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Chapter 5 Local Area Network Concepts and Architecture

Chapter 5 Local Area Network Concepts and Architecture. Network Fundamentals Local Area Network (LAN) Open Systems Interconnection (OSI) LAN Architectures. Network Fundamentals. Definitions Classifications Network topology Network types Local Area Network. Definition. Network

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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

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