5. Network Basics

Foundation Course on Information Technology Outsourcing UNIT - 5: NETWORK BASICS Structure 5.0 Learning Objectives 5.1 Introduction 5.2 Basics of networking 5.3 Various Network Devices at TCP/IP & OSI Layer 5.4 IP Addressing & Subnetting 5.5 Network Topologies & Administration 5.6 Summary 5.7 Glossary 5.8 References 5.0 Learning Objectives After studying this unit, you will be able to • Apply Networking - Concepts • Recall Networking Features • Identify TCP/IP & OSI Layers • Recognise IP Addressing & Subnetting, Network Topologies & Administration 5.1 Introduction A computer network is a system that connects numerous independent computers in order to share information (data) and resources. The integration of computers and other different devices allows users to communicate more easily. A computer network is a collection of two or more computer systems that are linked together. A network connection can be established using either cable or wireless media. Hardware and software are used to connect computers and tools in any network. A computer network consists of various kinds of nodes. Servers, networking hardware, personal computers, and other specialized or general-purpose hosts can all be nodes in a computer network. Hostnames and network addresses are used to identify them.

Foundation Course on Information Technology Outsourcing Aim of Networking: • Programs do not have to execute on a single system because of resource and load sharing. • Reduced costs – Multiple machines can share printers, tape drives, and other peripherals. • Reliability – If one machine fails, another can take its place. • Scalability (it’s simple to add more processors or computers) • Communication and mail (people living apart can work together) • Information Access (remote information access, access to the internet, e-mail, video conferencing, and online shopping) • Entertainment that is interactive (online games, videos, etc.) • Social Networking 5.2 Networking Concepts A network consists of two or more computers that are linked in order to share resources (such as printers and CDs), exchange files, or allow electronic communications. ReliabilityComputer network can use the alternative source for the data communication in case of any hardware failure. Features of Networking A list of Computer network features is given below. ▪ Communication speed ▪ File sharing ▪ Back up and Roll back is easy ▪ Software and Hardware sharing ▪ Security ▪ Scalability ▪ Reliability

Foundation Course on Information Technology Outsourcing Features of Computer Network • Communication speed: Network provides us to communicate over the network in a fast and efficient manner. For example, we can do video conferencing, email messaging, etc. over the internet. Therefore, the computer network is a great way to share our knowledge and ideas. • File sharing: File sharing is one of the major advantage of the computer network. Computer network provides us to share the files with each other. • Back up and Roll back is easy: Since the files are stored in the main server which is centrally located. Therefore, it is easy to take the back up from the main server. • Software and Hardware sharing: We can install the applications on the main server, therefore, the user can access the applications centrally. So, we do not need to install the software on every machine. Similarly, hardware can also be shared. • Security: Network allows the security by ensuring that the user has the right to access certain files and applications. • Scalability: Scalability means that we can add the new components on the network. Network must be scalable so that we can extend the network by adding

Foundation Course on Information Technology Outsourcing new devices. But, it decreases the speed of the connection and data of the transmission speed also decreases, this increases the chances of error occurring. This problem can be overcome by using the routing or switching devices. • Reliability: Computer network can use the alternative source for the data communication in case of any hardware failure. Types of Networks 1. Division based on the communication medium • Wired Network: As we all know, “wired” refers to any physical medium made up of cables. Copper wire, twisted pair, or fiber optic cables are all options. A wired network employs wires to link devices to the Internet or another network, such as laptops or desktop PCs. • Wireless Network: “Wireless” means without wire, media that is made up of electromagnetic waves (EM Waves) or infrared waves. Antennas or sensors will be present on all wireless devices. Cellular phones, wireless sensors, TV remotes, satellite disc receivers, and laptops with WLAN cards are all examples of wireless devices. For data or voice communication, a wireless network uses radiofrequency waves rather than wires. 3. Based on types of communication : Point To Point networks: Point-to-Point networking is a type of data networking that establishes a direct link between two networking nodes. A direct link between two devices, such as a computer and a printer, is known as a point-to-point connection.Broadcast networks: In broadcast networks, a signal method in which numerous parties can hear a single sender. Radio stations are an excellent illustration of the “Broadcast Network” in everyday life. The radio station is a sender of data/signal in this scenario, and data is only intended to travel in one direction. Away from the radio transmission tower, to be precise. 4. Based on type of architecture: P2P Networks: Computers with similar capabilities and configurations are referred to as peers. “Peer to Peer” is the abbreviation for “peer to peer.” The “peers” in a peer-to-peer network are computer systems that are connected to each other over the Internet. Without the use of a central server, files can be shared directly between systems on the network. • Client – Server Networks: Each computer or process on the network is either a client or a server in a client-server architecture (client/server). The client asks services from the server, which the server provides. Servers are high-performance

