In a computer network, special standards called protocols are used to ensure compatibility of the levels of network architecture. They are hardware and software. Hardware devices (interfaces) support standards at the physical level, and at the data level they work using special software support tools.
Local and global networks are determined by what protocols they use. In a local area network, computers use mainly a single set of standards for all network participants, and combine computers in a room, building, or floor.
Global networks cover, as a rule, large areas. They combine both individual computers and local networks using various protocols.
The activity of a civilized society in modern conditions is impossible without the means of quick communication and rapid exchange of information. Global networks are designed to solve this problem. The main condition for the functioning of these networks is the instant transfer of information regardless of how far the computers are from each other.
A global network is a network that includes computers located in vast territories with an unlimited number of computer systems included in the network. The data transfer speed in such a network is lower than in the local one.
Computer Network Protocols
WANs are supported by TCP / IP, ATM, MPLS and some others. The most common protocol is TCP / IP, which includes sub-protocols. This is the applied sub-protocol, transport, network, channel and physical.
Most programs work at the application level and have their own protocols. These are HTTP, WWW, etc. Protocols are responsible for the visualization and display of the information sought.
The transport protocol ensures the delivery of data to a specific application that can process them. It is called TCP.
The IP network protocol is responsible for receiving and sending requests to a lower level to obtain all the necessary information.
The channel and physical layers are responsible for determining the methods and conditions for transmitting information.
Well-known global networks: for example, WWW (WorldWide Web). The network consists of servers that store the information users need and individual computers that receive information from servers and download it to them. The WWW network is convenient and easy to use.
WANs include a subnet made up of separate components such as communication lines and switching elements. Communication lines are otherwise called channels or highways, through which data moves from machine to machine.
The switching elements that are used to connect the communication lines are routers. These are specialized computers.
WANs mainly contain a large number of telephone lines and cables that connect a pair of routers.
The second option to connect routers is radio communication using satellites or ground-based relays. Each router has its own antenna, thanks to which it is able to receive and send a signal. Network routers can easily receive signals from the satellite, and in some cases, they can hear the transmitted information of neighboring routers sending data to the satellite. In separate global networks, all routers are interconnected by an ordinary point-to-point subnet, and only some of them are equipped with a satellite dish. Satellite networks are broadcast and most in demand where it is necessary to provide broadcasting.