Internet Services 61.1 FTP and Telnet

61.2 E-Mail and Newsgroups 61.3 World Wide Web

61.4 Gopher, Ethernet, and Extranet Chapter 62 - World Wide Web Services 62.1 Web Directories and Search Engines 62.2 Metasearch Engines

62.3 White Pages and Yellow Pages

Chapter 63 - Internet Searching and the E-Mail 63.1 Search Fundamentals

63.2 Queries

63.3 Search Strategies

63.4 Search Mechanism in Search Engines 63.5 The E-Mail

Chapter 58 - The History of the Internet 58.1 ARPANET: The Predecessor of the Internet

In 1958, the US government formed the Advanced Research Project Agency (ARPA) to create a worldwide network that would monitor and control weapons located in the different parts of the globe. ARPA reports directly to the US Department of Defense and developed at that time a state-of-the-art technology in order for US to maintain its leading military research position.

At that time, networked computers were in telephone companies and used circuit switching. ARPA developed a better way of sending messages through packet switching. A new experimental WAN (Wide area Network) was born, which was called ARPANET. Larry Roberts is the principal architect of ARPAET. Initially, only four nodes, connected by AT%T 50 kbps lines, comprised ARPANET. The four nodes are based at the following sites:

• University of California, Los Angeles (host is SDS Sigma 7)

• Stanford Research Institute (host is SDS 490)

• University of Cambridge, Sta. Barbara (host is IBM 360/75)

• University of Utah (host is DEC PDP-10)

In 1971, ARPANET grew and had a total of 15 nodes. ARPANET became a network of about 60,000 medium-to-large-scale computers. ARPANET was established to function as a vehicle for enabling universities and research organizations to exchange information freely. ARPANET, although part of the Department of Defense, is not a classified government or military network. ARPANET operated on UNIX which uses TCP/IP (Transmission Control Protocol/Internet Protocol), a network protocol which became a standard for interconnecting to the ARPANET.

TCP/IP was developed by Vinton Cerf, who is considered as the Father of Internet.

In 1972, Ray Tomlinson invented the e-mail (electronic mail). Tomlinson also introduced the "at sign" (@). Studies showed that in 1973, 75% of the traffic in the ARPANET. In 1976, Queen Elizabeth II used the ARPANET to send an e-mail. It was also during this when ARPANET began sending packets (small pieces of a message for transmission through a computer network) via satellite.

From the late 1970s up to early 1980s, many networks independent of ARPANET were built. Some of these include:

• CSNET (Computer Science Network), which was founded by the National Science Foundation,

• BITNET ("because It's True" Network), which started as a cooperative network, and

• JJANET (Joint Academic Network) in the United kingdom.

• ARPANET was eventually split into two - ARPANET (for research) and MILNET (for military use). The use of computer networks was expanded.

• FTP (File transfer Protocol) - a set of rules or standard procedure that allows a user on one computer to transfer files to and from another computer over a network, for example the Internet. Full form file-transfer protocol

• Telnet - a terminal emulation program that allows computer users to connect interactively to a server and access remote sites, for example on the Internet

• Mailing lists - a list, typically computerized, of names and addresses to which advertising material or information can be posted

• UseNet - a worldwide system that uses the Internet and other networks to distribute articles of news or information

• Newsgroups - a discussion group maintained on a computer network such as the Internet in which people leave messages on topics of mutual interest for other participants to read

• Online games – software programs played for entertainment, challenge, or educational purposes

In 1990 ARPANET was replaced by the National Science Foundation Network (NSFNET) to connect its supercomputers to regional networks. NSFNET now operates as the high-speed backbone of the Internet.

58.2 The Birth of the Internet and the World Wide Web

The Internet technology was created by Vinton Cerf in early 1973 as part of a project headed by Robert Kahn and conducted by ARPA. In 1984 the technology and the network were turned over to the private sector and to government scientific agencies for further development. The growth has continued exponentially, from four computers of the ARPANET in 1969 to over 300,000 computers by 1990. The distribution and decentralization of the Internet is actually a strategic move to avoid unwanted events that might harm and destroy the technology.