Foundation Course on Information Technology Outsourcing computers or processes that manage disc drives (file servers), printers (print servers), or network traffic (network servers) • Hybrid Networks: The hybrid model refers to a network that uses a combination of client-server and peer-to-peer architecture. Eg: Torrent. A computer network is mainly of four types: • LAN (Local Area Network) • PAN (Personal Area Network) • MAN (Metropolitan Area Network) • WAN (Wide Area Network) Types of Computer 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 Local Area Network. • Local Area Network provides higher security. 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. • Personal Area Network covers an area of 30 feet.

Foundation Course on Information Technology Outsourcing • Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media players, and play stations. PAN There are two types of Personal Area Network: Types of PAN • Wired Personal Area Network • Wireless 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.

Foundation Course on Information Technology Outsourcing Wired Personal Area Network: Wired Personal Area Network is created by using the USB. 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 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). MAN

Foundation Course on Information Technology Outsourcing Uses 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. 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 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. WAN

Foundation Course on Information Technology Outsourcing Examples of Wide Area Network: • 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. 5.3 Various Network Devices at Tcp/Ip & OSI Layer TCP/IP stands for Transmission Control Protocol/Internet Protocol and is a suite of communication protocols used to interconnect network devices on the internet The TCP/IP Protocol Stack is made up of four primary layers: The Application, Transport, Network, and Link layers. Physical layer of TCP/IP model is responsible for physical connectivity of two devices. Some of the devices used in Physical layers are as follows: • Hubs: Hubs are devices commonly used to connect segments of a LAN. It contains multiple input/output ports. when signal is at any input port, this signal will be made at all output ports except the one it is coming from. • Cables: In Wired network architecture (e.g Ethernet), cables are used to interconnect the devices. some of the types of cables are coaxial cable, optical fiber cable, and twisted pair cable. • Modem: A modem converts digital signals generated by the computer into analog signals which, then can be transmitted over a cable line and transforms incoming analog signals into digital equivalents. • Repeaters: Repeaters are used in transmission systems to regenerate analog or digital signals distorted by transmission loss. Analog repeaters can only amplify the signal whereas digital repeaters can reproduce a signal to near its original quality. The Data Link layer is responsible to transfer data hop by hop (i.e within the same LAN, from one device to another device) based on the MAC address. Some of the devices used in the Data Link layer are, some of the devices used in Physical layers are as follows: • Bridges: A bridge is a type of computer network device that provides interconnection with other networks that use the same protocol, connecting two different networks together and providing communication between them.

Foundation Course on Information Technology Outsourcing • Switch: A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches. Network Interface Card: Network interface card is an electronic device that is mounted on ROM of the com that connects a computer to a computer network, usually a LAN. It is considered a piece of computer hardware. Most modern computers support an internal network interface controller embedded in the motherboard directly rather than provided as an external component. Network Layer layer is responsible for creating routing table, and based on routing table, forwarding of the input request. Some of the Devices used in Network Layer are, • Routers: A router is a switch like device that routes/forwards data packets based on their IP addresses. Routers normally connect Local Area Network (LANs) and Wide Are Network (WANs) together and have a dynamically updating routing table based on which they make decisions on routing the incoming packets. • Brouters: A bridge router or brouter is a network device that works as a bridge and as a router. The brouter routes packets for known protocols and simply forwards all other packets as a bridge would. Brouters operate at both the network layer for routable protocols (or between network with different data link layer protocol ex. one is running on ethernet (802.3) and other network is running on Token ring (802.5)) and at the data link layer for non-routable protocols (or both network is using same data link layer protocol).

