What is the primary purpose of a Layer 3 device?

A Layer 3 device, such as a router, operates at the network layer of the OSI model. Its primary function is to route data packets between different IP networks (subnets). This involves examining the destination IP address of a packet and using its routing table to determine the best path to forward the packet to its destination, even if it's on a completely different network. Transmitting wireless traffic is the role of a wireless access point (Layer 2). Analyzing and dropping unauthorized traffic is a firewall's function. Forwarding traffic within the same broadcast domain is handled by a Layer 2 switch.