Re: Loss of connection when users are on the move

netgus2010 · ‎08-19-2018

Good morning, everyone,

I currently have a wlc with 4 APs and I have the impression that the reconnection between the APs is not being done. Users tell me they lose their Wifi connection and switch to LTE on their phones.

How can I verify that when users move, they automatically switch to the nearest AP.

Thank you for your help.

Haydn Andrews · ‎08-19-2018

Hi netgus,

My suggestion firstly if possible would be to replicate it yourself and see if your also experiencing the issue.

Was a wireless survey conducted to verify there isn't any coverage holes, as if there are this would explain drop outs when roaming. If utilising software like Ekahau Site Survey is abit out of reach, then testing what the RSSI is accross the floors from each of the APs would be a good start with something like Metageek Inssider.

From a WLC point of view, if you do a debug client <mac> and watch what happens when the client roams, you will be able to see if the client roams successfully, or does a full re-auth or drops off.

Some useful sites to check out around client troubleshooting:

https://www.cisco.com/c/en/us/support/docs/wireless/5508-wireless-controller/200072-Cheat-Sheet-Common-Wireless-issues.html

https://community.cisco.com/t5/wireless-mobility-documents/how-to-debug-client-roaming-the-deep-dive/ta-p/3137412

cheers

Haydn

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Leo Laohoo · ‎08-20-2018

@netgus2010 wrote:

How can I verify that when users move, they automatically switch to the nearest AP.

1. As what Andrew Haydn said, replicate the issue yourself. Bring a smartphone and a tablet. Tune into a live video streaming service and walk around.

2. What kind of wireless clients are these? iPhone? Android?

3. What are the firmware of these phones?

4. Do you have enough coverage overlap?

5. Ask the users what is the most common location where they observed their phones losing coverage. Go there and take a reading of your phone. While there, jump into the controller and issue the command "sh client detail <MAC address of your wireless client>". Post it here.

netgus2010 · ‎08-21-2018

After running tests to try to reproduce the problem, I found nothing abnormal. If I move from one AP to another, you can see that you automatically change APs. You can see it on the iPhone, the bars go down and they go up afterwards. It's a little long. Maybe we can change or customize the delay? I could also check it with the command "sh client sum" and "sh client detail mac". You can see the change.

Finally, that's the problem that came to me on my iPhone. At one point, my iPhone lost the Wifi connection. It was LTE when I opened it and it stayed LTE for at least 60 seconds and then it went Wifi. I realized this because I wanted to access an internal resource and it is only accessible from our network. The iPhones are all at the latest IOS version 11.4.1 and the version just before. The problem is random.

I put you the result of the order of my iPhone just after the switch from LTE to Wifi. I'm not here before.

Thank you for your help.

(Cisco Controller) >show client detail 98:00:c6:xx:xx:xx
Client MAC Address............................... 98:00:c6:xx:xx:xx
Client Username ................................. N/A
AP MAC Address................................... cc:d5:39:9c:8d:c0
AP Name.......................................... LAP1142N-3        
AP radio slot Id................................. 1  
Client State..................................... Associated     
Client User Group................................ 
Client NAC OOB State............................. Access
Wireless LAN Id.................................. 1  
Wireless LAN Network Name (SSID)................. Our_SSID
Wireless LAN Profile Name........................ Our_SSID_Profil
Hotspot (802.11u)................................ Not Supported
BSSID............................................ cc:d5:39:9c:8d:cf  
Connected For ................................... 76 secs
Channel.......................................... 100
IP Address....................................... 192.168.xxx.xxx
Gateway Address.................................. 192.168.xxx.xxx
Netmask.......................................... 255.255.255.0
Association Id................................... 1  
Authentication Algorithm......................... Open System
Reason Code...................................... 1  
Status Code...................................... 0  
Session Timeout.................................. 1800
Client CCX version............................... No CCX support
QoS Level........................................ Platinum
Avg data Rate.................................... 0
Burst data Rate.................................. 0
Avg Real time data Rate.......................... 0
Burst Real Time data Rate........................ 0
Avg Uplink data Rate............................. 0
Burst Uplink data Rate........................... 0
Avg Uplink Real time data Rate................... 0
Burst Uplink Real Time data Rate................. 0
802.1P Priority Tag.............................. 5
CTS Security Group Tag........................... Not Applicable
KTS CAC Capability............................... No
Qos Map Capability............................... Yes
WMM Support...................................... Enabled
  APSD ACs.......................................  BK  BE  VI  VO 
Current Rate..................................... m15
Supported Rates.................................. 6.0,9.0,12.0,18.0,24.0,36.0,
    ............................................. 48.0,54.0
Mobility State................................... Local
Mobility Move Count.............................. 0
Security Policy Completed........................ Yes
Policy Manager State............................. RUN
Audit Session ID................................. 1964a8c000000a2d4dc77c5b
AAA Role Type.................................... none
Local Policy Applied............................. none
IPv4 ACL Name.................................... none
AAA FlexConnect ACL Applied Status............... Unavailable
IPv4 ACL Applied Status.......................... Unavailable
IPv6 ACL Name.................................... none
IPv6 ACL Applied Status.......................... Unavailable
Layer2 ACL Name.................................. none
Layer2 ACL Applied Status........................ Unavailable
mDNS Status...................................... Disabled
mDNS Profile Name................................ none
No. of mDNS Services Advertised.................. 0
Policy Type...................................... WPA2
Authentication Key Management.................... FT-PSK
Encryption Cipher................................ CCMP-128 (AES)
Protected Management Frame ...................... No
Management Frame Protection...................... No
EAP Type......................................... Unknown
FlexConnect Data Switching....................... Local
FlexConnect Dhcp Status.......................... Local
FlexConnect Vlan Based Central Switching......... No
FlexConnect Authentication....................... Central
FlexConnect Central Association.................. No
FlexConnect VLAN NAME............................ lan_wifi
Quarantine VLAN.................................. 0
Access VLAN...................................... 5
Local Bridging VLAN.............................. 5
Client Capabilities:
      CF Pollable................................ Not implemented
      CF Poll Request............................ Not implemented
      Short Preamble............................. Not implemented
      PBCC....................................... Not implemented
      Channel Agility............................ Not implemented
      Listen Interval............................ 20
      Fast BSS Transition........................ Implemented
      11v BSS Transition......................... Implemented
Client Wifi Direct Capabilities:
      WFD capable................................ No
      Manged WFD capable......................... No
      Cross Connection Capable................... No
      Support Concurrent Operation............... No
Fast BSS Transition Details:
      Reassociation Timeout...................... 20
      Total Preauth APs.......................... 0

