CS 4873 Computer Networks Final Exam Review Fall 1999

• Network Layers
  • Know the names of the layers in order
  • Know the function of each of the frist three layers
• Chapter 2, The Physical Layer
  • Concept of bandwidth limited signals
  • Fourier series and how it relates to bandwidth limited signals
  • Sampling Theorem: bandwidth H, 2H exact samples to reconstruct the signal
  • Nyquist theorem: maximum data rate is 2H lg V bits/sec
  • Shannon theorem: maximum data rate is H lg (1 + S/N)
  • Using dB
  • Relation between frequency and wavelength
  • Modems and codecs
  • T1 carrier, PCM
  • Circuit, message, and packet switching
• Chapter 3, the Data Link Layer
  • Character stuffing
  • Bit stuffing
  • Error detection and correction
  • Hamming distance
  • Hamming code
  • Error detection using parity and CRC
  • Protocols 1-6
    • Know the names of each of the protocols
    • Know the assumptions made by each protocol
    • Know how the protocols are related
    • Know the strengths and weaknesses of each protocol
    • Know how to determine what happens under given conditions
• Introduction to Queueing Theory
  • M/M/1 queues
  • Poisson formula
  • mean number of customers
  • average time in the system
• Chapter 4, The Medium Access Sublayer
  • Static channel allocation
  • ALOHA
    • pure infinite
    • slotted infinite
    • slotted finite
  • CSMA: 1-persistent, non-persistent, p-persistent
  • CSMA/CD: contention slot, contention interval
  • Manchester encoding
  • 802.3 and Ethernet
    • frame size, cable length and propagation delay
    • repeaters, bridges and routers
    • frame size, cable length and propagation delay
    • binary exponential backoff
    • performance under heavy load
  • 802.4: Token Bus
    • distinction between logical and physical topology
    • token passing
    • ring entry and exit
  • 802.5: Token Ring
    • physical length of a bit
    • listen and transmit mode
    • wire controllers
    • token size and delays
• Chapter 5, The Network Layer
  • Services: Connection-oriented, connectionless
  • Implementation: circuit switching, packet switching (datagrams)
  • Routing: virtaul circuits, datagrams
  • Routing: nonadaptive and adaptive
  • Optimality Principle
  • Sink Tree
  • Shortest path routing and flooding

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