The Net connections can be based on wire-line and wireless access technolgies.
|
Usually several kinds of network connections are employed at once. Generally speaking, when an E-mail message is sent it travels from the user's computer via copper wires or coaxial cables
Satellite communication
Although facing competition from fiber-optic cables as cost-effective solutions for broadband data transmission services, the space industry is gaining increasing importance in global communications. As computing, telephony, and audiovisual technologies converge, new wireless technologies are rapidly deployed occupying an increasing market share and accelerating the construction of high-speed networks.
Privatization of satellite communication
Until recently transnational satellite communication was provided exclusively by intergovernmental organizations as
Scheduled privatization of intergovernmental satellite consortia:
|
When Intelsat began to accumulate losses because of management failures and the increasing market share of fiber-optic cables, this organizational scheme came under attack. Lead by the USA, the Western industrialized countries successfully pressed for the privatization of all satellite consortia they are members of and for competition by private carriers.
As of February 2000, there are 2680 satellites in service. Within the next four years a few hundred will be added by the new private satellite systems. Most of these systems will be so-called Low Earth Orbit satellite systems, which are capable of providing global mobile data services on a high-speed level at low cost.
Because of such technological improvements and increasing competition, experts expect satellite-based broadband communication to be as common, cheap, and ubiquitous as satellite TV today within the next five or ten years.
Major satellite communication projects
|
Source: Analysys Satellite Communications Database
TEXTBLOCK 1/4 // URL: http://world-information.org/wio/infostructure/100437611791/100438659839
900 B.C.
A postal service is used for governmental purposes in China.
500 B.C.
In ancient Greece trumpets, drums, shouting, beacon, fires, smoke signals, and mirrors are used for message transmission.
4th century B.C.
Aeneas Tacitus, a Greek military scientist and cryptographer, invented an optical communication system that combines water and beacon telegraphy. Torches indicated the beginnings and the ends of a message transmission while water jars were used to transmit the messages. These jars had a plugged standard-size hole drilled on the bottom side and were filled with water. As those who sent and those who received the message unplugged the jars simultaneously, the water drained out. Because the transmitted messages corresponded to water levels, the sender indicated by a torch signal that the appropriate water level had been reached. The methods disadvantage was that the possible messages were restricted to a given code, but as the system was mainly used for military purposes, this was offset by the advantage that it was almost impossible for outsiders to understand the messages unless they possessed the codebook.
With communication separated from transportation, the distant became near. Tacitus' telegraph system was very fast and not excelled until
For further information see Joanne Chang & Anna Soellner, Decoding Device,
3rd century B.C.
Wax tablets are used as writing material in Mesopotamia, ancient Greece, and Etruria.
2nd century B.C.
In China paper is invented.
1st century B.C.
The use of codices instead of scrolls - basically the hardcover book as we know it today - is an essential event in European history. To quote accurately by page number, to browse through pages and to skip chapters - things that were impossible when reading scrolls - becomes possible.
In the computer age we are witnesses to a kind of revival of the scrolls as we scroll up and down a document. The introduction of hypertext possibly marks the beginning of a similar change as has taken place with the substitution of scrolls with codices.
TEXTBLOCK 2/4 // URL: http://world-information.org/wio/infostructure/100437611796/100438659723
Eli Whitney's proposal for a simplification and standardization of component parts marked a further milestone in the advance of the
By the middle of the 19th century the general concepts of
TEXTBLOCK 3/4 // URL: http://world-information.org/wio/infostructure/100437611663/100438659364
Pre-infringement
Contracts
Contracts are a pre-infringement control method, which very often is underestimated. Properly formed contracts enable copyright holders to restrict the use of their works in excess of the rights granted under copyright laws.
Copy Protection
This approach was standard in the 1980s, but rejected by consumers and relatively easy to break. Still copy protection, whereby the vendor limits the number of times a file can be copied, is used in certain situations.
Limited Functionality
This method allows copyright owners to provide a copy of the work, which is functionally limited. Software creators, for example, can distribute software that cannot print or save. A fully functional version has to be bought from the vendor.
Date Bombs
Here the intellectual property holder distributes a fully functional copy but locks off access at a pre-specified date or after a certain number of uses.
TEXTBLOCK 4/4 // URL: http://world-information.org/wio/infostructure/100437611725/100438659616
The ongoing World Wide Web History Project was established to record and publish the history of the World Wide Web and its roots in hypermedia and networking. As primary research methods are used archival research and the analysis of interviews and talks with pioneers of the
http://www.webhistory.org/home.html
A server is program, not a computer, as it sometimes said, dedicated to store files, manage printers and network traffic, or process database queries.
Web sites, the nodes of the
The Internet Software Consortium (ISC) is a nonprofit corporation dedicated to the production of high-quality reference implementations of Internet standards that meet production standards. Its goal is to ensure that those reference implementations are properly supported and made freely available to the Internet community.
http://www.isc.org
The bandwidth of a transmitted communications signal is a measure of the range of frequencies the signal occupies. The term is also used in reference to the frequency-response characteristics of a communications receiving system. All transmitted signals, whether analog or digital, have a certain bandwidth. The same is true of receiving systems.
Generally speaking, bandwidth is directly proportional to the amount of data transmitted or received per unit time. In a qualitative sense, bandwidth is proportional to the complexity of the data for a given level of system performance. For example, it takes more bandwidth to download a photograph in one second than it takes to download a page of text in one second. Large sound files, computer programs, and animated videos require still more bandwidth for acceptable system performance. Virtual reality (VR) and full-length three-dimensional audio/visual presentations require the most bandwidth of all.
In digital systems, bandwidth is data speed in bits per second (bps).
Source: Whatis.com
Communications satellites are relay stations for radio signals and provide reliable and distance-independent high-speed connections even at remote locations without high-bandwidth infrastructure.
On point-to-point transmission, the transmission method originally employed on, satellites face increasing competition from
In the future, satellites will become stronger, cheaper and their orbits will be lower; their services might become as common as satellite TV is today.
For more information about satellites, see How Satellites Work (
Microwave transmission systems based on terrestrial antennas are similar to satellite transmission system. Providing reliable high-speed access, they are used for cellular phone networks.
The implementation of the