Client Statistics:
      Number of Bytes Received................... 68309
      Number of Bytes Sent....................... 64225
      Total Number of Bytes Sent................. 64225
      Total Number of Bytes Recv................. 68309
      Number of Bytes Sent (last 90s)............ 64225
      Number of Bytes Recv (last 90s)............ 68309
      Number of Packets Received................. 186
      Number of Packets Sent..................... 134
      Number of Interim-Update Sent.............. 0
      Number of EAP Id Request Msg Timeouts...... 0
      Number of EAP Id Request Msg Failures...... 0
      Number of EAP Request Msg Timeouts......... 0
      Number of EAP Request Msg Failures......... 0
      Number of EAP Key Msg Timeouts............. 0
      Number of EAP Key Msg Failures............. 0
      Number of Data Retries..................... 3
      Number of RTS Retries...................... 0
      Number of Duplicate Received Packets....... 0
      Number of Decrypt Failed Packets........... 0
      Number of Mic Failured Packets............. 0
      Number of Mic Missing Packets.............. 0
      Number of RA Packets Dropped............... 0
      Number of Policy Errors.................... 0
      Radio Signal Strength Indicator............ -67 dBm
      Signal to Noise Ratio...................... 31 dB
Client Rate Limiting Statistics:
      Number of Data Packets Received............ 0
      Number of Data Rx Packets Dropped.......... 0
      Number of Data Bytes Received.............. 0
      Number of Data Rx Bytes Dropped............ 0
      Number of Realtime Packets Received........ 0
      Number of Realtime Rx Packets Dropped...... 0
      Number of Realtime Bytes Received.......... 0
      Number of Realtime Rx Bytes Dropped........ 0
      Number of Data Packets Sent................ 0
      Number of Data Tx Packets Dropped.......... 0
      Number of Data Bytes Sent.................. 0
      Number of Data Tx Bytes Dropped............ 0
      Number of Realtime Packets Sent............ 0
      Number of Realtime Tx Packets Dropped...... 0
      Number of Realtime Bytes Sent.............. 0
      Number of Realtime Tx Bytes Dropped........ 0
Nearby AP Statistics:
DNS Server details:
      DNS server IP ............................. 192.168.xxx.xxx
      DNS server IP ............................. 0.0.0.0
Assisted Roaming Prediction List details:

 Client Dhcp Required:     True
Allowed (URL)IP Addresses
-------------------------

AVC Profile Name: ............................... none
Fastlane Client: ................................ No

Leo Laohoo · ‎08-22-2018

The output shows good wireless signal.
The way you're describing things, it sounds like you've got a black spot.
You can either crank up the power of the AP or install an AP where the blackspot is.

pieterh · ‎08-22-2018

Yes a black-hole may be the cause

Be aware it is the client driver that decides to roam!

apart from troubleshooting , debugging and a good sitesurvey,

the main trick may be not to just turn the radio higher, but lower!!!!

when the client detects the signal strength is below it's limit it wil select a new access point to associate to.

other option is using directional antenna, so the area that an AP serves has a shaper boundary.(the signal strength goes down fast)

also relying on the behaviour of the client is network authentication. if you use some form of authentication like dot1x and it takes too long, the client may decide the network is unreachable (even when the signal is strong)

netgus2010 · ‎08-22-2018

Thanks for all this information, but I doubt the black hole, because when I had this problem and I had it again this morning, I was for the first within 4 meters of the AP (no wall between me and the AP) and this morning at 8 meters.

Perhaps an important point is that we have had this problem since we switched to vWLC. Before we had a WLC 2106 and we didn't have that problem and the APs didn't move.

Software Version

8.3.141.0

patoberli · ‎08-24-2018

How is your SSID configured? This could also be related to the chosen security settings.