Transcript How to Communicate via Internet Press a key to start

How to Communicate via Internet
Press a key to start
a Technical Overview
Preface
Problem
Ideal
state
ACTION
DECISION
MONITORING
„SOMETHING”
Actual
state
INFORMATION
KNOWLEDGE
DATA
Preface
What is the INFORMATION?
Cookie Monster:
„ - News or facts about something.”
This definition is consistent with the common notions that
information must:
• be SOMETHING, although the exact
nature (substance, energy, or abstract
concept) isn’t clear;
• provide NEW information: a repetition
of previously received message isn’t
informative;
• be TRUE: a lie or false information is
mis-information, not information itself;
• be ABOUT something.
Communication in General
What is the COMMUNICATION?
- Cookie Monster:
„ Exchanging information.”
( … in time and space … )
1. CODING the information (at the sender side).
2. SENDING - RECEIVING codes (via channel).
3. DECODING the information from codes (at the
receiver side).
Communication in General
Communication Types
on-line / off-line
point - point / broadcasted
Communication in General
INTERNET - History
he Internet, sometimes called simply "the Net,” is a
worldwide system of computer networks - a network of
networks in which users at any one computer can, if they have
permission, get information from any other computer (and
sometimes talk directly to users at other computers). It was
conceived by the Advanced Research Projects Agency
(ARPA) of the U.S. government in 1969 and was first known
as the ARPANet. The original aim was to create a network
that would allow users of a research computer at one
university to be able to "talk to" research computers at other
universities. A side benefit of ARPANet's design was that,
because messages could be routed or rerouted in more than
one direction, the network could continue to function even if
parts of it were destroyed in the event of a military attack or
other disaster.
T
Communication in General
INTERNET - Today
Today, the Internet is a public, cooperative, and selfsustaining facility accessible to hundreds of millions of people
worldwide. Physically, the Internet uses a portion of the total
resources of the currently existing public telecommunication
networks. Technically, what distinguishes the Internet is its
use of a set of protocols called TCP/IP (Transmission Control
Protocol/Internet Protocol).
• Many cases e-mail has practically replaced the Postal
Service for written transactions. Electronic mail is a widely
used application on the Net.
• Internet telephony allows real-time voice conversations.
• The most widely used part of the Internet is the World
Wide Web. Its outstanding feature is hypertext.
Internet as the Medium of Human-Human Communication
E-Mail (Electronic Mail)
• E-mail was one of the first uses of the Internet and is still
one of the most popular use. A large percentage of the total
traffic over the Internet is e-mail.
• Off-line (but the duration of delivery can be less than a minute).
• Point to point connection, but you can send the same letter
to several address (multipoint).
• You can send:
– plain (ASCII text) or formatted (HTML) text
– binary files (images, sound) as attachment
– voice- or videomail
• E-mail client programs eg.:
– ThunderBird, Outlook Express
Internet as the Medium of Human-Human Communication
Mailing Lists
• Off-line (e-mail). Your e-mail client enough to use this
feature.
• If you subscribed, you will automatically get every e-mail
has sent to the list.
• Broadcasted. If you send a message to the address of the list,
everybody who subscribed will get your mail. (You don`t
(have to) know exactly who will get your message).
Internet as the Medium of Human-Human Communication
On-line Chat
• On the Internet, chatting is talking to other people who are
using the Internet at the same time you are. (on-line)
• Usually, this "talking" is the exchange of typed-in messages
(low bandwidh needed).
• It could be broadcasted - group chat (everybody has joined
the chat room can see your message) or point-point - private
chat (between two person).
• A chat can also be conducted using sound, video; assuming
you have the bandwidth access.
• Such services:
– MSN, ICQ, IRC, Chat rooms
Internet as the Medium of Human-Human Communication
Phone via Internet
• Internet telephony is the use of the Internet rather than the
traditional telephone company infrastructure to exchange
spoken or other telephone information.
• You can call
– Another computer (if your parner have registered to the
service, and actually online)
– Telephone (a provider connects the telephone network to
the internet on the other side, for a fee)
• Programs and services eg.:
• Skype,
• MSN,
• Nonoh
Internet as the Medium of Human-Human Communication
Phone via Internet
Sound Digitalization
(real-time voice transfer needs more bandwidth than typed in chat)
Internet as the Medium of Human-Human Communication
Video Transfer via Internet
• Real-time (on-line) video transfer require much wider
band than voice transfer.
