Interfaces: AP-Manager and Management - function

MARK HEUZENROEDER · ‎08-09-2006

Hi,

I've read that from the point of view of the WLC, the interface which the LWAPP tunnel is terminated on is the AP-Manager Interface, right?

If so, why does DHCP option 43 dish up the Management Interface IP address and not the AP-Manager IP address?

Thanks

jakew · ‎08-09-2006

It's actually an artifact of the early generations of the Airespace architecture. However, putting the management interface as DHCP option 43 allows the WLC to return multiple AP manager interfaces in the LWAPP discovery response when multiple APMs are configured. The AP selects the least loaded APM and that allows load balancing across the WLC ports.

MARK HEUZENROEDER · ‎08-10-2006

Hi Jake,

You're obviously a guru in this!

Please tell me what APM is.

I got a capture of LWAPP traffic.

Here's what I observed,

LWAPP Control packets use management or AP-Manager interface depending on the exact packet type

Management Interface

- Discovery_REQUEST

- Discovery_REPLY

- PRIMARY_DISCOVERY_REQ

- PRIMARY_DISCOVERY_RES

AP-Manager Interface

- JOIN_REQUEST

- CONFIGURE_REQUEST

- CONFIGURE_RESPONSE

- various other CONFIGURE packets

- ECHO_REQUEST

- ECHO_RESPONSE

- STATISTICS_INFO

- STATISTICS_INFO_RES

Regards, mh

jakew · ‎08-11-2006

Hi MH,

APM = AP Manager

The APM is where the LWAPP control and data tunnels get terminated on the controller.

As you've observed, the only LWAPP control messages that get sent to the management interface are discovery messages and the only LWAPP control messages that come from the management interface are the discovery reply messages.

HTH,

Jake