$1.$ In HDLC$,$ what is poll$/$final bit used for?

$2.$ In Stop?and?Wait, the sender can transmit how many packets consecutively at any given point in time?

$3.$ In all ARQ protocols, why is the purpose of timeout?

$4.$ What problem does bit stuffing solve?

$1.$ Suppose the following sequence of bits arrives on a link:

$1101011111010111110010111110110$

If the flag is $01111110,$ show the resulting frame after any stuffed bits has been removed.

$2.$ Bit stuff the following data $($assume the flag given above$)$:

$000111111111111111111111111111110011111001$

$3.$ The HDLC frame shown below is sent from a secondary to a primary. Answer the following questions

$011111100000011110101011$ FCS $01111110$

$($a$)$ What is the address of the secondary$?($b$)$ What is the type of the frame?

$($c$)$ What is the sender sequence number $($if present$)?($d$)$What is the acknowledgment number $($if present$)?$

$($e$)$ Does the frame carry user data? If yes, what is the value of the data?

$($f$)$ Does the frame carry management data? If yes, what is the value of the data? $($g$)$What is the purpose of the frame?

$4.$ Assuming even parity, find the parity bit for the following data units:

a$)1001011$ b$)0001100$