The service loop is where clients and servers do most of their work. In the service loop, a client and its server communicate with each other asynchronously, sending and receiving messages as often as necessary and in a stateless fashion.
Most messages are sent with parameters. These parameters are described in the documentation for each message. Since many messages use similar parameter types, it is instructive to first discuss the frequently occuring parameter types and their representations before reviewing the actual specifications for each individual message.