The Dispatcher works by acting as a central receiver for the TCP ports listed in its configuration. For each defined service, the Dispatcher may create one or more Worker Processes that will actually handle the connections after they've been established.
In general, when the Dispatcher receives a connection for a defined TCP port, it checks its pool of available Worker Processes and chooses the best candidate for the new connection. If no suitable candidate is available and the configuration permits it, the Dispatcher may create a new Worker Process to handle this and subsequent connections. The Dispatcher may also proactively create a new Worker Process in expectation of future incoming connections. There are several configuration options which may be used to tune the Dispatcher's control of its various services, and in particular, to control the number of Worker Processes and the number of connections each Worker Process handles; see Creation and expiration of Dispatcher Worker Processes and Dispatcher options.