High Level Data Link Control

Question 1

what does HDLC stand for

Answer 1

high level data link control

Question 2

hat does SDLC stand for

Answer 2

synchronous data link control

Question 3

what is the frame format for HDLC frame

Answer 3

Beginning
Header
Body/ Payload
CRC
Ending

Question 4

How many bits in the beginning of the HDLC frame

Answer 4

8

Question 5

How many bits in the header of the HDLC frame

Answer 5

16

8 address field
8 control field

Question 6

How many bits in the body of the HDLC frame

Answer 6

varying

Question 7

How many bits in the CRC of the HDLC frame

Answer 7

16

Question 8

which two parts of the HDLC frame are the same

Answer 8

beginning and ending

Question 9

what is the bit sequence of the beginning and ending of the HDLC frame

Answer 9

01111110

Question 10

when is the beginning and ending frame also transmitted

Answer 10

any time the link is idle so that the sender and receiver can keep their clocks synchronised

Question 11

the address field of the header may be extended, how does this happen

Answer 11

if last bit of address field is 0, need to keep reading in address

Question 12

what are the types of HDLC frames

Answer 12

I frame
S frame
U frame

Question 13

what is the i frame for

Answer 13

information frame

Question 14

what is s frame for

Answer 14

supervisory frame

Question 15

what is u frame for

Answer 15

unnumbered frame

Question 16

what could cause an error in HDLC framing

Answer 16

if there is a bit sequence somewhere in the data that resembles the beginning/ending bit sequence

the frame will think its ending

Question 17

how is bit stuffing used to help prevent framing errors

Answer 17

0 is stuffed after 5 consecutive 1s to stop reading in as a beginning/ending frame (sender)

the receiver will remove the 0 and interpret the original data