Let us Revise A wwwv A COMPUTER NETWORKING A network is a coll | Computer hardware and networking

Let us Revise A wwwv A COMPUTER NETWORKING A network is a collection of interlinked computers by means of a communication system . fast communication . The networks facilitate resource sharing , increased reliability , reduced costs , and increased and Every computer needs a network card in order to become part of a network . unique hardware number on a network . The hardware address of the networks card is called MAC address , which becomes computer's 33 communication , known as IP address . When two or more networks are interconnected , they need a special type of address for > Internet is a worldwide network of computer networks . Alphabetical name of a website is called its URL ( Uniform Resource Locator ) and numbered address ( 4 parts separated by periods ) of a website is called its IP address . Internally , computer follows a mechanism to obtain IP address of a website from a URL . This mechanism is known as Domain Name Resolution . InterSpace is said to be the future of Internet . On the basis of geographical spread , networks can be classified into PAN ( Personal Area Networks ) , LAN ( Local Area Network ) , MAN ( Metropolitan Area Network ) , and WAN ( Wide Area Network ) . Small computer networks that are confined to a localised area e.g. , an office , a building etc. , are called LANS . MANS are the networks spread over city . A WAN is a group of computers that are separated by large distances and tied together . It can even be a group of LANS that are spread across several locations and connected together to look like a big LAN . The pattern of interconnection of nodes in a network is called topology . Most popular topologies are star , bus , ring , graph and mesh , tree . A modem is a computer peripheral that allows you to connect and communicate with other computers via telephone lines . A hub is a hardware device used to connect several computers together . Hubs can be either active hubs or passive hubs . A switch is a device that is used to segment networks into different subnetworks called subnets or LAN segments . A repeater is a device that amplifies a signal being transmitted on the network . A bridge is a device that links two networks together . A router is a device that works like bridge but can handle different protocols .. a A gateway is a device that connects dissimilar networks . > A protocol is a set of standardized rules for data packets , techniques for detecting and correcting errors and so on . > Networks experience a greater degree of vulnerabilities and risk because of their connectedness . Major forms of intrusion problems are : Snooping and eavesdropping . Snooping refers to unauthorized access of someone else's data , email , computer - activity , or data communication . * Eavesdropping is the act of secretly listening / intercepting someone else's private communi cation / data / information . Denial - of - Service ( DoS ) attacks are those attacks that prevent the legitimate users of the system , from accessing or using the resources , information , or capabilities of the system . a With proper network security policy and tools , the network - security threats can be effectively countered