A router routes traffic between IP subnets. Routers route traffic based on destination IP addresses. A router is usually a stand alone device, but if the routing capability is included in switch hardware, then that switch is called a “layer 3 switch.”
It’s common to use a router to connect different types of network topologies, such as LAN, WAN, copper, fiber. So you can connect an Ethernet copper connection and Ethernet fiber connection on the same router.\
A router uses a routing table inside the device to determine where traffic goes.
- A router has at least 2 IPs:
- 1 IP that connects to your LAN’s switch (has IP that’s part of your network ID)
- 1 IP that connects to the next network (ISP, or another router). The IP address of the “LAN” side of the router is the IP used to send data to anything outside of your network ID and is called the default gateway.