3.5 Responder (Quick Discovery) Details

A responder MAY support multiple network interfaces. If a responder supports multiple network interfaces, it MUST create a separate instance of the responder protocol specified in this section for each supported network interface.

The following figure shows the workings of a responder's quick discovery state engine, also known as the enumeration state engine.

Possible Responder's Quick Discovery states

Figure 1: Possible Responder's Quick Discovery states

While in Quiescent state, responders only listen to broadcast frames and wait for a Discover frame to trigger an association with a mapper (only for topology discovery) or initiate enumeration session.

The Pausing state is critical to scalable discovery of the responders. During Pausing state, responders execute the RepeatBAND algorithm (see section 3.5.6.2) to estimate the overall network load and to delay the transmission of the Hello frame accordingly. The Pausing state is the only state where responders send the Hello frame. During the Wait state, the responder waits for enumerators or the mapper to finalize their sessions via the Reset frame. Responders leave the Wait state for the Quiescent state when all enumerators have either timed out due to inactivity or have successfully sent the Reset command.

Message request/response pairs applicable to quick discovery are defined as follows.

 Sent by mapper

 Sent by responder

Discover (as BROADCAST)

Hello (as BROADCAST)

Reset (as either UNICAST or BROADCAST)

N/A