The Internet and the World Wide Web

• Local Area Network (LAN)

  A network of devices connected to a switch, some connected by Ethernet cables and some connected wirelessly to a wireless router
• Router


  A device that connects the LAN to the Internet
• Internet


  The worldwide collection of networks that use the Internet Protocol suite (TCP/IP)
• World Wide Web


  The virtual collection of web pages hosted on web servers, accessed using the HTTP protocol
• URL (Uniform Resource Locator)

  An address that specifies the location of a web resource, including the protocol, host name, and file path
• Router


  • Forwards packets between networks, as the Internet is a network of networks
• IP Address


  A unique identifier for a device on a network, which also defines its geographic location
• Packet Switching


  Each packet can take a different route to reach its destination, in contrast to circuit switching where a fixed path is created
• Packet


  A unit of data that contains a header with information about the data, the actual data, and a trailer with a checksum for error checking
• Packet headers contain information like packet number, sender and receiver addresses, and protocol being used
• Packet trailers contain a checksum to validate the data and detect transmission errors