Wireless Speed Issue

[vinovinom]

Hi

Problem: When trying to connect to the network using AP it takes about 10 - 15 secs to get reply. But if connected through ethernet its as normal.

Scenario: 2 WLC ----> Cisco Switches  (3550/3750) ----- > Cisco AP ----> Scanners/Guest Vlans. Authentication is done by Cisco ACS.

I just want to know where to start troubleshooting this problem. All the networking bit is working properly, but its just speed issue.

Your comments are of much value.

Thanks

Vin

[Leo Laohoo]

All the networking bit is working properly, but its just speed issue.

A few things to look for:

1.  What model is your AP?

2.  Have you done a wireless site survey?

3.  What is the signal strength of the AP to the area where you are observing low speed?

4.  What is the make and model of your scanner?

5.  Some scanners don't like hidden SSID and prefer broadcast SSID.

6.  Have you checked for signal interference from nearby APs?

[vinovinom]

Hi  Many thanks for ur reply... I will try to find out more info as I don't have them at present...

[vinovinom]

1.  What model is your AP? ---------- AIR-LAP1252AG-E-K9

2.  Have you done a wireless site survey? --- Survey done.

3.  What is the signal strength of the AP to the area where you are observing low speed? --- Seems to be good

4.  What is the make and model of your scanner? ---- not known yet.

5.  Some scanners don't like hidden SSID and prefer broadcast SSID. -- SSID Broadcasted.

6.  Have you checked for signal interference from nearby APs? --- Interference not checked.

Only thing that I need to add to it is that there is a separate Wifi Vrf used for this Wifi Implementation and devices authenticated with ACS 5.0.

Thanks

Vin

[vinovinom]

Psion Teklogix Barcode scanner

Regards

Vin

[George Stefanick]

How do you know the network is slow? What is happening ...

Do you have other type of wireless clients (laptops, phones etc ) what is their performance?

[vinovinom]

Hi George

What we had tested (using dhcp) was an application that runs on a Scanner and it takes 15 secs to run the transactions in it and after 10 mins it gets disconnects. When used with a static IP it takes around  2 secs to do the same.

please share ur thoughts with us.

Thanks

Vin

[George Stefanick]

Ok, but how does that translate to network being slow?

So what is the nature of the application ? Are you stating it is taking a long time to get a DHCP? Can you walk through the steps of what is happening? What  type of handhelds motorols, LXEs, Intermec ?

[vinovinom]

Well usually the Psion Scanner devices have this application running on it and user logs into the application via the scanner. This access to the application is very slow. The same devices aer used in another WIFI network with the same WLC with a different SSID and it works fine.

SSIDs are not broadcasted and also there is WPA security with additional ACS security.

Vin

[George Stefanick]

wireless troubleshooting is backwards engineering, i like to call it .. Lets do these so we can get a base line...

1) Test this same app on the switch the controller plugs into.. Extend the vlan if need be. Is the performance same, better or worse

2) Connect a laptop to your wireless connection ... is the performance same, better or worse

3) have you check the area with a spetrum analyzer?

4) What channels are your APs? 1,6, 11?

Do you have a network topology ?

[vinovinom]

1)It seems to be fine when connected with the Wired network the issue is when its connecting to the wireless network.

2)Laptop seems to be the encounter same issue when connected.

3)Area has been surveyed prior to installation.

4)Also there was AP channels I am unaware of at present.

Thanks

Vin

[vinovinom]

Hi Guys

I am trying to troubleshoot this issue still ... The issue seems to be only when connecting via dhcp ... I am trying to troubleshoot from the client point of view like running a packet analyzer in the laptop and check what packets client sees and check if I recieve any errors in it... next step would be debugging from the WLC for particular test client MAC and check if any errors...

If anybody else have brighter ideas please do share

Thanks

Vin