How to configure the serial interface of a cisco Router

You can configure a serial interface through a virtual terminal. to configure a serial interface, follow these steps:

1. In Global mode, enter the command "interface serial 0" to enter the serial interface configuration mode.

2. Each connected serial interface must have an IP address and subnet mask to forward IP packets, in interface configuration mode, enter the "ip address <IP address> <netmask>" command to configure the ip address of the serial interface.

3. If the serial interface is connected to a DCE device, we also need to configure a clock frequency for the serial interface. If it is a DTE device, it is not required. By default, a cisco router is a DTE device, but we can configure it as a DCE device by using commands.

In the serial interface configuration mode, enter the "clockrate" command to configure the clock frequency, available clock frequencies include 1200, 2400, 9600, 19200,384, 56000, 64000, 72000, 125000, 148000, 500000, 800000, 1000000, or 1300000.

4. By default, the cisco router interface is closed. We need to enter the "no shutdown" command to activate the interface, you need to close an interface. You can type "shutdown" in the corresponding interface mode to disable this interface in management.

Connect to an instance:

In this instance, we will configure the serial interfaces of the routers lilongwe and dar_es_salaam to enable communication between the two routers. Many of these commands have been mentioned in previous articles. If you do not understand them, you can refer to other articles on this topic. The topology is as follows:

The configuration command on lilongwe:

Configuration command on dar_es_salaam: