Using and understanding Internet services

1  What are Internet services?

• The Internet is a collection of interconnected computers, sharing data and services. A service is a program running on a computer that allows you to perform a useful activity such as:
  • browsing the World Wide Web (WWW)
  • sending and receiving email
  • downloading video and music files
  • communicating with friends and family using voice and video.
• Many of the services supported by the Internet operate as client/servers. This allows one device (server) to provide a service to a requesting device (client):

Figure 1

• In many smaller networks, devices operate as peers. This is where devices can behave as either client or server, depending on which services they are using. This operation is referred to as peer-to-peer, and is commonly found in home networks as it is easily configured. The mode of operation is difficult to use within larger networks, but it is often used within Internet-based file sharing services.

Figure 2