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Homework 1

  1. Which of the OSI layers handles each of the following:
    1. Breaking the transmission stream into frames
    2. Determining which route through the subnet to use.
  2. When transferring a file between two computers, (at least) two acknowledgment strategies are possible. In the first one, the file is chopped up into packets, which are individually acknowledged by the receiver, but the file transfer as a whole is not acknowledged. In the second one, the packets are not acknowledged individually, but the entire file is acknowledged when it arrives. Discuss advantages and disadvantages of these two approaches.
  3. Shannon and Nyquist place an upper limit on the bit rate of a channel based on two different approaches. How are the two related?
  4. Is the Nyquist theorem true for optical fiber, or only for copper wire ?
  5. When bit stuffing is used, is it possible for the loss, insertion, or modification of a single bit to cause an error not detected by the checksum? If not, why not? If so, how? Does the checksum length play a role here?
  6. a) Describe the principle of operation of the following medium access control methods as used in LANs: