Intro. to Computer Network

Transcription

1 Intro. to Computer Network n Wed. 2:20pm-5:20pm, in CSIE 101 n Instructor: Cheng-Fu Chou ccf@csie.ntu.edu.tw Office hours: by appointments n TAs: (506) 晧 : nypgand1@gmail.com : victorsun1221@gmail.com n Lecture Format: Slides Interactive P. 1

2 Class Resources n Class web page: Computer Networks 2012 Includes message archives (send by the instructor or the TA) Reading list Proj. assignment & HWs You should check this site regularly P. 2

3 Course Reading n Textbook: Computer Networking: A Top Down Approach Featuring the Internet, 5th edition, Jim Kurose and Keith Ross, Addison-Wesley n Reference books: Computer Networks: A Systems Approach - by Larry Peterson and Bruce Davie, 4th Edition, Morgan Kaufman, TCP/IP Illustrated volume I and volume II P. 3

4 Important Info. n Grading: HW (paper reading and discussion) 20% projects (I,II, and III) 35% midterm 20% final 25% class participation: 5% P. 4

5 Assignments n HW Based on readings and discussions n Projects: C/C++ only Paper reading n Late Policy TBD: check the class web site P. 5

6 Things to Do Today n Read class web page Check course description P. 6

7 Student Commitments n Keep up with your reading n Do your own work n Turn in assignments on times n You are encouraged to study with other students and discuss (no sharing) programming assignments and HWs P. 7

8 Objective n This course will cover the basic principles of networking with a focus on protocols, implementations, and issues specific to the Internet. We will selectively implement new protocols and network services; In addition, we will discuss new ideas and issued published in recent network papers in Cloud Computing. P. 8

9 Contents n Computer Networks and Internet n Application Layer n Transport Layer n The Network Layer P. 9

10 Contents n Wireless and Mobile Networks n Multimedia Networking n Security in Computer Networks n Network Management P. 10

11 Question 1 n Suppose you are at a workstation with IP address and are running IE. You are click on an URL pointing to (IP addr ). Assume that the web page is available, loaded and displayed by your browser. Describe, in as much details as you can, the steps that occur between the mouse-click and the displaying of the web page. P. 11

12 Ans. n 6 messages to translate the server name ( into its IP address n 3 messages to set up TCP connections n 2 messages for the browser to send HTTP get request n 2 messages for the server to send back the requested page n 4 messages to tear down the TCP connections P. 12

13 Question 2 n What are the requirements as you design a computer network P. 13

14 n Definition of a computer network: A shared platform through which a large number of users and applications communicate with each other. n Connectivity: who and how to connect? n Scalability: how many to connect? n Resource sharing: how to utilize the connectivity? Packet switching in datacom Circuit switching in telecom P. 14

15 Connectivity: Node, Link, Path (1/2) n Another definition of a computer network (connectivity version): A connected platform constructed from a set of nodes and links, where any two nodes can reach each other through a path consisting of a sequence of nodes and links. P. 15

16 Connectivity: Node, Link, Path (2/2) n Node: host or gateway Host: end-point where users or applications reside Gateway: device to interconnect hosts n Link: point-to-point or broadcast Point-to-point: two end-points Broadcast: many attach-points n Path: routed or switched Routed: stateless concatenation of links Switched: stateful concatenation of links P. 16

17 Scalability: Number of Nodes n Another definition of a computer network (scalability version): A scalable platform to group a large number of nodes so that each node knows how to reach any other node. n Hierarchy of Nodes n LAN, MAN, WAN LAN: Local Area Network MAN: Metropolitan Area Network WAN: Wide Area Network P. 17

18 Resource Sharing n Yet another definition of a computer network (resource sharing version): A shared platform where the capacities of nodes and links are used to carry communication messages between nodes. n How to share? Store-and-forward packet switching Packetization: message to packets Queuing: network of queues At node: queuing/buffering and processing At link: queuing/buffering, transmission, propagation P. 18

19 Requirements n Connectivity n Cost-Effective Resource Sharing n Scalability n What else? P. 19

20 Question 3 n What are the requirements as you design a network for Cloud Computing P. 20

21 Requirements n Connectivity n Scalability n Performance (resource sharing) Reliability & Availability Virtualization n Security and Privacy n What else? P. 21

22 The End n Questions? interested issues, topics P. 22