3 computer network - basic concepts
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This document provides an overview of computer network concepts including: - A computer network allows interconnected computers to share resources and communicate. The first major network was ARPANET funded by the US Department of Defense. - Networks can be classified by scale, structure, and topology. Examples include LANs, WANs, MANs, and topologies like bus, star, ring, mesh, and tree. - Network components include nodes, servers, clients, and different types of transmission media like twisted pair cable, coaxial cable, fiber optic cable, and wireless. - An internetwork connects two or more networks and includes intranets within organizations and extranets with limited external connections, as well as
3 computer network - basic concepts
- 2. Computer Network Basic Concepts Computer Networks Communication Model Transmission Modes Communication Types Classification Of Computer Networks By Scale By Structure By Topology Network Media Internetworking
- 3. Computer Network A computer network is a group of interconnected computers. It allows computers to communicate with each other and to share resources and information. First Network : The Advanced Research Projects Agency (ARPA) funded the design of the "Advanced Research Projects Agency Network" (ARPANET) for the United States Department of Defense
- 5. Communication Model Source Transmitter Carries data Receiver Converts data into transmittable signals Transmission System generates data to be transmitted Converts received signal into data Destination Takes incoming data
- 7. Transmission Modes Simplex One direction Half duplex Either direction, but only one way at a time e.g. Television e.g. police radio Full duplex Both directions at the same time e.g. telephone
- 8. Communication Types Unicasting (one-to-one) Multicasting (one-to-many) Broadcasting (one-to-all)
- 9. Network Classification By Size or Scale LAN WAN MAN CAN PAN
- 10. Local Area Network (LAN) Contains printers, servers and computers Systems are close to each other Contained in one office or building Organizations often have several LANS
- 11. Wide Area Networks (WAN) Two or more LANs connected Over a large geographic area Typically use public or leased lines Phone lines Satellite The Internet is a WAN
- 12. Metropolitan Area Network (MAN) Large network that connects different organizations Shares regional resources A network provider sells time
- 13. Campus Area Networks (CAN) A LAN in one large geographic area Resources related to the same organization Each department shares the LAN
- 14. Personal Area Network (PAN) Very small scale network Range is less than 2 meters Cell phones, PDAs, MP3 players
- 15. Network Classification By Structure / Functional Relationship Client / Server Peer to Peer (P2PN)
- 16. Client/Server network Nodes and servers share data roles Nodes are called clients Servers are used to control access Database software Access to data controlled by server Server is the most important computer
- 17. Peer to peer networks (P2PN) All nodes are equal Nodes access resources on other nodes Each node controls its own resources Most modern OS allow P2PN Distributed computing is a form Kazaa
- 18. Network Classification By Topology / Physical Connectivity BUS STAR RING MESH TREE
- 19. Network Topology Logical layout of wires and equipment Choice affects Network performance Network size Network collision detection
- 20. BUS Also called linear bus One wire connects all nodes Terminator ends the wires Advantages Easy to setup Small amount of wire Disadvantages Slow Easy to crash
- 21. STAR All nodes connect to a hub Packets sent to hub Hub sends packet to destination Advantages Easy to setup One cable can not crash network Disadvantages One hub crashing downs entire network Uses lots of cable Most common topology
- 22. RING Nodes connected in a circle Tokens used to transmit data Nodes must wait for token to send Advantages Time to send data is known No data collisions Disadvantages Slow Lots of cable
- 23. MESH All computers connected together Internet is a mesh network Advantage Data will always be delivered Disadvantages Lots of cable Hard to setup
- 24. TREE Hierarchal Model Advantages Scaleable Easy Implementation Easy Troubleshooting
- 25. Network Media Links that connect nodes Choice impacts Speed Security Size
- 26. Twisted-pair cabling Most common LAN cable Called Cat5 or 100BaseT Four pairs of copper cable twisted May be shielded from interference Speeds range from 1 Mbps to 1,000 Mbps
- 27. Coaxial cable Similar to cable TV wire One wire runs through cable Shielded from interference Speeds up to 10 Mbps Nearly obsolete
- 28. Fiber-optic cable Data is transmitted with light pulses Glass strand instead of cable Immune to interference Very secure Hard to work with Speeds up to 100 Gbps
- 29. Wireless Media Data transmitted through the air LANs use radio waves WANs use microwave signals Easy to setup Difficult to secure
- 30. Internetwork An Internetwork is the connection of two or more distinct computer networks or network segments via a common routing technology. Any interconnection among or between public, private, commercial, industrial, or governmental networks may also be defined as an internetwork.
- 31. Internetwork Intranet Extranet An intranet is a set of networks, using the Internet Protocol and IP-based tools such as web browsers and file transfer applications, that is under the control of a single administrative entity. Most commonly, an intranet is the internal network of an organization An extranet is a network or internetwork that is limited in scope to a single organization or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network. Internet The Internet consists of a worldwide interconnection of governmental, academic, public, and private networks based upon the networking technologies of the Internet Protocol Suite. It is the successor of the Advanced Research Projects Agency Network (ARPANET) developed by DARPA of the U.S. Department of Defense. The Internet is also the communications backbone underlying the World Wide Web (WWW).