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This section describes the functions, callbacks, and data structures
that make up the DNS Service Discovery API.

The DNS Service Discovery API is part of Bonjour, Apple's implementation
of zero-configuration networking (ZEROCONF).

Bonjour allows you to register a network service, such as a
printer or file server, so that it can be found by name or browsed
for by service type and domain. Using Bonjour, applications can
discover what services are available on the network, along with
all the information -- such as name, IP address, and port --
necessary to access a particular service.

In effect, Bonjour combines the functions of a local DNS server and
AppleTalk. Bonjour allows applications to provide user-friendly printer
and server browsing, among other things, over standard IP networks.
This behavior is a result of combining protocols such as multicast and
DNS to add new functionality to the network (such as multicast DNS).

Bonjour gives applications easy access to services over local IP
networks without requiring the service or the application to support
an AppleTalk or a Netbeui stack, and without requiring a DNS server
for the local network.