# Optical Communications Questions and Answers – Wavelength Routing Networks

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This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “Wavelength Routing Networks”.

1. Which of the following is used to provide wavelength signal service among the nodes?
a) Regularization
b) Optical enhancing
c) Hopping
d) Pulse breakdown

Explanation: The optical layer is dependent on wavelength. The entire physical interconnected network provides wavelength signal service among the nodes using hopping technique.

2. How many types of hopping are present?
a) Two
b) One
c) Three
d) Four

Explanation: There are two types of hopping. They are single hop and multihop. These techniques provide wavelength dependent service for interconnected physical network among the nodes.

3. How many switching layers are possessed by MG-OXC?
a) Two
b) Three
c) One
d) Six

Explanation: An MG-OXC has three switching layers. They are wavelength cross-connect (WXC), waveband cross-connects (BXC), and fiber cross-connects (FXC). These layers help to terminate the wavebands and individual wavelength channels.

4. _____________ supports a great number of wavelength channels and reduces the number of switches within the optical network.
a) Waveband switching
b) Optical remuneration
c) Optical genesis
d) Wavelength multiplexing

Explanation: Waveband switching reduces the number of ports within the optical network. It reduces the complexity of numerous wavelength-driven channels and makes it efficient.

5. Individual wavelength channels and wavebands are terminated through ________________ layers.
a) WXC and PXC
b) WXC and FXC
c) BXC and FXC
d) WXC and BXC

Explanation: The individual wavelength channels are terminated and the terminated waveband is then de-multiplexed. The de-multiplexing is in the form of individual channels which are sent to WXC layer as inputs.

6. The routing and wavelength assignment problem addresses the core issue of _____________
a) Traffic patterns in a network
c) Wavelength continuity constraint
d) Design problem

Explanation: The routing and wavelength assignment problem includes selecting a suitable path and allocating an available wavelength. These problems fall into two categories of sequential or combinational selections.

7. How many techniques of implementation are there for routing wavelength assignment (RWA)?
a) Two
b) Six
c) Three
d) Four

Explanation: The implementation of RWA can be static and dynamic. This depends on the traffic patterns in the network. Static RWA techniques are semi-permanent and dynamic RWA techniques are random in nature.

8. ____________ deals with establishing the light path in frequently varying traffic patterns.
a) Wavelength routing
b) Wavelength multiplexing
c) Static RWA
d) Dynamic RWA

Explanation: In dynamic RWA, the traffic patterns are not known. Thus, the connection requests are initiated in random fashion. Its random nature depends on the network state at the time of request.

9. Static RWA problem is also known as _____________
a) Routing problem
b) Virtual topology problem
c) Static wavelength problem
d) Light path problem

Explanation: Static RWA problem refers to the connection problems which remain connected for a smaller duration of time. Thus, network resources are assigned to each connection. It is also called as virtual topology design problem.

10. The ___________ provides information about the physical path and wavelength assignment for all active light paths.
a) Network state
b) RWA
c) LAN topology
d) Secluded communication protocol

Explanation: The physical path i.e. route is associated with the routing problem. Each connection is provided with network resources to reduce complexity in functioning. The network state is basically required to provide information related to routing and assignment problems.

11. ________________ plays an important role in determining the blocking probability of a network.
a) CGA algorithm
b) Semi-pristine environment
c) RWA algorithm
d) Pass key protocol

Explanation: RWA algorithm’s efficiency is calculated on the basis of no blocking or lowest blocking probability. It also provides the information about the availability of the path between the source and destination.

12. Wavelength assignment in RWA is independent on the network topology.
a) True
b) False

Explanation: RWA algorithm deals with the wavelength assignment, physical path and blocking probability. Network topology plays a crucial role in the wavelength assignment. The network state and topology enables the RWA algorithm to function smoothly.

13. Static RWA technique is semi-permanent.
a) True
b) False

Explanation: The connections employs in static RWA are semi-permanent but remain active for a relatively longer period of time. The traffic patterns are known in advance and thus the optimization can be done by assigning network resources to each connection. 