复旦大学：《计算机网络 Computer Networking》课程教学资源（PPT课件讲稿）An Introduction to Networking

计算机网络 胥正川( XU Zhengchuan) 管理学院信息管理与信息系统系 办公室:思源楼708室,电话:25011237 Email:zexu@fudan.edu.cn

1 计算机网络 胥正川（XU Zhengchuan） 管理学院 信息管理与信息系统系 办公室：思源楼708室，电话：25011237 Email: zcxu@fudan.edu.cn

自编教材: 上一网络基础知识材料汇编 下一移动通信技术材料汇编 Course evaluation Class Contribution 10% Case study10%(3人组) · Presentation10% ·Fina|EXam70%

2 Course evaluation • Class Contribution 10% • Case study 10% （3人组） • Presentation 10% • Final Exam 70% 自编教材： 上—网络基础知识材料汇编 下– 移动通信技术材料汇编

An introduction to Networking Chapter 1 Updated January 2009 XU Zhengchuan Fudan University

An Introduction to Networking Chapter 1 Updated January 2009 XU Zhengchuan Fudan University

Part l: Basic networks Concepts eoo Concepts we will see eo throughout the book

Part I: Basic Networks Concepts Concepts we will see throughout the book

Figure 1-1: Basic Networking Concepts · What is a network? a network is a transmission system that connects two or more applications running on different computers Network 5

5 Figure 1-1: Basic Networking Concepts • What Is a Network? – A network is a transmission system that connects two or more applications running on different computers. Network

Figure 1-1: Basic Networking Concepts Client/Server Applications Most Internet applications are client/server applications Clients receive service from servers The client is often a browser C lient Server Program Program Services Client Computer Server computer 6

6 Figure 1-1: Basic Networking Concepts • Client/Server Applications – Most Internet applications are client/server applications – Clients receive service from servers – The client is often a browser Client Computer Server Computer Server Program Client Program Services

Part l: the nine elements of a Network Although the idea of network is simple, you must understand the nine elements found in most networks

Part II: The Nine Elements of a Network Although the idea of “network” is simple, you must understand the nine elements found in most networks

Figure 1-3: Elements of a Network Client Application Server Application Message(Frame) Access Switch Client Networks connect Server Computer applications on different computers Computer SWItC Switch Networks connect computers 2. Clients(fixed and mobile) and Mobile 3. Servers Client Outside World Wireless Access point Router 8

8 Figure 1-3: Elements of a Network Wireless Access Point Mobile Client Router Outside World Server Computer Client Computer Switch 1 Switch 2 Switch 3 Message (Frame) Access Line Trunk Line Client Application Server Application 1. Networks connect applications on different computers. Networks connect computers: 2. Clients (fixed and mobile) and 3. Servers

Figure 1-3: Elements of a Network Client application Server Application Message(Frame) Client Server Computer Computer Switch Computers(and routers) 3 usually communicate Mol by sending messages Cli called frames Outside World Wireless Access point Router

9 Figure 1-3: Elements of a Network Wireless Access Point Mobile Client Router Outside World Server Computer Client Computer Switch 1 Switch 3 Message (Frame) Trunk Line Client Application Server Application 4. Computers (and routers) usually communicate by sending messages called frames

Figure 1-3: Elements of a Network e Client Application Server Application Client Sends Sw1 Sends Maasage( Sw2 Sends Frame Frame Frame to Sw1 to sw2 To SW3 Client Switch 2 Computer Sw3 Sends Frame to ter Switch 1 Server Trunk Switch 3 ine. Switches forward Switch Outside Frames Sequentially World Access point Router 10

10 Figure 1-3: Elements of a Network Wireless Access Point Mobile Client Router Outside World Server Computer Client Computer Switch 4 Message (Frame) Trunk Line Client Application Server Application Switch 2 Switch 1 Switch 3 Client Sends Frame to Sw1 Sw1 Sends Frame to Sw2 Sw2 Sends Frame To Sw3 Sw3 Sends Frame to Server 5. Switches Forward Frames Sequentially