Part I: Introduction to Scalable Networks

This chapter covers the following topics:

Building Scalable Networks—Describes how scalability and multiplexing simplify network design.
Enterprise Architecture—Describes the older hierarchical model and the newer enterprise composite model.
SONA and IIN—Describes the three phases of the Intelligent Information Network (IIN) and how Services-Oriented Network Architecture (SONA) applies the IIN ideas to enterprise networks.
Comparing Routing Protocols—Compares the different features of RIP (versions 1 and 2), OSPF, EIGRP, IS-IS, and BGP.

This first chapter includes a variety of concepts, some of which are expanded on later in the book, some of which are simply here to expose you to a set of ideas. Regardless of the motivation, all the topics covered in this chapter are on the Building Scalable Cisco Internetworks (BSCI) exam and should be understood.

Network design is an important topic and is covered here at the depth necessary to define terms and standards about implementation. These terms form a foundation for the rest of the book.

Services-Oriented Network Architecture (SONA) and Intelligent Information Network (IIN) are also broadly described in this chapter. They are only covered to the extent you might expect to see them on the exam.

This is a book about routing protocols, and a comparison and theoretical discussion of the different routing protocols is found here. Again, this section is important because it helps describe similarities and unique features and sets the stage for the chapters to come.

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

The 12-question quiz, derived from the major sections in the "Foundation Topics" portion of the chapter, helps you determine how to spend your limited study time.

Table 1-1 outlines the major topics discussed in this chapter and the corresponding quiz questions.

Table 1-1. "Do I Know This Already?" Foundation Topics Section-to-Question Mapping
Foundation Topics Section	Questions Covered in This Section	Score
Building Scalable Networks	1–2
Enterprise Architecture	3–5
SONA and IIN	6–8
Comparing Routing Protocols	9–12
Total Score

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 the question wrong for purposes of the self-assessment. Giving yourself credit for an answer you correctly guessed skews your results and might provide you with a false sense of security.

1.	How many links are required to form a full mesh of eight devices? 7 28 80 Not possible
2.	What does a "scalable" design indicate? The design can be "unfolded" to fit various sizes. The design grows without causing the endpoint costs to grow. Only large enterprises can use this design. The design uses EIGRP and BGP.
3.	Which of the following describe the hierarchical network model? Switching, Routing, Provider Access, Distribution, Core Physical, Data Link, Network Red, Blue, Black

4.	In the standard hierarchical design, what elements are found within a switch block? Two core switches and some number of distribution switches Two distribution Layer-2 switches and some number of Layer-1 access switches Two distribution Layer-3 switches and some number of Layer-2 access switches One access switch per department
5.	What are the key differences between traditional hierarchical design and the enterprise composite model? Hierarchical design has three layers, the Enterprise Composite Model has five. Servers and WAN connections are defined. The hierarchical design model is Cisco-specific. The enterprise composite model is superseded by AON.
6.	What is the goal of the SONA network infrastructure layer? Provide a hierarchical and converged network Allow for integration of Service and Network Support dynamic resource allocation Provide for accounting and billing services
7.	Which SONA layer corresponds to IIN phase two? Network infrastructure Application Session Interactive services
8.	What is the goal of IIN phase three? To create service-aware networks To converge voice and data networks To provide complete redundancy To allow for pervasive network management

9.	Which of the following routing protocols is proprietary? RIP OSPF EIGRP BGP
10.	Which of the following routing protocols is meant to work between autonomous systems? RIP OSPF EIGRP BGP
11.	Which of the following routing protocols converge much more quickly than the others? RIP IGRP OSPF EIGRP
12.	Which of the following routing protocols are classless? RIP OSPF EIGRP BGP

The answers to the "Do I Know This Already?" quiz are found in Appendix A, "Answers to Chapter 'Do I Know This Already?' Quizzes and Q&A Sections." Compare your score with the following suggestions to determine how to proceed:

8 or less overall score—Read the entire chapter. This includes the "Foundation Topics," "Foundation Summary," and "Q&A" sections.
9 or 10 overall score—Begin with the "Foundation Summary" section, and then go to the "Q&A" section at the end of the chapter. If you have trouble answering the Q&A questions, read the appropriate sections in "Foundation Topics."
11 or 12 overall score—If you want more review on these topics, skip to the "Foundation Summary" section and then go to the "Q&A" section at the end of the chapter. Otherwise, move to the next chapter.