Answer: A router filters and forwards data packets based on layer 3 IP addresses.

Routing Functionality

Routers operate at the network layer (Layer 3) of the OSI model and make forwarding decisions based on IP addresses contained within data packets.

Packet Filtering

Routers examine the destination IP address of incoming packets to determine the appropriate outgoing interface. They maintain routing tables that contain information about network destinations and associated next-hop addresses.

Forwarding Decisions

When a router receives a packet, it compares the destination IP address against entries in its routing table to determine the most efficient path for forwarding the packet. This process involves selecting the next-hop router or directly connected network interface.

Interconnecting Networks

Routers are used to interconnect multiple networks, enabling communication between devices on different subnets or even disparate networks.

Network Segmentation

Routers define broadcast domains and segment networks into smaller, more manageable subnetworks. They prevent broadcast storms by filtering broadcast traffic and forwarding packets only to the intended destination.

Conclusion

Routers play a crucial role in network communication by filtering and forwarding data packets based on layer 3 IP addresses. They facilitate interconnectivity between networks while enforcing network segmentation and optimizing traffic routing.