tailieunhanh - CCENT/CCNA ICND1 Official Exam Certification Guide - Chapter 2

The TCP/IP and OSI Networking Models Mô hình kết nối mạng hạn, hoặc kiến trúc mạng dùng để chỉ một tập hợp các văn bản tổ chức. Cá nhân, các tài liệu này mô tả một chức năng nhỏ cần thiết cho một mạng. Những tài liệu này có thể định nghĩa một giao thức, mà là một tập hợp các quy tắc hợp lý rằng các thiết bị phải tuân theo để giao tiếp. Các tài liệu khác có thể xác định một số yêu cầu vật chất cho mạng, ví dụ, nó có thể xác định các. | C H A P T E R 2 The TCP IP and OSI Networking Models The term networking model or networking architecture refers to an organized set of documents. Individually these documents describe one small function required for a network. These documents may define a protocol which is a set of logical rules that devices must follow to communicate. Other documents may define some physical requirements for networking for example it may define the voltage and current levels used on a particular cable. Collectively the documents referenced in a networking model define all the details of how to create a complete working network. To create a working network the devices in that network need to follow the details referenced by a particular networking model. When multiple computers and other networking devices implement these protocols physical specifications and rules and the devices are then connected correctly the computers can successfully communicate. You can think of a networking model as you think of a set of architectural plans for building a house. Sure you can build a house without the architectural plans but it will work better if you follow the plans. And because you probably have a lot of different people working on building your house such as framers electricians bricklayers painters and so on it helps if they can all reference the same plan. Similarly you could build your own network write your own software build your own networking cards and create a network without using any existing networking model. However it is much easier to simply buy and use products that already conform to some well-known networking model. And because the networking product vendors use the same networking model their products should work well together. The CCNA exams include detailed coverage of one networking model the Transmission Control Protocol Internet Protocol or TCP IP. TCP IP is the most pervasively used networking model in the history of networking. You can find support for TCP IP on