Lower Sixth Revision - Structure of the Internet

The Internet is a network of interconnected computer networks that uses a ‘packet switching’ system

• Can you describe packet switching? 

This means that messages are broken into ‘packets’ of fixed size.  Each packet has the source and destination address added, together with a message ID.  The message is then sent through a series of routers, which use the address information to pass on the packet to its destination.

• Can you explain what a router does and how it is distinct from a gateway? 
  

Routers connect different networks using the same link layer protocol.  Gateways connect different networks that use different link layer protocols

• Can you explain the difference between the internet, an intranet and the world wide web? 
  

• Can you describe the term URL and explain what it does? 
  
• Can you explain the relationship between an URI and a URL? 
  
• Can you explain how domain names are organised, the role of internet registries and registrars? 
  
• Can you explain how an IP address is split into a network identifier and a host identifier part? 
  
• Can you explain the operation of DNS? 
• What is the role of an ISP? 
  
• What are the four layers of the TCP/IP protocol stack? What do they do?
  
• What is a socket? 
  
• Do you understand the role of a web browser in retrieving and rendering web pages?