TDC 461/Session 6

Local Area Networks

Announcements:

Review #1: List two advantages of a T-Carrier?

Review #2: Is a T-carrier a physical medium or a service (at what layer of the OSI model does the T-carrier live?

Review #3: Compare and Contrast Channelized and Unchannelized T1 lines.

 

  1. LAN Topologies
    1. Star Topology
      1. All stations attached to one common point
      2. Advantages:
      3. Most common topology in use today
    2. Ring Topology
      1. All stations are repeaters in a closed loop (NIC)
      2. Unidirectional
      3. Disadvantages
      4. Used for Token Ring and FDDI LANs.
    3. Bus and Tree Topologies
      1. All workstations connected to a single length of cable
      2. No stations are repeaters
      3. Bus/backbone must be terminated
    4. Topology Summary
      1. Topologies only represent cable plant (physical vs. logical)
      2. Topologies are commonly intermixed
      3. No specific topology for any one LAN
  2. Wiring Systems
    1. Metrics:
      1. speed=>how fast can it transmit?
      2. repeaterless distance=>distance before a repeater is needed(max segment length)
      3. security=>can it be tapped or not?
      4. method of access=>device required for access
      5. cost=>cheap/expensive
      6. robustness=>durability;
    2. Cable Naming Conventions
    3. Thick Coax
    4. ThinNet (Thin Coax)
    5. Unshielded Twisted Pair (UTP)
    6. Fiber Optic
  3. The Ethernet Standard
    1. History
      1. Developed at Xerox PARC in 1972.
      2. Addresses only layers 1 and 2 of OSI
      3. =d>Multi-access, packet-switched communications system for carrying digital data among locally distributed computing system.
    2. Three Functions of Ethernet
      1. Transmit and receive packets
      2. Decode packets and check address validity before handing off to higher layers
      3. Error detection within packet
    3. Ethernet Defined
    4. Ethernet Transmission
    5. CRC=>
    6. Media Access Control
    7. Collision Detection
    8. Ethernet Reception
    9. Promiscuous Mode Reception
  4. Token Ring
    1. Topology is ring or star-wired ring
    2. Parts
    3. Multistation Access Unit
    4. Operation
    5. Connectors
      1. 4 Types:
        1. Universal Data Connector (UDC)=>old style; used for STP
        2. RJ-11 (4-pin)
        3. RJ-45 (8 pin)=>Used with aUTP
        4. DB-9=>9 pin connector shaped like a D. Only 4 pins are used. STP or UTP application.
    6. Cable Plant
      1. Shielded Twisted Pair (STP)
      2. Category 4 or 5 Twisted UTP
    7. Data Link Layer
      1. Responsible for:
    8. Frame Fields (9) for Token Ring
      1. Field 1: Starting Delimiter (SD)
      2. Field 2: Access Control (AC)
      3. Field 3: Packet (Frame) Control=>Tells receiving station whether or not frame contains data or maint. Controls for network
      4. Field 4: Destination Address (DA)=>Physical address of destination device
      5. Field 5: Source Address (SA)
      6. Field 6: Information=>payload
      7. Field 7: Frame Check Sequence=>runs CRC on fields: FC, DA, SA, and Information fields
      8. Field 8: Ending Delimiter (ED)
      9. Field 9: Frame Status (FS)=>status of error checking and provides some duplicate error checking
  5. FDDI
    1. Overview
    2. Physical Layer
    3. Cable Plant
    4. Connectors
    5. FDDI Port Types
    6. Data Link Layer
    7. Data Delivery
    8. FDDI Uptime
    9. FDDI Timers
  6. Other LAN Hardware
    1. Hubs
      1. Active
      2. Passive
    2. Bridges=>
    3. LAN Switch=>
    4. Routers
    5. Gateways
  7. LAN Internetworking
    1. =>networking (connecting) two or more LANs
    2. Via MANs and WANs
    3. Internetworking Protocols
    4. TCP
      1. =>transmission control protocol
    5. IP
      1. =>internet protocol
  8. Virtual LANs
    1. =>software defined LANs, via an intelligent hub or Switch