CSN200 Introduction to Telecommunications, Winter 2000Review Questions for Test-1 (with Answers)
Review Questions for Test-1 (with Answers):
Chapter 1: Introduction to Data Communications
Outline
1.1 Network Basics
1.2 Network Layer Model (most important)
1.3 Network Standards
1.4 Future Trends (least important)
Answers to End-of-Chapter Questions
- Describe the progression of communications systems from the 1800s to the present.
Communications systems progression from the 1800s to the present:
1837Invention of the telegraph
1876Invention of the telephone
1877Telephone system regulation begins in Canada
1878Telephone system regulation begins in the United States
1879Direct dialed long distance service begins
1880Satellites begin to transmit international telephone calls
1881Caterfone court decision permits non-Bell telephone equipment to be used
1970Court permits MCI to provide long distance services
1984Breakup of AT&T
1985Cellular phones enter service
1996Telecommunications Act of 1996 deregulates American telephone system
- Why are network layers important?
Communication networks are often broken into a series of layers, each of which can be defined separately, to enable vendors to develop software and hardware that can work together in the overall network.
- Describe the four layers in the network model used in this book and what they do.
- The application layer is the application software used by the user.
- The network layer takes the message generated by the application layer and if necessary, breaks it into several smaller messages. It then addresses the message(s) and determines their route through the network, and records message accounting information before passing it to the data link layer.
- The data link layer formats the message to indicate where it starts and ends, decides when to transmit it over the physical media, and detects and corrects any errors that occur in transmission.
- The physical layer is the physical connection between the sender and receiver, including the hardware devices (e.g., computers, terminals, and modems) and physical media (e.g., cables, and satellites).
- Explain how a message is transmitted from one computer to another using layers.
The application layer is the application software used by the network user. The network layer takes the message generated by the application layer and if necessary, breaks it into several smaller messages. It then addresses the message(s) and determines their route through the network, and records message accounting information before passing it to the data link layer. The data link layer formats the message to indicate where it starts and ends, decides when to transmit it over the physical media, and detects and corrects any errors that occur in transmission. The physical layer is the physical connection between the sender and receiver, including the hardware devices (e.g., computers, terminals, and modems) and physical media (e.g., cables, and satellites).
- Describe the three stages of standardization.
The formal standardization process has three stages: specification, identification of choices, and acceptance. The specification stage consists of developing a nomenclature and identifying the problems to be addressed. In the identification of choices stage, those working on the standard identify the various solutions and choose the optimum solution from among the alternatives. Acceptance, which is the most difficult stage, consists of defining the solution and getting recognized industry leaders to agree on a single, uniform solution.
- How are Internet standards developed?
The Internet Engineering Task Force (IETF) sets the standards that govern how much of the Internet will operate. Developing a standard usually takes 1-2 years. Usually, a standard begins as a protocol developed by a vendor. When a protocol is proposed for standardization, IETF forms a working group of technical experts to study it. The working group examines the protocol to identify potential problems and possible extensions and improvements, and then issues a report to IETF. If the report is favorable, the IETF issues a Request for Comment (RFC) that describes the proposed standard and solicits comments from the entire world. Once no additional changes have been identified, it becomes a Proposed Standard. Once at least two vendors have developed software based on it, and it has proven successful in operation, the Proposed Standard is changed to a Draft Standard. This is usually the final specification, although some protocols have been elevated to Internet Standards, which usually signifies a mature standard not likely to change.
- Describe two important data communications standards-making bodies. How do they differ?
The International Organization for Standardization (ISO) makes technical recommendations about data communication interfaces. The Telecommunications group (ITU-T) is the technical standards-setting organization of the United Nations International Telecommunications Union (ITU). Postal Telephone and Telegraphs (PTTs) are telephone companies outside of the United States. ITU-T establishes recommendations for use by PTTs, other common carriers, and hardware and software vendors.
- What is the purpose of a data communication standard?
The use of standards makes it much easier to develop software and hardware that link different networks because software and hardware can be developed one layer at a time. The software or hardware defined by the standard at one network layer can be easily updated, as long as the interface between that layer and the ones around it remains unchanged.
- Discuss three trends in communications and networking.
Pervasive networking will change how and where we work and with whom we do business. With virtually every everyone able to connect to any other person or organization in the world, we will see a rise in telecommuting, EDI, and the globalization of industries. The integration of voice, video, and data onto the same networks will greatly simplify networks and enable anyone to access any media at any point. The rise in these pervasive, integrated networks will mean a significant increase the availability of information and new information services.
TRUE/FALSE
The the answer is provided in square brackets.
1.In an information society, the strategic resource is capital. [False, it is information.]
