Telecommunications systems are composed of computers (both client on the desktop and host computers, such as servers and mainframes), communication processors, communication media and communication software.
The eight basic types of communications media are twisted-pair wire, coaxial cable, fiber optic cable, microwave, satellite, radio, cellular radio and infrared transmission. The first three media are cable media and the remaining five are broadcast media.
A local area network (LAN) connects two or more connecting devices within 2000 feet (typically within the same building). Every user device on the network can communicate to every other device.
Wide area networks (WANs) are long haul, broadband (analog), generally public-access networks covering wide geographic areas, provided by common carriers.
Value-added and virtual private networks are types of WANs. VANs are private, multipath, data-only, third-party-managed networks that can provide economies in the cost of service and in network management because they are used by multiple organizations. A virtual private network (VPN) is a WAN operated by a common carrier that provides what appear to be dedicated lines when used, but that actually consists of backbone trunks shared among all customers, as in a public network.
The three types of distributed processing are terminal-to-host, file server, and client/server. In terminal-to-host processing, the applications and databases reside on the host computer, and the users interact with the applications with dumb terminals. With file server processing, the applications and databases reside on the host computer, called the file server. The database management system runs on the users' PC. When the user needs data from the file server, the file server sends to the user the entire data file, and the downloaded data can be analyzed and manipulated on the user's personal computer. Client/server architecture divides processing between clients and servers. Both are on the network, but each processor is assigned functions it is based suited to perform. In a client/server approach, the components of an application (i.e. presentation, application, and data management) are distributed over the enterprise rather than being centrally controlled.
The three types of distributed processing are terminal-to-host, file server, and client/server. In terminal-to-host processing, the applications and databases reside on the host computer, and the users interact with the applications with dumb terminals. With file server processing, the applications and databases reside on the host computer, called the file server. The database management system runs on the users' PC. When the user needs data from the file server, the file server sends to the user the entire data file, and the downloaded data can be analyzed and manipulated on the user's personal computer. Client/server architecture divides processing between clients and servers. Both are on the network, but each processor is assigned functions it is based suited to perform. In a client/server approach, the components of an application (i.e. presentation, application, and data management) are distributed over the enterprise rather than being centrally controlled.
The eight telecommunications applications include electronic mail, video conferencing, electronic data interchange, electronic funds transfer, facsimiles, telecommuting, distance learning, and telematics.
Electronic mail is the transmission of computer-based messages that can be electronically manipulated, stored, combined with other information, and transmitted through telephone wires or wireless networks. Video conferencing allows two or more people to have face-to-face communication with a group in another location(s) without having to be present in person. Electronic data interchange (EDI) is the electronic transmission of routine, repetitive business documents directly between the computer systems of separate companies doing business with each other. Electronic funds transfer (EFT) is the electronic transmission of funds, debits, credits, charges, and payments among banks and between banks and customers. Facsimile (Fax) equipment encodes documents and then transmits them electronically to a receiving fax machine. Telecommuting means that employees work at home, using personal computers and telecommunications technology to communicate electronically with other workers and to send and receive business work. Distance learning is the use of telecommunications technology to connect teachers and students outside the classroom, either all at the same time or at different times. Telematics systems facilitates internet and wireless cellular services, which provide services for location, navigation, traffic monitoring and control, toll collection, safety, and traveler information.
THE INTERNET The Internet is a network of networks, which exchange information seamlessly by using open, nonproprietary standards and protocols. It is a collection of more than one million individual computer networks owned by government, universities, nonprofit groups and companies. The internet is a packet-switched network that uses the Transmission Control Protocol (TCP/IP). Users can connect to the Internet via a LAN server, SLIP/PPP or through an online service (an Internet service provider).
The Internet provides three major types of services: communications, information retrieval, Web services and the World Wide Web. Communications services include E-mail, USENET newsgroups, LISTSERVs, chatting, telnet, internet telephony and internet fax. Information retrieval services include gophers, Archie, WAIS, File Transfer Protocol (FTP) and Veronica. Web services are software applications delivered as services over the Internet.
The Web is a system with universally accepted standards for storing, retrieving, formatting and displaying information via client/server architecture. The Web handles all types of information including text, hypermedia, graphics and sound and is very easy to use because it uses graphical user interfaces. The Web is not synonymous with the Internet. The Internet functions as the transport mechanism, and the Web is an application that uses those transport functions. Other applications also run on the Internet, with e-mail being the most widely used.
Users primarily access the Web through software applications called browsers. Offline browsers (or pull method) enable a user to retrieve pages automatically from websites at predetermined times, often during the night. Search engines are programs that return a list of Web sites or pages (designated by URLs) that match some user-selected criteria. Metasearch engines automatically enter search queries into a number of other search engines and return the results.
Internet challenges include security and all aspects of electronic commerce, the rapid evolution of new technologies, Internet regulation and expansion, and concerns about privacy. New technologies are being developed faster than they can be employed over the internet. The Internet is not regulated by any one government or agency. The Internet Engineering Task force and the World Wide Web Consortium have been instrumental in the development of the Internet, but are not formally charged in any legal or operational sense with responsibility for the Internet. However they define the standards that govern the internet's functionality. Recent government attempts to regulate the content of Internet-connected computers have generated concerns about privacy, security and the legal liability of service providers. The massive growth of Internet traffic has strained some elements of the network, manifested by slowdowns in retrieval time, unreliable transmission of streamed data and denial of service by overloaded servers. Cookie technology and Web-site registration have caused privacy concerns.
INTRANET
An intranet is a private network that uses Internet software and TCP/IP protocols. In essence, an intranet is a private Internet, or group of private segments of the public Internet network, reserved for use by people who have been given the authority to use that network. Companies are putting numerous applications on their intranets, including policies and procedures, document sharing, corporate telephone directories, human resources forms, training programs, search engines, customer databases, product catalogs and manuals, groupware, customer records, document routing and data warehouse and decision support access.
EXTRANET
An extranet is a network that links business partners to each other over the Internet by providing access to certain areas of one another's corporate intranets. An extranet is open to selected suppliers, customers and other business partners who access it through the internet. Using an extranet, external business partners and telecommuting employees can enter the corporate intranet via the Internet to access data, place orders, check status and send e-mails. The Internet-based extranet is far less costly than proprietary networks.
Enterprise Information Portals (EIPs) are Web-based applications that enable companies to unlock internally and externally stored information, and provide users a single gateway to personalized information needed to make informed business-decisions. EIPs consolidate content management, business intelligence, data warehouse, and data mart and data management applications.
MOBILE INTERNET
The mobile Internet refers to the use of wireless communications technologies to access network-based information and applications from mobile devices. Mobile Internet applications include location-based services and presence-based services. Mobile
Internet devices know they are somewhere in particular and use that knowledge to perform that take advantage of geographic information. These applications are called LOCATION-BASED SERVICES. Mobile Internet devices also know the type of location they are in and allow the user to act in ways that make sense only in that location. These applications are called PRESENCE-BASED SERVICES.
Internet devices know they are somewhere in particular and use that knowledge to perform that take advantage of geographic information. These applications are called LOCATION-BASED SERVICES. Mobile Internet devices also know the type of location they are in and allow the user to act in ways that make sense only in that location. These applications are called PRESENCE-BASED SERVICES.
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