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Networks

Networks. CSCI-N 100 Dept. of Computer and Information Science. The Basics. Early years networks were scarce Early PCs worked as standalone Interaction limited to one person with software Engineers anticipated networking has advantages Bob Metcalf, 1975, Ethernet.

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Networks

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  1. Networks CSCI-N 100 Dept. of Computer and Information Science

  2. The Basics • Early years networks were scarce • Early PCs worked as standalone • Interaction limited to one person with software • Engineers anticipated networking has advantages • Bob Metcalf, 1975, Ethernet

  3. PAN – personal area network NAN – neighborhood area network LAN – local area network MAN – metropolitan area network WAN – wide area network Network Classification

  4. Personal devices Usually within 30 feet No cables or wires Example – wireless transmission of data from computer to PDA, cell phone, printer PAN – personal area network

  5. Limited within a geographic area Spread over several buildings Example - local Starbucks NAN – neighborhood are network

  6. Limited to a very small geographic area Usually one building Can be wired or wireless Type of network most likely to work with in school, business, home Example – school computer labs, home networks LAN – local area network

  7. Public High speed access Voice and data transmission Range about 50 miles Example – ISP, cable television, local telephone MAN – metropolitan area network

  8. LAN Standards • Standard by the Institute of Electrical and Electronic Engineers (IEEE) • Designation number refers to standard • Helps to identify compatible network technologies • Ethernet, WiFi for home, business

  9. Connections • Node • point on a network • Network interface card (NIC) – usually circuitry built in- - Add on slot on system board, USB port, notebook PC slot

  10. Client The user Ask for information Data sent to server Server Responds to the user (client) Application server Print server Sends back data Client/Server – Why not both

  11. Network topology • Two types of topologies: Physical and Logical • Physical topology of a network refers to the layout of cables, computers and other peripherals • network cables coming out of every computer that is part of the network, then those cables plug into a hub or switch • Logical topology is the method used to pass the information between the computers • the network works with all the computers talking (think of the computers generating traffic and packets of data going everywhere on the network) • computers will be talking to each other and the direction of the traffic is controlled by the various protocols (like Ethernet) • Star • Ring • Bus • Mesh • Tree • Hybrid

  12. Star • Reduces risk of failure. • Expanding the network is simple. • Managing the network is centralized. • If the hub breaks down, the system fails.

  13. Ring • All clients have equal access to data. • This gives even performance under heavy demand conditions. • Difficult to add another host to the ring.

  14. Bus • Simple, cheap, reliable, efficient use of cable. • Isolating problems is hard. • One error can halt the system.

  15. Mesh • This redundancy allows the system to continue if some connections fail. • However, multiple connections are expensive.

  16. Tree • Point-to-point wiring for individual segments. • Supported by several hardware and software venders • Overall length of each segment is limited by the type of cabling used. • If the backbone line breaks, the entire segment goes down. • More difficult to configure and wire than other topologies

  17. Hybrid – Star and Bus • Network expansion is simple. • If one client fails, the entire network does not fail. • If one hub fails, all connections to that hub fail, although other hubs continue to function.

  18. Devices • Any electronic device that broadcast network data • Can include • Hubs, links 2 or more nodes of wired network • Routers, ships data from one network to another • Switches, only sends data to specified destination • Gateways, used to join 2 networks using different protocols, different address ranges • Bridges, connects 2 similar networks without regard to network format • Repeaters

  19. References • Slide 11 • http://www.firewall.cx/topologies.php • Slides12, 13, 14 • http://www.geocities.com/richard_leigh_bowles/theory/summaries/ntf/chap1.htm • Slide 15 • http://chauncy-ict.pbwiki.com/Mesh%20Topology • Slide 16 • http://fcit.usf.edu/Network/chap5/chap5.htm#TreeNetwork

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