Tài liệu giảng dạy CCNA - module 01 chapter 02 -The TCP IP and OSI Networking Models

1 Module 01 InterNetwork Overview Chapter 02 The TCP/IP and OSI Networking Models 2 Table of Content 1 The TCP/IP protocol architecture 2 The OSI model. 3 1. THE TCP/IP PROTOCOL ARCHITECTURE 4 The TCP/IP Application Layer  TCP/IP application layer protocols provide services to the application software running on a computer. The application layer does not define the application itself, but rather it defines services that applications need—like the ability to transfer a file in the case of HTTP. In short, the application layer provides an interface between software running on a computer and the network itself. 5 The TCP/IP Application Layer (cont.)  First, the request for the file and the actual transfer of the file are performed according to the Hypertext Transfer Protocol (HTTP).  The other protocol used is the Hypertext Markup Language (HTML). HTML defines how Bob’s web browser should interpret the text inside the file he just received. TCP/IP Network Give me your home page This is file home.htm Web server Web client Larry Bob 6 The TCP/IP Application Layer (cont.)  To get the web page from Larry, Bob sends something called an HTTP header to Larry. This header includes the command to “get” a file.  The response from Larry includes an HTTP header as well, with something as simple as “OK” returned in the header. HTTP Header: get home.htm HTTP Ok Contents home.htm Web server Web client Larry Bob 7 The TCP/IP Transport Layer HTTP Get HTTP GetTCP HTTP Ok Web pageTCP TCP Acknowledgment TCP Acknowledgement Please Reliably Send This, Mr. TCP! Web server Web client 8 Summary: Same-Layer and Adjacent-Layer Interactions Source Destination Physical Medium Peer layers - PDUs 4 4 Request services Provide services 9 The TCP/IP Internetwork Layer  IP defines logical addresses, called IP addresses, that allow each TCP/IP speaking device (called IP hosts) to communicate.  It also defines routing—the process of how a router should forward, or route, packets of data. HTTP Get HTTP GetTCP HTTP GetTCPIP Destination 1.1.1.1 Source 2.2.2.2 Bob 2.2.2.2 Larry 1.1.1.1 10 The TCP/IP Network Interface Layer  The network interface layer defines the protocols and hardware required to deliver data across some physical network. The term network interface refers to the fact that this layer defines how to connect the host computer to the network; it is the interface between the computer and the network.  The network interface layer includes a large number of protocols: LAN standards such as Ethernet, WAN standards such as PPP, Frame Relay. [...]... Both have comparable transport and network layers  Both models need to be known by networking professionals  Both assume packets are switched 16 Comparing TCP/ IP with OSI (cont.) Differences:  TCP/ IP combines the presentation and session layer issues into its application layer  TCP/ IP combines the OSI data link and physical layers into the network access layer  TCP/ IP appears simpler because it...Encapsulation example: E-mail 11 2 THE OSI MODEL 12 OSI reference model development  Researched and developed by the ISO - International Organization for Standardizations  1977: establish a subcommittee to develop a communications architecture  1984: publish ISO-7498, the Open System Interconnection (OSI) reference model 13 OSI reference model A framework that is used to understand how information travels... fewer layers 17 Layers of OSI reference model  Layer  Layer  Layer  Layer  Layer  Layer  Layer 7: 6: 5: 4: 3: 2: 1: Application Presentation Session Transport Network Data Link Physical 18 OSI layers: layer 1 19 OSI layers: layer 2 20 OSI layers: layer 3 21 OSI layers: layer 4 22 OSI layers: layer 5 23 OSI layers: layer 6 24 OSI layers: layer 7 25 OSI layers: Summary 26 OSI reference model (cont.)... travels throughout a network  It provided vendors with a set of standards that ensured greater compatibility and interoperability between the various types of network technologies that were produced by the many companies around the world  The OSI reference model: model Proprietary vs Open 14 Comparing TCP/ IP with OSI 15 Comparing TCP/ IP with OSI (cont.) Similarities:  Both have layers  Both have application... protocol specifications  Easier to learn  Easier to develop  Multivendor interoperability  Modular engineering 28 OSI Encapsulation Process 29 Encapsulation example: E-mail 30 Summary  You learned about how TCP/ IP protocols at the various layers work with each other and how TCP/ IP encapsulates data  Each layer provides a service to the layer above it in the protocol specification  Each layer... smaller, more manageable parts  It standardizes network components to allow multiple vendor development and support  It allows different types of network hardware and software to communicate with each other  It prevents changes in one layer from affecting other layers  It divides network communication into smaller parts to make learning it easier to understand 27 Benefits of layered protocol specifications... specification  Each layer communicates with the same layer’s software or hardware on other computers  To accomplish these tasks, the data is encapsulated progressively with new headers when sending the data and is de-encapsulated when receiving the data 31 . 1 Module 01 InterNetwork Overview Chapter 02 The TCP/ IP and OSI Networking Models 2 Table of Content 1 The TCP/ IP protocol architecture 2 The OSI model. 3 1. THE TCP/ IP PROTOCOL ARCHITECTURE. client Larry Bob 7 The TCP/ IP Transport Layer HTTP Get HTTP GetTCP HTTP Ok Web pageTCP TCP Acknowledgment TCP Acknowledgement Please Reliably Send This, Mr. TCP! Web server Web client 8 Summary: Same-Layer and. transport and network layers.  Both models need to be known by networking professionals.  Both assume packets are switched. 17 Comparing TCP/ IP with OSI (cont.) Differences:  TCP/ IP combines