Wireless & Mobile Communications Multiple Choice Questions on “Integrated Services Digital Network (ISDN)”.
1. ISDN stands for ___________
a) Integrated Services Digital Network
b) Integrated Services Discrete Network
c) Integrated Services Digital Node
d) Integrated Services Discrete Node
Answer: a
Clarification: ISDN stands for integrated services digital network. It defines the dedicated signalling network that has been created to complement the PSTN for more flexible and efficient network access and signalling.
2. ISDN is based on the concept of __________
a) SS7
b) CCS
c) ARDIS
d) CDPD
Answer: b
Clarification: ISDN is a complete network framework designed around the concept of common channel signalling. While telephone users throughout the world rely on the PSTN to carry conventional voice traffic, new end-user data and signalling services can be provided with a parallel, dedicated signalling network.
3. Signalling component that supports traffic between the end-user and network is called ________
a) Network signalling
b) Digital subscriber signalling
c) Access signalling
d) Subscriber system signalling
Answer: c
Clarification: Access signalling supports traffic between the end user and the network. It defines how end users obtain access to the PSTN and the ISDN for communication or services.
4. Access signalling is governed by the SS7 suite of protocols.
a) True
b) False
Answer: b
Clarification: The second signalling component of ISDN, network signalling is governed by the SS7 suite of protocols. For wireless communication systems, the SS7 protocols within ISDN are critical to providing backbone network connectivity between MSCs throughout the world.
5. Information bearing channels in ISDN are called ______
a) D channels
b) Data channels
c) B channels
d) Voice channels
Answer: c
Clarification: The ISDN interface is divided into three different types of channels. Information bearing channels called bearer channels (B channels) are used exclusively for end user traffic (voice, data and video).
6. ISDN provides integrated end user access to only packet switched networks.
a) True
b) False
Answer: b
Clarification: ISDN provides integrated end-user access to both circuit switched and packet switched networks with digital end-to-end connectivity.
7. PRI interface in ISDN serves small capacity terminals.
a) True
b) False
Answer: b
Clarification: ISDN end users may select between two different interfaces. The BRI (basic rate interface) is intended to serve small capacity terminals while the PRI (primary rate interface) is intended for large capacity terminals.
8. Which of the following is based on ATM technology?
a) SS7
b) CCS
c) ARDIS
d) B-ISDN
Answer: d
Clarification: Emerging networking technique, broadband ISDN (B-ISDN) is based on asynchronous transfer mode (ATM) technology. It allows packet switching rates up to 2.4 Gbps and total switching capacities as high as 100 Gbps.
9. Which of the following is true for ATM?
a) Circuit switched
b) Multiple access technique
c) Multiplexing technique
d) Handle only voice users
Answer: c
Clarification: ATM is a packet switching and multiplexing technique which has been specifically designed to handle both voice users and packet data users in a single physical channel.
10. ATM supports unidirectional transfer of data.
a) True
b) False
Answer: b
Clarification: ATM supports bidirectional transfer of data packets of fixed length between two end points. It preserves the order of transmission.
11. The data unit of ATM is ___________
a) Cell
b) Atom
c) Molecule
d) Packet
Answer: a
Clarification: The data unit of ATM is cell. They are routed based on header information in each unit (called a label) that identifies the cell as belonging to a specific ATM virtual connection.
12. ATM cells have fixed length of __________
a) 48 bytes
b) 47 bytes
c) 5 bytes
d) 53 bytes
Answer: d
Clarification: ATM cells have a fixed length of 53 bytes. It consists of 48 bytes of data and 5 bytes of header information. Fixed length packets result in simple implementation of fast packet switches.
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