Advantage:
A network has several advantages over a collection of stand-alone microcomputers.
It allows the sharing of resources such as disk storage, printers, image scanners, modems, and central servers.
It allows sharing of information held on disc drives accessible by users.
It is easier to store application programs on a computer and make them available to all user rather to all users rather than having copies individually installed in each computer.
It allows electronic mail to be sent between users.
It is easier to set up new users and equipment.
It allows the connection of different types of computers, which can communicate with each other.
The main disadvantages of networks are:
The user becomes dependent on them. If for example, the network file server develops a fault, then many users will be unable to run application programs. (On many sites, a back-up file can be switched in to action if the main server fails.)
If the network stops operating, then it may not be possible to access various hardware and software resources.
The efficiency of a network is very dependent on the skill of the system manager. A badly managed network may operate less efficiently than stand-alone machines.
It is difficult to make a system secure from hackers, novices, or industrial espionage.
As traffic increases on the network, the performance degrades unless it is properly designed.
TYPES OF NETWORKS
Networking has been developed on all levels, from local to international, in different sectors of society. Networks used by banks and retail merchants for the transfer of money or credit verification. Depending upon the area covered by the network system, there are three basic types of networks. They are: –
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
Local Area Network
A Local Area Network (LAN) is a network that is confined to a relatively small area. It is limited to a geographic area such as a room, school, or building. Rarely are LAN computers more than a mile apart.
In a typical LAN configuration, one computer is designated as the file server. It stores all of the software that controls the network, as well as the software that can be shared by a computers attached to the network. Computers connected to the file server are called workstations. The workstation can be less powerful than the file server, and they may have additional software on their hard drives. On most LANs, cables are used to connect the network interface cards in each computer.
Metropolitan Area Network
A Metropolitan Area Network (MAN) is limited to only one metropolis. It is basically a bigger version of a LAN and normally uses similar technology. A MAN might cover a group of nearby corporate offices or a city and might be either private or public. It can support both data and voice and might even be related to the local cable television network.
For communication there must be a network, either in a computer or in we human community. In case of computer network the vast or enormous number of data is shared, and for sharing or interchanging these data required complex networks. For successful sharing, order maintenance is also necessary. To maintain order during the interchange of data, a rule to control the process and network is necessary. In early times, interchanging was happening between the control computer and the remote site, and at that time a rule was made to control it called “handshaking.” As the age developed, the interchange of data rate also heightened. In a single word, the complication of the data computation system increased. Handful “handshaking” was not enough to control the process. Thus, to control the complex process, a set of rule developed that is followed by both sender and receiver to make communication possible.
A protocol may be defined as a set of rule designed to force the device sharing a channel to observe orderly communication procedures.
A simple example of protocol is public mail service. The letter must be directed to a specified person for those that were written without opening and seeing whatever data is inside the envelope. This simply means a protocol is a simple group of rules that bound the communication system.
According to the use of protocol, it has some function. There are four major functions listed below: –
- Framing
- Line control
iii. Flow control
- Sequence control