iPad / iPhone SSID change issue

[Vinay Sharma]

• Introduction
• Scenario
• Solution
• Reference

 

Introduction

iPad / iPhone SSID change issue

Scenario

An issue with iPhone has been seen when there are two SSID's from same WLC / AP. If connected to one and try to connect to other, iPhone shows unable to connect (whereas the debugs in WLC showing it getting connected and getting an IP ! ).

WLC is running latest 7.0.220. Also tried different combination like two open SSID's and changing between them or one SSID with 802.1x and other open SSID, not working.

Solution

Configuring Fast SSID Changing

When fast SSID changing is enabled, the controller allows clients to move between SSID's. When the client sends a new association for a different SSID, the client entry in the controller connection table is cleared before the client is added to the new SSID. When fast SSID changing is disabled, the controller enforces a delay before clients are allowed to move to a new SSID.

Using the GUI to Configure Fast SSID Changing

Using the controller GUI, follow these steps to configure fast SSID changing for mobile clients.

Step 1          Choose Controller to open the General page.

Step 2          From the Fast SSID Change drop-down box, choose Enabled to enable this feature or Disabled to disable it. The default value is disabled.

Step 3          Click Apply to commit your changes.

Step 4          Click Save Configuration to save your changes.

Using the CLI to Configure Fast SSID Changing

Using the controller CLI, follow these steps to configure fast SSID changing for mobile clients.

Step 1          To enable or disable fast SSID changing, enter this command:

config network fast-ssid-change {enable | disable}

Step 2          To save your changes, enter this command:

save config.

Reference

This document was generated from the following discussion: Ipad/Iphone SSID change issue

Configuring Fast SSID Changing

Wireless LAN Controller (WLC) Design and Features FAQ

[Patrick Murphy]

Thanks for the information.  I tested it and works as you documented.  Is there a reason this is not on by default?  Is there any drawbacks from enabling it?

Thanks,

Patrick

[dennischolmes]

It is disabled by default to meet FIPS and other compliance standard requirements. It's meant to keep a person from bouncing between SSIDs and launching attacks.

[csco11030279]

I have the issue but with PC win XP and win 7, the cenario like this"The PC connected with one SSID when it changed the SSID the same IP of the old SSID still there" the WLC do not remove the IP inforamtion from it clients database

?????

Thanks for the suggestion and resolution

[johnnylingo]

Thanks for writing this.  I'd noticed that iPads/iPhones could only connect to one SSID in our office (WLC4402 + AP 1141Ns).  I kept thinking the problem was something to do with the encryption settings or preample. 

[Tarunkumar Vyas]

Hi Vinay,

I have WLC 5508 with 7.6 version in HA mode

when i am doing Fast SSID enable, it gives me below error. also  i have tested with another mobile device like android phone it is working find but I am having issue with only  iPhone.

I have checked on device no passive client feature is enable also im running on unicast., please find screenshoot below.

No passive client enable

[davidhpalmer]

Wow, I've been banging my head against the wall on this one; I had also gone through every other setting such as preamble etc as my iphone/ipad wouldn't switch between ssid's on the same WLC... this saved me!

Appreciate the info!

[Daniel Ordóñez Flores]

Great Document Vinay.

Thanks a lot.

[Tom Tran]

Thank you for the post. 

I have a scenario where as iPad randomly move to a guess SSID. Is there a way to prevent that? I have Fast SSID change enable.

Thanks,

Tom

[rubenjaldin]

Hi;

do yo fix this problem , and how , would you explain me ??

[cisco5508]

When fast SSID changing is enabled, the iPad / iPhone SSID change well,but my macbook still have the problem.
Will you have any good suggestions？

Thanks.

[Supermantech]

Would  like a better explanation.  Changing said ssid to another preference said is mostly functions of clients.   How can this effect much on client wifi logic?,