Transcript Internet
Local Area Network Router (T1 - 1.544Mbps) Internet Internet Service Provider (ISP) E.g. AOL, Freeserve ISDN (64kbps/128kbps) Modem (28.8/56kbps) 7. WWW Router (Frame Relay: 256kbps) 7.1 WWW operation HTML/Java WWW page HTTP protocol WWW browser WWW browser HTTP protocol Internet (TCP/IP) WWW server HTML/Java Presentation HTTP Session TCP Transport IP Network WWW server 7.2 WWW Topology Hyper Text Language UK Japan Hyper Text Language Hyper Text Language USA Canada Hyper Text Language Hyper Text Language Hyper Text Language Germany France Hyper Text Language Sweden Links to other Web servers User 7.3 Advantages/Disadvantages of the WWW Global information flow Less control of information by the media, governments and large organisations. Lack of control on criminal material, such as certain types of pornography and terrorist activity. Internet connections Many different types of connections are possible, such as dial-up facilities (perhaps over a modem or with ISDN) or through frame relays. The user only has to pay for the service and the local connection. Data once on the Internet is relatively easy to tap into and possibly easy to change. Increasing WWW usage Helps to improve its chances of acceptance into the home. Increased traffic swamps the global information network and slows down commercial traffic. Education Increased usage of remote teaching with full multimedia education. Increase in surface learning and lack of deep research. It may lead to an increase in time-wasting (too much surfing and too little learning). Global transmission Communication between people and organisations in different countries which should create the Global Village. Data can easily get lost or state secrets can be easily transmitted over the world. Global information Creation of an ever-increasing global information database. Data is relatively easy to tap into and possibly easy to change. Multimedia integration Tailor-made applications with good presentation tools. Lack of editorial control leads to inferior material, which is hacked together. WWW links Easy to set up and leads users from one place to the next in a logical manner. WWW links often fossilise where the link information is out-of-date or doesn’t even exist. 7.4 Example Connections to the Internet Local Area Network Router (T1 - 1.544Mbps) Internet Internet Service Provider (ISP) E.g. AOL, Freeserve ISDN (64kbps/128kbps) Modem (28.8/56kbps) Router (Frame Relay: 256kbps) 7.5 URLs <Protocol><Server name><Path name><Filename> aaaa:bbb.bbb.bbb/ccc/ccc/ccc?dddd Examples mailto:fred.bloggs.co.uk http://www.intel.com/search/index.html ftp://anonymous:[email protected]/src/info.txt telnet://fred:[email protected]/ + http (hypertext transmission protocol) + ftp (file transfer protocol) + https (secure hypertext transmission protocol) + mailto (mail to) + telnet (remote login program) + news (news server) + Server name (e.g www.intel.com) + File path name + Additional 7.6 WWW browser design Back Forward History Stop Refresh Home Search Favs. History