Meru Technical Note - How does the keep-alive between the AP and controller work, and what is the port on which the keep-alives are sent?
How does the keep-alive between the AP and controller work, and what is the port on which the keep-alives are sent?
Scope
KB Article Type - Design
Related Products - All controller and AP models
Related Software Versions - All S/W versions
Keywords - Keep-alive
Solution
Keep-alives are sent from the controller to all Enabled/Online APs. Here are some key points to know about the keep-alive function:
Keep-alive "request" packets are sent by the controller to each Enabled/Online AP.
The keep-alive "response" is sent from the AP -> controller.
Keep-alives are sent to every AP once per second. This one-second time window also serves as the timeout. That is, if a keep-alive response is sent back by an AP to the controller, but it is received > 1 second after the keep-alive request was sent, that constitutes a "missed" keep-alive.
Keep-alive requests and responses are sent using "COMM", which is a UDP port 5000 packet when using L3 and an Ethernet type 0x4001 when using L2.