High latency between PDA and Laptop in the same SSID and VLAN

[rockzhang1]

Hi, 

we are using CISCO 5508 WLC and got High latency between PDA and Laptop in the same SSID and VLAN, latency is around 300ms...but between laptop, the latency is 5ms. 

May I know what can cause this problem? 

thank you so much indeed.

[Stephen Rodriguez]

There could be a lot of things that could cause that. What band the devices are on, what their chipset is, what the driver version is, what the CPU on the device is etc.

What is the particular PDA? what are it's specs? does it have enough RAM and CPU power?

what are you using to test the latency, ping? I don't trust ICMP, it's low priority traffic and can be dropped or delayed if there is any congestion.

Steve

[rockzhang1]

Hi, Stephen,

WIFI phone detais

OpenStage WL3

SW version

5.1.24

WLAN version

3.5.d

WLAN information

FAVO SSID

Security mode

WPA-PSK/WPA2-PSK

Beacon period : 102

DTIM :1

QOS: WMM&WMM-PS

Txpower 14dbm

[shabeer G]

Hi,

 What band do you see on the controller for the devices which has high latency?

If it is on 2.4 try enabling band select on the WLC and see if it improves the latency as the clients will try to connect to the 5Ghz band if it supports.

Thanks

[George Stefanick]

Small devices like to use power save. For example if I ping my Cisco phones they show high latency because they are constantly going to sleep to save battery. Once in a call the radio is active and latency is gone. A packet capture could show this or your pda may allow you to configure power save. 

[Abhishek Abhishek]

Please refer to the link for troubleshooting network latency issues-

http://support.internetconnection.net/THE_WWW/Troubleshooting_Network_Latency.shtml

[Prakash Parvathala]

Check the power save setting on wireless client, if enabled for max battery then set to CAM or continuous awake mode.

[abwahid · Accepted solution]

Hi,

Enterprise grade equipment will have more features. Some will help you identify the issue. Use a tool like inssider to check if there are other APs in the area which may be interfering. Any nearby network on the same channel, or adjacent channels for that matter.

[gohussai]

inssider is a great tool no doubt to check the neighbor LAPs. But you do proper survey with the said tool given below ,it also gives you best results.

http://www.ekahau.com/wifidesign/ekahau-site-survey

inssider