CSD008/COMP3616, Networks & Internet Systems: Problem Set 3
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Reminders: There are no marks associated with these problems,
 and you do not hand in your answers. "Tanenbaum" refers to
 the 4th Edition.

1. Suppose the data string to be transmitted is 1110010. What
 is the transmitted codeword using
 (a) the single parity check code?
 (b) the Hamming code?

2. Suppose you are using the Hamming code. Given the received
 word 10111010110, detect and correct any errors. You may
 assume there is a maximum of one error in the transmitted
 data and no errors in the transmitted check bits.

3. In the General Parity Check error-handling scheme, if the
 minimum Hamming distance is D, this scheme can detect any
 combination of <= D-1 bit errors and correct any combination
 of strictly less than D/2 bit errors. Give a plausible
 explanation (NOT a proof) of these results, based on the
 definition of Hamming distance and the way this scheme works.

4. In a broadcast network with a shared communication channel,
 there are 3 basic contention resolution strategies:
 (1) divide the channel into independent sub-channels,
 (2) collision resolution, and (3) reservations.

 (a) Briefly explain under what circumstances the strategy of
 dividing the channel into independent sub-channels is NOT a
 good idea.

 (b) Given the circumstances mentioned in part (a), what are
 the advantages and disadvantages of the other two contention
 resolution strategies?