Service-provider companies that make "gateways" to the Internet available to home and business users enter the market in ever-increasing numbers. In the 1990s, the US government eased restrictions on commercial activities on the Internet. Much of the Internet became privatized and commercial activities increased. The number of hosts grew dramatically, and Internet traffic consisted of other types of information media, such as graphics, sound, and video).

In 1991, Tim Berners-Lee and Robert Calliau created the World Wide Web (WWW) at the European Laboratory of Particle Physics (CERN), an international research centre straddling the French-Swiss border west of Geneva. It is a system of hyperlinked documents created in HTML.

By 1993, web browsers were introduced to Internet users. Mosaic, a graphical Internet browser, was released by Marc Andreesen at the National Center for Supercomputer Applications (NCSA) in the University of Illinois at Urbana, Champaign. It was immediately followed in 1994 by Netscape, also by Marc Andreesen with Jim Clark. By 1996, 75% of Internet surfers use Netscape. In 1998, America On-Line (AOL) bought Netscape for US$4.2 billion.

By early 2000, access was available in over 200 countries and encompassed around 100 million users. The Internet and its technology continue to have a profound effect in promoting the sharing of information, making possible rapid transactions among businesses, and supporting global collaboration among individuals and organizations.

In 1999, 205 countries and territories in the world had at least one connection to the Internet. The development of the World Wide Web is fuelling the rapid introduction of new business tools and activities that may by then have led to annual business transactions on the Internet worth hundreds of billions of pounds.

The potential of web-based commerce is immense. Techniques that allow safe transactions over the Net (for payment and funds transfers), the construction of faster, more secure networks and the development of efficient search techniques make the Internet an ideal trading medium.

Future concerns are focused in a number of areas, including the efficiency of search engines-even the most efficient of them cover less than a sixth of all publicly available pages-as well as privacy, security, and Internet piracy. By its very nature, the Internet does not cope well with traffic that requires a dedicated link between two points (such as voice) as end-to-end delay cannot readily be controlled. Several protocols that allow greater predictability are being developed to guarantee an assured quality of service. The ability to integrate applications is of increasing importance. Common data formats allow e-business applications to cooperate and services such as Internet phones that are easy to install are being refined and deployed.

In addition to these extra features, the core of the Internet-the network hardware that connects everyone together-is undergoing an overhaul that will enable it to cope with ever-increasing traffic loads. The "Internet 2" project has been under way for several years now and is building faster links and bigger switches that will power the Internet for years to come.

58.3 Cyber Crimes

There are several kinds of cyber crimes that take place nowadays. Computer networks, specially the Internet, are the usual commonplaces of these. Below are some of these cyber crimes.

• Internet worm and computer viruses - A virus that propagates itself across computer networks, usually via e-mail, is sometimes referred to as a worm, especially if it is composed of many separate segments distributed across the network. In 1988, Robert Morris, a Computer Science graduate of the Cornell University, wrote an experimental, replicating, self-propagating program, which was called worm. This was distributed to over 6,000 of 60,000 computers hooked in the Internet at that time. Morris was sentenced of three years of probation, 400 hours of community work, and a fine of US$10,050. A known virus is the Trojan Horse, though technically not a virus, is a program disguised as something useful, which when run does damage to the computer system while appearing to do something else. Another is the Melissa virus, a virus that invades computers via e-mail and IRC (Internet relay Chat). It is a distinct program which can run unaided.

• Hackers, hacking and cracking - Originally, a hacker is a computerphile-a person totally engrossed in computer programming and computer technology. Hacker also means someone who, beyond mere programming, likes to take apart operating systems and programs to see what makes them tick. In the 1980s, with the advent of personal computers and dial-up computer networks, hacker acquired a pejorative connotation, often referring to someone who secretly invades the computers of others, inspecting or tampering with the programs or data stored on them. The correct term such person is actually cracker, and their activity is cracking.

58.4 Governing the Internet

Nobody owns the Internet. However, there are some institutions and organizations which define the standards that must be observed in the Internet. Among these are:

• Internet Architecture Board - for Internet Protocol (IP) development

• Internet Society (ISOC) - a professional membership society for the Internet

• World Wide Web Consortium (W3C) - an organization that develops technologies, inclusing specifications, guidelines, software, and tools

• Internet Network Information Center (InterNIC) - an organization that governs domain registration

• Internet Engineering Task Force (IETF) - a large open international community of network designers, networks, operators, vendors, and researchers.

