Computer Networks and the Internet

According to Wikipedia, a computer Network are a collection of computers and devices interconnected by Communicati On channels this facilitate communications among users and allows users to share resources. Computer networks can be classified based on different standards.

An important concept relevant to computer networking is Protocol, which "defines the format and the Order of mess Ages exchanged between or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event ". The Internet standards documents, which is called requests for Comments (RFCs), is developed by the Internet En gineering Task Force (IETF) and define protocols such as TCP, IP, HTTP and SMTP. The Eithernet and wireless WiFi standards is developed by IEEE 802 Lan/man Standards Committee.

In order to reduce design complexity, protocols is organized into a layered architecture, which also guarantees the INDEP Endence and flexibility of different protocols. A layer provides services to a layer above by using the services of the layer directly below it and performing certain act ions within that layer. A service is connection-orientated If a connection are established before communication, otherwise it is Conne Ctionless. Services that never lose data is called reliable services.

The TCP/IP Reference Model consists of four protocol layers: application layer, Transport Layer , Network layer and link layer. In the Internet, a protocol called IP bridges different applications over different networks and thus interconnects a ll autonomous computers.

References:

1. Kurose, James F., Keith W. Ross. computer networking:a top-down approach [M]. Beijing: Higher Education Press, 2009-08

Computer Networks and the Internet