Engineering Questions with Answers - Multiple Choice Questions
Computer Networks MCQ – SONET
SONET stands for ___________
a) synchronous optical network
b) synchronous operational network
c) stream optical network
d) shell operational network
Explanation: SONET stands for synchronous optical network. Frame relay uses SONET to physically transmit data frames over a Frame Relay network as SONET is cheaper and provides better network reliability than other carriers.
In SONET, STS-1 level of electrical signalling has the data rate of _________
a) 51.84 Mbps
b) 155.52 Mbps
c) 2488.320 Mbps
d) 622.080 Mbps
Explanation: STS-1 level provides the data rate of 51.84 Mbps, STS-3 provides a data rate of 155.52 Mbps, STS-12 provides a data rate of 622.080 Mbps and STS-48 provides a data rate of 2488.320 Mbps.
The path layer of SONET is responsible for the movement of a signal _________
a) from its optical source to its optical destination
b) across a physical line
c) across a physical section
d) back to its optical source
Explanation: The path layer in SONET is responsible for finding the path of the signal across the physical line to reach the optical destination. It is ideally expected to find the shortest and the most reliable path to the destination.
The photonic layer of the SONET is similar to the __________ of OSI model.
a) network layer
b) data link layer
c) physical layer
d) transport layer
Explanation: The photonic layer in SONET is like the physical layer of the OSI model. It is the lowest layer among the four layers of SONET namely the photonic, the section, the line, and the path layers.
In SONET, each synchronous transfer signal STS-n is composed of __________
a) 2000 frames
b) 4000 frames
c) 8000 frames
d) 16000 frames
Explanation: SONET defines the electrical signal as STS-N (Synchronous Transport Signal Level-N) and the optical signal as OC-N (Optical Carrier Level-N). The building block of SONET is the STS-1/OC-1 signal, which is based on an 8-kHz frame rate and operates at 51.84 Mbps.
Which one of the following is not true about SONET?
a) frames of lower rate can be synchronously time-division multiplexed into a higher-rate frame
b) multiplexing is synchronous TDM
c) all clocks in the network are locked to a master clock
d) STS-1 provides the data rate of 622.080Mbps
Explanation: In SONET, STS-N stands for Synchronous Transport Signal Level-N. STS-1 level provides the data rate of 51.84 Mbps, and STS-12 provides a data rate of 622.080 Mbps.
A linear SONET network can be ________
c) both point-to-point and multi-point
d) single point
Explanation: Synchronous Optical Network (SONET) is basically an optical fiber point-to-point or ring network backbone that provides a way to accommodate additional capacity as the needs of the organization increase to multipoint networks.
Automatic protection switching in linear network is defined at the _______
a) line layer
b) section layer
c) photonic layer
d) path layer
Explanation: The Line layer in SONET operates like the data link layer in the OSI model and it is responsible for the movement of signal across a physical line. The Synchronous Transport Signal Mux/Demux and Add/Drop Mux provide the Line layer functions.
A unidirectional path switching ring is a network with __________
a) one ring
b) two rings
c) three rings
d) four rings
Explanation: One ring is used as the working ring and other as the protection ring in which each node is connected to its respective adjacent nodes by two fibers, one to transmit, and one to receive.
What is SDH?
a) sdh is similar standard to SONET developed by ITU-T
b) synchronous digital hierarchy
c) sdh stands for synchronous digital hierarchy and is a similar standard to SONET developed by ITU-T
d) none of the mentioned
Explanation: SDH is a standard that allows low bit rates to be combined into high-rate data streams and as it is synchronous, each individual bit stream can be embedded into and extracted from high-rate data streams easily.