Chapter 5 Local Area Network Concepts and Architecture - PowerPoint PPT Presentation

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Chapter 5 Local Area Network Concepts and Architecture

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  1. Chapter 5Local Area Network Concepts and Architecture • Network Fundamentals • Local Area Network (LAN) • Open Systems Interconnection (OSI) • LAN Architectures

  2. Network Fundamentals • Definitions • Classifications • Network topology • Network types • Local Area Network

  3. Definition • Network • Backbond network

  4. Classification • Topology • Ownership • Geography • Transmission

  5. Network Topology • Star • Hierarchical • Mesh • Bus • Ring • Hybrid

  6. Star Network • Usage • Centralized processing or communication • Pros • Expansion • Implementation • No limit to no. and length of arms • Cons • Single point of failure • Overload of mater during peak traffic

  7. Hierarchical Network • Usage • Distributed processing • Tree structure with a root • pro • No single point of failure

  8. Mesh Network • Web structure • Usage • Public telephone system • Pro • Alternative communication route • Con • Line cost

  9. Bus Network • Usage • Date entry or office environment • Pros • Independent between nodes • High reliability • Cons • Limited number of attached device • Hard to locate the problems

  10. Ring Network • Usage • Manufacturing • Pros • Less attenuation • Error control • Network management • Cons • Failing of a node

  11. Hybrid Networks • Usage • Connecting different networks • Pro • Communication between networks • Con • Conversion device and costs • Compatibility

  12. Network Ownership • Private networks • Public networks • Valued added networks

  13. Private networks • Full control • Special needs • Expense

  14. Public networks • Controlled by carriers • Regulated by government • Inexpensive

  15. Valued Added Networks • Functions • Code translation • Speed conversion • Store message and delivery • Examples • Telex • SWIFT • SITA (airline) • IVAN (insurance)

  16. Networks by Geography • Wide area network (WAN) • Metropolitan area network (MAN): 30 miles • Local area network (LAN): 5 miles

  17. LAN Characteristics • Limited distance within a few miles • High data rate - 2 to 1000Mbps • Low error rate • Good response time • Private owned • No regulation • Share hardware, software, and data files

  18. Business Needs • Corporate asset for competitive edge • Data accessibility (information distribution) • Less expenses • Better service - response time and reliability • Higher productivity • Control or secure

  19. LAN Analysis & Design • Meet business objectives (strategic planning) • Prevent technological obsolescence

  20. LAN Hardware & Software • Hardware • PC: servers and clients • Network interface card (NIC): physical address • Media or Cables • Unshielded twisted pair (inexpensive) • Coaxial cable (faster, expensive) • Optical fiber (fastest, expensive) • Air for wireless • Hub (compatible) • connect wires and cables, repeater, error detection • Software: network operating system

  21. Open System Interconnection Model • International Standards Organization • Interconnection of dissimilar network • Seven Layers • Application • Presentation • Session • Transport • Network • Data Link • Physical

  22. Application Layer • Utilities support end-user application program • Determine data to be send at originating end • Process data at receiving end

  23. Presentation Layer • Change data format • Compression/expansion • Encryption/decryption

  24. Session Layer • Communication rules of machines or application programs • Accounting functions

  25. Transport Layer • Identify receiving address • Flow control: rate of transmission • Recovery: calculate and check checksum of entire message

  26. Network Layer • Route message • Dissemble and assemble data (packets) • Accounting functions

  27. Data Link Layer • By IEEE 802 • Establish link between two ends • Detect and correct transmission error • Add header and trailer • Divide data unit for transmission (frames) • Sublayers • Media access control (MAC): token ring or Ethernet • Logical link control (LLC): assembling and disassembling frames, error control, flow control

  28. Physical Layer • Electrical, mechanical, procedural specifications for data transmission • Hardware specification by RS-232-C

  29. Other Concepts • Protocol • Encapsulation/ de-encapsulation

  30. Standards • IEEE 802.2: LLC protocol • IEEE 802.3: CSMA/CD baseband bus • IEEE 802.4: token passing bus • IEEE 802.5 token passing ring • Fiber Distributed Data Interface (FDDI) Standard

  31. LAN Architecture Model • Network architecture includes • Access methodology • Logical topology • Physical topology • Network configuration includes • Network architecture • Media choice

  32. Access Methods • Contention: carrier sense multiple access with collision detection (CSMA/CD) • Inexpensive NIC • For: office application • Not for: manufacturing due to inconsistent response time • Token passing: 24 bits of token (free or busy) • More efficient at higher network utilization rate • More expensive NIC • Supported by IBM

