The internet is a wide area network that connects computer systems around the globe. I order to understand the internet one must look to the basic network. There are two types of networks. Peer to peer (P2P) and Client / provider networks. In a peer to peer network no node has more authority than another node. File sharing is possible on a P2P network but there may be multiple copies of a document at different revision states. It is for this reason that corporations and firms use Client provider networks at their locations to facilitate and keep databases current for all users.
Using a shared Server computer everyone connected receives the same information which allows for consistency and uniformity. A local network will have differing topologies. A topology is the physical structure of how components are connected on the network. Networks can have as little as two computers or any number more that are connected in some way. A buss topology is used to connect several computers using a common media line. This topology is limited by the maximum amount of information that the media can carry. Other topologies include: Star, ring and mesh.
A star network uses a single device at the center called a hub to connect all devices. In a ring network each node is connected to the two closest nodes around a circle. All nodes are connected to every other node in a mesh network. Hybrid systems use two or more different topologies in the same network. Bandwidth sharing happens when two or more computers or components share the same media for data transfer. Bandwidth is a term that describes the frequency spectrum and space available for communication across a medium. Channel bandwidth is the rate in which information can be transferred1.
The medium is the type of physical structure which the information travels across to reach its destination. In band width the frequency spectrum is divided into small sections called channels. Two components connect along the medium using the same channel. Local area networks are contained to a single location. Firms will have local area networks called intranets that interconnect the devices within their building for data and information sharing. Some intranets are larger than one building and may even connect two different cities withi company. This is called a wide area network.
Intranets are not connected to outside sources and are private networks. Extranets will have information available to the internet. These networks have servers that not only serve their local intranet but the internet as well. The local portion of these networks is placed behind a firewall or maybe even two. The internet is not the World Wide Web (WWW). The internet is the structure of how connections are made across the World Wide Web. The WWW is a set of standards that are use to communicate from one internet node to another. Protocols are the standards used. The most used protocol on the internet is (HTML) hypertext markup language.
HTML is currently in its fifth revision or HTML53. With HTML5 a standard is set for how to display the web page; where pictures are displayed, fonts used for text and total layout of the page. XML (extensible markup language) is used for web documents. CCS (cascading style sheet) is written into the HTML document or attached as a file to define the appearance of the displayed page. TCP/IP is a suite of standards that computers use to communicate with across a medium 4. TCP (transmission control protocol) is a protocol that requires a connection to transfer data from one node to another.
UDP (user datagram protocol) does not require a connection. Information is split up into small sections called packets and sent over the medium. UDP does not require as much packet overhead as TCP and is more efficient to send data quickly. TCP is better for error checking of the data sent and received. Any protocol used has its purpose. The internet uses the same protocols to transfer information that a local area network would use. The topologies of the internet are the same that are use in intranets the only difference is the size and scope. The ways which you can connect to the internet vary.
Dial up service was one of the first options used by consumers at home. Your phone service provided you with a phone number to dial via your home computer and a modem would answer and communicate with the computer’s modem. This used audio across the phone line to transfer the data to and from the internet. This option was limited to a speed of 56 Kbps. DSL (direct signal link), cable modem, and WiMAX5 (Worldwide Interoperability for Microwave Access) give the consumer faster service than dial up access. An intranet may accessible from the internet by use of tunneling.
This procedure uses encryption and authentication to make a secure connection between the local host computer and the client computer. This does not mean that the local intranet is accessible to the internet the connection is being accomplished across the internet but other computers and users are not admitted access. This is one way that is being used by corporations to allow employees to work from home on projects. Wide area networks will use internet connections to connect one location to another. It would be difficult to run your own lines that distance.
