Internet

� Interconnected computer networks which follow the Internet Protocol Suite

� Operates on a global scale

� Network of networks which can be local or global in scale

� Used to link computers worldwide

Servers and clients

� Everything using the internet is either directly or indirectly connected to a series of cables underground which link the computers and networks together

� Servers connected to these cables can communicate directly

o Servers are simply computers which are connected to these cables directly

o They hold important data such as webpages which are just files stored on the server�s hard drive

o Each server has its own unique internet protocol (IP) address, like an actual address, this is used to identify the servers and help them to find one another

� Most computers are not servers since they are not connected directly to the internet, instead these computers are called clients

o Clients connect to the internet indirectly through Internet Service Providers (ISP)

Sending and receiving data

� To access a certain webpage, the client must communicate with the ISP which links it to the appropriate server which holds the desired webpage

� Another example is that of email. For this, the client connects to the appropriate email provider�s server, composes the email and sends it. The email server then sends it to the other email provider�s server. When the recipient connects to their email provider�s server, they receive the email on their client computer

� When data is sent across the internet, the data is broken into smaller pieces called packets which are reassembled when they arrive at their location

� Not only servers have IP addresses, but everything connected to the internet, indirectly or directly has an IP address

� Anywhere two or more parts of the internet intersect, a router is needed

� To send information, a packet is sent to the router which can be sent directly to the destination by referencing the IP address

Pros

� Easy communication between computers

� Easy file sharing

� Connects people all over the world without being physically near each other

� Information becomes readily available

� Opens up new services and options which would be unavailable otherwise

Cons

� Security becomes an issue

� Private information is at risk of being stolen

o This can lead to identity theft, credit fraud, etc.

� Dependency on internet can cause problems, especially when internet connection fails