  33. Topology • Logical • Sequential • Broadcast • Physical • Bus: line broken • Ring: PC or NIC broken • Star (hub, concentrator, MAU (multistation access unit, repeater, switching hub): single point of failure

  34. Ethernet • Functionality • Access method: CSMA/CD • Logical topology: broadcast • Physical topology: bus or star • Ethernet II • Header (preamble) for synchronizing • Destination & source address (MAC layer address) • Type field for network protocol • Data field • Frame check sequence (FCS): CRC-32 • IEEE 802.3 replace type field with length field

  35. Media-related Ethernet • 10BaseT • 10Base2 (Thinet with RG-58 coax) • 10Base5 (thick coaxial cable RG-11) • 100BaseT Fast Ethernet with 100-Mbps • 100BaseTX (2 pair of Category 5 UTP or 1 pair of Type 1 STP) • 100BaseT4 (4 pair of Category 3, 4, or 5 UTP) • 100BaseFX (fiber optic cable) • Trade off between speed and maximum network diameter • Gigabit Ethernet (1000Base-X)

  36. Token Ring • Functionality • Access method: token passing • Logical topology: sequence • Physical topology: ring or star • IEEE 802.5 • Starting delimiter alert NIC about token approaching • Access control field (1 for busy, 0 for free) • Frame control field indicate regular data or network management frame • Destination & source address (MAC layer address) • Routing information field for multiple token ring LANs • Data field • Frame check sequence (FCS): CRC-32 • Ending delimiter (ending or intermediate frame) • Frame status field for successful delivery

  37. Fiber Distributed Data Interface • Fiber distributed data interface (FDDI) by American National standard Institute (ANSI) • Functionality • Access method: Modified token passing • Logical topology: sequential • Physical topology: dual counter-rotating rings • Build-in reliability and longer distance • Single-attachment stations (SAS) or dual-attachment stations (DAS)

  38. Fiber Distributed Data Interface • High speed backbone between LANs • Primary ring and secondary ring - 100Mbps token ring • Fault tolerance • High-priority station having longer access time • Maximum 500 stations • Maximum length of 200 kilometers (rings) • Maximum 2 kilometers between stations • Constant data rate for video and voice

  39. Fiber Distributed Data Interface • Applications • Campus backbone • High-bandwidth workgroups (multimedia application) • High-bandwidth subworkgroup connection (servers) • Hardware: FDDI concentrator or hub, FDDI/Ethernet bridge • Media: fiber optic cable or copper distributed data interface (CDDI) for limited distance (100m)

  40. 100VG-AnyLAN • Ethernet and token ring packets • Demand priority access (DPA) or demand priority protocol: round robin polling scheme • Priority is assigned by application program and ports • Max 4 hubs between two nodes

  41. 100VG-AnyLAN • Hardware: 100VG-AnyLAN hubs arranged in a hierarchical form • Media: 4 pair of Category 3, 4, or 5 UTP; 1 pair of Type 1 STP; or single mode and multimode fiber optic cable

  42. Isochronous Ethernet • Iso-Ethernet in IEEE802.9a (Isochronous Ethernet Integrated Services) • Synchronize all circuits with a single common clocking reference • Guaranteed delivery time for voice and video • Use ISDN WAN link

  43. Isochronous Ethernet • 16.144-Mpbs bandwidth • P channel for Ethernet traffic • C channel ( B channel and D channel) • Service Modes • 10BaseT • Mutiservice: multimedia • All-isochronous: real time video or voice distribution

  44. Isochronous Ethernet • Hardware: • hubs: Iso-Ethernet attachment units (AU) • Workstation with Iso-Ethernet NIC: integrated service terminal equipment (ISTE)

  45. Wireless • Transmitter and receiver • 100 - 300 feet • Infrared technology (line-of-sight) • Spread spectrum technology (no ling-of-sight) • Special application

  46. Performance Factors • Protocol (CSMA/CD, token ring) • Speed of transmission (line) • Amount of traffic • Error rate • Software • Hardware

  47. Selection Process • Long range thinking, planning and forecasting • Selection team • Checklist of criteria • Cost & benefit analysis • Technical alternatives • Management and Maintenance

  48. Selection Criteria - I • Number of user • Geographic spread • Applications • Performance • Cost • Security • Wiring

  49. Selection Criteria - II • Installation • Maintenance • Vendor support and training • Future expansion • Workstations • Compatibility to existing LANs • Interface to other networks

  50. Costs • Workstations • Servers • Printers • Cabling • Bridges, routers, brouters, gateways • Training • People (consultant, administrator etc.) • Maintenance • Space & Environment