1. 

How many digits of the DNIC (Data Network Identification Code) identify the country?

A. first three
B. first four
C. first five
D. first six

2. 

A station in a network forwards incoming packets by placing them on its shortest output queue. What routing algorithm is being used?

A. hot potato routing
B. flooding
C. static routing
D. delta routing

3. 

The probability that a single bit will be in error on a typical public telephone line using 4800 bps modem is 10 to the power -3. If no error detection mechanism is used, the residual error rate for a communication line using 9-bit frames is approximately equal to

A. 0.003
B. 0.009
C. 0.991
D. 0.999

4. 

Frames from one LAN can be transmitted to another LAN via the device

A. Router
B. Bridge
C. Repeater
D. Modem

5. 

Which of the following condition is used to transmit two packets over a medium at the same time?

A. Contention
B. Collision
C. Synchronous
D. Asynchronous