The
network layer of the OSI model is responsible for end-to-end packet delivery.
This
is done by using another addressing scheme that can logically identify each
node connected to the Internet. This addressing scheme is known as an Internet
Protocol address or IP address.
It
is considered logical because the IP address is not a permanent identification
of the computer. Unlike MAC addresses which are considered physical addresses,
IP addresses are not burned into any computer hardware by manufacturers.
Router
is a Network Device that operates at Layer 3 of the OSI model. The main
responsibility of the Router is to facilitate communication between Networks.
Thus, Router creates a boundary between two networks. In order to communicate
with any device that is not directly on your network, a router must be used.