Computer Networks PDF

ComputerNetworks Chapter 3 everyoneand everything is connected communicate. digital world where to...

ComputerNetworks Chapter 3 everyoneand everything is connected communicate. digital world where to help us exchan We are living in a interconnections These one way or other: share resources. information and ComputerNetworks together to sh connected devices collectionof include computers, sm network is a devices can A computer exchange data. These most common type resources and devices. The and other computing of computersarou phones, tablets millions Internet, which connects the computernetworkis networ the world. known as a Node. Computer network is Each device connected to a entertainment,education, etc. business, help in communication, includes Communication in a network Message exchanged Itrefers to the information being Sender originated The node which acts as the source from which the message is Receiver The node which acts as the destination ofthe message being sent Protocols The rules that govern the working of a network and guides the communication 44>  TransmissionMedia channels Such as cable or radio signals through which the message radio The transmitted fNetworking Advantagesof Networkingcan greatly enhance the functionality and productivity of devices The are many connectivity. There while also providing security and anduserswhile and. devices. networking computers dvantages of Resourcesharina to share resources such Networking.allows: devices as printers, Scanners, and storage devices, which money.andincrease efficiency. cansave Forexample, considera network in which only one installed. Allthe computers connected to printeris. network can usethe printer, which reduces the cost of installing individual that printersfor each computer. Data sharing and files from any connected Networking enables users to share and access data productivity. device, which can improve collaboration and Communication devices and users, Networking allows for easy communication between. including email, instant messaging, and video conferencing. Remote access Networking enables users tO access and control devices and data from remote locations, which can increase flexibility and mobility. Scalability expansion thenetworkvtoaccommodatn of easv Networkingallowsfor the devices and users as needed. Backup and security protection of important Networking allows for the backup and againstcyberthreats. data an protects Itpreventsdatalossand systems. Centralised Management management of devices and resource centralized Networking allows for the administration and reduce costs. which cansimplify TypesofNetwork geographical are computer networks based on the of There are various types covered. They are broadly categorised as: LAN (Local Area Network) PAN (Personal Area Network) WAN(WideArea Network) MAN (Metropolitan Area Network) Personal Area Network (PAN) Personal Area Network (PAN)is a network formed by connecting devices like computers, laptops, mobile phones, printers, etc., in the vicinity ofa person. Handphone Fax The area covered by a PAN lies within an (HUB) Laptop approximate range of 10 metres. A Handphone personal area network may be wired or wireless. 46> Forexample,a,mobile phone connected to the laptop through USB forms a wired PANwhile connecting two smartphones with each other through Bluetooth wireless PAN. technologyformsa Area Network(LAN) Local network that connects devices LANis a LAN A geographic area, such as ahome, withina.small abuilding. LANs are typically used anoffice,ora share resources and exchange data among a to groupofusers. Metropolitan. Area Network(MAN) Metropolitan Area Network is an extended form ofLAN Nwhich Covers alarger geographical LAN LAN town. arealikea cityora Metropolitan Arss 5Network Cable TV network is an example of MAN, This LAN LAN extended up to 30-40 kind of network can be Metropolitan Area Network (MAN) km. Many LANS are connected together to form MAN. Wide Area Network (WAN) Wide Area Network is a collection of local-area networks (LANs) or other networks that communicate with one another. WAN spreads across different geographical locations of a country or in different countries. Large business, educational and government organisations connect with their different branches in differentlocations across the world through WAN. Ihe Intermet is the largest WAN that connects billions of computers from different continents. Network Devices devices are Modem. Hub, Some of the commonly used network Letus discuss them indetail. Swite Gateway,etc. Kepeater,Router, Modulator. Itisa device that enables Modem 'Modulatorand De cablelines. for telephoneor Modemstands dataover orreceive computertosend is computer stored on the The data line or cable telephone digital whereas a analog data.The transmit only wire can is to convert the modem main function of signal into analogand vice versa. digital of modems : Internal of tH There are two types mounted on the motherboard External. Internal modems are and computer. Ethernet Card also known as Network Interface Ethernet card, used to set up a Card (NIC), is a network adapter between the computer wired network. It acts as an interface and thenetwork. networking devices such as computers an It is used to connect different network. servers and toshare data over the connected Hub A hub is one of the simplest networking device that connects several computers or other NETGEAR network devices. Ahub isahardware device that allows multiple 48  devices or nodes to connect to a computer. Message received by a hub is transmittedIto all the nodes connected to it. Thus, hub is a broadcasting device. Switch hub, aswitch is used to connect devices Like a suchas computers, printers, etc., in a network to and allows them to communicate by each other, exchangingdata packets. data arrives, the switch extractsthe destination address and sends signals Whenn selected devices instead of sending it to all, like ahub. This is done by toonly at the physical device address or the MAC(Media Access Control) looking address. is unique for every computer. Switch virtually provides direct MACaddress Connection between nodes connected to it and increase the efficiency of a network. Repeater regenerates the signal over the same network before the signal Arepeater signal can be hecomes too weak or corrupted to extend the length to which the transmitted over the same network. Bridge Bridge is a network device that connects two or more LANS to form a larger LAN. A bridge Soman 2 BRIDGE connects the various components, making them appeartobe partofa single network. Srdges can also expand the physical size of a ework. Bridges are used to split large, busy networks into smaller, Interconnected networks to improve performance. 