P$8.(15$ pts$.)-$ a$)$ Using HDLC$,$ station A has issued $3$ consecutive I frames numbered $2,3,$ and

Station $B$ has no data to send to station A and is ready to receive further frames. What

response should station $B$ send?

b$)$ Using HDLC$,$ station A has issued $3$ consecutive I frames numbered $1,2,$ and $3.$ Station B has

no data to send to station A$,$ but its buffer is full and it is not ready to receive further frames yet.

What response should station B send?

c$)$ Using HDLC$,$ station A is sending the following data to station B: $1001011010110.$ The CRC

divisor is $1011.$ What will be in the FCS frame of the frame containing the data?

P$9.(10$ pts$.)-$ In a data link protocol two dedicated bytes are used: FLAG$=011111110$ and

ESC$=10111110.$ Assume to data bytes $A=01000111$ and $B=11100011.$ Write the bit sequence

transmitted $($in binary$)$ for the four$-$character frame $\{$A B ESC FLAG$\}$ if the framing method is:

a$)$ Starting and ending Flag bytes with byte stuffing

b$)$ Starting and ending Flag bytes with bit stuffing

P$10.(10$ pts$.)-$ i$)$ The following data fragment occurs in the middle of a data stream:

A B ESC C ESC FLAG FLAG D

where A$,$ B$,$ C and D are random data bytes and ESC and FLAG are special bytes as defined in

P$9.$ What is the actual sequence transmitted if byte stuffing is used?

ii$)$ The stream of bits $0111101111101111110$ needs to be transmitted at the data link

layer. What is the actual stream of bits transmitted if bit stuffing is used?