What is the Internet?

The "Internet is a collection (or network) of computers connected over cables, phone lines, power lines, radio or satellite links" (Topic 1.1 What is the Internet  2011) basically its a big network made up of smaller networks that interconnect with each other.

ABOUT NETWORKS

Server / Client Networks:

Fig a. Client/Server Model (Bieg, 2007a)

In this type of network the term "client" refers to a computer, smartphone, tablet etc who requests information. The "Server" holds the information and sends it back the client upon request.

Peer to Peer Networks:

Fig b. Peer to Peer Model (Bieg, 2007b)

In this type of network there is no centralised server holding the information. Information is stored on individual computers who act as both servers and clients. Information is shared between computers without the server as the middle man.

There are pros and cons to both. Servers can hold a lot more information than a single computer but a peer to peer network has strength in numbers. There more computers (aka nodes) connected to the network, the greater its capacity.

The idea of networking computers as explained by Bigil was first developed in America in 1957 during the cold war as a way of sharing information. The satellite technology of the Soviet Union (who launched Sputnik 1 in 1957) had America worried about missile attack. This saw the establishment of  DARPA (Defence Advanced Research Project Agency) - an American technological research agency. During this time DARPA developed a computer network called the ARPANET as way of sharing information quickly and efficiently (Bilgil 2009).

The French scientific  agency CYCLADES furthered the idea by developing a system that allowed for differing networks to be networked together. In their system each computer (or node) worked as a "transfer node" - passing information through to the next node until it reached its final destination. This system eliminated the need for information to sent via radio waves (seen as a threat to USA military operations) and meant that any node on any network could be used to transfer information. The interconnection between networks is where the term Internet came from (Bilgil 2009).

HOW INFORMATION IS SENT AROUND THE NETWORK:

 Packet Switching:

Information is broken up into small pieces  which are sent over the network and reassembled at the other end. This system was developed in the UK by the NPL (National Physical Laboratory) who were trying to develop this type of technology for commercial purposes (Bilgil 2009). Sending information in small pieces or packets was seen to reduce congestion on the network meaning that greater numbers of people could use the network at the same time.

Protocols:

The internet uses many protocols to move information around. The main ones used to in packet switching are called TCP / IP

IP - is the INTERNET PROTOCOL and is an address. Each node has an address and each packet is sent from one IP address to another IP address. Each address is numeric which works well for communication between computers but can be difficult for people to remember. Therefore an alphabetised version was also developed = Domain names. Therefore each computer has an IP address and each IP address has a domain name.

TCP is the TRANSMISSION CONTROL PROTOCOL - this protocol is in charge of breaking apart the information into packets and ensuring they are assembled in full at the receiving end.

ROUTING: a router takes the packet of information, reads the address and sends it via the fastest available rout. The packet is sent from router to router and network to network until it reaches its final destination  (Elam, Stephanson, and Hanberger 2002).

Bandwidth: Refers to the amount of data that can be sent from one connection to another - the less the bandwidth the less space,  and the less information that can be sent through at any one time. Bandwidth is measured in amounts of bits that can pass through it per second eg 56k = 56 kbits per second - dial up.  while 10G - 10 gig per second = 10 gig Ethernet connection (Topic 1.1 What is the Internet  2011).

Therefore the internet is a series of interconnected networks that information can be passed around via packet switching. Information is broken up into small pieces via the TCP protocol, addressed via the IP protocol and sent over the network via a series of routers that determine the best way for the packet to reach its destination. Once the packet has reached its final address it is reassembled with its other pieces via the TCP protocol.

 Bilgil, M. 2009. History of the Internet. http://www.youtube.com/watch?v=9hIQjrMHTv4 (accessed 10/12/11).

 Elam, G., T. Stephanson, and N. Hanberger. 2002. Warriors of the Net. http://www.youtube.com/watch?v=Ve7_4ot-Dzs&feature=player_embedded#! (accessed 20/12/11).

  Topic 1.1 What is the Internet. 2011. http://lms.curtin.edu.au/webapps/portal/frameset.jsp?tab_id=_2_1&url=%2fwebapps%2fblackboard%2fexecute%2flauncher%3ftype%3dCourse%26id%3d_40430_1%26url%3d (accessed 15/12/11).