If you run or work in a business, you can’t do without networks.
Networking and Communication Trends
Firms in the past used two fundamentally different types of networks: telephone networks, handled voice communication, and computer networks handled data traffic. Both voice and data communication networks have also become more powerful (faster), more portable (smaller and mobile), and less expensive. In few years, more than half the Internet users in the United States will use smartphones and mobile netbooks to access the Internet.
It is a network consists of two or more connected computers. Each computer on the network contains a network interface device called a network interface card (NIC). The network operating system (NOS) routes and manages communications on the network and coordinates network resources. Hubs are very simple devices that connect network components, sending a packet of data to all the other connected devices. A switch has more intelligence than a hub and can filter and forward data to a specified destination on the network. A router is a communications processor used to route packets of data through different networks, ensuring that the data sent gets to the correct address.
Fig. Components of a simple computer networks
Fig. Today’s Corporate Network Infrastructure
Key Digital Networking Technologies
Contemporary digital networks and the Internet are based on three key technologies: client/server computing, the use of packet switching,a dn the development of widely used communications standards (the most important of which is Transmission Control Protocol/Internet Protocol, or TCP/IP) for linking disparate networks and computers.)
Signals: Digital vs. Analog
An analog signal is represented by a continuous waveform that passes through a communications medium and has been used for used for voice communication. A digital signal is a discrete, binary waveform, rather than a continuous waveform.
Type of Networks
|Local area network (LAN)||Up to 500 meters (half a mile); an office or floor of a building|
|Campus area network (CAN)||Up to 1,000 meters (a mile); a college campus or corporate facility|
|Metropolitan area network (MAN)||A city or metropolitan area|
|Wide area network (WAN)||A transcontinental or global area|
The Global Internet
The Internet has become the world’s most extensive, public communication system that now rivals the global telephone system in reach and range. An Internet service provider (ISP) is a commercial organization with a permanent connection to the Internet that sells temporary connections to retail subscribers.
The Domain Name System
Because it would be incredibly difficult for Internet users to remember strings of 12 numbers, the Domain Name System (DNS) converts domain names to IP addresses.
|.org||Nonprofit organizations and foundations|
Internet Services And Communication Tools
|Person-to-person messaging; document sharing|
|Chatting and instant messaging||Interactive conversations|
|Newsgroups||Discussion groups on electronic bulletin boards|
|Telnet||Logging on to one computer system and doing work on another|
|File Transfer Protocol (FTP)||Transferring files from computer to computer|
|World Wide Web||Retrieving, formatting, and displaying information (including text, audio, graphics, and video) using hypertext links|
Fig. How Voice Over IP Works
A typical web site is a collection of web pages linked to a home page.
Web pages are based on a standard Hypertext Markup Language (HTML), which formats documents and incorporates dynamic links to other documents and pictures stored in the same or remote computers. Hypertext Transfer Protocol (HTTP) is the communications standard used to transfer pages on the web.
A Web server is software for locating and managing stored Web pages.
Searching for Information on the Web
Search Engines attempt to solve the problem of finding useful information on the Web nearly instantly, and arguably, they are the “killer app” of the Internet era. Search engines have become major shopping tools by offering what is now called search engine marketing. Search engine optimization (SEO) is the process of improving the quality and volume of Web site achieve a higher ranking with the major search engines when certain keywords and phrases are put in the search field.
The second-generation interactive Internet-based services are referring to as Web 2.0. It has four defining features: interactivity, real-time user control, social participation (sharing), and user-generated content. A blog, the popular term for a Weblog, is a personal Web site that typically contains a series of chronological entries (newest to oldest) by its author, and links to related web pages.
Web 3.0: The Future Web
The future of the Web involves developing techniques to make searching the 100 billion public Web pages more productive and meaningful for ordinary people. Web 1.0 solved the problem of obtaining access to information. Web 2.0 solved the problem of sharing that information with others and building new Web experiences. Web 3.0 is the promise of a future Web where all this digital information, all these contacts, can be woven together into a single meaningful experience. Sometimes this is referred to as the Semantic Web which means “meaning”.
The Wireless Revolution
Wireless communication helps businesses more easily stay in touch with customers, suppliers, and employees and provides more flexible arrangements for organizing work. In addition to voice transmission, they feature capabilities for e-mail, messaging, wireless Internet access, digital photography and personal information management. The features of iPhone and BlackBerry illustrate the extent to which cellphones have evolved into small mobile computers.
Wireless Computer Networks and Internet Access
If you have a laptop computer, you might be able to use it to access the Internet as you move from room to room in your dorm, or table to table in in your university library.
Bluetooth is the popular name for the 802.15 wireless networking standard, which is useful for creating small personal area networks (PANs). Although Bluetooth lends itself to personal networking, it has uses in large corporations.
Wi-Fi and Wireless Internet Access
The 802.11 set of standard for wireless LANs and wireless Internet access is also known as Wi-Fi. The first of these standards to be widely adopted was 502.11b, which can transmit up to 11 Mbps in the unlicensed 2.4-GHz band and has an effective distance of 30 to 50 meters. Hotspots typically consist of one or more access points providing wireless Internet access in a public place.
Fig. A Bluetooth Network (PAN)
The range of Wi-Fi systems is no more than 300 feet from the base station, making it difficult for rural groups that don’t have cable or DSL service to find wireless access to the Internet. The IEEE developed a new family of standards known as WiMax to deal with these problems. WiMax, which stands for Worldwide Interoperability for Microwave Access, is the popular term for IEEE Standard 802.16.
Radio Frequency Identification (RFID)
Radio frequency identification (RFID) systems provide a powerful technology for tracking the movement of goods throughout the supply chain. RFID systems use tiny tags with embedded microchips containing data about an item and its location to transmit radio signals over a short distance to RFID readers.
Fig. How RFID works
Wireless Sensor Networks
Wireless sensor networks (WSNs) are networks of interconnected wireless devices that are embedded into the physical environment to provide measurements of many points over large spaces. These devices have built-in processing, storage, and radio frequency sensors and antennas. Wireless sensor networks are valuable in areas such as monitoring environmental changes, monitoring traffic or military activity, protecting property, efficiently operating and managing machinery and vehicles, establishing security perimeters, monitoring supply chain management, or detecting chemical, biological, or radiological material.