Welcome back to this CCNA Prep video series where we have been looking at the configuration and verification objectives of the 200-120 exam.

In the last video, we discussed password management on the Cisco router and saw various commands including the password command under the console line and also the enable password and enable secret commands.

CCNA Training – Resources (Intense)

In this video, we will be setting up network connectivity on Cisco routers by configuring interfaces and using various connectivity testing tools such as Ping and Traceroute.

New tutorial videos are posted every Monday, so keep checking back!

If you have any questions, or would like to suggest topics for future videos, please leave them in the comments section below.

Further reading:

CCNA Cheat-Sheet Study Guide: IP Routing: http://resources.intenseschool.com/ccna-cheat-sheet-study-guide-ip-routing/

Transcription: 

Welcome back to this CCNA Prep video series where we have been looking at the configuration and verification objectives of the 200-120 exam.

In this video, we will be setting up network connectivity on Cisco routers by configuring interfaces and using various connectivity testing tools such as Ping and Traceroute.

As the name suggests, the primary reason of a router is routing and how can it route if it is not connected to any network? Therefore, one of the most important configurations you will make on a router is the interface configuration.

Routers normally come with a number of interfaces so that you can connect them to different parts of your network. A common example is putting a router between your internal network, that is, your LAN and a public network such as the Internet. Such a router will have an interface on the LAN and another interface on the Internet-facing side, probably connected to the ISP in some way.

Let’s create a sample topology that we will use in this video. I will add two routers, one switch and a VPCS to serve as a host on the LAN. VPCS stands for Virtual PC simulator and allows you to add test PCs to your topology and do basic things from these PCs such as ping and traceroute.

I will like a serial interface on both routers so let’s just configure those.

Now let’s add our connections.

I will start the routers now so we can begin the configuration.

Before we go to the configuration, let’s view the running configuration of the router.

You can see the available interfaces there. By default, router physical interfaces are in the shutdown state. This means that even if you connect cables to them and configure IP addresses, data will not flow through them. You need to bring them up.

Earlier I said physical interfaces are in shutdown state because virtual interfaces like loopback interfaces are in the no shutdown state when you add them.

In our topology, Fa0/0 is connected to the LAN and s1/0 is connected to the ISP router. Let’s begin with the FastEthernet interface.

We need to get under the interface configuration mode. You can either use the long interface name or use a short form such as Fa0/0.

To configure an interface on a Cisco router, there are two basic things you need to do: configure an IP address and bring the interface up if it is shutdown.

We configure an IP address using the “ip address” command. You need to specify the IP address and the subnet mask. It would have been cool if we could use prefix length e.g. 192.168.1.1/24 but the Cisco IOS doesn’t support this format for IP addresses. The Cisco IOS XR and NX-OS support that format though.

Let’s configure the router with an IP address of 192.168.1.1 and /24 subnet i.e. 255.255.255.0.

Next we just bring up the interface using the “no shutdown” command. no shut as the short form will also work.

Let’s go ahead and configure the serial interface. The same steps apply as with the FastEthernet interface.

The additional step is that you may need to configure a clock rate on the serial interface if the router is acting as a DCE for a DTE device. In GNS3, the “clock rate” command is irrelevant and all you need to do to bring up a serial interface is what we have already done.

Let’s look at a couple of commands to verify our interface configuration.

The configuration we have made is in the running configuration. We can use the pipe to filter the output.

We can also just use show run interface name.

Another great command is the “show ip interface brief” which gives us a high level overview of our interface settings and state.

We can also view interface statistics using the “show interface” command. If you don’t specify any interface name, the output will include all interfaces.

This brings us to the end of this video where we have looked at how to configure interfaces on Cisco routers. We also used various show commands to verify our configuration.

In the second part of this video, we will finalize the configuration on the other devices in our topology and also use various verification tool such as Ping, Traceroute and CDP.

I hope you have found this video helpful and I look forward to the next one in the series.