7. WWW

InternetService

Provider (ISP)E.g. AOL, Freeserve

InternetService

Provider (ISP)E.g. AOL, Freeserve

ISDN(64kbps/128kbps)

Modem(28.8/56kbps)

Router(T1 - 1.544Mbps)

Internet

Router(Frame Relay: 256kbps)

Local Area Network

7.1 WWW operation

HTML/JavaHTML/Java

WWW server

WWW server

WWW browser

HTTP protocol

WWW browser

HTTPHTTP

TCPTCP

IPIP

HTTP protocolHTML/Java WWW page

PresentationPresentation

SessionSession

TransportTransport

NetworkNetwork

Internet(TCP/IP)

7.2 WWW Topology

Germany

Japan

UK

USA

France

UserLinksto otherWeb servers

Sweden

Canada

HyperText

Language

HyperText

Language

HyperText

Language

HyperText

Language

HyperText

Language

HyperText

Language

HyperText

Language

7.3 Advantages/Disadvantages of the WWWGlobal 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.

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.

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 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.

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.

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.

Global information Creation of an ever-increasing global

information database. Data is relatively easy to tap into and

possibly easy to change.

Global information Creation of an ever-increasing global

information database. Data 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.

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.

Multimedia integration Tailor-made applications with good

presentation tools. Lack of editorial control leads to inferior

material, which is hacked together.

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.

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.

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).

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).

7.4 Example Connections to the Internet

InternetService

Provider (ISP)E.g. AOL, Freeserve

InternetService

Provider (ISP)E.g. AOL, Freeserve

ISDN(64kbps/128kbps)

Modem(28.8/56kbps)

Router(T1 - 1.544Mbps)

Internet

Router(Frame Relay: 256kbps)

Local Area Network

7.5 URLs

<Protocol><Server name><Path name><Filename>

+ http (hypertext transmission protocol)

aaaa:bbb.bbb.bbb/ccc/ccc/ccc?dddd

+ 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

Examplesmailto:fred.bloggs.co.ukhttp://www.intel.com/search/

index.htmlftp://anonymous:none@www.co.uk/

src/info.txttelnet://

fred:pword@www.dcs.napier.ac.uk/

Examplesmailto:fred.bloggs.co.ukhttp://www.intel.com/search/

index.htmlftp://anonymous:none@www.co.uk/

src/info.txttelnet://

fred:pword@www.dcs.napier.ac.uk/

7.6 WWW browser design

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