QUESTION: Alice and Bob want use the polynomial 11011 compute a CRC that is added to
the end of their messages for error detection.
Find the CRC that will be appended to the message 10111100011.
QUESTION: Alice and Bob want to set up a layer 2 connection to exchange
frames over a direct link. They agree to:
- reserve the 5-bit string 01110
to be used as a frame separator and to fill in idle periods; and
- to use a CRC code for error checking, using 101 as the generator polynomial.
Also, assume that the first message that the application running on
Alice wants to send to the application running on Bob over the link is
the string 1001110011.
PART (a): Briefly explain how bit stuffing
works, and describe how Alice and Bob would use it to maintain data
transparency across this link.
PART (b): Suppose Alice and Bob decide that the combination of bit
stuffing and error checking should be done by first running the
application
layer message through the "bit stuffing" encoder, and then applying the
CRC polynomial algorithm to the "encoded" message to generate the error
check field. Show me what the encoded message looks like after "bit
stuffing" has been completed.
PART (c): Find the CRC that will be appended to the encoded message
from part (b).
PART (d): Will Bob accept the message when it arrives, assuming there
are no bit errors along the way? If not, explain what went wrong, and
how they can solve the problem.