OPTICAL COMMUNICATION NETWORKS 2 MARK QUESTIONS

UNIT: I OPTICAL NETWORKING COMPONENTS

Part A (2 Marks for each question)

                                       

1. How do you measure sheath miles?
2. What do you understand by the term optical time division multiplexing?
3. What is a lightpath?
4. List the optical networking components.
5. Give the applications of directional couplers.
6. Differentiate between reciprocal and non-reciprocal devices.
7. What is a directional coupler?
8. State excess loss.
9. Differentiate between isolators and circulators.
10. What is insertion loss?
11. Write down any four requirements of a good optical filter.
12. Draw the structure of Fabry-Perot filter.
13. Mention the various methods of tuning Fabry-Perot filter.
14. Draw the structure of three cavity resonant dielectric thin film filter.
15. State the advantages of dielectric thin film filter.
16. Mention the applications of Mach-Zehnder Interferometer.
17. What is an arrayed waveguide?
18. Give the principle of operation of Acousto Optic Tunable filter.
19. State stimulated emission.
20. What is spontaneous emission?
21. State extinction ratio.
22. Differentiate between blocking and non-blocking switches.

Part A (2 Marks for each question)

                                       

1. What is SONET/SDH?
2. What is STS?
3. What does a SONET regenerator do?
4. What are the layers in a SONET standard?
5. What is the content of a byte in a SONET frame?
6. How do clocks function in SONET?
7. How is synchronous TDM multiplexing achieved in SONET?
8. Give the taxonomy of SONET networks.
9. Give the structure of an STS-N frame.
10. What is the function of an ADM?
11. How are devices connected in a SONET?
12. What is an ‘order wire byte’?
13. What is the contents of an SPE?
14. What is the user data rate of an STS-1 frame without considering the overhead?
15. What is byte interleaving?
16. Pictorially represent a point-to-point SONET network.
17. What are the configurations of a SONET ring network?
18. Find the data rate of an STS-3 signal.

UNIT: III BROADCAST AND SELECT NETWORKS

Part A (2 Marks for each question)

1. Mention the number of couplers used for an ‘n’ node network of star

and bus topologies.

2. Name the most popular topologies used for broadcast and select networks.
3. Define MAC protocol.
4. What is the output optical power of a 2x2 directional coupler?
5. What is the optimum value of α that minimizes Lbus?
6. What is a selective repeater?
7. How is performance measured in a MAC protocol?
8. What is the function of a synchronizer node?
9. On what assumption is the SA/SA family of protocols designed?
10. How does the basic SA/SA protocol operate?
11. What is wait-and-see-modification?
12. Define throughput per data channel.
13. How are the data and control slots different in DT-WDMA compared to SA/SA?
14. Define a frame with respect to DT-WDMA.
15. Define the (α, S) constraint of input traffic.
16. Name the three different traffic classes of a network.
17. Give the connection setup protocol used in Rainbow-1.
18. How is data sent in STARNET-II?
19. What is the wavelength partitioner used in lightning testbed.
20. Give the topology of the BBC television studio testbed.

UNIT: IV WAVELENGTH ROUTING NETWORKS

Part A (2 Marks for each question)

1.  Give the block diagram of a wavelength cross connect node.

2.   Name the types of regeneration techniques for digital data.

3.   Give the diagrammatic representation of the NTT ring testbed.

4. Differentiate between a static and a reconfigurable network.
5. Give the diagrammatic representation of the network design problem.
6. What is the use of wavelength conversion?
7. What the types of wavelength conversion that may be realized in a node?
8. What is the use of multiple fiber-pairs between nodes?
9. What is the degree of transparency of a fully optical network?
10. How are different types of WXC nodes realized?
11. Why is reliability needed in an optical switch?
12. How many wavelengths are required to build a reasonable network?
13.  How much do wavelength converters help in improving the capacity of a network?
14. What are good techniques for routing and assigning wavelengths to lightpaths?
15.  List the traffic models commonly employed to study optical networks.
16.  Give the bipartite graph representation of a static network.
17.  List the constraints of wavelength assignment for a network with undirected    

 lightpaths and edges.

18.  What is graph coloring?
19.  List the factors governing wavelength reuse.
20.  Draw the ONTC network testbed.

UNIT: V HIGH CAPACITY NETWORKS

Part A (2 Marks for each question)

1. List the approaches in increasing the transmission capacity on a link.
2. What are the drawbacks of the SDM approach?
3. Name the major system impairments the TDM faces.
4. Differentiate Unidirectional and Bidirectional WDM systems.
5. What is a soliton pulse? Where is it usually used?
6. Draw the optical Demux to extract one of the multiplexed channels from a packet-interleaved TDM stream.
7. Draw the block diagram of a soliton-trapping logical AND gate.
8. Define Synchronization with regard to a photonic packet-switching network.
9. What is an optical phase lock loop?
10. What are the functions of a routing node?
11. Draw the block diagram of a generic store and forward network.
12. Explain delay with respect to, i) deflection routing and ii) store and forward networks.
13. What is deflection index?
14. What is hot-potato routing?
15. Define Livelock.
16. Give an example of a 2x2 routing node using a  feed-forward delay line architecture.
17. What is the use of low differential loss characteristic in a network?
18. List some of the key features of OTDM testbeds.
19. Name some of the OTDM testbeds.
20. Draw the helical LAN topology proposed to be used in the AON TDM testbed.