Experience case of resolving the problem of packet loss in terminals

Null

During initial testing, the AC was operating in an environment of approximately minus 8℃, and a PSK authentication method was used for a wireless network card terminal that only supports 2.4GHz to access the network. The terminal, AC, and AP were all in the same network segment. However, when the terminal attempted to ping the AC or the AP, the packet loss was severe, and connectivity was even lost.

(1) Upon checking, the AC configuration appears normal, including the service template configuration:

wlan service-template git

 ssid GIT

 akm mode psk preshared-key pass-phrase cipher $c$3$tn5dnzFVvkCAGEOMqazFdElulOVytrLKvpxF0Q==

 cipher-suite ccmp

 cipher-suite tkip

 security-ie rsn

 security-ie wpa

 service-template enable

AP template configuration:

#

wlan ap 38ad-8eca-0f20 model WA5320-C-EI

 serial-id 219801A18R817AE00486

 vlan 1

 radio 1

 type dot11an

 radio enable

 option keep-active enable

 service-template git service-template wapi

 service-template wapi2

 radio 2

 radio enable

 option keep-active enable service-template git

 service-template wapi

 service-template wapi2

 gigabitethernet 1

 gigabitethernet 2

(2) Suspecting the issue may beCompatibility issues between the special terminal and the AP, testing was conducted using a regular smartphone terminal. However, the issue persisted.

(3) As the testing environment was around minus 8℃, it was also suspected that the AC may not be functioning properly in low temperatures. Therefore, the device was moved to a normal temperature environment for testing, but the symptoms persist.

(4) After ruling out terminal and environmental factors, the configuration was reviewed and it was discovered that in addition to the PSK testing service, there was also a WAPI authentication service on the AP, and there was indeed a WAPI authenticated terminal working on-site. After disconnecting the WAPI authenticated terminal and restarting the AP, the packet loss issue disappeared.

(5) It was confirmed that the same frequency cannot simultaneously provide PSK and WAPI authentication services as WAPI affects the aggregation of PSK frames, which can lead to severe packet loss in terminals.

By using WAPI authentication for the 5GHz frequency and PSK authentication for the 2.4GHz frequency, the issue was resolved.