Foundation Course on Information Technology Outsourcing Routers 4. Transport Layer is responsible for end-to-end communication (or process-to- process communication). Some of the transport layer devices are, • Gateways: In computer networking, a gateway is a component that is part of two networks, which use different protocols. The gateway is a protocol converter which will translate one protocol into the other. A router is a special case of a gateway. • Firewall: A firewall is a system designed to prevent unauthorized access to or from a private network, some of the functionalities of firewall are, packet filtering and as a proxy server. Application Layer is the top most layer of TCP/IP Model that provides the interface between the applications and network. The application layer is used to exchange messages. Some of the devices used in Application layer are,

Foundation Course on Information Technology Outsourcing • PC’s (Personal Computer), Phones, Servers • Gateways and Firewalls 5.4 IP Addressing & Subnetting IP addressing IP address stands for internet protocol address; it is an identifying number that is associated with a specific computer or computer network. When connected to the internet, the IP address allows the computers to send and receive information. An IP address allows computers to send and receive data over the internet. Most IP addresses are purely numerical, but as internet usage grows, letters have been added to some addresses. There are four different types of IP addresses: public, private, static, and dynamic. While the public and private are indicative of the location of the network i.e. private being used inside a network while the public is used outside of a network i.e. static and dynamic indicate permanency. A static IP address is one that was manually created, as opposed to having been assigned. A static address also does not change, whereas a dynamic IP address has been assigned by a Dynamic Host Configuration Protocol (DHCP) server and is subject to change. Dynamic IP addresses are the most common type of internet protocol addresses. Dynamic IP addresses are only active for a certain amount of time; after which they expire. The computer will either automatically request a new lease, or the computer may receive a new IP address. An IP address can be compared to a Social Security Number (SSN) since each one is completely unique to the computer or user it is assigned to. The creation of these numbers allows routers to identify where they are sending information on the internet. They also make sure that the correct devices are receiving what is being sent. Much like the post office needs a mailing address to deliver a package, a router needs an IP address to deliver to the web address requested. IP address

Foundation Course on Information Technology Outsourcing Subnetting Each IP class is equipped with its own default subnet mask which bounds that IP class to have a prefixed number of Networks and prefixed number of Hosts per network. Classful IP addressing does not provide any flexibility of having less number of Hosts per Network or more Networks per IP Class. Benefits of Subnetting • Subnetting divides broadcast domains, meaning that traffic is routed efficiently, improving speed and network performance. • A subnet mask ensures that traffic remains within its designated subnet. This reduces major congestion and reduces the load imparted on the network. With sub- networks, less distance needs to be traveled by data packets, enhancing network performance. • With different subnets within your larger network, you can be more aware of route maps. These will help you to identify potential threats. With subnets, devices will not be able to access the whole network, meaning that companies can dictate which hardware and users have access to more sensitive data. Network security can be boosted. • Sound organization is crucial within large businesses. This extends to your network and routers. With subnetting, companies have full control over their traffic and data packets. 5.5 Network Topologies & Administration Network topology refers to how various nodes, devices, and connections on your network are physically or logically arranged in relation to each other. The layout of your network is important for several reasons. Above all, it plays an essential role in how and how well your network functions. Choosing the right topology for your company’s operational model can increase performance while making it easier to locate faults, troubleshoot errors, and more effectively allocate resources across the network to ensure optimal network health. A streamlined and properly managed network topology can increase energy and data efficiency, which can in turn help to reduce operational and maintenance costs. Network topology types

Foundation Course on Information Technology Outsourcing Network Topologies There are several different logical and physical network topologies from which administrators can choose to build a secure, robust, and easily maintainable topology. The most popular configurations include: • Bus network topology -Also known as backbone network topology, this configuration connects all devices to a main cable via drop lines. The advantages of bus network topology lie in its simplicity, as there is less cable required than in alternative topologies, which makes for easy installation. • Mesh network topology -A dedicated point-to-point link connects each device on the network to another device on the network, only carrying data between two devices. • Ring network topology -Two dedicated point-to-point links connect a device to the two devices located on either side of it, creating a ring of devices through which data is forwarded via repeaters until it reaches the target device. • Star network topology - The most common network topology, star topology connects each device in the network to a central hub. Devices can only communicate with each other indirectly through the central hub. • Hybrid network topology - Any combination of two or more topologies is a hybrid topology. • Tree network topology -This topology consists of a parent-child hierarchy in which star networks are interconnected via bus networks. Nodes branch out linearly from one root node, and two connected nodes only share one mutual connection.

