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CompTIA Network+ Certification Study Guide part 60

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CompTIA’s Network+ certification Study Guide part 60 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. | 576 CHAPTER 12 Network Troubleshooting Methodology The first networking protocols were proprietary that is each networking vendor developed its own set of rules. Computers using an individual vendor s protocol would be able to communicate with each other but not with computers that were using the networking product of a different vendor. This had the effect of locking a business into a particular product the business would always have to use the same vendor s products to maintain compatibility. The solution to this problem was the development of protocols based on open standards. Organizations such as the International Organization for Standardization ISO were charged with overseeing the definition and control of these standards and publishing them so they would be available to any vendor that wanted to create products that adhered to them. The advantage to the consumer is that no longer is he forced to patronize a single vendor. The advantage to the vendor is that its products are more widely compatible and therefore can be used in networks that started out using a different vendor s products. A model provides an easy-to-understand description of the networking architecture and serves as the framework for the standards. The OSI model has become a common reference point for discussion of network protocols and connection devices. As we look at the OSI and DoD models you ll see that they both use layers to represent areas of functionality. In OSI terms each of the layered specifications uses the services of the layer below it to build an enriched service. The layered approach provides a logical division of responsibility where each layer handles only the functions that are specific to that layer. You can think of this like the teamwork exhibited by a good assembly-line crew that s building an automobile. One worker may be responsible for fitting a wheel onto the axis another for inserting and tightening the screws and so forth. There are several advantages to this .