Name 

Description 

Describing Sockets 

Sockets let your network application communicate with other systems over the network. Each socket can be viewed as an endpoint in a network connection. It has an address that specifies:

• The system on which it is running.
• The types of interfaces it understands.
• The port it is using for the connection.

A full description of a socket connection includes the addresses of the sockets on both ends of the connection. You can describe the address of each socket endpoint by supplying both the IP address or host and the port number.
Before you can make a socket connection,... more 

Describing the Host 

The host is the system that is running the application that contains the socket. You can describe the host for a socket by giving its IP address, which is a string of four numeric (byte) values in the standard Internet dot notation, such as  

Using Ports 

While the IP address provides enough information to find the system on the other end of a socket connection, you also need a port number on that system. Without port numbers, a system could only form a single connection at a time. Port numbers are unique identifiers that enable a single system to host multiple connections simultaneously, by giving each connection a separate port number.
One way to look at port numbers is as numeric codes for the services implemented by network applications. This is a convention that allows listening server connections to make themselves available on a fixed port... more