached Clients............................. 2 clients
  Coverage Information
    Coverage Profile............................. PASSED
    Failed Clients............................... 0 clients
  Client Signal Strengths
    RSSI -100 dbm................................ 0 clients
    RSSI  -92 dbm................................ 0 clients

--More-- or (q)uit
    RSSI  -84 dbm................................ 0 clients
    RSSI  -76 dbm................................ 0 clients
    RSSI  -68 dbm................................ 0 clients
    RSSI  -60 dbm................................ 0 clients
    RSSI  -52 dbm................................ 2 clients
  Client Signal To Noise Ratios
    SNR    0 dB.................................. 0 clients
    SNR    5 dB.................................. 0 clients
    SNR   10 dB.................................. 0 clients
    SNR   15 dB.................................. 0 clients
    SNR   20 dB.................................. 0 clients
    SNR   25 dB.................................. 0 clients
    SNR   30 dB.................................. 0 clients
    SNR   35 dB.................................. 0 clients
    SNR   40 dB.................................. 0 clients
    SNR   45 dB.................................. 2 clients
  Nearby APs
    AP 80:e0:1d:6b:01:20 slot 0..................  -88 dBm on   6 (c0:a8:fa:05:00:4b)
    AP 80:e0:1d:92:db:60 slot 0..................  -91 dBm on   6 (c0:a8:fa:05:00:4b)
    AP b0:aa:77:75:5a:00 slot 0..................  -66 dBm on   1 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:a5:00 slot 0..................  -78 dBm on  11 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:a7:30 slot 0..................  -63 dBm on  11 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:c4:40 slot 0..................  -85 dBm on  11 (c0:a8:fa:05:00:4b)

--More-- or (q)uit
    AP c4:72:95:9b:d3:20 slot 0..................  -89 dBm on   6 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:d4:a0 slot 0..................  -78 dBm on  11 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:da:90 slot 0..................  -72 dBm on   1 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:de:10 slot 0..................  -62 dBm on   6 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:ee:90 slot 0..................  -88 dBm on   1 (c0:a8:fa:05:00:4b)
    AP c4:72:95:9b:f5:20 slot 0..................  -92 dBm on  11 (c0:a8:fa:05:00:4b)
  Radar Information
  Channel Assignment Information
    Current Channel Average Energy............... unknown
    Previous Channel Average Energy.............. unknown
    Channel Change Count......................... 0
    Last Channel Change Time..................... Fri Feb  3 08:29:23 2023
    Recommended Best Channel..................... 1
  RF Parameter Recommendations
    Power Level.................................. 5
    RTS/CTS Threshold............................ 2347
    Fragmentation Threshold...................... 2346
    Antenna Pattern.............................. 0

  Persistent Interference Devices
  Class Type                 Channel  DC (%%)  RSSI (dBm)  Last Update Time
  -------------------------  -------  ------  ----------  ------------------------
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 Any help would be greatly appreciated!

[balaji.bandi]

short answer NO i guess, you can not do that.. Tweaking other like signal and others just waste of time as i feel.

[Leo Laohoo]

The wireless clients themselves make the final decision which AP to join.  

When WiFi started taking off 10 years ago, all of the wireless NIC had problems with "roaming" -- The wireless NIC were NOT roaming.  It took a while until the wireless NIC manufacturers released updated firmware which enabled the wireless NICs to roam properly.  

Until now, we are still getting threads about brand-new laptops, with obsolete wireless NIC drivers, unable to properly roam.  And my response would be to update the wireless NIC drivers.

[James H]

Thank you for responding. Unfortunately Updating the wireless NIC drivers was the first thing I tried after researching the forums.

[johnd2310]

Hi

The client determine which AP it ultimately associates to. You can encourage the client to associate with the strongest signal by modifying " roaming aggressiveness" to medium or high on the wireless NIC properties.

Thanks

[James H]

Thank you! I will try this.

[Rich R · Accepted solution]

Do as the others have mentioned already (update drivers, fiddle with roaming aggressiveness).

From WLC point of view - you don't mention software version but if not already done then update to 8.5.182.7 (subject to which APs you're using - refer compatibility matrix below).

Depending on coverage impact (survey required) you might want to reduce power on those 2 APs now that you have the AP in the office.

Possible workaround: create a different AP group with a different SSID for the office AP and have those users join the "office SSID" and make sure it highest on their list of known SSID.  Since that SSID is only available from the office AP they will always be on the office AP while in the office.  They can still use the regular SSID when away from the office.

[James H]

Perfect! I like the alternative solution of creating a new SSID and making it priority.

Thank you so much!

[Scott Fella]

You should also take a look at what you have defined for the allowed minimum data rates.  Removing some of the lower rates can help prevent devices from connecting.  However, if your ap's are sparse and you require these lower rates, then that will not work for you.  Other options are to set you min and max power, for example, you can set the office ap to power level 1 which is the highest and devices should join that ap when in the office since the other ap's are at -75.  Sometimes its all about tweaking your environment.

[James H]

Thank you! That's the kind of tweaks I was looking for when I made this post. I just don't have a lot of experience with wireless to know what I should be tweaking.