Networking Concepts PDF

## Chapter 1: Networking Concepts ### _Learning Outcomes_ - Learn about the basic concept of a computer network, its advantages and disadvantages. - Know about the different types of networking components, networks, network architecture, and topologies. - Know how to access a file from a shared dri...

## Chapter 1: Networking Concepts ### _Learning Outcomes_ - Learn about the basic concept of a computer network, its advantages and disadvantages. - Know about the different types of networking components, networks, network architecture, and topologies. - Know how to access a file from a shared drive. - Understand network security. ### Introduction Have you ever observed the different types of networks that you come across in your daily life? Can you think of some? Let us understand this concept by some examples: - A network of roads, railway lines, canals, etc., which is used for transportation and travel. - Communication network of telephone system, which enables you to talk to anyone, anywhere, anytime. - A network of banks/ATMs (Automated Teller Machines) for financial transactions. - Radio/Television network that broadcasts programs live across the globe. - Video conferencing, which allows discussions between people at distant places. - A network of malls, schools, hospitals, etc., all over the country. The internet is one such network that is an outcome of cyber networking. Imagine how your life would be without networking - without phones, television, internet, etc. Computer networks have extended the power of a computer beyond the expanse of a room. It has transformed the world into a global village. ### Networking A computer network can be defined as a group of computers and other peripheral devices that are linked together for the purpose of sharing data and hardware resources. For example, if one of the computers in a network has a printer attached to it, then all the computers in that network can access the printer and use it to print documents. ### Advantages of Networking Networking in computers brings efficiency, economy, and effectiveness in any organization. Some of the advantages of networking are: - **Resource Sharing**: In a computer network, all hardware and software resources are shared among the users of the network. The additional peripheral devices, such as printer, scanner, modems, fax machines, etc., can be connected to one central computer and shared among the others. It also becomes very easy and convenient to share data and files among users of a computer network. It saves the time that is spent in transferring a file from one machine to another using a storage device. - **Reduction in Cost**: The cost of hardware is considerably less in a computer network as all the computers share the hardware resources. The software cost can also be saved by purchasing the software and licenses for the server, and distributing them to the clients. - **Increased Storage Capacity**: As in a network, users can store their files on remote computers, so they get more space to store their data. - **Fast Data Transfer**: Networking provides a facility to transfer soft copies from one computer to another at a high speed. - **Easy to Take Backup**: It is difficult to maintain regular backups on a number of standalone computers. You can set the server in a network to take regular backup of data automatically. - **Reduces Data Inconsistency**: When multiple mismatching copies of a file are stored at different computers, it is called data inconsistency. In a network, the deletion, modification, or updation of the file can be done at a single point only. This reduces data inconsistency and brings in more efficiency. - **Reduced Redundancy**: Data redundancy means duplication of data at multiple places. A computer network helps in reducing the data redundancy by providing a central server to store the data. The client computers can access the data whenever required by sending a request to the server. - **Increases Security**: In a computer network, users are assigned IDs and passwords for authentication to access the data and files. Only the authorized users are allowed to access the hardware and software resources. It is the duty of the network administrators to adopt preventive measures to protect the networks from potential security threats. ### Disadvantages of Networking There are few disadvantages of computer networks. Some of them are: - **Additional Cost of Networking Equipment**: A network's cost might get reduced by sharing the hardware resources. However, additional cost of establishing the network gets incurred. - **Management of Large Network**: Managing a large computer network can be a challenging task. It requires expertise and special training. - **Server Breakdown**: If the server breaks down in a network, then all the computers become isolated. - **Security Issues**: A computer network is always at the risk of being attacked by external threats, such as unauthorized use of resources, virus attacks, and alike. If the network is not secured, then the data of the organization may be at a high risk. ### Networking Components To establish wired networking in a group of computers, you require some additional components: - **Network Card**: A network card is used to physically attach a computer to a network, so that it can participate in network communication. Ethernet Network Card is the most commonly used network card. (Nowadays, most computer motherboards have an inbuilt network card.) - **Networking Cable**: Modern Ethernet networks use twisted pair cable, containing eight wires. These wires are arranged in a special order, and an RJ-45 connector (similar in design, but bigger than the connector used with the telephone wire) is crimped at both the ends of the cable. - **Modem**: A modem enables you to connect your computer to the available internet connection over the existing telephone lines. It converts the digital signals of a computer into analog signals to enable their transmission via phone lines. At the destination, the receiving modem further converts the analog signal into digital signals so that the data can be understood at the receiving end. It comes as a separate part that can be installed on the Peripheral Component Interconnect (PCI) slots found on the mother board. - **Hub**: A hub is a network device that is used to connect all the computers in a network with each other. When a computer sends a request in a network, it is first sent to the hub by the cable. The hub then transmits that request to all the other computers in the network, which check whether the message belongs to them or not. If not, then the message is dropped. This process is called broadcasting. - **Switch**: A switch works similar to a hub. However, unlike a hub, the switch does not broadcast the message on the entire network. It transmits the message from the source computer to the destination computer only by using the physical