January 26, 2020
Amitraj
Computer Network Types
computer network is a system of interconnected computers and peripheral devices.
eg: it may connect computers, scanners, printers and cameras.
1. Local Area Network (LAN) -
-> A local area network is a computer network covering a small geographical area like a home, office or group of buildings.
-> It connects workstations, personal computers, printers, servers and many other devices.
-> LAN uses low speed communication lines for connections like Twisted Pair Cable, Coaxial Cable and Fiber Optics.
-> The cost of sending/receiving data is negligible.
-> LAN networks are also widely used to share resources like printers, shared hard-drive etc.
Advantages of LAN
Resource Sharing: Computer resources like printers, modems, DVD-ROM drives and hard disks can be shared with the help of local area networks. This reduces cost and hardware purchases.
Data Security: Since, data is stored on server computer centrally, it will be easy to manage data at only one place and the data will be more secure too.
Easy and Cheap Communication: Data and messages can easily be transferred over networked computers.
Disadvantages of LAN
Data Security Threat: Unauthorised users can access important data of an organization if centralized data repository is not secured properly by the LAN administrator
Covers Limited Area: Local Area Network covers a small area like one office, one building or a group of nearby buildings.
2. Metropolitan Area Network (MAN) -
-> A Metropolitan Area Network (MAN) is a computer network covering a town or city.
-> MANs are larger LANs in terms of geographic area covered.
-> MANs use high speed connections using coaxial cable and microwave links.
-> Best example of MAN is Cable Television network in many cities.
-> MAN is formed by connections several LANs which may belong to various organizations.
Characteristics of MAN
1. It generally covers towns and cities (50 km).
2. Communication medium used for MAN are optical fibers, cables etc.
Advantages of MAN
1. Extremely efficient and provide fast communication via high-speed carriers, such as fibre optic cables.
2. The dual bus used in MAN helps the transmission of data in both directions simultaneously.
3. A MAN usually encompasses several blocks of a city or an entire city.
Disadvantages of MAN
1. More cable required for a MAN connection from one place to another.
2. It is difficult to make the system secure from hackers and industrial espionage(spying) graphical regions.
3. Wide Area Network (WAN) -
-> A Wide Area Network (WAN) is a computer network covering a very large geographic area, like a country or continent.
-> WAN uses very high speed communication links like satellite communication, telephone lines and microwave links.
-> The cost of sending data in a WAN may be very high because public communication systems such as telephone lines, microwave links or satellite communication are used.
-> The largest WAN in existence is the Internet.
Characteristics of WAN
1. It generally covers large distances(states, countries, continents).
2. Communication medium used are satellite, public telephone networks which are connected by routers.
Advantages of WAN
1. Covers a large geographical area so long distance business can connect on the one network.
2. Shares software and resources with connecting workstations.
3. Messages can be sent very quickly to anyone else on the network. These messages can have picture, sounds or data included with them(called attachments).
Disadvantages of WAN
1. Setting up a network can be an expensive, slow and complicated. The bigger the network the more expensive it is.
2. Security is a real issue when many different people have the ability to use information from other computers. Protection against hackers and viruses adds more complexity and expense.
4. Wireless networks -
Wireless networks are computer networks that are not connected by cables of any kind. The use of a wireless network enables enterprises to avoid the costly process of introducing cables into buildings or as a connection between different equipment locations.
Modern digital wireless systems have better performance, but the basic idea is the same.
Wireless Networks can be divided into three main categories:
1. System interconnection
2. Wireless LANs
3. Wireless WANs
System Interconnection
System interconnection is all about interconnecting the components of a computer using short-range radio. Some companies got together to design a short-range wireless network called Bluetooth to connect various components such as monitor, keyboard, mouse and printer, to the main unit, without wires. Bluetooth also allows digital cameras, headsets, scanners and other devices to connect to a computer by merely being brought within range.
In simplest form, system interconnection networks use the master-slave concept. The system unit is normally the master, talking to the mouse, keyboard, etc. as slaves.
Wireless LANs
These are the systems in which every computer has a radio modem and antenna with which it can communicate with other systems. Wireless LANs are becoming increasingly common in small offices and homes, where installing Ethernet is considered too much trouble. There is a standard for wireless LANs called IEEE 802.11, which most systems implement and which is becoming very widespread.
Wireless WANs
The radio network used for cellular telephones is an example of a low-bandwidth wireless WAN. This system has already gone through three generations.
The first generation was analog and for voice only.
The second generation was digital and for voice only.