2.The information lag is the time it takes for information to be disseminated around the world. [True]
3.The World Wide Web was initially developed in a United States research lab. [False, it was developed in a Swiss research lab.]
4.In the 1870’s, Alexander Graham Bell developed the first telephone that could transmit understandable conversation. [True]
7.The Internet began in 1969 as a network of American military and academic computers. [True]
8.The most important aspect of computers is networking as we enter the new century. [True]
9.The strict definition of data communications is the movement of voice, video, and data information from one point to another by means of electrical or optical transmission systems. [False, that is the definition of telecommunications, a broader term.]
13.One of the most important models for describing network layers is the Open Systems Interconnection (OSI) Model. [True]
14.The data link layer of this book’s simplified four-layer network model is the physical connection between the sender and receiver. [False, that is the definition of the physical layer.]
15.Data communication standards enable each layer in the sending computer to communicate with its corresponding layer in the receiving computer. [True]
16.Network standards permit customers to purchase hardware and software from different vendors, as long as the equipment meets the standards. [True]
17.In the formal standardization process, the specification stage consists of defining the solution and getting recognized industry leaders to agree on a single, uniform solution. [False, that is the Acceptance stage.]
18.The International Organization for Standardization (ISO) is based in Geneva, Switzerland. [True]
19.Pervasive networking, a key trend for the future, means that virtually any computer will be able to communicate with any other computer in the world. [True]
20.The high bandwidth requirements (high communications needs) for video has slowed its integration into all types of networks. [True]
MULTIPLE CHOICE
The answer is provided under the choices.
- An information society is dominated by:
- capital and natural resources
- computers, communications, highly skilled individuals
- unions and transportation
- farmers and agriculture
- labor and management
Answer: b
- The value of a current high speed data communication network is that it:
- can handle or process all the quantities of information it receives
- brings the message sender and receiver closer together in time
- increases the information lag
- can be used primarily for batch processing
- can tie ‘dumb’ terminals to a central mainframe
Answer: b
- The software used by the network user is located in the:
- resident layer
- application layer
- network layer
- data communication layer
- physical layer
Answer: b
- Which of the following is not a function of the network layer?
- defining what messages are sent over the network
- translating the destination of the message into an address understood by the network
- deciding which route the message should take
- breaking long messages into several smaller messages
- none of the above are appropriate answers
Answer: a
- Which of the following is not a function of the data link layer?
- deciding when to transmit messages over the media
- specifying the type of connection, and the electrical signals, radio waves, or light pulses that pass through it
- formatting the message by indicating where messages start and end, and which part is the address
- detecting and correcting any errors that have occurred in the transmission of the message
- controlling the physical layer by determining when to transmit
Answer: b
- Which of the following is a type of network application software?
- Web browser
- router
- gateway
- hub
- fiber optic cable
Answer: a
- The primary reason for networking standards is to:
- ensure that hardware and software produced by different vendors can work together
- make it more difficult to develop hardware and software that link different networks
- ensure that all network components of a particular network can be provided by only one vendor
- lock customers into buying network components from one vendor
- simplify cost accounting for networks
Answer: a
- Which of the following is not true about formal standards?
- They can take several years to develop.
- They can be developed by an official industry body.
- One example exists for network layer software (TCP/IP).
- They are always developed before de facto standards.
- They can be developed by a government body.
Answer: d
- Which of the following is not true about de facto standards?
- They tend not to be developed by an official industry or government body
- They never evolve into formal standards
- They are those that standards that emerge in the marketplace
- They are generally supported by more than one vendor
- They tend to emerge based upon the needs/response of the marketplace
Answer: b
- Which of the following is a stage of the formal standardization process?
- implementation
- identification of choices
- post-implementation review
- analysis
- testing
Answer: b
- Which of the following is not true about ISO:
- It is based in Geneva, Switzerland
- It is an acronym for title of the organization, International Organization for Standardization, per the original language (French) used for the organization’s title
- It is one of the most important standards-making bodies
- It was formerly called the Consultative Committee on International Telegraph and Telephone
- It makes technical recommendations about data communications interfaces
Answer: d
- Which of the following is not true about ITU-T:
- It is the technical standards-setting organization of the United Nations International Telecommunications Union
- It was formerly called the CCITT
- It is based in Geneva, Switzerland
- Its membership is limited to U.S. telephone companies
- Its membership is comprised of over 150 representatives
Answer: d
- Which of the following is not a member of ITU-T?
- PTTs
- private telecommunications agencies
- the Canadian Supreme Court
- RBOCs
- scientific organizations
Answer: c
- Which of the following is not an important future trend in communication and networking?
