Communication Networks ppt

computer networks introduction ppt and communication networks ppt presentation and computer networks introduction ppt
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Published Date:08-07-2017
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Chapter 15 NetworksChapter Goals • Describe the core issues related to computer networks • List various types of networks and their characteristics • Explain various topologies of local-area networks • Explain why network technologies are best implemented as open systems • Compare and contrast various technologies for home Internet connections 2Chapter Goals • Explain packet switching • Describe the basic roles of various network protocols • Explain the role of a firewall • Compare and contrast network hostnames and IP addresses • Explain the domain name system • Describe cloud computing and its benefits 3Networking Computer network A collection of computing devices connected in order to communicate and share resources Connections between computing devices can be physical using wires or cables or wireless using radio waves or infrared signals Can you name some of the devices in a computer network? 4Networking Node (host) Any device on a network Data transfer rate (bandwidth) The speed with which data is moved from one place to another on a network Why is bandwidth so key? 5Networking Computer networks have opened up an entire frontier in the world of computing called the client/server model 6Networking Protocol A set of rules that defines how data is formatted and processed on a network File server A computer dedicated to storing and managing files for network users Web server A computer dedicated to responding to requests for web pages P2P model A decentralized approach that shares resources and responsibilities among many “peer” computers 7Types of Networks Local-area network (LAN) A network that connects a relatively small number of machines in a relatively close geographical area Ring topology connects all nodes in a closed loop on which messages travel in one direction Star topology centers around one node to which all others are connected and through which all messages are sent Bus topology nodes are connected to a single communication line that carries messages in both directions 8Types of Networks Ethernet The industry standard bus technology for local-area networksTypes of Networks Wide-area network (WAN) A network that connects local-area networks over a potentially large geographic distance Metropolitan-area network (MAN) The communication infrastructures that have been developed in and around large cities Gateway One particular set up to handle all communication going between that LAN and other networks 10Types of Networks 11Types of Networks Internet A wide area network that spans the planet So, who owns the Internet? 12Internet Connections Wireless network A network in which devices communicate with other nodes through a wireless access point Bluetooth A technology used for wireless communication over short distances 13Internet Connections Internet backbone A set of high-speed networks that carry Internet traffic, provided by companies such as AT&T, Verizon, GTE, British Telecom, and IBM Internet service provider (ISP) An organization providing access to the Internet 14Internet Connections Various technologies available to connect a home computer to the Internet Phone modem converts computer data into an analog audio signal for transfer over a telephone line, and then a modem at the destination converts it back again into data Digital subscriber line (DSL) uses regular copper phone lines to transfer digital data to and from the phone company’s central office Cable modem uses the same line that your cable TV signals come in on to transfer the data back and forth 15Internet Connections Broadband A connection in which transfer speeds are faster than 768 kilobits per second – DSL connections and cable modems are broadband connections – The speed for downloads (getting data from the Internet to your home computer) may not be the same as uploads (sending data from your home computer to the Internet) 16Packet Switching Packet A unit of data sent across a network Router A network device that directs a packet between networks toward its final destination Packet switching Messages are divided into fixed-sized, numbered packets; packets are individually routed to their destination, then reassembledPacket Switching Take a message, break it into three packets, and simulate this process 18Open Systems A logical progression... Proprietary system A system that uses technologies kept private by a particular commercial vendor Interoperability The ability of software and hardware on multiple machines and from multiple commercial vendors to communicate Open systems Systems based on a common model of network architecture and a suite of protocols used in its implementation 19Open Systems Open Systems Interconnection Reference Model A seven-layer logical break down of network interaction to facilitate communication standards Each layer deals with a particular aspect of network communication 20