The third generation is digital and is for both voice and data.
computer network is a system of interconnected computers and peripheral devices.
eg: it may connect computers, scanners, printers and cameras.
1. Local Area Network (LAN) -
-> A local area network is a computer network covering a small geographical area like a home, office or group of buildings.
-> It connects workstations, personal computers, printers, servers and many other devices.
-> LAN uses low speed communication lines for connections like Twisted Pair Cable, Coaxial Cable and Fiber Optics.
-> The cost of sending/receiving data is negligible.
-> LAN networks are also widely used to share resources like printers, shared hard-drive etc.
Advantages of LAN
Resource Sharing: Computer resources like printers, modems, DVD-ROM drives and hard disks can be shared with the help of local area networks. This reduces cost and hardware purchases.
Data Security: Since, data is stored on server computer centrally, it will be easy to manage data at only one place and the data will be more secure too.
Easy and Cheap Communication: Data and messages can easily be transferred over networked computers.
Disadvantages of LAN
Data Security Threat: Unauthorised users can access important data of an organization if centralized data repository is not secured properly by the LAN administrator
Covers Limited Area: Local Area Network covers a small area like one office, one building or a group of nearby buildings.
2. Metropolitan Area Network (MAN) -
-> A Metropolitan Area Network (MAN) is a computer network covering a town or city.
-> MANs are larger LANs in terms of geographic area covered.
-> MANs use high speed connections using coaxial cable and microwave links.
-> Best example of MAN is Cable Television network in many cities.
-> MAN is formed by connections several LANs which may belong to various organizations.
Characteristics of MAN
1. It generally covers towns and cities (50 km).
2. Communication medium used for MAN are optical fibers, cables etc.
Advantages of MAN
1. Extremely efficient and provide fast communication via high-speed carriers, such as fibre optic cables.
2. The dual bus used in MAN helps the transmission of data in both directions simultaneously.
3. A MAN usually encompasses several blocks of a city or an entire city.
Disadvantages of MAN
1. More cable required for a MAN connection from one place to another.
2. It is difficult to make the system secure from hackers and industrial espionage(spying) graphical regions.
3. Wide Area Network (WAN) -
-> A Wide Area Network (WAN) is a computer network covering a very large geographic area, like a country or continent.
-> WAN uses very high speed communication links like satellite communication, telephone lines and microwave links.
-> The cost of sending data in a WAN may be very high because public communication systems such as telephone lines, microwave links or satellite communication are used.
-> The largest WAN in existence is the Internet.
Characteristics of WAN
1. It generally covers large distances(states, countries, continents).
2. Communication medium used are satellite, public telephone networks which are connected by routers.
Advantages of WAN
1. Covers a large geographical area so long distance business can connect on the one network.
2. Shares software and resources with connecting workstations.
3. Messages can be sent very quickly to anyone else on the network. These messages can have picture, sounds or data included with them(called attachments).
Disadvantages of WAN
1. Setting up a network can be an expensive, slow and complicated. The bigger the network the more expensive it is.
2. Security is a real issue when many different people have the ability to use information from other computers. Protection against hackers and viruses adds more complexity and expense.
4. Wireless networks -
Wireless networks are computer networks that are not connected by cables of any kind. The use of a wireless network enables enterprises to avoid the costly process of introducing cables into buildings or as a connection between different equipment locations.
Modern digital wireless systems have better performance, but the basic idea is the same.
Wireless Networks can be divided into three main categories:
1. System interconnection
2. Wireless LANs
3. Wireless WANs
System Interconnection
System interconnection is all about interconnecting the components of a computer using short-range radio. Some companies got together to design a short-range wireless network called Bluetooth to connect various components such as monitor, keyboard, mouse and printer, to the main unit, without wires. Bluetooth also allows digital cameras, headsets, scanners and other devices to connect to a computer by merely being brought within range.
In simplest form, system interconnection networks use the master-slave concept. The system unit is normally the master, talking to the mouse, keyboard, etc. as slaves.
Wireless LANs
These are the systems in which every computer has a radio modem and antenna with which it can communicate with other systems. Wireless LANs are becoming increasingly common in small offices and homes, where installing Ethernet is considered too much trouble. There is a standard for wireless LANs called IEEE 802.11, which most systems implement and which is becoming very widespread.
Wireless WANs
The radio network used for cellular telephones is an example of a low-bandwidth wireless WAN. This system has already gone through three generations.
The first generation was analog and for voice only.
The second generation was digital and for voice only.
The third generation is digital and is for both voice and data.