• The following types of video transfer occur on the Net:
– On-line, point to point videoconference
– On-line, broadcasted audiovisual feeds (internet
tv channels, youtube).
– Off-line, pre-recorded audio/video archives.
Real-time transfer is rarely
demanded in this case. You
can download the whole file
(slowly) and playit from your
local (fast) harddrive.
Internet as the Medium of Human-Human Communication
Video Transfer via Internet
- Videoconference
• A videoconference is a group or a person-to-person discussion
in which participants are at different locations but can see and
hear each other as though they were together in one place.
• Most off-the-Internet videoconferences today involve the use of
a room at each geographic location with special video camera
and document presentation facilities. In general, traditional
videoconferencing requires special telephone interconnections
with wide bandwidth.
• On the Web, a lot of product (skype, webinars,
msn), offers a simple form of videoconference
with each user (optionally aiming a small
video camera at herself or himself) connected to
other users in a pre-arranged chat session.
Internet as the Medium of Human-Human Communication
Video Transfer via Internet
- Streaming Video
• Streaming video is a sequence of "moving images" that are
sent in compressed form over the Internet and displayed by
the viewer as they arrive. Streaming media is streaming
video with sound.
• The user needs a player, which is a special program that
uncompresses and sends video data to the display.
• Streaming video is usually sent from prerecorded video
files, but can be distributed as part of a live broadcast
"feed”.
• Eg: YouTube, internet television
Internet as the Medium of Human-Machine Communication
Why Human-Machine communication?
• The previous services are to facilitate the direct human
communication. The next services are to use the resources
of a far computer (run a program on it, access files, etc.)
• You can download data (text, picture, sound, video...)
stored on an Internet connected computer without other
people direct assistance.
• You have to say to the server computer what do you want
to get and the server will send it to you automatically.
• Previously of course the owner of the server has to allow
the accessing.
Internet as the Medium of Human-Machine Communication
A few Technical Concepts
The following technical points haven`t been mentioned at
the part of e-mail, telephony, chat, etc. In general you
don`t have to know them to use that services. But now
these concepts will be more visible for the average user.
Client / Server architecture
TCP/IP protocol
DNS
URL
Internet as the Medium of Human-Machine Communication
Remote access
• Remote access is the way you can access someone else's
computer, assuming they have given you permission. With
these client-server programs, you log on as a regular user
with whatever privileges you may have been granted to the
specific applications and data on that computer.
• The result of this request would be an invitation to log on
with a userid and a prompt for a password. If accepted, you
would be logged on like any user who used this computer
every day.
• You can use applications running on the server.
• Eg. Telnet, VNC, Remote Desktop
Internet as the Medium of Human-Machine Communication
FTP (File Transfer Protocol)
• FTP, a standard Internet protocol, is the simplest way to
exchange files between computers on the Internet. FTP is
an application protocol that uses the Internet's TCP/IP.
• FTP is commonly used to transfer Web page files from
their creator to the computer that acts as their server. It's
also commonly used to download files to your computer
from other servers. Using FTP, you can also update files at
a server.
• You need to log on to an FTP server. However, publicly
available files are easily accessed using anonymous FTP.
• Commonly used FTP client programs eg.:
– CuteFTP, WsFTP,
Internet as the Embodiment of Human Knowledge
World Wide Web
What Is It?
• A technical definition of the World Wide Web is: all the
resources and users on the Internet that are using the
Hypertext Transfer Protocol (HTTP).
• A broader definition comes from the organization that
Web inventor Tim Berners-Lee helped found, the World
Wide Web Consortium:
"The World Wide Web is the universe
of network-accessible information,
an embodiment of human knowledge."
Internet as the Embodiment of Human Knowledge
World Wide Web
- Getting Started
• Using the Web, you have access to millions of pages of
information. Web "surfing" is done with a Web browser, the
most popular of which are Firefox and Microsoft Internet
Explorer.
• A browser is an application program that provides a way to
look at and interact with all the information on the World
Wide Web.
• Technically, a Web browser is a client program that uses the
HTTP (Hypertext Transfer Protocol) to make requests of Web
servers throughout the Internet on behalf of the user.
• HTML (Hypertext Markup Language) is the set of "markup"
symbols or codes. This language is used to define the
content ans structure of the web pages, understanded by the
browsers.