Router | Computer for GCSE/IGCSE - Year 11 PDF Download

Router

• A router serves as a crucial component of network hardware, facilitating the connection between distinct networks. 
  • For instance, it enables linking a local area network (LAN) with the internet, which represents a wide area network (WAN).
• An essential function of a router involves examining data packets and guiding them to their intended destinations.

Role of a Router in Network Communication

• Routers play a crucial role in connecting Local Area Networks (LANs) to Wide Area Networks (WANs).
• Each router involved in this process is assigned a public IP address by the Internet Service Provider.
• This public IP address is used by other routers to identify and direct data packets to the network.
• The router analyzes data packets to determine their destination and forwards them accordingly.
• Data packets contain the IP addresses of both the sender and the recipient in their headers.
• The header of a packet holds essential information about the data being transmitted.
• The actual data being sent is referred to as the payload of the packet.
• When a data packet enters a LAN, the router directs it to the specific device it is intended for within the LAN.
• If a packet is generated within the LAN, the router reads the header to determine the destination IP address and forwards it accordingly.
• The packet may traverse multiple routers (hops) before reaching its final destination.
• Home network devices like network access devices or 'home hubs' typically have routers built into them.

A summary of the steps a router takes when it receives a data packet

Routing Functions of Routers

• Routers repeat the process for each data packet until it reaches its destination.
• Routers not only route data between networks but also have additional functions:
  • Assigning IP addresses within the LAN
  • Filtering incoming traffic based on criteria like IP address, port number, or protocol type