1, Network World

Internet connection is secondary by many smaller-scale networks, these small networks may be only a few hundred computers in a local area network, there may be a wide area network.

We say "the Internet" is actually a subset of the Internet access WWW (World Wide Web), which is based on HTTP protocol, such as HTML hypertext transfer resources capacity is limited to the HTTP protocol.

Other resources on the Internet such as e-mail, BT, P2P download, FTP, SSH secure login, they have their own protocol, need to use their own proprietary protocol to access.

Since HTTP Hypertext table v relatively strong, many other application layer protocols may be encapsulated using the HTTP protocol layer, hence the micro-channel version of the page, and the like on the web mail application.

2, browser

The official name of the browser is "Web Browser", Web here is the "World Wide Wed", is used to retrieve, view the application on the Internet web resources. The browser is essentially a room request HTTP protocol, HTTP protocol access to resources on the network.

In the HTTP protocol, the role of the browser is called User Agent (User Agent), meaning that the browser as a proxy for the user to initiate HTTP requests.

3, Web server

HTTP Web Server is a responder request, there are usually two levels of meaning: hardware and software.

Hardware: The physical form or in the "cloud" in the form of an assembly, under normal circumstances is to use a reverse proxy, load balancing technology clusters consisting of large, it seems from the outside world, it is still the performance of a machine.

Software: meaning runs on hardware servers, providing Web services applications. It has a strong ability to respond to massive hardware HTTP request processing page on the disk, images and other static resources, or forwards the request to the back of the Tomcat, Node.js and other business applications to return dynamic information.

Apache, Nginx, Tomcat is a typical server.

4, CDN (content delivery network)

CDN stands for Content Delivery Network. Typically HTTP client and server is not directly connected to the source station in response caching CDN content, the results of a request back to the client directly, thus reducing the pressure side service, dramatically shorten the response time, the source station amplified exponentially service capabilities of the server.

CDN is now an important Internet infrastructure, in addition to the basic network acceleration, also provides load balancing, security, edge computing, inter-carrier network functions.

5、Web Service

Web Service is an application service development standards defined by the W3C, is based on a Web (HTTP) server architecture technology. It uses the client-server one master service interface using WSDL definitions, the HTTP protocol using XML or SOAP message transmission. In the Web Service architecture, server and client due to the use of such means of communication HTTP platform-independent data exchange to achieve, so you can use different operating systems and language development, has the advantage of cross-platform, cross-language.