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Aironet 1130: Use a controller or not?

A colleague told me that whenever you want to deploy over half a dozen APs that you should use a controller rather than set up autonomous APs but he does not know why.

Cisco says: When configured with LWAPP, the Cisco Aironet 1130AG Series can automatically detect the best-available Cisco wireless LAN controller and download appropriate policies and configuration information with no manual intervention.

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Can someone explain why this would be better than copying an appropripriate startup-config to each of the APs running autonomously? In our network, the configs are usually stable for a long time after the access lists are debugged and even when a change is needed, it doesn't take long to apply.

Reply to
Bob Simon
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It's not just the config; the portion of the electromagnetic spectrum that Wifi occupies [especially 2.4GHz] is fast changing and dynamic, as it's unlicensed. So to combat this, WLAN controllers employ RF management. Each AP senses the environment around it and reports back to the WLAN controller. The controller then picks the optimum channel and power level for each AP.

Reply to
alexd

Also with a controller, roaming between AP's is completely transparent to the AP and the client. All traffic from the wireless network passes through through the controller so it controlls all authentication. With autonomous AP's, each time you roam to a different AP, the client must reauthenticate to the AP. This only takes a second or two, but it can cause some client application issues if you have mobile clients.

Reply to
Thrill5

Thrill5 schrieb:

The WPA standard *requires* a full authentication after roaming to another BSS (a.k.a. Accesspoint's radio MAC address) and therefor the full WPA handshake for pushing group key and pairwise master key to the client also happens using a WLAN controller as the client station sees another MAC address for the new AP.

The controller may cache the RADIUS communication between NAS and RADIUS server. If you configure standalone Aironet APs with WDS and perhaps a WLSE this is done in the WDS (which acts kindof a RADIUS proxy) too.

If the infrastructure is built on a single WLAN controller a single point of failure is introduced.

You cannot upgrade the APs one by one during normal working hours. If you upgrade/downgrade the image on the WLAN controller, all connected APs will reboot twice, resulting in a complete WLAN outage of at least

10 minutes. If your site survey has some overlap in cells you can reboot a single autonomous AP and the clients will transparently roam to its neighbours.
Reply to
Uli Link

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