The networking of computers is nearly as old as computing itself. It’s roots can be traced back as far as 1961 when the idea of ARPANET was proposed Leonard Kleinrock. Since that time there have been a series of gradual improvements to the ideas and technologies.
Significant points in the timeline can be shown as
1965 when the term packet was used to describe data been sent between computers on a network
1969 the Internet was officially born
1973 Ethernet is developed
1974 first Routers are used. However, these Routers are not considered to be true IP Routers
1976 development of the first IP Router
1978 the invention of the TCP/IP protocol
1983 implementation of the first DNS
1988 details of the first firewall are published
1990 the first network switch is developed and introduced
A computer network is a collection of computing nodes connected in a number of ways that allow them to communicate with each other. The network comprises Routers, Hubs, Bridges, and Switches.
In order the ensure interoperability between computers on a network, standards must be defined and adhered to. The most important one is the OSI 7 layer model. It is a reference model that specifies standards for communications protocols and also the functionalities of each of the 7 layers.
Computers communicate with each other using predefined protocols. A protocol is the set of rules that define the way how two entities can communicate across the network. It would speicify patterns of communcation and data structures. Each layer of the OSI 7 layer models is goverend by 1 or more protocols, such as TCP, IP, UDP, ARP, DHCP, FTP and so on.