address. This way, the switch provides a direct connection between the source and destination. As a result the speed of the network increases. - **Router**: A router is a device that connects two different types of networks with each other, for example, a LAN with WAN. Apart from transmitting the messages on the network from a source computer to the destination computer, a router also provides the best suitable route to deliver that message. It, therefore, helps to decrease the time of transmitting the message. ### Wireless Networking To establish Wireless Networking, you require the following components: - **Wireless Network Cards**: Wireless Network Cards are used instead of the normal network cards that are used in the wired networks. Most laptop computers come with the inbuilt wireless network cards. Radio signals are used for transferring data, therefore the Ethernet cable is not required. - **Access Points or Routers**: Access Points or Routers have a wireless antenna, which increases the communication range of the radio signals. They can also be used to join a wired network, thus making the network a combination of wired as well as wireless networks. ### Types of Networks Depending on the geographical area covered by a network, there are various types of computer networks used worldwide, which are: - **Personal Area Network (PAN)**: PAN is a computer network that is mainly created for an individual person. It is used for communication among devices, such as laptops, mobile phones, Personal Digital Assistants (PDAs), or smartphones. Personal area networks can either be wired or wireless. It generally covers a range of less than 10 metres (about 30 feet). You can use these networks to transfer the files including mails, calendar appointments, digital photos, and music. - **Local Area Network (LAN)**: In Local Area Networks, two or more computers and peripheral devices are connected within a small area, such as a room, an office building, or campus. In LAN, computer terminals are physically connected with wires. The data transmission speed in LAN is very fast. Since it is operated in a small area, it can be controlled and administered by a single person or an organization. - **Metropolitan Area Network (MAN)**: MAN is a larger network than LAN and is spread across a city. Since it covers an entire city, it is called metropolitan. The most common example of MAN is the city cable network or branches of a local bank in a city. - **Wide Area Network (WAN)**: This kind of network connects two or more computers located at distant places. They are linked by communication facilities, like telecommunication or satellite signals. The main characteristic of WAN is that it requires a public telecommunication media to transfer data. The common examples of WAN are: - Internet - ATM facility - National and multinational bank customer services ### Network Architecture A network architecture is an overall design of a computer network that describes how a computer network is configured and what strategies are being used in it. Network architectures are mainly of the following two types: - **Client-Server Network**: In a Client-Server network, several computers called clients or workstations are connected to the main computer called the server. A server is a computer that provides services to clients and controls access to hardware, software, and other resources. Clients are the computers that request services, like data retrieval, storage, etc., from the server. - **Peer-to-Peer Network**: A peer-to-peer network is the one where a few computers of equal capacity and capabilities are connected together to use the resources available on the network. In a peer-to-peer network, there is no central server; instead each computer can act both as a server as well as a client. ### Network Topologies Network topology refers to the layout in which the various components of a network, like nodes, links, peripherals, etc., are connected and communicate with each other. A topology can either be physical or logical. Physical topology is the physical layout of nodes, workstations, and cables in the network, whereas logical topology is the way how information flows between the different components. Network topologies are categorised into the following basic types: - **Point-to-Point**: Point-to-point topology is the simplest form of network structure in which two nodes are directly connected with each other. This type of network is more suitable for small areas where computers are in close proximity. This technology provides a faster and reliable connection. - **Bus Topology**: This topology uses a single communication line or one main cable to which all the nodes are directly connected. The main cable acts as a backbone for the network. It transmits data only in one direction. In this type of structure, one of the computers in the network acts as the computer server, that provides data to all the clients. This topology is used in small networks where cable requirement is relatively small. One of the disadvantages of such type of network is that if the main cable fails, the entire network becomes unusable. For this reason, this type of topology is not used for large networks, such as those covering an entire building. - **Star Topology**: In star topology, each device is connected to a central computer using a point-to-point connection. The central server acts as a hub. The devices communicate across the network by passing data through this hub. Star topology is very popular because the setup cost is low. It is easy to add a new device to the network as only one cable is required and the configuration is simple. Moreover, the network is robust; even if a connection in the network fails, the other connections remain intact. But if the central hub fails, the entire network goes down. - **Ring Topology**: In ring topology, all the nodes in the network are connected in a circular manner. Each node connects with exactly two other nodes, forming a single-continuous pathway for signals. When one node sends message to the other node, which is not adjacent to it, the data travels through all the intermediate nodes until it reaches its final destination. Ring topologies are used in both LAN and WAN setups. The main disadvantage of this topology is that if one workstation goes down, the entire network gets affected. Since the data being transferred over the network has to pass through each workstation, this makes it slower than the star topology. - **Tree Topology**: Tree topology is one of the most common network setups that consists of a group of star-figured workstations connected to a linear bus backbone cable. In this, one star network is connected to the other star networks. In a tree network, a cable failure in one of the star networks will affect only the workstation that is linked to the central computer of that star network; all the other workstations will continue to function