tailieunhanh - CompTIA Network+ Certification Study Guide part 26

CompTIA’s Network+ certification Study Guide part 26 is a globally-recognized, vendor neutral exam that has helped over 235,000 IT professionals reach further and higher in their careers. The 2009 Network+ exam (N10-004) is a major update with more focus on security and wireless aspects of networking. Our new study guide has been updated accordingly with focus on network, systems, and WAN security and complete coverage of today’s wireless networking standards. | 236 CHAPTER 6 The OSI Model and Networking Protocols closely together and that is why it s hard to discuss one without the other. As a matter of fact no matter how long you are in networking you will find the OSI model is referenced on a daily basis all the way from the beginning as a student to a networking master. In this chapter we look at the networking models that provide guidelines for vendors of networking products including the early Department of Defense DoD model as well as the International Organization for Standardization ISO OSI model. Next we move into the protocol suite. The majority of TCP IP fundamentals will be covered in Chapter 7. You ll also learn about the protocols that are used throughout the network communication process to ensure that data sent from a computer reach their intended destination. We also discuss popular networking protocols upon which majority of the Internet applications run. Now let s start with the OSI model and understand why it s so important. Understanding the Purpose and Function of Networking Models This chapter discusses several specific networking models so it s important to begin our discussion with an overview of the purpose and function of networking models. Just about everywhere we look in the world today we can see examples of agreed-upon rules that help people work together more effectively and efficiently to achieve a specific aim. This is especially true in the world of technology where standards specifications and protocols are used to accomplish a particular task. Why is it you can pop a DVD in your player and watch it regardless of who made the DVD the DVD player or the television It s because everyone involved agreed to certain parameters such as the circumference of the DVD disk the method of recording and reading the DVD and the interface between the DVD player and the television. The same is true in computer technology. A wide variety of methods can be used to transmit and receive data across a .