Foundation Course on Information Technology Outsourcing • Multi-access network topology, also known as a non-broadcast multiple access network (NBMA), consists of multiple linked hosts in which data is transferred directly from one computer to another single host across a switched fabric or over a virtual circuit. 5.6 Summary • Computer network is a group of two or more interconnected computer systems • Computer networks help you to connect with multiple computers together to send and receive information. • Computer network has Switches, it works as a controller which connects computers, printers, and other hardware devices • Comuter network has different topologies like bus, ring, star, mesh etc. 5.7 Glossary • LAN: It stands for Local Area Network and covers a small area such as a small office or home. It physically connects all the computers located in the premises. • WAN: It stands for Wide Area Network and covers a wide area such as a city. • IP address: An IP address is a unique set of numbers or combination of letters and numbers that are assigned to each device on an IP network • IP: Internet protocol (IP) is the set of rules governing the format of data sent over IP networks. 5.9 References • https://www.geeksforgeeks.org/types-of-network-topology/ • https://www.javatpoint.com/computer-network-topologies • https://www.cloudflare.com/en-in/learning/network-layer/what-is-a-subnet/ • https://www.wpbeginner.com/glossary/ip-address/

Foundation Course in Information Technology Outsourcing: Network Basics • Mesh network topology – Mesh topology has multiple connections between each of the nodes on the network. The advantage of a mesh topology is that if one cable breaks, the network can use an alternative route to deliver its packets. Mesh networks are not very practical in a LAN setting. For example, to network eight computers in a mesh topology, each computer would have to have seven network interface cards, and 28 cables would be required to connect each computer to the seven other computers in the network. Obviously, this scheme is not very scalable. However, mesh networks are common for metropolitan or wide area networks. These networks use devices called routers to route packets from network to network. For reliability and performance reasons, routers are usually arranged in a way that provides multiple paths between any two nodes on the network in a mesh- like arrangement. ● Ring network topology - In a ring topology, packets are sent around the circle from computer to computer. Each computer looks at each packet to decide whether the packet was intended for it. If not, the packet is passed on to the next computer in the ring. Ring topology was also used by FDDI, one of the first types of fiber-optic network connections. So ring networks have all but vanished from business networks. Years ago, ring topologies were common in LANs, as two popular networking technologies used rings: ARCNET and Token Ring. ARCNET is still used for certain applications such as factory automation but is rarely used in business networks. Token Ring is a popular network technology for IBM midrange computers. ● Star network topology - In a star topology, each network node is connected to a central device called a hub or a switch. Star topologies are also commonly used with LANs. If a cable in a star network breaks, only the node connected to that cable is isolated from the network. The other nodes can continue to operate without interruption — unless, of course, the node that is isolated because of Page 16 of 18 All Rights Reserved. Vol. TLE001/03-2022

Foundation Course in Information Technology Outsourcing: Network Basics the break happens to be the file server. Simply put, a hub does not know anything about the computers that are connected to each of its ports. So, when a computer connected to the hub sends a packet to a computer that is connected to another port, the hub sends a duplicate copy of the packet to all its ports. In contrast, a switch knows which computer is connected to which of its ports. As a result, when a switch receives a packet intended for a particular computer, it sends the packet only to the port that the recipient is connected to. ● Hybrid network topology - Any combination of two or more topologies is a hybrid topology. ● Tree network topology -This topology consists of a parent-child hierarchy in which star networks are interconnected via bus networks. Nodes branch out linearly from one root node, and two connected nodes only share one mutual connection. 5.6 SUMMARY ● Computer network is a group of two or more interconnected computer systems ● Computer networks help you to connect with multiple computers together to send and receive information. ● Computer network has Switched, it works as a controller which connects computers, printers, and other hardware devices ● Computer network has different topologies like bus, ring, star, mesh, etc. 5.7 GLOSSARY ● LAN: It stands for Local Area Network and covers a small area such as a small office or home. It physically connects all the computers located on the premises. Page 17 of 18 All Rights Reserved. Vol. TLE001/03-2022

Foundation Course in Information Technology Outsourcing: Network Basics ● WAN: It stands for Wide Area Network and covers a wide area such as a city. ● IP address: An IP address is a unique set of numbers or combination of letters and numbers that are assigned to each device on an IP network ● IP: Internet protocol (IP) is the set of rules governing the format of data sent over IP networks. 5.9 REFERENCES ● https://www.geeksforgeeks.org/types-of-network-topology/ ● https://www.javatpoint.com/computer-network-topologies ● https://www.cloudflare.com/en-in/learning/network-layer/what-is-a- subnet/ ● https://www.wpbeginner.com/glossary/ip-address/ Page 18 of 18 All Rights Reserved. Vol. TLE001/03-2022