Clients and Servers
Much of the Internet uses a client-server model.
Clients are devices that request data from a resource or service.
Servers are the locations of those resources or services.
Web browsers (Chrome, Firefox) and web applications (SnapChat) are examples of clients.
Data Transfer¶
Data transfer starts with the client. * The client initiates communication with a server by making a request for the server's content or service function. * The server then handles the request and returns a response, such as a Web page.
This transfer of data is called the request-response cycle.
- Client initiates a request.
- Server processes (handles) the request.
- Server returns a response.
A server does not have to be something out on the Internet. * The diagram below shows a Web browser client making a request to a program running on Eclipse, both on the same laptop.
This is the same request-response cycle, just on a single computer. 1. Browser (client) makes a request. 2. Program (server) running on IDE handles it. 3. Program returns a response to browser.
Skill++¶
The client-server model is different than a Peer-to-Peer (P2P) model where all devices are considered peers, and thus communicate with each other directly to share resources and services.