Internet and Packets

What is the internet?

A collection of inter-connected networks

What is WAN?

Wide Area Network, where computers communicate using resources from a third party carrier

What transmits the internet?

Cables, telephone lines, satellites, radio waves

What do WANs connect over?

A large geographical area

What are other examples of WANs?

Large companies with many offices such as banks, governments which have employees in many locations, research organisations which are located in more than one place

What are the two types of data switching?

Circuit and packet

What is data switching?

Methods where data is broken down and transmitted

What is circuit switching?

When you make a telephone call, a dedicated connection is set up between you and the person you are calling for the duration of the call

Why wouldn’t circuit switching work on the Internet?

There could never be enough lines for all the billions of people sending data across the Internet

What is packet switching?

A file is broken into data packets of equal size and each packet is redirected by routers across networks until it arrives at its destination and then the data will reassemble into the original file

How do computers know where the location is?

An Internet Protocol Address is used to identify a specific network and allow data packets to be sent to the correct location

How is data reassembled?

The recipient router reorders the packets into the correct order using the sequence number on each packet and each packet is checked for errors