Optical Communications Multiple Choice Questions on “Optical Switching Networks”.
1. Optical switching can be classified into ________ categories.
a) Two
b) Three
c) Four
d) One
Answer: a
Explanation: Optical switching is classified into two categories same as that of electronic switching.
The two categories are circuit switching and packet switching.
2. ___________________ are the array of switches which forms circuit switching fabrics.
a) Packet arrays
b) Optical cross connects
c) Circuit arrays
d) Optical networks
Answer: b
Explanation: Optical cross-connects incorporate switching connections or light paths. These larger arrays can switch signals from one port to another.
3. ___________ is an example of a static circuit-switched network.
a) OXC
b) Circuit regenerator
c) Packet resolver
d) SDH/SONET
Answer: d
Explanation: The circuit is said to be static when the network resources remain dedicated to the circuit connection. This should be followed during the entire transfer and the complete message follows the same path.
4. What is the main disadvantage of OCS?
a) Regenerating mechanism
b) Optical session
c) Time permit
d) Disability to handle burst traffic
Answer: d
Explanation: In traffic conditions, data is sent in the form of bursts of different lengths. Thus, the resources cannot be readily assigned. The OCS cannot efficiently handle burst traffic.
5. Optical electro-conversions takes place in _________________ networks.
a) Sessional
b) Optical packet-switched
c) Optical circuit-switched
d) Circular
Answer: c
Explanation: In an optical packet-switched network, data is transported in the optical domain. This is done without intermediate optic-electrical conversions. Optical electro-conversions takes place in circuit-switched networks.
6. How many functions are performed by an optical packet switch?
a) Four
b) Three
c) Two
d) One
Answer: a
Explanation: An optical packet switch performs four basic functions. These include routing, forwarding, switching and buffering.
7. ____________ provides data storage for packets to resolve contention problems.
a) Switching
b) Routing
c) Buffering
d) Reversing
Answer: c
Explanation: Switching involves directing the packets. Routing provides network connectivity while forwarding and reversing involves defining a packet. Buffering usually provides data storage for packets.
8. What is usually required by a packet to ensure that the data is not overwritten?
a) Header
b) Footer
c) Guard band
d) Payload
Answer: c
Explanation: A packet consists of a header and the payload. The label points to an entry in the lookup table. A guard band is usually included to ensure the data is not overwritten.
9. Routing technique is faster than the labeling technique. State whether the given statement is true or false.
a) False
b) True
Answer: a
Explanation: Labeling suggests where the packet should be directed. Routing routes the data in the given direction. Thus, labeling technique is efficient and faster than the routing technique.
10. ______________ provides efficient designation, routing, forwarding, switching of traffic through an optical packet-switched network.
a) Label correlation
b) Multiprotocol label switching
c) Optical correlation
d) Routing
Answer: b
Explanation: Multiprotocol label switching (MPLS) was first proposed by CISCO systems. Earlier, it was called as tag switching. MPLS uses labels to forward, switch, designate the traffic.
11. MPLS is independent of layer 2 and 3 in the OSI model. State whether the given statement is true or false.
a) True
b) False
Answer: a
Explanation: MPLS is flexible in the current protocol landscape. It supports Ethernet, frame relay as a data link layer but is independent of layer 2 and 3 in the OSI model.
12. Which of the following service is provided by Multiprotocol label switching (MPLS)?
a) Data forwarding
b) Routing
c) VPN’s
d) Switching
Answer: c
Explanation: One of the important services provided by MPLS is IP virtual private networks. All others are provided by packet switched networks. These VPN’s provide a secure, dedicated wide area network (WAN) in order to connect the offices all over the world.
13. Burst header cell is also known as _____________
a) Burst channel
b) Burst header circuit
c) Burst regenerator
d) Burst header packet
Answer: d
Explanation: Burst header cell consists of information regarding switching and destination address. It works with the use of transmission units called as data bursts.
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