Using TCP, UDP, and Sockets
The System.Net.Sockets namespace
includes types that
provide protocol-level support for TCP and UDP. These types are built
on the underlying Socket type, which is itself
directly accessible for transport-level access to the network.
Two classes provide the
TCP
support: TcpListener and
TcpClient. TcpListener listens
for incoming connections, creating Socket
instances that respond to the connection request.
TcpClient connects to a remote host, hiding the
details of the underlying socket in a
Stream-derived type that allows stream I/O over
the network.
A class called UdpClient
provides
the UDP support. UdpClient serves as both a client
and a listener, and includes multicast support, allowing individual
datagrams to be sent and received as byte arrays.
Both the TCP and the UDP classes help to access the underlying
network socket (represented by the Socket class).
The Socket class is a thin wrapper over the native
Windows sockets functionality and is the lowest level of networking
accessible to managed code.
The following example is a simple implementation of the Quote of the
Day (qotd) protocol, as defined by the IETF in RFC 865. It
demonstrates the use of a TCP listener to accept incoming requests
and the use of the lower-level Socket type to
fulfill the request:
// QOTDListener.cs // Run QOTDListener.exe to service incoming QOTD requests using System; using System.Net; using System.Net.Sockets; using System.Text; class QOTDListener { static string[ ...