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Client–Server Communication
Clients ask, servers answer: the request–response model behind the web, email and apps — and how peer-to-peer differs.
Clients and Servers
Request and response
- A client is the device or program that requests something: a browser, an email app, a phone app.
- A server is the computer or program that provides it: a web server, mail server, database server or file server.
- One server can answer thousands of clients at the same time.
Peer-to-Peer
Client–server vs peer-to-peer
| Client–server | Peer-to-peer (P2P) |
|---|---|
| Central server provides the service | Every computer (peer) can be both client and server |
| Easy to back up, secure and manage centrally | No central control; harder to secure |
| If the server fails, the service stops | Keeps working if one peer leaves |
| Examples: websites, email, online banking | Examples: some file-sharing and blockchain systems, sharing a folder between two PCs |
Types of Server
| Common servers on the internet | |
|---|---|
Practice
What is one disadvantage of the client–server model?
More lessons in Internet Technologies · Next: How a Web Page Reaches Your Browser · Previous: The Internet vs the World Wide Web