Fall 2001 CSCI 363 Homework 9 Solution for Selected Problems

Problem 1

If odd parity is being used, what parity bit is added to the following seven-bit sequences?

Input sequence Parity
1011011 0
1111111 0
0000000 1
0000000 1

Problem 2

If 10011 is being used as the generator G for a Cyclic Redundancy Check, what is the remainder R left after dividing G into the 12-bit message 101010101011?

  101010101011
⊕ 10011
   01100101011
⊕  00000
    1100101011
⊕   10011
     101001011
⊕    10011
      01111011
⊕     00000
       1111011
⊕      10011
        110111
⊕       10011
         10001
⊕        10011
          0010

Problem 3

Suppose the 48-bit, or six-yte, pattern 10101011 00110100 01000001 01111110 00000000 01111101 is to be transmitted within the data section of a PPP packet. How are these six bytes transmitted?

10101011 00110100 01000001 01111101 01111110 00000000 01111101 01111101