Computer Networks Multiple Choice Questions on “Virtual Circuit”.
1. Which of the following is not a characteristic of Virtual Circuit Network?
a) There are setup and teardown phases in addition to the data transfer phase
b) Resources can be allocated during setup phase or on demand
c) All packets follow the same path established during the connection
d) Virtual circuit network is implemented in application layer
Answer: d
Clarification: Virtual circuit network is normally implemented in data link layer. It is a combination of circuit-switched network and datagram network which are implemented in the physical layer and network layer respectively.
2. The address that is unique in the scope of the network or internationally if the network is part of an international network is called as ______
a) Global address
b) Network address
c) Physical address
d) IP address
Answer: a
Clarification: Global address is a network address that is unique internationally and is used as a common address by all the users of the network. It is used to create a virtual circuit identifier.
3. The Identifier that is used for data transfer in virtual circuit network is called _______
a) Global address
b) Virtual circuit identifier
c) Network identifier
d) IP identifier
Answer: b
Clarification: A virtual circuit identifier is a type of numeric identifying address that is used to distinguish between different virtual circuits in a circuit-switched network. It is used for data transfer and has a switch scope.
4. Which of the following is not a phase of virtual circuit network?
a) Setup phase
b) Data transfer phase
c) Termination phase
d) Teardown phase
Answer: c
Clarification: There are three phases in a virtual circuit network: setup, data transfer and teardown phase. There is no termination phase in it.
5. Steps required in setup process are ___________
a) Setup request and acknowledgement
b) Setup request and setup response
c) Setup request and setup termination
d) Setup and termination steps
Answer: a
Clarification: Setup request (sent by a source) and acknowledgement (sent by the destination) are the steps in the setup process. Both the ends’ switches make table entries during the setup process.
6. During teardown phase, the source, after sending all the frames to destination, sends a _____ to notify termination.
a) teardown response
b) teardown request
c) termination request
d) termination response
Answer: b
Clarification: The source, after sending all the frames to destination sends teardown request to which, destination sends teardown response. The switches then delete the corresponding table entries.
7. Delay of the resource allocated during setup phase during data transfer is ________
a) constant
b) increases for each packet
c) same for each packet
d) different for each packet
Answer: c
Clarification: If a resource is allocated during setup phase, delay is same for each packet as there is only one-time delay during the setup phase and no delay during the data transfer phase.
8. Delay of the resource allocated on demand during data transfer is ________
a) constant
b) increases for each packet
c) same for each packet
d) different for each packet
Answer: d
Clarification: If a resource is to be allocated on demand during the data transfer phase, the delay for each packet would be different depending upon the resource requirement of the packets.
9. In virtual circuit network, the number of delay times for setup and teardown respectively are _______
a) 1 and 1
b) 1 and 2
c) 2 and 1
d) 2 and 2
Answer: a
Clarification: There is one-time delay for both setup and teardown phase. The one-time delay in setup phase is for resource allocation and the one-time delay in teardown phase is for the de-allocation of the resources.
10. In data transfer phase, how many columns does the table contain?
a) 1
b) 2
c) 3
d) 4
Answer: d
Clarification: The switch maintains a table for each Virtual Circuit Network. In the data transfer phase, it maintains 2 columns each for incoming data and outgoing data. The columns are in the following order: Source port, Source VCI, Destination port, Destination VCI.