Shruti Speak's

RADIOWAVES:- Radio  is the wireless transmission of signals through free space by electromagnetic radiation with frequency significantly below that of visible light, in the radio frequency range, from about 30  KHz  to 300 GHz. These waves are called radio waves. Electromagnetic radiation travels by means of oscillating electromagnetic field that passes through the air and the vacuum of space. Transducing information such as sound into an electronic signal, this is then sent as an electromagnetic radio wave from a transmitter. A receiver intercepts the radio wave and extracts the information-bearing electronic signal, which is converted back using another transducer such as a speaker. Information, for example sound, is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency phase or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The i

WIRELESS COMMUNICATION Introduction:- Wireless communication  is the communication between two or more points that are not connected by an electrical conductor. It permits services, such as long-range communications, that are impossible or impractical to implement with the use of wires The common wireless technologies use electromagnetic wireless telecommunications, such as radio. With radio waves distances can be short, such as a few meters for television or as far as thousands or even millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including  cellular telephones ,personal digital assistants (PDAs), and wireless networking . Other examples include GPS units, garage door openers, wireless computer mice, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones .Less common methods of achieving wireless communications include the us

Intranet is Intra+ Net so an Intranet is an internal or private Internet used strictly within the confines of a company, university, or organization. "Inter" means "between or among," hence the difference between the Internet and an Intranet. Some formal definitions of Intranets ¢ “Intranets help present and   circulate boundary objects” ¢ “Intranets… support the creation, sharing, and use of knowledge” ¢ “Intranets are organizationally restricted”

¢ The Internet Corporation for Assigned Names and Numbers   (ICANN) is an internationally organized, non-profit corporation that has responsibility for Internet Protocol (IP) address space allocation, protocol identifier assignment, Top-Level Domain name system management, and root server system management functions. — ICANN performs the IANA functions — ICANN accredits domain-name registrar for .com, .org., .net (and other domain)   ¢ Since ICANN performs the IANA functions, it is in charge for allocating all numbers. However, the main concern is the allocation of domain names. ¢ ICANN role is to oversee the domain-name registration system's   transition from government hands to private hands and to coordinate its decentralization and the integration into a global community.

¢ The functions associated with the assignment of   numbers in the Internet is referred to as Internet Assigned Number Authority (IANA). ¢ IANA serves as a registry that keeps records of assigned numbers: — IP addresses — Protocol numbers — Domain names (until 1992) ¢ There is no charge for allocation.

¢ Internet Society (ISOC): Founded in 1992, an international nonprofit professional organization that provides administrative support for the Internet. Founded in 1992, ISOC is the organizational home for the standardization bodies of the Internet. ¢ Internet Engineering Task Force (IETF): Forum that   coordinates the development of new protocols and standards. Organized into working groups that are each devoted to a specific topic or protocol. Working groups document their work in reports, called Request For Comments (RFCs). ¢ IRTF (Internet Research Task Force): The Internet Research Task Force is a composed of a number of focused, long-term and small Research Groups. ¢ Internet Architecture Board (IAB) : a technical advisory group of the Internet Society, provides oversight of the architecture for the protocols and   the standardization process ¢ The Internet Engineering Steering Group (IESG) : The IESG is responsible for technical managem

¢ Traditional core applications:   Email   News   Remote Login   File Transfer ¢ The killer application:   World-Wide Web (WWW) ¢ New applications:   Videoconferencing   Telephony   P2P applications   Internet Broadcast

Mid 1960   :   Papers on “Packet Switching” emerge. End 1969s:   ARPA sponsors the development of a                       packet-switching network, called the                      ARPANET.   1974:   The TCP/IP protocols and model are               being   p roposed by Cerf/Kahn.   1980:   IPv4 is introduced   1983:   ARPANET adopts TCP/IP. At this time,                      the ARPANET has 200 routers.   1984:   NSF funds a TCP/IP based backbone             network. This backbone grows into the             NSFNET, which becomes the   successor of             the ARPANET.     1995:   NSF stops funding of NSFNET. The                       Internet is completely commercial.