计算机网络第一章课件————卢罡

Do you know any others?
E-commerce
Ubiquitous Computing（普适计算）
• Power-line Networks, 电线网络 • RFID, Radio Frequency Identification, 射频识别 • IoT, Internet of Things, 物联网
Some terms
• World Wide Web (WWW): Network of Web pages • Internet: A network of networks
互联网
• Computer Network: A collection of autonomous computers interconnected by a single technology
The key issue is Resource Sharing for everything. Attempting to end the tyranny of geography
-------Virtual Private Networks, VPN
client/server (C/S) model
E-mail, MSN, QQ, CVS(Concurrent Version control System), SVN(Subversion) WWW: Videoconferencing: MIS: Management Information System E-commerce (electronic commerce):
1.1.4 Social Issues
Tech is always a doubleedged sword. Any examples?
new social, ethical, and political problems
1.1.4 Social Issues
• Cookies issue. • Anonymouse messages.(Anonymous accusations cannot be used as evidence) • ill-informed, misleading, downright wrong information. Nobel Prize winner, or a high school dropout. • Electronic junk mail (spam). • Identify theft. • Music or video copyright violations
BitTorrent (BT)
What do you know about it?
do not have any central database of content. Instead, each user maintains his own database locally and provides a list of other nearby people who are members of the system. A new user can then go to any existing member to see what he has and get the names of other members to inspect for more content and more names. This lookup process can be repeated indefinitely to build up a large local database of what is out there. It is an activity that would get tedious for people but computers excel at it.
Online Social Networks
In 2004 In 2006
Do you know any others?
In 2005 In 2009
In 2009
In 2011
Wiki
What do you know about it?
Even more loosely, groups of people can work together to create nt. A wiki, for example, is a collaborative Web site that the members of a community edit. The most famous wiki is the Wikipedia, an encyclopedia anyone can edit, but there are thousands of other wikis.
1.1.2 Home Network Applications
• • • • Access to remote information Person-to-person communication Interactive entertainment Electronic commerce
What do you do?
His home page on the World Wide Web can be found at URL http://www.cs.vu.nl/~ast/.
A single technology dominates the each of the past three centuries. • 18th century: Mechanical systems accompanying the Industrial Revolution. • 19h century: the age of the steam engine. • 20th century: information gathering , processing , and distribution. • 21th century: something related to information, computers, and networks.
CHAPTER 1
INTRODUCTION
卢罡 lugang@ sizheng@ @四正 /sizheng
About the Book
• • Each edition has corresponded to a different phase in the way computer networks were used. 1980, first edition, networks were an academic curiosity. 1988, second edition, networks were used by the universities and large businesses. 1996, third edition, computer networks, especially the Internet, has become a daily reality for millions of people. 2003, fourth edition, the new items are wireless networks, security, etc. 2010, fifth edition, about content distribution and mobile phones are small computers on the Internet.
• Distributed System: A model with coherence, between which and OS there’s a middleware
1.1 Uses of Computer Networks
Why people are interested in computer networks and what they can be used for.
1.1.3 Mobile Network Users
On what device can you use mobile network?
Some examples of applications on mobile network?
GPS, 全球定位系统 Sensor Network, 传感器网络 Wearable Computer, 可穿戴计算机
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About the Author
Andrew S. Tanenbaum has an S.B. degree from M.I.T. and a Ph.D. from the University of California at Berkeley. He is currently a Professor of Computer Science at the Vrije Universiteit in Amsterdam, The Netherlands, where he heads the Computer Systems Group. Nevertheless, he is trying very hard to avoid turning into a bureaucrat（官僚）.
ACM
IEEE
1.1.2 Home Network Applications
Peer-to-Peer (P2P) model
In a peer-to-peer system there are no fixed clients and servers. Every person can, in principle, communicate with one or more other people. Napster was shut down in 2000.
The recent developments are regarding mobile users and home networking.
– Business Applications – Home Applications – Mobile Users – Social Issues
1.1.1 Business Applications
(surfing, paperboy, digital library, newsgroup, chat room) ACM: (Association for Computing Machinery) IEEE: (Eye-triple-e) (Institute of Electrical and Electronics Engineers)
1.1.1 Business Applications
The client-server model involves requests and replies.
1.1.1 Business Applications
A computer network can provide a communication medium among employees. powerful
1.1.2 Home Network Applications
• Peer to peer systems to share resources(BT) • Electronic gambling: slot machines, roulette wheels, blackjack dealers,etc. Casino • Using Internet to carry telephone calls, video phone, and Internet radio • Entertainment. The killer application is video in demand. • Game playing • Electronic commerce and finance • E-Flea（网上跳蚤市场） • Short message service