49) Gateway hardware whichactslike a'gate' Agatewayis basicallya device ora is a key It stopping on pointfor data, its way to or fro among different networks, other networks. Router devicethatforwards networking Arouterisa networks.It between computer packets data two networks, typically connected toatleast (Wide Wireles is Network) anda WAN Area aLAN(Local tables and routing Network), and it uses Area for determine the best path protocols to forwardingthedatapackets. together, allowing devices networks connect multiple network. They are a Routers are used to devices on another to communicate with acce one network allowing devices on the LAN to to connect a LAN tothe internet, used the internet. resources and services on Network Terminology Internet Internet is aglobal network connecting trillions of The organisations to computer systems. It allows people and resources. connect, share, and exchange information and The Internet is made up of millionsof connected networks, Internet including LANs (Local Area Networks), WANs (Wide Area Networks), and other types ofnetworks. These networks are connected to one another via gateways, routers, and othe networking devices. S0 Intranet An.intranetisa private computer network that uses internet and protocols and technologies to share information resources within an organization. It is similar totheinternet, is only accessible to authorized users within the Intranet but it organization,such asemployees, contractors, and partners. advantages ofan intranet is that it allows for better communication ofthe key One easily share and collaboration within an organization. Employees can and and resources and they can communicate and collaborate access information otheremployees in real-time. with esecurity by providing a private, internal networkthat isprotected Theyimprove. externalthreats such as hacking and malware. from Web page resource that is accessible on the World Wide Web Aweh pageis adocument or browser. (WwW) through a web webpage is typically written in HTML (Hypertext Markup Language), which A other webpage, and can include nrovides the structure and layout of the functionality. languages such as PHP and JavaScript for styling and dynamic Website identified by a Awebsite is a collection of web pages and related content that is common domain name. Websites can be created and maintained by an individual, group, business or organization to serve avariety ofpurposes. Search Engine Search Engine is a software system that works to search information on the World Wide Web.Common examples of online search engines are Google, Yahoo, and Bing,  keywords and phrases to to search you These programs allow information on the Internet. yahoof Google mfereg trty URL(Uniform Resource Locator) resource on the characters that identifies a specific interng URL isthe string of page, an image, or afile. typically entered in asa web such these resources,and it is and access internetresource is used tolocate or another It access aweb page browser's address bar to web IPAddress Protocol address)m DNS WINS 802.1X Proxies Hardware (Internet Wi-Fi TCPIP An IP address label assigned to Configure IPy4: Using DHCP Renew DHCP Lease is a unique numerical IPv4 Address: 192.168.31.155 DHCP Client ID: Subnet Mask: 255.255.255.O computer tf reguired ) every device connected to a Router: 192.168.31.1 Internet Protocol Configure IPv6: Automatically network that uses the Router IPV6 Address: for communication. Prefix Length: identifying It serves two main functions: location of the host in th the host or network interface, and providing the network. An IPaddress is a series ofnumbers that are separated by periods. Example:192.168.1.1 Domain Name System (DNS) DNS (Domain Name System) is the systemn that translates human-friendly domain names such as 'www.example.com' into machine-friendly IP addresses suchas 192.168.1.1: DNS isdatabase that maps domain names to IP addresses. It is organized into a 52) tree-likestructurecalled the domain namespace, with each node in the tree representinga domain name and its associated IP address(es). www.google.com DNS 192.163.8.32 192.196.123.12 182.35.46.123 123.145.65.24 WebPortal variety of webportal is a website that serves as a central point of access to a A informationand services on the internet. It typically provides a single point of a wide range of resources and services, such as news, email, search, entryto entertainment, and e-commerce. Hyperlink known as a link, is a clickable element in a web page or Ahyperlink, also document or location document that directs the user to another web page, within the same web page or document. images Hyperlinks are typically displayed as underlined or colored text or as and are used tonavigate between differentpages or sectionsofa website. htic Ocean.Amajor tourist destination, the Outer Banks are known for the hfront and the Cape Hatteras National Seashore."Theseashore and s rtant biodiversity zones, inclub.hg l Cape Hatteras National Outer Banks were sites of eary se Seashore is a United States ral sites. Most notably the English national seashore which ocation where an English person v preseryes the portion of the Outer 53)