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Local Area Networks

Local Area Networks. A data communication system that allows a number of independent devices to communicate directly with each other in a limited geographic area. Four Architectures. Ethernet Token Bus Token Ring Fiber Distributed Data Interface (FDDI)

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Local Area Networks

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  1. Local Area Networks A data communication system that allows a number of independent devices to communicate directly with each other in a limited geographic area.

  2. Four Architectures • Ethernet • Token Bus • Token Ring • Fiber Distributed Data Interface (FDDI) *The first 3 are IEEE standard while FDDI is an ANSI standard

  3. OSI Model and Project 802 MAC – medium access control - resolves the contention for the shared media - contains the synchronization, flag, flow and error control - contains the physical address of the next station LLC – logical link control - non architecture specific, common to all LANs - contains the logical addresses, control information and data

  4. Project 802

  5. PDU Control Field

  6. ETHERNET Access Mechanism CSMA/CD Carrier Sense Multiple Access/Collision Detection LLC MAC Frame PDU length = 46 to 1500 bytes

  7. Thick Ethernet / Thicknet Transceiver Connection

  8. Ethernet Segments

  9. Thin Ethernet/Thinnet/Cheapnet/Cheapernet

  10. Max length (hub to station) – 100m

  11. StarLAN Up to 10 stations in a chain

  12. Fast EthernetIEEE 802.3u

  13. Why do we need to increase the speed of Ethernet LAN Introduction of more sophisticated operating system and applications, faster processors and greater disk and memory capacities. Many companies now use Internet technologies to build private corporate intranets, for accessing critical data. Multimedia client/server applications.

  14. Fast Ethernet • Data rate: 100 Mbps • Increases the speed limit of the highway by orders of magnitude from 10 Mbps to 100 Mbps to 1000 Mbps (Gigabit Ethernet) • Reduces the amount of time it takes to transmit 1 bit by a factor of 10. • Employs a star topology at the physical layer and supports twisted pair and fiber-optic cable.

  15. Fast Ethernet • 3 different media specifications • 100BASE-TX • 100BASE-T4 • 100BASE-FX The first 2 use twisted pair cable and the third uses fiber optic cable. All 3 are designed to interoperate with one another

  16. 100BASE-TX • Transmits and receives data over two pairs of Cat 5 UTP cable • Uses full duplex signaling system • Distance between station and hub is 100m • Networks based on this standard must be Cat-5 compliant, including wire, connectors, patch panels 1 pair for transmission 1 pair for reception 2 pairs are extra wires that can be used for voice communication or reserved for further network enhancements*

  17. 100BASE-T4 • Uses half-duplex signaling system to transmit and receive data over 4 pairs of Cat 3, 4, 5 UTP cable. • 1 pair for transmitting data • 1 pair for receiving data and collision detection • 2 pairs are used for either transmitting or receiving * 100BASE-TX vs. 100BASE-T4 ?

  18. 100BASE-FX • Uses 2 strands of 62.5/125 micron multimode fiber optic cable • 1 strand for transmission • 1 strand for reception • Distance between station and hub is less than 2000m • Signaling system is the same as100BASE TX

  19. Gigabit Ethernet

  20. Why do we need 1000Mbps technology? Deployment of multimedia applications Integration of faster computer systems Migration of Fast Ethernet from backbone to the desktop

  21. Gigabit Ethernet 1000 Mbps - 1 billion bits per second IEEE 802.3z - Gigabit Ethernet over fiber IEEE 802.3ab - Gigabit Ethernet over copper Used as the backbone in many enterprise networks. Alleviates congestion at server level or at interswitch connections. *

  22. Gigabit Ethernet – over fiber • 1000BASE-SX (short wavelength fiber) • 62.5 micron multimode fiber Max distance: 220-275 m • 50 micron multimode fiber Max distance: 500-550 m • 1000BASE-LX (long wavelength fiber) • 62.5 micron multimode fiber, Max distance: 550 m • 50 micron multimode fiber, Max distance: 550 m • 9 micron single-mode fiber, Max distance: 5,000m (5km) • 1000BASE-CX (short haul copper) • initial standard for Gigabit Ethernet connections over Shielded single twisted-pair cable • Max distance: 25m

  23. Gigabit Ethernet- over copper • IEEE 802.3ab - Gigabit Ethernet over copper • 1000BASE-T, running over Cat 5 cable at a distance up to 100 m. More info about thet types http://en.wikipedia.org/wiki/Gigabit_Ethernet

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