• Internet Assigned Numbers Authority (IANA) - an organization in-charge of assigning IP addresses

Chapter 59 - Methods of Internet Connection 59.1 Differentiating Media of Electronic Communication

The medium of connection for electronic communication can either be cable-based (or wire-based) or wireless. Cable-based communication uses wires and cables in transmitting information. Wireless communication, on the other hand, uses electromagnetic waves propagated through space. The following are specific media for these two.

• Cable based communication

o Twisted pair (e.g. RJ45 connector) - This is the electric cable composed consist of numerous pairs of paper-insulated wire, encased in a lead sheath; the individual pairs of wire are intertwined to minimize induced interference with other circuits in the same cable.

o Coaxial cable (e.g. BNC connector) - This type of cable consists of several copper tubes; each tube contains a wire conductor that extends along its centre. The entire cable is sheathed in lead and is generally filled with nitrogen under pressure to prevent corrosion. Because the coaxial cable has a broad frequency range, it is valuable in the transmission of carrier-current telephony

o Fiber-optic cable (e.g. ST or SC connector) - Fiber-optic cables, which are composed of bundled optical fibers, are rapidly replacing bulky copper-wire cables in the telecommunications industry. A single pair of such cables can carry over a thousand conversations simultaneously. The medium of transmission within the cable is light.

• Wireless communication

o Infrared rays (IR) - This is used in the familiar television remote control. Infra-red signals only work over a short distance. Even so, it can be used to carry significant amounts of information and has been adopted as the basis for the "wireless" office.

o Microwaves - This is a short, high-frequency radio wave lying between infrared waves, which have higher frequency, and conventional radio waves. Microwaves have many applications:

in radio and television, radar, meteorology, satellite communications, distance measuring, research into the properties of matter, and cooking.

o Bluetooth - This is a short-range radio standard used to connect a range of devices into a fixed network. This is very common in handheld PCs.

o Satellite connection - The maximum carrying capacity of a line in an electronic communications network is known as bandwidth.

For digital devices, bandwidth is measured in bits or bytes per second (bps); for analog devices, in Hertz (cycles per second).

Bandwidth determines the amount of data that can be transmitted in a fixed amount of time and is often described as narrow or broad, with broadband having greater capacity. During periods of peak use, it may also determine speed of transmission, particularly for large data files (graphics, audio, video, etc.) known as bandwidth hogs. On the Internet, the fiber-optic backbone has highest bandwidth.

59.2 Internet Connection

There are several ways on how to get hooked in the Internet. Connect to the Internet is provided by any of the following.

• ISP (Internet Service Provider) - This is a business that provides access to the Internet, usually for a monthly fee. Some large providers offer users a wide range of news, information, and entertainment services

• Cable Television - Also known as cable, this is a television system in which signals are sent to a central antenna and then transmitted by cable to subscribers. Connection to an ISP can be through dial up, which uses a telephone line to connect, or LAN (Local Area Network) in schools or offices. Other channels that can facilitate Internet connection are the following.

• Plain Old Telephone Service (POTS) - This is a simple connection to the public telephone system with no special features, as distinguished from a private line or high-speed network connection. Dial-up connection to the Internet uses the POTS.

• DSL (Digital Subscriber Line) - This is a high-speed telephone line that can supply television, video, Internet access, and video telephoning, often over standard copper wire. It has recently been introduced and is capable of operating at up to 2 Mbps. In its most common format

• ISDN (Integrated Services Digital Network) - ISDN is an all-digital network that allows a whole host of services to be carried together on the same circuits. It can be regarded as an extension of the public switched telephone network, the key similarity to that being that it permits any two compatible pieces of connected equipment to talk to each other. It can transmit both voice and data messages.

• ADSL (Asymmetrical Digital Subscriber Line) - This is a technology that enables high-speed data to be carried between modems located at the customer site and local telephone exchange via the twisted-pair copper local loop normally used for telephone calls. It provides up to 512 kbps downstream and 128 kbps upstream.

• T1 and T3 (synonymous with DS7 and DS3 respectively) - T1 is a term introduced by AT&T to refer to a dedicated digital circuit provided by the telephone companies capable of transmitting data point-to-point at the rate of 1.544 Mbps, containing 24 individual channels, each capable of transmitting voice or data at the rate of 64 kbps. Individuals may purchase one of these channels in an arrangement known as fractional T1 access.

