1. A list of protocols used by a system, one protocol per layer, is called ?

Answer. protocol stack

2. Network congestion occurs ?

Answer. in case of traffic overloading

3. Which of the networks extends a private network across public networks?

Answer. storage area network

4. Which is not a constituent of residential telephone line?

Answer. A low-speed downstream channel

5. DSL telcos provide Wired phone access and ISP service true or false?

Answer. false

6. The function of DSLAM is to ?

Answer. Convert analog signals into digital signals

7. The data link layer takes the packets from and encapsulates them into frames for transmission.

Answer. network layer

9. Which of the tasks is not done by data link layer?

Answer. channel coding

10. Which sublayer of the data link layer performs data link functions that depend upon the type of medium?

Answer. media access control sublayer

11. Header of a frame generally contains

Answer.
• synchronization bytes
• addresses
• frame identifier

12. Automatic repeat request error management mechanism is provided by

Answer. logical link control sublayer

13. When 2 or more bits in a data unit has been changed during the transmission, the error is called

Answer. burst error