Types of network - Shawon Notes

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Types of Network

Local area networks (LANs):

A LAN consists of a collection of computers that can share peripherals, share information and communicate with each other over  a network. These are likely to be in the same room, building, department, school or workplace. Each computer that forms part of the network can function both as an independent personal computer running its own software and as a workstation on the network accessing information from the network server.

Advantages of LAN:

  • Software and data files can be shared by many users.
  • Users can work together on a single shared document.
  • Users can communicate using instant messaging.
  • Users can stream media.
  • Users can access the network from any computer or other device that can be attached to the network.
  • It is usually cheaper to buy one copy of a software application and pay the license fee for several computers, than to buy individual licenses for each computer.
  • Users can share hardware devices.
  • Users can share an Internet connection.
  • User’s access rights can be controlled centrally.
  • Computers attached to the network can be maintained either centrally or from any network station.

Disadvantages of LAN:

  • Set-up of server and network cabling costs high.
  • Data can get corrupt easily.
  • There is a risk from viruses as they can spread easily between the computers.

Types of LAN:

  • On a client/server network, one or more computers are designated as the servers. Client computers are those computers available for you to use. Clients communicate with each other and externally through the server. The server will have a faster processor, more RAM and a lot more backing storage space than the client computers. A large LAN may have several servers to perform different tasks. For instance, a file server may look after the organization of the files on the network, while a print server coordinates printing on the network. Each server will also have software that manages the services it provides: email and Internet access, shared peripherals and the security of the system. Any computer that gives a user access to any type of network, including a connection to a mainframe computer, can be called a terminal.
  • A peer-to-peer network allows every computer to communicate directly with very other computer in the network. A user can access data from any computer on the network. They are used mainly in small business and departments.

Cabled LAN: In a cabled LAN, all the computers and other peripheral devices on the network are attached o cables that are used to transmit data between them. A computer must be connected to a cabled LAN using a network interface (NIC). The network cable is plugged into the NIC.

Wireless LAN (WLAN): A wireless LAN differs from a cabled LAN in that computers can use wireless link to connect to the network instead of being attached using a cable. The wireless connection is made possible by three sets of components: wireless access points; wireless network interface cards (NICs) and routers.

A wireless access point contains a radio receiver, encryption and communications software so that it can broadcast and receive wireless communications. It translates computer signals into wireless signals, so that it can broadcast to and receive signals from wireless network interface cards (NICs) on the network. NICs equipped for wireless communications have a fixed or detachable radio antenna instead of usual coaxial cable. Routers enable several computers to communicate through a wireless access point at the same time.

Bluetooth: Bluetooth is a form of wireless communication designed to enable PDAs, mobile phones, computers and similar devices to share information and to synchronise data. Bluetooth requires a transceiver chip in each device. The data transfer rate is 720 kbps with a 10 metre range.

Wide area networks (WANs):

A WAM can connect networks across a large geographical area, such as a city or a country or even internationally. Information can be transmitted in many ways: for example using high-speed telephone lines, fibre optic cables, microwave links and satellite links, or a combination of these. WANs are used mainly by universities, large companies and banks with branches in different countries, to share information and processing loads.

IP address:

Each computer on the Internet has a unique address that identifies it. This unique address is a number called IP address (Internet Protocol address), which is a 32-bit address consisting of four sets of up to three digits each, separated by full stops. The IP address could be static or dynamic. To connect to a computer on the Internet, your computer needs to know its IP address.