The LWAPP architecture provides for a heartbeat timer that is
accomplished by a series of Echo Requests and Echo
Responses. An AP periodically sends Echo Requests in order to
determine the state of the connection between the AP and the WLC. In response,
the WLC sends the Echo Response in order to acknowledge the receipt of the Echo
Request. The AP, then, resets the heartbeat timer to the
EchoInterval. The LWAPP protocol specification draft contains
a detailed description of these timers. The system heartbeat, coupled with
fallback mechanism, is 4 packets every 30 seconds and is comprised of these
packets:
LWAPP ECHO_REQUEST from AP (78 bytes)
LWAPP Echo-Response to AP (64 bytes)
LWAPP PRIMARY_DISCOVERY_REQ from AP (93 bytes)
LWAPP Primary Discovery-Response to AP (97 bytes)
This exchange generates 33 bytes of traffic every 30 seconds.
There are two ongoing RRM exchanges. The first one, at every 60-second interval, is the load and signal measurement and consists of 4 packets. This exchange always adds up to 396 bytes:
LWAPP RRM_DATA_REQ from AP (107 bytes)
LWAPP Airewave-Director-Data Response to AP (64 bytes)
LWAPP RRM_DATA_REQ from AP (161 bytes)
LWAPP Airewave-Director-Data Response to AP (64 bytes)
The second sequence of packets is the noise measurement that includes a statistics information request and response sequence. It is done every 180 seconds. This short exchange of packets averages approximately 2,660 bytes and typically lasts 0.01 seconds. It consists of these packets:
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP STATISTICS_INFO from AP
LWAPP Statistics-Info Response to AP
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP RRM_DATA_REQ from AP 00:14:1b:59:41:80
LWAPP Airewave-Director-Data Response to AP
LWAPP RRM_DATA_REQ from AP
LWAPP Airewave-Director-Data Response to AP
LWAPP STATISTICS_INFO from AP
LWAPP Statistics-Info Response to AP