Optical Communications Multiple Choice Questions on “Optical Ethernet”.
1. What is the exception in the similarities between the optical Ethernet and the Ethernet LAN?
a) Physical layer
b) Data-link layer
c) Refractive index
d) Attenuation mechanism
Answer: a
Explanation: Optical Ethernet is similar to the conventional Ethernet LAN with the exception of the physical layer. Physical layer includes the flow of data in the form of binary digits. This transmission takes place on the bit level.
2. Which technology is used by optical Ethernet?
a) GP-technology
b) HJ-technology
c) IP-technology
d) GB-technology
Answer: c
Explanation: Optical Ethernet is the fourth generation of the Ethernet family. The earlier generations include X.25, Frame Relay and ATM. Unlike these technologies, optical Ethernet uses IP-based technology.
3. When was the Gigabit Ethernet network developed?
a) 1977
b) 1988
c) 1990
d) 2002
Answer: b
Explanation: The Gigabit Ethernet (Gbe) network was developed in 1988. It was developed by merging two technologies namely 802.3 Ethernet and ANSI X3T11 fiber channel.
4. Optical Ethernet can operate at the transmission rates as low as ______________
a) 10 M bits per second
b) 40 M bits per second
c) 100 M bits per second
d) 1000 M bits per second
Answer: a
Explanation: Usually, high transmission rates define optical Ethernet. The ITU-T Recommendation specifies the physical layer for optical Ethernet. It can operate at transmission rates as low as 10 M bits per second.
5. How many types of optical Ethernet connections are developed?
a) Two
b) One
c) Four
d) Three
Answer: d
Explanation: There are three different types of optical Ethernet connections. They are point-to-point, point-to-multipoint, and multipoint-to-multipoint. Multipoint refers to more number of connections on either side.
6. Which type of connection can be used as an Ethernet switch?
a) Point-to-point
b) Multipoint-to-multipoint
c) Multipoint-to-point
d) Point-to-multipoint
Answer: b
Explanation: The multipoint-to-multipoint configuration refers to the bus, tree or mesh topology. Such a mesh can be made to work as a switching hub with non-blocking switching features. It facilitates switching between different optical Ethernet users.
7. How many aspects are included in the standard Ethernet protocol?
a) One
b) Two
c) Four
d) Three
Answer: c
Explanation: Optical Ethernet follows standard Ethernet protocol. This protocol includes four different aspects: Frame, MAC, signaling components and the physical medium.
8. Which of the following is not included in the Ethernet frame format?
a) MAC
b) Preamble
c) Destination address
d) Source address
Answer: a
Explanation: The Ethernet frame format includes preamble, destination and source addresses, length, data and the check sequence. MAC is the protocol which is used for sharing the network nodes.
9. The _______________ provides point-to-point access to a bidirectional single-mode optical fiber.
a) Optical regenerator
b) Optical session
c) Optical distribution node
d) Optical buffer
Answer: c
Explanation: The ODN is abbreviated as Optical distribution node. It can access an optical fiber on a point-to-point basis. Thus, a single mode bidirectional optical fiber can be accessed by an Optical distribution node.
10. _______________ is the de-multiplexing technique used to split SONET bandwidth into logical groups.
a) SDH
b) Virtual concatenation
c) STS-1
d) Optical breakdown
Answer: b
Explanation: Virtual concatenation (VC) is basically a splitting technique. It can split the SONET bandwidth into groups. These groups may be transported or routed independently.
11. Ethernet switches support multiprotocol label switching.
a) True
b) False
Answer: a
Explanation: Ethernet switches support multiprotocol label switching. This feature is desired mainly in MAN. The use of such switches in LAN exceeds the network capabilities.
12. Length field in MAC frame ensures that the frame signals stay on the network in order to detect the frame within the correct time limit.
a) True
b) False
Answer: b
Explanation: MAC frame includes Length field to identify the type or length of the network protocols. The data field is used to ensure that the frame signals stay on the network long enough to detect the frame within the desired limit.
13. The ___________ protocol is not used when the Ethernet connections are configured for a full duplex operation.
a) TCP/IP
b) MAC
c) CSMA/CD
d) DTH
Answer: c
Explanation: In Ethernet connections, the full-duplex operation situation may lead to an increased frame dropping rate. The dropped frame cannot be detected without collision. Thus, CSMA protocol is not used in full duplex mode.
14. Optical Ethernet provides switching capabilities in layers ________
a) 1 and 2
b) 2 and 3
c) 3 and 4
d) 1 and 4
Answer: b
Explanation: Layer 2 and 3 are data link and network layers. IP routing is usually considered to be ⅔ switched network. Thus, unlike conventional LAN, optical Ethernet provides switching capabilities between layers 2 and 3.
15. The ______________ approach can provide interconnection among multiple site locations within 40 km range.
a) 3 Gbe
b) 5 Gbe
c) 1 Gbe
d) 10 Gbe
Answer: d
Explanation: The 10Gbe approach uses a 40 km window range. It can be used in LAN’s and MAN. It provides switch-to-switch network within data centers.
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