A computer network is a group of computers linked to each other that enables the computer to communicate with another computer and share its resources, data, and applications.
A computer network can be categorized by its size.
A computer network is mainly of three types:
LAN(Local Area Network)
MAN(Metropolitan Area Network)
WAN(Wide Area Network)
LAN (Local Area Network)
Local Area Network is a group of computers connected to each other in a small area such as building, office.
LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc.
It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and Ethernet cables.
The data is transferred at an extremely faster rate in the Local Area Network.
Local Area Network provides higher security. Fig: LAN[/caption]
Characteristics of Local Area Network
LANs are privately owned-network, can be extended up to a few kilometers.
LANs operate at relatively high speed as compared to the typical WAN
It connects computers within a single office, building, block, or campus, i.e. they work in a relatively small geographical area.
Advantages of LAN
Resource Sharing: LAN provides resource sharing such as computer resources like printers, scanners, modems, DVD-ROM drives, and hard disks that can be shared within the connected devices. This reduces cost and hardware purchases.
Software Applications Sharing: In a Local Area Network, it is easy to use the same software in a number of computers connected to a network instead of purchasing them separately licensed software for each client's network.
Easy and Cheap Communication: Data and messages can easily be shared with the other computer connected to the network.
Centralized Data: The data of all network users can be stored on a hard disk of the central/server computer. This helps users to use any computer in a network to access the required data.
Data Security: Since data is stored on the server computer, it will be easy to manage data in only one place and the data will be more secure too.
Internet Sharing: Local Area Network provides the facility to share a single internet connection among all the LAN users. In school labs and internet Cafes, a single internet connection is used to provide internet to all connected computers.
Disadvantages of LAN
High Setup Cost: The initial setup costs of installing Local Area Networks is high because there is special software required to make a server. Also, communication devices like an Ethernet cables, switches, hubs, routers, cables are costly.
Privacy Violations: The LAN administrator can see and check the personal data files of each and every LAN user. Moreover, he can view the computer and internet history of the LAN user.
Data Security Threat: Unauthorized users can access important data of an office or campus if a server hard disk is not properly secured by the LAN administrator.
LAN Maintenance Job: Local Area Network requires a LAN Administrator because there are problems such as software installations, program faults or hardware failures or cable disturbances in Local Area Network. A LAN Administrator is required to maintain these issues.
Covers Limited Area: LANs are restricted in size they cover a small area like a single office, single building, or a group of nearby buildings.
MAN (Metropolitan Area Network)
A metropolitan area network is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network.
Government agencies use MAN to connect to the citizens and private industries.
In MAN, various LANs are connected to each other through a telephone exchange line.
The most widely used protocols in MAN are RS-232, Frame Relay, ATM, ISDN, OC-3, ADSL, etc.
It has a higher range than Local Area Network (LAN).
There are many advantages of the MAN network, some of them given below.
Less expensive:
It is less expensive to attach MAN with WAN. MAN gives you good efficiency of data. All data on MAN is easily manageable in a centralized way.
Sending local emails:
You can send local emails fast and free on MAN.
High speed than WAN:
Speed of data can easily reach 1000 Mbps, as MAN uses fiber optics. Files and database transfer rates are fast.
Sharing of the internet:
With the installation of MANs, users can share their internet connection. In this way, multiple users can get the same high-speed internet.
Conversion of LAN to MAN is easy:
MAN is a combination of two or more LAN networks. So it is a faster way to connect two LAN networks together. It is possible by the fast configuration of links.
High Security:
MAN’s has a high-security level than WAN.
Disadvantages of metropolitan area network (MAN)
Difficult to manage:
It is very difficult to manage if the size and number of LANs network increase. This is due to security and extra configuration problems. Internet speed difference:
As it cannot work on phone copper wires. Copper wires affect the speed of MAN. So high cost is needed for fiber optics.
Hackers attack:
In this network, there is a high risk of attacking hackers as compared to LAN. So data may be a leak. Highly security staff is the need in MAN.
Technical staff requires to set up:
Highly technical people require to set up MAN. The technical people are network administrators and troubleshooters.
Need More wires:
In MAN more than LAN network, cables require. As you know, it is a combination of two LANs.
WAN (Wide Area Network)
A Wide Area Network is a network that extends over a large geographical area such as states or countries.
A Wide Area Network is quite a bigger network than a LAN.
A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fiber optic cable, or satellite links.
The internet is one of the biggest WANs in the world.
A Wide Area Network is widely used in the field of Business, government, and education.
Mobile Broadband: A 4G network is widely used across a region or country.
Last-mile: A telecom company is used to provide internet services to customers in hundreds of cities by connecting their homes with fiber.
Private network: A bank provides a private network that connects the 44 offices. This network is made by using the telephone leased line provided by the telecom company.
Advantages Of Wide Area Network:
Following are the advantages of the Wide Area Network:
Geographical area: A Wide Area Network provides a large geographical area. Suppose if the branch of our office is in a different city then we can connect with them through WAN. The internet provides a leased line through which we can connect with another branch.
Centralized data: In the case of the WAN network, data is centralized. Therefore, we do not need to buy emails, files, or backup servers.
Get updated files: Software companies work on the live server. Therefore, the programmers get the updated files within seconds.
Exchange messages: In a WAN network, messages are transmitted fast. The web application like Facebook, Whatsapp, Skype allows you to communicate with friends.
Sharing of software and resources: In a WAN network, we can share the software and other resources like a hard drive, RAM.
Global business: We can do business over the internet globally.
High bandwidth: If we use the leased lines for our company then this gives the high bandwidth. The high bandwidth increases the data transfer rate which in turn increases the productivity of our company.
Disadvantages of Wide Area Network:
The following are the disadvantages of the Wide Area Network:
Security issue: A WAN network has more security issues as compared to LAN and MAN network as all the technologies are combined together that creates the security problem.
Needs Firewall & antivirus software: The data is transferred on the internet which can be changed or hacked by hackers, so the firewall needs to be used. Some people can inject the virus into our system so antivirus is needed to protect from such a virus.
High Setup cost: An installation cost of the WAN network is high as it involves the purchasing of routers, switches.
Troubleshooting problems: It covers a large area so fixing the problem is difficult.
Fig: LAN[/caption]
Fig: WAN[/caption]