THE INTERNET

The Internet is the worldwide "network of networks" that links millions of computers together via copper wires, fiber-optic cables, wireless connections, and other telecommunications channels. It is a massive network of networks, a networking infrastructure, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols.This publicly accessible network of interconnected computer networks communicate using a set of protocols and standards, the most basic of which are TCP/IP. TCP/IP consists of the Transmission Control Protocol in conjuntion with the Internet Protocol. Other protocols such as DHCP, DNS, FTP, HTTP, IRC, MIME, POP3, SMTP, SSH, TELNET, RTP and many more help hold the whole thing together.
This learning resource will look mostly at the technical aspects of the Internet, but may eventually cover social, economic, historical and other aspects.
A popular way to visualize the complexity of the Internet is to see it as a stack of layers known as the OSI model, short for Open Systems Interconnection model.

OSI Layers:
* Layer 7: Application Layer – the main interface for the user(s) to interact with the application and therefore the network
* Layer 6: Presentation Layer – transforms data to provide a standard interface for the Application layer
* Layer 5: Session Layer – controls the dialogues (sessions) between computers
* Layer 4: Transport Layer – provides transparent transfer of data between end users and machines
* Layer 3: Network Layer – provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks
* Layer 2: Data Link Layer – provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the physical layer
* Layer 1: Physical Layer – defines all the electrical and physical specifications for devices and the communications media

CONNECTING TO THE INTERNET

Wired

Communication that uses wired is unlimited to access.

Wired connection is most common type of network connection. By plugging your computer is the nest in the wall you get network access. There are some advantages and disadvantages of a wired connection.

Advantages:

1. the fastest and most reliable access to compare with wireless and cable and
2. it is “extremely secure against anyone seeing data that they are not supposed to”.

Disadvantages:

1. cost materials and labor for each installation,
2. additional cost if it needs to be moved,
3. must be a way to get a wire from your computer to “the closest networking equipment in the building.

Wireless

Networks that use radio waves to transmit data, such as Wi-Fi. This type of network allows people to access the internet without having a wired connection. Wireless networks operate over one of three types of transmission: microwave, radio or infrared. Recently concerns have arisen over the effects of such networks on the health of the general populous. Various studies have suggested links between wireless interference and: memory loss, poor concentration, premature senility, nausea and even some varieties of cancer.
Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The most common use is to connect laptop users who travel from location to location.