1. LOGICAL TOPOLOGY
    1. def
      1. how data is transmitted
    2. BUS
      1. a common tranmission medium
      2. Ethernet
    3. TOKEN RING
      1. data received from one neighbour
        1. pass onto another neighbor
      2. Token Ring
  2. TRAFFIC CONTROL
    1. def
      1. ACCESS METHOD
        1. how computer places data into media access
    2. BUS
      1. physical topology
        1. STAR
        2. BUS
      2. Multiple Access
        1. Carrier Sense
          1. if the wire is used by other devices
          2. wait
      3. COLLISION HANDLING
        1. CSMA/CA
          1. used in wireless system
          2. use for BUS
          3. "clear to send" signal
          4. acknowledged to proceed
          5. wait until it is allowed to go
          6. next time, double the time
        2. CSMA/CD
          1. used in ethernet
          2. threshold bandwidth
          3. lower, keep requesting
          4. higher, stop requesting
      4. pros
        1. simple software
        2. little overheat
        3. complete control of the media
          1. as long as no other hv access
      5. cons
        1. access times r not predictable
        2. can't give faster access
        3. chance of collisions increase, when new device join network
    3. TOKEN RING
      1. used for RING topology
        1. very high performance system
      2. TOKEN
        1. sent around the ring
        2. 1 direction
      3. Sent data
        1. 1
          1. "grab" token
          2. attach data to "token"
          3. address "token" to sender
        2. 2
          1. target picks up packet
          2. target release token back to the ring
        3. 3
          1. sender receive the token
          2. sender knows token has arrived
        4. 4
          1. token is marked free
          2. token released to the ring again
      4. PROS
        1. deterministic
          1. predictable load/delay
        2. prioritise for faster transmission
        3. eliminate collision
      5. CONS
        1. requires interactive software
    4. Polling
      1. used for mainframe
  3. MAC ADDRESSING
    1. MAC address
      1. aka Ethernet address
        1. unique ID for NIC
        2. 3 char manufacturers - 3 char serial number
    2. Physical passing
      1. Ethernet frames
      2. procedure
        1. slide 22/23
      3. Subnet
        1. hub
        2. switch
        3. bridge
        4. repeater
        5. separate traffic
      4. Multiple subnet
  4. LAYER 2 PROTOCAL
    1. MICROSOFT
      1. NET BUI protocol
    2. VPN
      1. security purpose
      2. adds a protective layer
  5. LOGICAL LINK CONTROL
    1. TRANMISSION SYNCRONISATION
      1. Asynchronous
        1. 2 devices dont sync
        2. only send/receive
          1. uncomplicated
          2. no separate control signals
        3. overhead packet
          1. detect errors
      2. Synchronous
        1. faster transmission
        2. more reliable
          1. improved error detection
      3. Isochronous
        1. fastest
        2. hybrid of Asynchronous & Synchronous
    2. CONNECTION SERVICES
      1. LLC - Level Flow Control
      2. Error control
  6. STANDARDS
    1. 802
      1. 802.11
    2. cable standards
      1. 10base
        1. base T