What is internet???? The Internet, sometimes called simply “the Net,” is a worldwide system of computer networks – a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers).
today, the Internet is a public, cooperative, and self-sustaining facility accessible to hundreds of millions of people worldwide. Physically, the Internet uses a portion of the total resources of the currently existing public telecommunication networks. Technically, what distinguishes the Internet is its use of a set of protocols called TCP/IP (for Transmission Control Protocol/Internet Protocol). Two recent adaptations of Internet technology, the intranet and the extranet, also make use of the TCP/IP protocol.
For many Internet users, electronic mail (e-mail) has practically replaced the Postal Service for short written transactions. Electronic mail is the most widely used application on the Net. You can also carry on live “conversations” with other computer users, using Internet Relay Chat (IRC). More recently, Internet telephony hardware and software allows real-time voice conversations. The most widely used part of the Internet is the World Wide Web (often abbreviated “WWW” or called “the Web”). Its outstanding feature is hypertext, a method of instant cross-referencing. In most Web sites, certain words or phrases appear in text of a different color than the rest; often this text is also underlined. When you select one of these words or phrases, you will be transferred to the site or page that is relevant to this word or phrase. Sometimes there are buttons, images, or portions of images that are “clickable.” If you move the pointer over a spot on a Web site and the pointer changes into a hand, this indicates that you can click and be transferred to another site.
Using the Web, you have access to millions of pages of information. Web browsing is done with a Web browser, the most popular of which are Microsoft Internet Explorer and Netscape Navigator. The appearance of a particular Web site may vary slightly depending on the browser you use. Also, later versions of a particular browser are able to render more “bells and whistles” such as animation, virtual reality, sound, and music files, than earlier versions on the Internet.
What is communication?
The term ‘communication’ covers just about any interaction with another person. It includes sharing information, ideas and feelings between people.
Communication on the internet…
Communication is the most popular use of the Internet, with email topping the list of all the technologies used. Some of the types of communication technologies used also include email discussion groups, Usenet news, chat groups, and IRC. These are unique to networked computer environments and have come into wide popularity because of the Internet. Other technologies, including video and audio conferencing and Internet telephony, are also available on the Internet. They require more multimedia capabilities of computer systems and are more taxing of network resources than the others. They also are adaptations of other technologies to the Internet.
Most of the technologies that are unique to the Internet require communication to be done in text—letters with some symbols and punctuation. Communicating effectively involves taking the time, except in informal communications, to use correct grammar, spelling, and punctuation and writing an appropriate message. When replying to a message includes the pertinent parts of the message and uses an appropriate and interesting subject header in any case.
When you’re communicating on the Internet take special care not to give out personal information to strangers and to treat others with respect. Be aware of the risks involved in communicating with people you cannot see and may never meet in person. Take time to consider what you write to others, and be careful to avoid humor and sarcasm except with the best of friends. You can’t assume that your messages are private, so be careful about what you write.
Several issues related to ethical and legal considerations arise from using the Internet for communication. The manner in which communication is implemented on the Internet makes it susceptible to monitoring. You can’t assume that communications are private. Some believe that sending email is like sending a message on a postcard. Some laws have been enacted to help protect privacy during electronic communications. These, however, have been difficult to enforce and are rarely applied. One way to protect privacy is to encrypt or code a message. A common way of encrypting messages is through the use of public and private keys. Although software for encryption is readily available, current policies and laws prohibit its export.
Another area of concern is dealing with abusive or offensive communications. Laws that apply to libel, harassment, and abuse have been applied to cases where the offending behavior has occurred on the Internet. Unsolicited email or other forms of communication is called spam. It definitely is an annoyance, but also quite costly to the people who receive the junk email or other communications. It’s relatively inexpensive to produce, because most of the cost of transporting the email is shifted to the receiver and all people that use the networks supporting the Internet.
Introduction to the Network Communication Devices
In this tutorial you will learn get the basic introduction to network devices such as nic adapters, routers, hubs, switches, modems, communication cables, lan/wan routers, gateway and other devices. A network is consists of a larger number of the communication devices. The simplest device that is used in the communication is the NIC adapter which is attached with the every computer in a network. If you want to build a LAN, you will need to have computers, hubs, switches, network adapters, UTP/STP cables, routers, internal/external modems, connectors, cable testers and clipping tool.
On the other hand if you need to build WAN, you will need to have routers, switches, dedicated or leased telephone lines such as ISDN lines, frame relay connection and other types of wan communication connections.
There are different communication mediums such as Ethernet cables, copper wire, coaxial cable, fiber optic cables, leased telephone lines and ever air is also a communication medium for the satellite communication. The most common networking medium is the LAN is the Ethernet cable (UTP/STP), which is used in the star topology. Hub is a central device of a network and every computer in a network is directly connected with the hub.
If the hub fails to work, the communication between the computers stops till the hub again starts working. Hub broadcasts the data to its every port, and then finding the destined computer, the data sent toward it. The switch is an advance form of the hub similar in functions but the advanced switches has a switching table in them. A advanced switch stores the MAC address of every attached computer and the data is only sent to the destined computer, unlike the hubs where data is sent to all ports. A router is a key device in the internet communication and wan communication system. A router has software called routing table and the source and destination addresses are stored in the routing table.
A router connects two logically and physically different networks. Router finds the IP address of the next hop (next router) and the data is sent toward it and so on. The well known routers developing companies are Cisco systems, Nortel, DLink and others. Every ISP, banks, corporate offices and multinational companies use routers for LAN and WAN communications and communication in their private networks. A gateway can be device or software in a network.
A gateway device connects the LAN with the internet. A gateway is directly exposed to the internet so it should be securely configured and in and out traffic should be monitored. If you are using DSL connection, you must need a DSL modem in your network. The telephone line is connected with the DSL modem and UTP/STP cable attaches your computer with the DSL modem. Modems are the devices that are used to modulate and demodulate the data. They convert analogue signals to digital and digital signals to analogue so that signals can travel on the telephone lines.
There are certain types of the cables that are used to connect two or more computers in a network. Fiber optic cable acts as a backbone between the ISPs and corporate offices. Data travels at the speed of light on the fiber optic cables. The cost and the installation cost of the fiber optic cable is very high but it is becoming very popular in the home networking and LANs also. In the local area networking, 10baseT/CAT5 cable is most commonly in use.
A server is a computer in network that provides services to the client computers such as logon requests processing, files access and storage, internet access, printing access and many other types of services. Servers are mostly equipped with extra hardware such as plenty of external memory (RAM), more data store capacity (hard disks), high processing speed and other features.
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