Classification of Computer Networks
- 1. Classification of Computer Networks Class Note - 2 Mostafizur Rahman Monna ID: 1834902509 Batch: 49th SEC: B
- 2. Computer Network Types A computer network can be categorized by their size. A computer network is mainly of four types: 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 Local Area Network. Local Area Network provides higher security. Computer Network Types LAN Local Area Network PAN Personal Area Network MAN Metropolitan Area Network WAN Wide Area Network
- 3. Advantages of local area network (LAN) Sharing of resources: All the resources are attached to one network and if any computer needs any resources then it can be shared with the required computer. Types of resources are the DVD drive, printers, scanners, modems and hard drives. So there is no need to purchase separate resources for each computer and it saves money. Client and server relationship: All the data from attached computers can be stored in one server. If any computer (Client) needs data then that computer user can simply log in and access the data from the server. For example movies and songs can be stored on the server and can be accessed by any authorized user (Client computer). Sharing of the internet: In offices and net cafes, we can see that one internet connection is shared between all computers. This is also the type of LAN technology in which main internet cable is attached to one server and distributed amoung attached computers by the operating system. Software program sharing: Software programs can also be shared on the LAN. You can use single licensed software and any user can use it in the network. It is expensive to buy a license for each user in the network so sharing software program is easy and cost-effective. Securing of data: Keeping data on the server is more secure. And if you want to change or remove any data you can do it easily on one server computer and other computers can access updated data. You can also give access or revoke access to specific users so that only authorized users can access the data in the network.
- 4. Disadvantages of local area network (LAN) Data security problem: If the server computer is not set up correctly and there is a leak in security then unauthorized users can access the data also. So there should be privacy policy and rules set up correctly on the server. Limitation of distance: Local area networks are usually made within a building or nearby building and cannot extend to the wider area. Server crashes may affect all computers: If any file on the server is corrupted or hard drive fails then all the attached computers face problems in functioning properly. Setting up a LAN is expensive: It is expensive to set up LAN because there is special software required to make a server. Also, communication devices like hubs, switches, routers, cables are costly. The special administrator is required to maintain and troubleshoot LAN for a large office. Communication is easy, fast, and time-saving: In LAN computers can exchange data and messages in the easy and fast way. It also saves time and makes our work fast. Every user can share messages and data with any other user on LAN. The user can log in from any computer on the network and access the same data placed on the server. Computer identification: Each computer is given a MAC address and is temporarily stored in the switch or router during communication. All computers on the LAN are identified by MAC addresses which are used to send and receive messages and data. Note that MAC address is stored in the network adapter that is attached in the motherboard of each computer. In old computers, network adapters were not built in with motherboards but in modern computers, they come built-in with motherboards.
- 5. PAN (Personal Area Network) Wired Personal Area Network Wireless Personal Area Network PAN(Personal Area Network) Personal Area Network is a network arranged within an individual person, typically within a range of 10 meters. Personal Area Network is used for connecting the computer devices of personal use is known as Personal Area Network. Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network. Personal Area Network covers an area of 30 feet. Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media player and play stations. There are two types of Personal Area Network: Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as WiFi, Bluetooth. It is a low range network. Wired Personal Area Network: Wired Personal Area Network is created by using the USB.
- 6. Examples Of Personal Area Network: Body Area Network: Body Area Network is a network that moves with a person. For example, a mobile network moves with a person. Suppose a person establishes a network connection and then creates a connection with another device to share the information. Offline Network: An offline network can be created inside the home, so it is also known as a home network. A home network is designed to integrate the devices such as printers, computer, television but they are not connected to the internet. Small Home Office: It is used to connect a variety of devices to the internet and to a corporate network using a VPN Advantages of personal area network No extra space requires: Personal area network does not require extra wire or space. For connecting two devices you only need to enable Bluetooth in both devices to start sharing data among them. For example, connecting wireless keyboard and mouse with the tablet through Bluetooth. Connect to many devices at a time: Many devices can be connected to one device at the same time in a personal area network. You can connect one mobile to many other mobiles or tablets to share files. Cost effective: No extra wires are needed in this type of network. Also, no extra data charges are involved so PAN is an inexpensive way of communication. Easy to use: It is easy to use. No advanced setup is required.
- 7. Disadvantages of personal area network Less distance range: Signal range is maximum 10 meters which makes limitation for long distance sharing. Interfere with radio signals: As personal area network also use infrared so it can interfere with radio signals and data can be dropped. Slow data transfer: Bluetooth and infrared have a slow data transfer rate as compared to another type of networks like LAN (local area network). Reliable: If you use this type of data connection within 10 meters then your network is stable and reliable. Secure: This network is secured because all the devices are authorized before data sharing. Third party injection and data hacking are not possible in PAN. Used in office, conference, and meetings: Infrared is the technology used in TV remotes, AC remotes, and other devices. Bluetooth, infrared and other types of PAN is used to interconnect digital devices in offices, meetings, and conferences. Synchronize data between different devices: One person can synchronize several devices i.e. download, upload and exchanging data among devices. Portable: A person can move devices as it is a wireless network and data exchange is not affected. That mean PAN is portable as well.
- 8. 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). Health problem: In some cases, PAN uses microwave signals in some digital devices which have a bad effect on the human body like brain and heart problems may occur. Costly in terms of communication devices: Personal area network is used in digital devices which are costly so it is another disadvantage of PAN. Examples are smartphones, PDA, laptops, and digital cameras. Infrared signals travel in a straight line: TV remote use infrared signals which have a problem that they travel in straight line. So this counts another disadvantage of PAN.
- 9. Examples Of Metropolitan Area Network MAN is used in communication between the banks in a city. It can be used in an Airline Reservation. It can be used in a college within a city. It can also be used for communication in the military. Advantages of a metropolitan area network (MAN) Less expensive: It is less expensive to attach MAN with WAN. MAN gives the good efficiency of data. In MAN data is easily managed in a centralized way. Sending local emails: On MAN you can send local emails fast and free. High speed than WAN: MAN uses fiber optics so the speed of data can easily reach upon 1000 Mbps. Files and databases can be transferred fast. Sharing of the internet: In some installation of MANs, users can share their internet connection. So multiple users can get the same high-speed internet. Conversion from LAN to MAN is easy: MAN is a faster way to connect two fast LANs together. This is due to the fast configuration of links. High Security: MAN has a high-security level than WAN.
- 10. Disadvantages of metropolitan area network (MAN) Difficult to manage: If MAN becomes bigger then it becomes difficult to manage it. This is due to a security problem and other extra configuration. Internet speed difference: MAN cannot work on traditional phone copper wires. If MAN is installed on copper wires then there will be very low speed. So it required the high cost to set up fiber optics for the first time. Hackers attack: In MAN there are high chances of attacking hackers on the network compared to LAN. So data may be leaked. Data can be secured but it needs high trained staff and security tools. Technical people required to set up: To setup MAN it requires technical people that can correctly setup MAN. The technical people are network administrators and troubleshooters. More wires required: In MAN additional cables are required to connect two LAN which is another problem.
- 11. WAN(Wide Area Network) Examples Of 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 bigger network than the LAN. A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fibre optic cable or satellite links. The internet is one of the biggest WAN 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 the internet services to the customers in hundreds of cities by connecting their home 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.
- 12. Advantages Of 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 case of WAN network, data is centralized. Therefore, we do not need to buy the emails, files or back up 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 WAN network, we can share the software and other resources like a hard drive, RAM. Global business: We can do the 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.
- 13. Disadvantages of 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 the hackers, so the firewall needs to be used. Some people can inject the virus in 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.