OSI Layer Network

In short: Layer 3 of the OSI model (network layer) chooses the path of packets through several networks.

In more detail: IP addresses and routing work here. Packets are passed from router to router until they reach the destination.

In Depth

Protocols and devices

IP (IPv4, IPv6), ICMP, router, layer 3 switch, IPsec.

Tools

Ping and traceroute check this layer. See OSI layers, subnet.

See also: OSI Layers, Router, IP Addresses, Ping