Do I Know This Already Quiz

The purpose of the "Do I Know This Already?" quiz is to help you decide whether you really need to read the entire chapter. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now.

The ten-question quiz, derived from the major sections in "Foundation Topics to portion of the chapter, helps you determine how to spend your limited study time.

Table 2-1 outlines the major topics discussed in this chapter and the "Do I Know This Already?" quiz questions that correspond to those topics.

Table 2-1 "Do I Know This Already?" Foundation Topics Section-to-Question Mapping

Foundations Topics Section

Questions Covered in This Section

The TCP/IP Protocol Architecture

1, 2, 7, 8, 9, 10

The OSI Reference Model

3, 4, 5, 6

CAUTION The goal of self-assessment is to gauge your mastery of the topics in this chapter. If you do not know the answer to a question or are only partially sure of the answer, you should mark this question wrong for purposes of the self-assessment. Giving yourself credit for an answer that you correctly guess skews your self-assessment results and might provide you with a false sense of security.

1. Which of the following protocols are examples of TCP/IP transport layer protocols?

a.

Ethernet

b.

HTTP

c.

IP

d.

UDP

e.

SMTP

f.

TCP

g.

PPP

2. Which of the following protocols are examples of TCP/IP network interface layer protocols?

a. Ethernet b. HTTP

e. SMTP

3. Which OSI layer defines the functions of logical network-wide addressing and routing?

a.

Layer 1

b.

Layer 2

c.

Layer 3

d.

Layer 4

e.

Layer 5

f.

Layer 6

g.

Layer 7

4. Which OSI layer defines the standards for cabling and connectors?

a.

Layer 1

b.

Layer 2

c.

Layer 3

d.

Layer 4

e.

Layer 5

f.

Layer 6

g.

Layer 7

5. Which OSI layer defines the standards for data formats and encryption?

a. Layer 1

b. Layer 2

c. Layer 3

d. Layer 4

e. Layer 5

f. Layer 6

g. Layer 7

6. Which of the following terms are not valid terms for the names of the seven OSI layers?

a.

Application

b.

Data link

c.

Transmission

d.

Presentation

e.

Internetwork

f.

Session

7. The process of HTTP asking TCP to send some data and make sure that it is received correctly is an example of what?

a. Same-layer interaction b. Adjacent-layer interaction c. The OSI model d. All of the above e. None of the above

8. The process of TCP on one computer marking a segment as segment 1, and the receiving computer then acknowledging the receipt of segment 1, is an example of what?

a. Data encapsulation b. Same-layer interaction c. Adjacent-layer interaction d. The OSI model e. None of the above

9. The process of a web server adding a TCP header to a web page, followed by adding a TCP header, then an IP header, and then data link header and trailer is an example of what?

a. Data encapsulation b. Same-layer interaction c. The OSI model d. All of the above e. None of the above

10. Which of the following terms is used specifically to identify the entity that is created when encapsulating data inside data-link headers and trailers?

a. Data b. Chunk c. Segment d. Frame e. packet f. None—there is no encapsulation by the data link layer

The answers to the "Do I Know This Already?" quiz are found in Appendix A, "Answers to the 'Do I Know This Already?' Quizzes and Q&A Sections." The suggested choices for your next step are as follows:

■ 8 or less overall score—Read the entire chapter. This includes the "Foundation Topics" and "Foundation Summary" sections and the Q&A section.

■ 9 or 10 overall score—If you want more review on these topics, skip to the "Foundation Summary" section and then go to the Q&A section. Otherwise, move to the next chapter.

Foundation Topics

It is practically impossible to find a computer today that does not support the set of networking protocols called TCP/IP. Every Microsoft, Linux, and UNIX operating system includes support for TCP/IP. Hand-held digital assistants and cell phones support TCP/IP. Even IBM Mainframe operating systems support TCP/IP. And because Cisco sells products that create the infrastructure that allows all these computers to talk with each other using TCP/IP, Cisco products also include extensive support for TCP/IP.

The world has not always been so simple. Once upon a time, there were no networking protocols, including TCP/IP. Vendors created the first networking protocols; these protocols supported only that vendor's computers, and the details were not even published to the public. As time went on, vendors formalized and published their networking protocols, enabling other vendors to create products that could communicate with their computers. For instance, IBM published its Systems Network Architecture (SNA) networking model in 1974. After SNA was published, you could buy computers from other vendors as well as IBM, and they could communicate—as long as they supported IBM's proprietary SNA.

Using only vendor-proprietary networking models allowed a business to successfully communicate between computers from multiple vendors. However, to talk to a computer using the hardware or software from vendor X, you needed to use the networking protocols created by vendor X. Imagine sitting at your desk in the late 1980s and needing to work with an IBM mainframe using SNA, a DEC minicomputer using DECnet, and a Novell server using NetWare, and having to transfer files with an Apple computer using AppleTalk. Believe it or not, it actually worked, and networks using all these different protocols were not at all uncommon.

A better solution was to create a standardized networking model that all vendors would support. The International Organization for Standardization (ISO) took on this task starting as early as the late 1970s, beginning work on what would become known as the Open Systems Interconnection (OSI) networking model. The ISO had a noble goal for the OSI: to standardize data networking protocols to allow communication between all computers across the entire planet. The OSI worked toward this ambitious and noble goal, with participants from most of the technologically developed nations on Earth participating in the process.

A second, less formal effort to create a standardized, public networking model sprouted forth from a U.S. Defense Department contract. Researchers at various universities volunteered to help further develop the protocols surrounding the original department's work. These efforts resulting in a competing networking model called TCP/IP.

The world now had many competing vendor networking models and two competing standardized networking models. So what happened? TCP/IP won the war. Proprietary protocols are still in use today in many networks, but much less so than in the 1980s and 1990s. OSI, whose development suffered in part because of the slow formal standardization processes of the ISO, never succeeded in the marketplace. And TCP/IP, the networking model created almost entirely by a bunch of volunteers, has become the most prolific set of data networking protocols ever.

In this chapter, you will read about some of the basics of TCP/IP. Although you will learn some interesting facts about TCP/IP, the true goal of this chapter is to help you understand what a networking model or networking architecture really is and how one works.

Also in this chapter, you will learn about some of the jargon used with OSI. Will any of you ever work on a computer that is using the full OSI protocols instead of TCP/IP? Probably not. However, you will often use terms relating to OSI. Also, the INTRO exam covers the basics of OSI, so this chapter also covers OSI to prepare you for questions about it on the exam.

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