Type:
Solution Manual
Resource:
Business Data Communications
Edition:
1st Edition
Author(s):
Manish Agrawal
Business Data Communications Instructor manual containing solutions to end-of-chapter questions This document has been created for the convenience of instructors. Answers to all the end of chapter questions have been provided here. All chapters have four kinds of questions. These questions are designed to give students the opportunity to learn the chapter material more effectively. The format has been motivated by Bloom’s taxonomy,1 which is shown Figure 1: Bloom’s taxonomy in Figure 1. Learning is believed to be classified into levels with recall at the lowest layer and increasingly complex and abstract mental levels at higher layers. The challenge Creating is that while most school work requires learning at the Evaluating remembering level, most professional work requires sustained performance at the evaluating and creating levels.
Analyzing Applying
Understanding The review questions at the end of chapter help students Remembering develop a base of knowledge at the remembering level. The hands-on exercises help students learn at the understanding and applying levels. The example case in each chapter is intended to facilitate applying and analyzing. Finally, the network design case promotes evaluation and creation. The questions do take time to answer. The hands-on exercise and network design case in particular, can be significantly time consuming. But most students express a strong desire for hands-on activities and fortunately, a lot of information about computer networks can be gathered using simple utilities available on every personal computer. I believe that the time invested in completing these end-ofchapter exercises will be well rewarded at the time of job interviews and in the workplace. Some chapters also have question(s) under the head “critical thinking”. The goal of these questions is to facilitate learning at the evaluating level. Unfortunately however, this section was not fully developed for this edition. I ask students to answer all four categories of end-of-chapter questions. Students overwhelmingly prefer being assigned one chapter at a time, immediately after the chapter has been covered in class. Since the questions involve a good amount of work in answering and grading, I find it useful to allow students to work in group of up to two students each. This gives students the opportunity to work in a team, and also to get to know another student in the class.
Comments to instructors are shaded for convenience. 1
http://www.odu.edu/educ/roverbau/Bloom/blooms_taxonomy.htm (accessed 11/18/2010)
Chapter 1 - Introduction Review questions 1. What is business data communications? Business data communications is the movement of information from one computer application on one computer to another application on another computer by means of electrical or optical transmission systems. 2. What are some of the ways in which computer networks are used in large businesses? Large businesses use computer networks in various ways. Web sites are used to provide marketing information to customers. Internal networks are used by employees to share inventory and other information from a central repository. Applications such as mail allow employees to communicate with internal and external stakeholders. Networks allow sharing of hardware such as printers. Instructors may like to identify a prominent local company and find out how they use computer networks. Even simple examples are interesting to students. This and the next question are a great topic for a guest speaker, who can be invited to come in and talk about how their company uses computer networks to add business value. 3. What are some of the ways in which small businesses can benefit from computer networks? Small businesses can use computer networks for things such as online marketing, email and printer sharing. Small businesses could also create small database applications to be shared from multiple computers. 4. Look at the websites of some departments of your county government. What three services offered at these sites do you find most interesting? County governments offer many services such as property records search, online property tax payments, traffic citation payments, library catalogs, meeting schedules and job postings. 5. Describe how the three online government services you chose could be helpful to you. Residents can verify tax property payment status and other information from the convenience of their homes; they can pay any traffic citations online, reserve library books online, find out about public meetings about issues that concern them and also apply for jobs online.
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6. Describe the major trends in the growth of Internet traffic. Projected statistics about the growth of the Internet are drawn from the Cisco report. It is estimated that the total volume of Internet traffic in 2008 was 7,294 Peta Bytes per month. And this number is growing at the rate of 42% per year. Internet traffic growth is being driven by both consumers and businesses, with consumers driving a larger share of the growth recently. This is because of the emergence of video as a major Internet application. The highest growth rates are in Latin America, driven by the entry of new Internet users in these countries. These statistics are primarily from the CISCO IP traffic forecast report for 2006 – 2012 that is referenced in the chapter. Students may note that there are few other business statistics that are already so large and yet are experiencing such high growth rates. 7. What is packetization? Packetization is the process of breaking down user data into small segments and packaging each of these segments appropriately so that they can be delivered and reassembled across the network. Data segments produced by packetization are generally called packets, although the terms frames and datagrams are also used. Packetization is therefore the idea of sending information as small blocks of information. 8. Why is packetization useful in business data communication? Packetization is useful in business data communication because it makes for easy transport of data. Packet networks can serve as a common infrastructure for all forms of information transfer, including phone, video and data. 9. What are some of the factors that make packet switching more complex technologically than traditional phone circuits (circuit switching)? Packet switching is more complex than circuit switching because it requires data to be segmented into packets at the sending end, and reassembled from packets at the receiving end. The packets need to be delivered reliably to the destination. However, the rewards of the complexity are efficiency. Experiments suggest that packet switching can send up to 100 times more data using the same network resources as circuit switching. 10. Provide a high-level overview of the structure of a typical data packet. What are the kinds of information you are likely to find in the header of a typical packet? Page 3
Each packet has 2 parts – the body and the header. The body of the packet is the segment from the original data carried by the packet. The header is the information added to the body during packetization. The header information aids in the delivery of the packet to the correct destination without errors. The header also enables the body of the packet to be correctly reassembled with the bodies delivered by other packets. The kinds of information in a typical packet header include the address of the data source, the destination, and error detecting information. 11. Consider a typical office memo as a data packet. What information in the memo would be characterized as header information? What information would be characterized as the body of the packet? The information in the memo that would be characterized as header information would be the identification of the sender, the receiver, and the subject line. Information that would be characterized as the body of the packet would be the actual writing in the main part of the memo - the content that the memo is intended to convey. The goal of this question is to motivate students to think in terms of analogies. The memo is a very close analogue of a data packet. 12. Why is Internet traffic considered “bursty” compared to voice traffic? Bursty traffic is traffic that occurs in distinct spurts, interspersed by periods of silence. Internet traffic is considered bursty compared to voice traffic because people generally speak in long sentences and the periods of silence are few and far between. By contrast, on the Internet, users typically ask for information that is delivered almost instantaneously by the network generating a burst of traffic. This burst is followed by a relatively long period of silence as the user processes the downloaded information before seeking additional information. Therefore on the Internet, the traffic flow generated by an individual user is quite bursty. 13. What is layering? Layering is the practice of arranging functionality of components in a system in a hierarchical manner such that lower layers provide functions and services that support the functions and services of higher layers. The end user in a layered system interacts only with the top-most layer. The lowest layer typically interacts with physical world to perform the task requested by the end user. 14. Why is layering useful in organizations?
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