1 - A protocol tester is to be used to investigate a link level fault where
would it be tee'd into the circuit ?
- between the modem and the equipment
- anywhere between the exchange modem and and the customers modem
- on the MDF
- on the IDF
2 - What is the main job of the link layer.
- routing.
- error correction.
- end-to-end flow control
- speed changing
4 - What is transmitted to line when no information is
available for transmission.
- flags
- permanent 1s
- permenant 0s
- idles
5 - By monitoring an X.25 line how can you tell if the link is in the down
state ?
a) the network polls with SABMs
b) the network polls with DISCs
c) the customer polls with SABMs
d) the customer polls with DISCs
6 - If a computer calls another computer through Public Network and sends a frame with
a sequence number N(S) of 5, what sequence number will be received by the distant
end computer ?
a) N(S) = 4
b) N(S) = 5
c) N(S) = 6
d) not enough information here to tell
7 - What is the P bit used for ?
a) to indicate a sequence number error
b) to indicate PAD data is being transmitted
c) to demand an immediate response from the other end.
d) to indicate a FCS error
8 - what are the 9 types of frame ?
what is each one used for ?
