Configuration requirements tracing ensures that the configuration changes are traceable back to user requirements either directly (e.g., a user-requested change) or indirectly (e.g., better user support through improved system performance).
Configuration status accounting reports the current status of components in the configuration and components undergoing change or about to be added.
61. Which of the following are countermeasures against network weaving?
1. Traffic flow signal
2. Traffic encryption key
3. Tunneling
4. Traffic padding
a. 1 and 2
b. 1 and 3
c. 2 and 4
d. 3 and 4
61. d. Network weaving is a penetration technique in which different communication networks are linked to access an information system to avoid detection and trace-back. Tunneling enables one network to send its data via another network’s connections. It works by encapsulating a network protocol within packets carried by the second network. Traffic padding generates mock communications or data units to disguise the amount of real data units being sent. The other two items cannot control network weaving penetration. Traffic flow signal is used to conduct traffic flow analysis. Traffic encryption key is used to encrypt plaintext or to super-encrypt previously encrypted text and/or to decrypt cipher-text.
62. Which of the following supports the cloud computing infrastructure most?
a. Virtualization technology
b. Service-oriented architecture
c. Web 2.0 services
d. Utility computing
62. a. Cloud computing, an emerging form of distributed computing, is an amalgamation of technologies, including virtualization, service-oriented architecture, Web 2.0 services, and utility computing. Out of these technologies, virtualization has taken a prominent role due to use of multiple virtual machines and guest virtual machines.
Virtualization technology enables multiple operating systems (OSs) to coexist on a computing platform. In virtualization, special purpose software successfully replicates the behavior of hardware. Through such methods, a single physical host computer can run multiple virtual machines, each with a distinct guest OS and associated applications. Various virtualization products exist that can be used to provide an isolated virtual machine environment for systems and applications to execute. Risky functions, such as Web browsing, may be confined to a virtual system designated and configured exclusively for that purpose. Should the virtual system be compromised, it can easily be restored to a known-good state.
Service-oriented architecture is a collection of services, which communicate with each other. The communication can involve either simple data passing or it could involve two or more services coordinating some activity. Web 2.0 service is the second-generation of Internet-based services that enables people to collaborate and create information online in new ways, such as social networking sites, wikis, and communication tools. Utility computing deals with on-demand network access and self-service facilities for subscribers.
63. Which of the following is an operational issue in data communications networks?
a. Network modularity and adaptability
b. Network performance and throughput
c. Network availability and redundancy
d. Network size and interoperability
63. b. Performance management consists of day-to-day system requirements and evaluation to assess current performance and to identify and implement system adjustments that can improve performance. To ensure efficiency, the performance management staff must know the workloads imposed by users, the levels of service required to satisfy workloads, and current capacity. The other three choices are incorrect because they are examples of network planning and design issues.
64. Asynchronous transfer mode (ATM) is an example of a fast packet-switching network. Which of the following statements about ATM is not true?
a. ATM networks can carry data communications.
b. ATM networks can carry video communications.
c. ATM networks use long packets with varying sizes.
d. ATM networks can carry voice communications.
64. c. There are two different kinds of fast packet-switching networks: ATM and PTM. Asynchronous transfer mode (ATM) networks use short packets called “cells” that are always the same length. Packet transfer mode (PTM) does not use short cells but more additional packets that can be longer if necessary. Most packet-switching networks use packets that can be long and vary in size depending on the data being carried. The ATM network can carry data communications where packets are broken into several ATM cells. After travelling through the network, the cells are reassembled into packets. It can also carry video communications where the digital video bits are put in cells and sent through the network. At the destination, the bits are removed from the cells. The ATM also carries voice communications, and the voice is handled in the same way as video.
65. Which of the following effectively facilitates telecommuting?
a. Integrated services digital network
b. Regular modems
c. Facsimile/modems
d. Intelligent modems
65. a. Telecommuting enables employees to work from a remote location. An integrated services digital network (ISDN) can be considered as an “intermediate” step between the current analog local loop and the use of fiber optics. Because of the cost of deploying fiber, it may take a long time before homes are connected. ISDN is cheaper than fiber, can be deployed sooner, and although its capacity is only a fraction of fiber, represents a significant improvement over the current analog local loop. To connect to the office computers, employees need a device called a modem, which enables them to send digital computer data over the analog local loop. ISDN provides higher bits-per-second channels than modems. This would enable videoconferencing of reasonable quality, faster transfer of graphics information, and better quality fax transmission. It would also permit much-improved access to the Internet for home users.
Regular modems, facsimile/modems, and intelligent modems do not have the bits-per-second-channel capacity as that of ISDN. A modem is a device that modulates and demodulates. Modems are primarily used for converting digital signals into quasi-analog signals for transmission over analog communication channels and reconverting the quasi-analog signals into digital signals.
Facsimile/modem combines the features of fax and modem. Intelligent modems are intelligent because they add random-access memory, read-only memory, and erasable programmable read-only memory. Some major functions of intelligent modems include automatic dialing, negotiation of the method of modulation used to communicate with a distant modem, error detection and correction operations to ensure data integrity, and responses to status requests. Regular modems do not have the intelligence so that they cannot perform fax operations.
66. Which of the following information technologies is better equipped to deliver multimedia applications?
a. Integrated services digital network (ISDN) and broadband ISDN
b. Narrowband ISDN, central office switches, and copper-based local loops