normally. However, if a central computer goes down, all the workstations connected to it will suffer either degraded performance or complete failure, but the rest of the network will continue to function normally. In case the bus gets damaged, it causes disruption in the entire network. In the tree topology, the expansion of the network is possible and easy but maintenance becomes difficult. - **Mesh Topology**: In the mesh network topology, each node is connected to every other node in the network. In this topology, every node not only sends its own signals but also relays data from the other nodes. This type of topology can handle a large volume of data traffic. It is commonly used in wireless networks. In case one of the components fail, there is always an alternative present so that the transfer of the data does not get affected. Expansion and modifications can be done in this topology without affecting the other nodes. A challenge of this topology is the expense of this network. The overall cost of this network is extremely high as compared to the other network topologies. ### Accessing a File from a Shared Drive To access a file from a shared drive, follow the given steps: - Double-click on the Network icon on the Desktop. - The Network window will appear, in which a list of shared drives are displayed in the Details pane. - Select the required shared drive to see its contents. - Find the required file in the drive. - If you want to open the file, double-click on it. - To copy the file. right-click on it, and select the Copy option from the Shortcut menu. - In the View pane, select This PC icon to view the storage drives on your computer. - Now, click on the drive where you want to place the copied file. - Right-click anywhere on the Details pane and select the Paste option. - The file will be copied to the selected drive on your computer. ### Network Security Network Security means protecting data and resources from any unauthorized access. It is the most important aspect in computer networking. Since many users are accessing the same data, it is essential that steps be taken to ensure its proper security. The right to access or modify any data should be given only to the authorized people. Consider the following points that may happen in any organization: - Some employees may try to change the data concerning their leave records, salaries, performance appraisals, etc. - Accidental deletion of important data may happen. - Former employees or some other people may try to harm the company's data. - People outside the company may try to access the confidential data. There are two general levels of network security. These are: - **Login Security**: A user is given a unique login name and password. - **Rights Security**: Based upon the username, the user is given rights, like Read-Only Access, or Read-Write Access, or No Access at all. A combination of rights can also be granted to the same user for the different sets of data. ### Recap - A computer network can be defined as a group of computers and other peripheral devices that is linked together for sharing data and hardware resources. - Networking in computers brings efficiency, economy, and effectiveness in an organization. - A modem is used to connect a computer to the available internet connection over the existing telephone lines. - PAN, LAN, MAN, and WAN are the various types of computer networks. - Network architecture is an overall design of a computer network that describes how a computer network is configured and what strategies are being used. - A server is a computer that provides services to the clients and controls access to the hardware, software, and other resources whereas, the clients are the computers that request services, like data retrieval, storage, etc., from the server. - Network topology refers to the layout in which the various components of a network, like nodes, links, peripherals, etc., are connected and communicate with each other. - The different kinds of network topology are Point-to-Point topology, Bus topology, Star topology, Ring topology, Tree topology, and Mesh topology. - Network security means protecting the data and resources from any unauthorised access. ### Exercises **A. Fill in the blanks.** 1. ___PAN___ is a computer network created for an individual person. 2. A computer network enables two or more computers to share ___data___ and ___hardware___ resources. 3. In a network, modification or upgradation of the software or data is done at a ___single point___ only. 4. The computers that communicate with each other are called ___nodes___. 5. A network maintained without using wires is called a ___wireless___ network. **B. Write T for True and F for False.** 1. Nodes and servers have the same function. (F) 2. Network cards are used to physically attach a computer with a network. (T) 3. In the client-server network, there is no central server. (F) 4. Mesh topology can handle a large volume of data traffic. (T) 5. In star topology, all the nodes in the network are connected in a circular manner. (F) **C. Application-based questions.** 1. Mr Hemant has set up his office with 50 computers. He wants to connect them and all the peripheral devices within his office building with wires. Which type of network should he use? _ Local Area Network_ 2. Which type of network architecture is the most suitable, when a few computers of similar power and capacity are to be networked together? _Peer to peer network_ 3. Arpit wants to attach his computer to a network so that it can participate in network communication. Which card should he use? _Ethernet network card_ 4. Raman wants to send a few photographs and songs to one of his friends by interconnecting mobile phones, using short-range wireless connection. Which technology would be the most suitable for him? _Bluetooth_ **D. Select the correct option.** 1. Which is the most commonly used network card? a. Wi-Fi b. Bluetooth c. Ethernet Network Card 2. When multiple mismatching copies of a file are stored at different computers, it is called data ___Inconsistency___. a. Inconsistency b. Consistency c. Redundancy 3. Network ___security___ means protecting data and resources from any unauthorized access. a. Security b. Information c. Resource Sharing 4. A ___peer-to-peer___ network is the one where a few computers of equal capacity and capabilities are connected together to use the resources available on the network. a. Peer-to-peer b. Client-server c. Client-peer 5. Which network among the following requires a single communication line or one main cable? a. Bus Topology b. Star Topology c. Tree Topology **E. Answer the following questions.** 1. Define networking with examples. Give two advantages. 2. Distinguish between LAN and WAN. 3. Give two advantages of Star topology. 4. Explain Client-Sever architecture in your own words. 5. Differentiate between a hub and switch. 6. What are the components required for wireless networking?