Trouble with clients moving from one AP to another.

[jaxstas11]

Hello all. I am in the midst of setting up WiFi using WAP561 model APs. Currently we are having issues when the clients switch from one AP to another. It takes too long and our app loses connection and fails. I've initially set them up as a cluster. I've been trying to read up on RADIUS and CCKM, but am unsure of which route to take. Which is the simplest? Does CCKM involve using WDS? Newbie in this world, so be patient.

[mohanak]

A Wireless Distribution System (WDS) bridge enables access points to communicate with each other using the wireless medium. This, in turn, allows seamless roaming of the wireless devices or clients connected to the WAPs. Multiple WAPs can be connected through WDS.

http://sbkb.cisco.com/CiscoSB/GetArticle.aspx?docid=4b50d3ca5d8c44fa83e4980304567be2_Wireless_Distribution_System__WDS__Bridge_Configuration_on_W.xml&pid=2

[jaxstas11]

Thanks a bunch! I'll give that a try.

[Dennis Bland]

Not sure if you got your setup working, but here is a bit more info:

CCKM is a Cisco-specific WPA/WPA2-Enterprise key exchange protocol used when fast-roaming from one Cisco AP to another Cisco AP on the same WLAN controller with the same SSID.  In order to use CCKM, both the wireless client and the AP need to support CCX (v2 or later).  With CCKM, a wireless client can roam from one AP to another within 125 mS without having to re-authenticate to the second AP, making it suitable for VoIP applications.

If you are not using a WLAN controller with Cisco APs in lightweight mode and instead using APs in "autonomous" mode, then you need to enable WDS to allow the APs to communicate with each other and share the client key information when the client moves to another AP.  

Finally, RADIUS is just the authentication part of WPA/WPA2-Enterprise (802.1X).  RADIUS provides the initial authentication of the client to the network, and CCKM provides the fast-roaming between the APs.

Unfortunately, I don't think the WAP561 supports CCX.  It should support PMK-caching, so at least enable that feature.  PMK-caching means the AP will "remember" the wireless client key material for a specified time, so that if the wireless client roams away from that AP and then back again within the timeout, it can effectively fast-roam without having to reauthenticate with the RADIUS server.

Dennis

dB Performance Inc.