Explain What The Internet

Explain What The Internet is

Every day millions of people exchange information through the Internet - but what exactly is the Internet? The Internet is a worldwide collection of computer networks, cooperating with each other to exchange information using common standards. Through telephone wires, fiber optic cables, wireless transmissions and satellite links, Internet users can exchange information in a variety of forms.

 The Internet is a network of networks that connects users in every country in the world. There are currently over one billion Internet users worldwide.

 Up to now the networks we have discussed have been controlled by one individual or organization. The Internet is a conglomerate of networks and is owned by no one individual or group. There are, however, several major International organizations that help manage the Internet so that everyone uses the same rules.

Internet Service Provider (ISPs)

Any home, business or organization that wants to connect to the Internet must use an Internet Service Provider (ISP). An ISP is a company that provides the connections and support to access the Internet. It can also provide additional services such as Email and web hosting.

ISPs are essential to gaining access to the Internet. No one gets on the Internet without a host computer, and no one gets on the Internet without going through an ISP.

 ISPs range in size from small to very large and differ in terms of the area they service. ISPs may provide limited services to a small geographical area or can have a wide variety of services and support entire countries with millions of customers. ISPs also differ in the types of connection technologies and speeds they offer. Examples of well known ISPs include AOL, EarthLink, and Roadrunner.

 Do you have Internet access? Who is your ISP?

·    The ISPs Relationship With The Internet

Individual computers and local networks connect to the ISP at a Point of Presence (POP). A POP is the connection point between the ISP's network and the particular geographical region that the POP is servicing.

An ISP may have many POPs depending on its size and the area it services. Within an ISP, a network of high-speed routers and switches move data between the various POPs. Multiple links interconnect the POPs to provide alternate routes for the data should one link fail or become overloaded with traffic and congested.

 ISPs connect to other ISPs in order to send information beyond the boundaries of their own network. The Internet is made up of very high-speed data links that interconnect ISP POPs and ISPs to each other. These interconnections are part of the very large, high capacity network known as the Internet Backbone.

 Connecting to the ISP at the POP provides users with access to the ISP's services and the Internet.

Option for Connecting to the ISP

ISPs provide a variety of ways to connect to the Internet, depending on location and desired connection speed.

In a major city there are typically more choices for ISPs and more connection options than in a rural area. For example, cable Internet access is only available in certain metropolitan areas where cable TV service is available. Remote areas may only have access via dial-up or satellite.

 Each Internet access technology uses a network access device, such as a modem, in order to connect to the ISP. It may be built in to your computer or may be provided by the ISP.

 The simplest arrangement is a modem that provides a direct connection between a computer and the ISP. However, if multiple computers connect through a single ISP connection, you will need additional networking devices. This includes a switch to connect multiple hosts on a local network, and a router to move packets from your local network to the ISP network. A home networking device, such as an integrated router, can provide these functions, as well as wireless capability, in a single package.

The choice of Internet access technologies depends on availability, cost, access device used, media used and the speed of the connection.

 Most of the technologies shown are used for both home and small business. Leased lines are typically used for business and large organizations, but can be used to provide high speed connectivity in areas where cable or DSL are not available.

 ISP Levels of Service

Depending on the ISP and the connection technology, various services are available such as virus scanning, video on demand, and file storage. The contract with the ISP determines the type and level of services that are available. Most ISPs offer two different contract levels: home service or business class service.

 Home service is normally less expensive than business services, and generally provides scaled-down services such as slower connection speed, reduced web space storage, and fewer email accounts. A typical home account may include a minimum of five email addresses with additional addresses being available for a fee.

 Business class service is more expensive but provides faster connection speeds and additional web space and email accounts. A business class service may include twenty, fifty or more email addresses. Business service also includes agreements between the ISP and the customer specifying items such as network availability and service response time. These are known as Service Level Agreements (SLAs).

 When data is transferred, it is either uploaded or downloaded. Downloading refers to information coming from the Internet to your computer, while uploading indicates the reverse path, from your computer to the Internet. When the download transfer rate is different from the upload transfer rate, it is called asymmetric. When the transfer rate is the same in both directions, it is called symmetric. ISPs can offer both asymmetric and symmetric services.

 Asymmetric:

Most commonly used for the home.

Download speeds are faster than upload speeds.

Necessary for users that download significantly more than upload.

Most Internet users, especially those who use graphics or multimedia intensive web data, need lots of download bandwidth.

 Symmetric:

Most commonly used for business or individuals hosting servers on the Internet.

Used when necessary to upload large amounts of traffic such as intensive graphics, multimedia, or video.

It can carry large amounts of data in both directions at equal rates.