- pervasive networking
- integration of voice, video, and data
- all computers will be networked to other computers
- using the same network for data, voice, and video
- developing online batch systems
Answer: e
- Pervasive networking means that:
- the cost of computers will be higher in the future
- virtually all computers will be networked in some way to other computers
- the four-layer network model will be used to design all networks
- common carriers must sell their services to all individuals
- cable companies will offer more than 150 network selections for viewers
Answer: b
- Which of the following is not a potential advantage for a telecommuter?
- higher quality of life
- more time driving to work
- lower expenses for commuting
- less stress
- lower expenses for clothing
Answer: b
- EDI is:
- Electronic Data Interchange, the paperless transmission between companies of orders, invoices, and other business documents
- Electric Data Image, the wiring of buildings for electricity, data communications, voice communications, image processing
- Electronic Document Interfacing, the automatic storage and forwarding of documents via facsimile machines
- Email Distribution Interchange, a new standard for email
- none of these
Answer: a
- As we enter the next century, we are moving from the ______era to the information era in which ______is the single most valuable resource of an enterprise.
- capital/labor, management
- manufacturing/management, information
- transportation/distribution, capital
- batch processing, transaction processing
- agricultural, management
Answer: b
- The study of data communications provides an:
- understanding of hardware, software, and transmission facility alternatives
- ability to make informed decisions among the alternatives and to integrate these decisions into a cohesive network design
- understanding of how to remain informed about changing technology
- understanding of the changing regulatory environment affecting the domestic and foreign telephone marketplace
- all of these
Answer: e
- Which of the following is not an objective of data communications networks?
- to reduce the time, effort, and cost required to perform various business tasks
- to capture business data at its source and rapidly distribute it
- to support improved management control, such as inventory control, of the organization
- to provide the COBOL programming ‘fix’ for the Year 2000 problem
- to support the ‘office of the future’ that can interconnects microcomputers, mainframe computers, FAX machines, teleconferencing equipment, and other equipment
Answer: d
- Which of the following business organizations would not benefit from the use of data communications?
- organizations using large numbers of microcomputers
- organizations having a high volume of mail and messenger service or numerous telephone calls between their various sites
- organizations with repetitive paperwork operations, such as re-creating or copying information
- organizations, such as Wal-Mart, with strong value chain ties to suppliers and customers
- all of these
Answer: e
- Which of the following has not contributed directly to the growing demand for networking expertise?
- the invention of the mouse as an input device for the computer
- the growth of use of the Internet and the World Wide Web
- the deregulation of the telephone industry
- the wide variety of hardware innovations that have changed the nature of networking
- the wide variety of software innovations that have changed the nature of networking
Answer: a
- Which of the following magazines would not be useful in the study of data communications?
- Communications Week
- LAN Times
- Network Computing
- Datamation
- all of the above would be useful
Answer: e
- An information society is dominated by:
- Capital and natural resources
- Computers, communications, highly skilled individuals
- Unions and transportation
- Farmers and agriculture
Answer: b
- Serial transmission is preferred over parallel transmission for longer distances. True or False?
- True
- False
Answer: a
- Use the following list of Standards Organizations to select the correct answers for the following question [Note: Not all choices in the list are valid Standards Organizations.]
- OSI
- EIA
- ISO
- IEEE
- ANSI
- Which standards organization created the 7-layer model for computer networks?
(A B C D E )
Answer: c
- For the following three questions match the best example from the list below for each of the three data communications modes identified:
- A conversation on CB radio.
- A television broadcast.
- A modem connection on the Internet in which you are downloading a file at the same time as you are searching for information using a browser.
- Simplex (A B C )
Answer: b
- Half Duplex (A B C)
Answer: a
- Full Duplex (A B C)
Answer: c
- A walkie-talkie link uses:.
- simplex transmission
- half duplex transmission
- full duplex transmission
- triplex transmission
Answer: b
- TV transmission of your favorite program is an example of:
- simplex transmission
- half duplex transmission
- full duplex transmission
- triplex transmission
Answer: a
- Data is transmitted from one computer to another in the ______layer.
- top
- data
- physical
- transmission
Answer: c
- The predominant method of transferring information in data communications is ______mode transmission.
- parallel
- serial
- broadbased
- monospaced
Answer: b
- The transmission of voice, graphics, images and video as well as data is called:
- data communications
- telecommunications
- telephony
- telegraphy
Answer: b
- The Common Carriers are companies provide public services by carrying:
- Nickel from Sudbury
- electronic messages
- Wood
- all of the above
Answer: b
- Standardization and layering of the communication network allows product development modularized results in easy development and time saving..
- True
- False
Answer: a