Similar to a Cisco switch, there are several ways to access the CLI environment on a Cisco router. The most common methods are:

The console and AUX port are located on the router.

In addition to these ports, routers also have network interfaces to receive and forward IP packets. Routers have multiple interfaces that are used to connect to multiple networks. Typically, the interfaces connect to various types of networks, which mean that different types of media and connectors are required.

Every interface on the router is a member or host on a different IP network. Each interface must be configured with an IP address and subnet mask of a different network. The Cisco IOS does not allow two active interfaces on the same router to belong to the same network.

Router interfaces can be grouped into two categories:

The figure shows the LAN Interfaces and serial interfaces on the router.