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Wireless Client Random/Frequent Disconnections. Checklist before debugging??

Be aware of each feature's change and its implications. RRM related changes takes time to come on effect. Try the '*' mentioned as last resort.

WLC level:

#Increase User idle timeout.

#Enable fast ssid.

#Check virtual ip, required for Mobility.

#RRM/static for power and channel. If most/all APs configured with static/dynamically power showing 1/1* then they've poor/excessive RF coverage.

#Are Mobility up between added Mobility members. If down or unconfigured client will do failover roaming between the APs connected to different wlc.

#Country code - Check Right CC selected for the joined AP.

#Check Datarates 2.4, 5ghz - Enable/Disable based on requirement(Based on channel utilization and coverage).

#Use Cleanair or 3rd party interference detector.

*Disable broadcast key rotation. This will be the last resort.

*WLC uptime, reboot if more than 200 days to free up garbage collection. This will be the last resort.

AP level:

#Are AP getting disconnected from wlc. Check AP uptime.

#Are Radio resetting frequently. Check AP log.

#Are High Channel Utilization observed on APs.

#Are appropriate Antennas connected to AP.

#Are client connecting AP joined to intended WLC and roaming to Autonomous/3rd party AP with similar ssid config.

#Disable RLDP on 'All-APs' or use only on monitor mode APs to avoid client disconnection. It interrupts client communication.

#Disable Auto/Manual Containment that interrupts client communication.

#Check wIDS trap/alert. See if DoS attack detected particularly disassocation/deauthentication.

wlan level:

#Security - If WPA with or without 802.1X, use either wpa-tkip only or wpa2-aes only for simiplicity

#Disable Aironet ie, if trying client is not ccx capable Ex: Apple

#Disable client load balancing, if required(it requires CCX)

#Disable client band select, if single band client - b/g is used and or non ccx

#Disable gtk randomize - It breaks broadcast/multicast on wpa/wpa2 wlan, let it be disabled unless cust had specific requirement.

#Disable dhcp required. It introduces delay in roaming due to force dhcp.

#Check detected Rogue APs. More Rogue AP means more interference on that radio band.

#Session timeout - Disable/Increase timeout.

#Disable client exclusion, if required.

#Disable Tkip countermeasure, if detected.

client level: (For isolated client issues)

#Monitor>> client>> wireless client - check up time

#wireless client side config:

#wmm enabled/disabled

#powersave enabled/disabled

#tweak Roaming Aggressiveness

#change supplicant

#change driver

Traplog:
Enable disassocation/deauth traps, Check the traps for deauth messages.

Msglog:
Check for unusual messages.

Narrow down the issue to wlc config, RF, dhcp, auth, specific client's supplicant/driver issue,...

Version history
Revision #:
1 of 1
Last update:
‎03-06-2013 05:53 PM
Updated by:
 
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Comments
Hall of Fame Super Silver

Saravanan,

Good information!

Cisco Employee

This is like the compendium of troubleshooting for wireless issues in the initial stage of troubleshooting