Businesses and academic institutions lease T1 lines to connect to the Internet and may also use them for local area networks. The monthly charge is usually determined by distance. T1 lines are also used by Internet service providers to provide Internet access to individuals and small businesses. The Internet backbone is constructed of higher-speed T3 lines. T3, also introduced by AT&T, is capable of transmitting data point-to-point at the rate of 44.736 Mbps, used mainly by Internet service providers to connect to the Internet backbone and for the backbone itself.

A T3 line contains 672 individual channels, each capable of transmitting 64 Kbps.

• Wi-Fi and WiMax - Wi-Fi (wireless fidelity) is a technology that uses radio waves to connect notebook computers and personal digital assistants (PDAs) to the Internet without cables, at least within 200 meters to a wireless access point. Its higher version, called WiMax can reach as far as several kilometers.

• Satellite connection - This connection is governed by an object put into orbit around Earth or any other planet in order to relay communications

signals or transmit data. It has a very wide coverage.relative to other network connection media.

59.3 Modem

A modem is a device that converts between analogue and digital signals. Digital signals, which are used by computers, are made up of separate units represented by a series of 1s and 0s (bits). Analogue signals vary continuously; an example of an analogue signal is a sound wave. The modem works by, and derives its name from, a process of modulating (the digital signal is used to vary an analogue carrier signal) and demodulating (the variations in the analogue carrier signal are translated into digital signals).

Modems are most frequently used to enable computers to communicate with each other across telephone lines. For instance, a modem can be used with a personal computer (PC) to connect to the Internet via an ISP. The service provider's premises are equipped with banks of modems so that many users can gain access. If each pair of modems transmit data to each other simultaneously, the modems are operating in full duplex mode; if only one modem can transmit at a time, the modems are operating in half-duplex mode.

Modern modems are faster, cheaper, and much more widely available. Speeds of over 56 kbps can be achieved with commercial modems over normal telephone lines, and can take the form of cards small enough to fit inside a PC. Modems can use coaxial cables to carry TV signals and high-speed Internet access.

Modems using ISDN lines or other forms of fast data transmission are capable of even higher speeds. A standard known as PCMCIA (Personal Computer Memory Card International Association) has evolved to cover internal PC modems. PCMCIA type 2 specifies a 5 mm card that can be plugged into a PC slot.

Some modems have become specialized in terms of function. For instance, one of the cards available for a PC is a facsimile transmission (fax) modem that allows the PC to talk directly to fax machines and to send and receive fax messages. High-speed modems have been developed that work at High-speeds of 2 Mbps. These are used as components in leading-edge communications services and are not as yet commercially available.

59.4 Broadband

Broadband is a communications channel that can support a wide range of frequencies or data rates. A broadband connection can transfer information at a rate of at least 2 Mbps. This is almost 40 times faster than a standard narrowband 56 kbps modem connection. Some broadband services can even offer 10 Mbps

connection but, in practice, most transfer information at a rate of around 512 kbps when downloading, and 128 kbps when uploading.

There are a number of options for providing broadband. All involve some sort of link between an end user and a switch connected to a wide area network (WAN).

• The simplest option is to install a dedicated link between the two and install suitable transmission equipment at each end. This allows very high-speed operation but is usually expensive.

• A more affordable approach is to reuse existing telephone lines by adding technology that enhances the rate at which information can be transferred over them. There are several ways in which this can be achieved.

o ISDN - This is widely available and allows connection speeds of up to 128 kbps.

o DSL - This has recently been introduced and is capable of operating at up to 2 Mbps. In its most common format,

o ADSL - This provides up to 512 kbps downstream and 128 kbps upstream. This means faster download and slower download.

o Etherloop - This shares many characteristics of DSL but which follows the format of the ubiquitous local area network technology, Ethernet. Its performance is a little better than DSL.

Cable modems, which are offered by cable providers for Internet access via existing cable television lines. Although capable of connection speed up to 2 Mbps, cable modems operate over shared media and are therefore liable to slow down when many users are active.

The real attraction of broadband from a user's point of view is that it provides true

The real attraction of broadband from a user's point of view is that it provides true