DEMO: Modes

It's time to really start digging into the Cisco IOS, and the first thing we must know is how to navigate through the Cisco IOS. There are two different modes within the Cisco IOS, and then there's sub modes to one of those modes. So we're going to talk about the user exec mode and the privileged exec mode, and then all the sub modes to that privileged exec mode.

User Exec Mode and Privileged Exec Mode

I'm on a switch right here. If I hit enter, it's going to come up with a prompt. This prompt consists of the host name and then something that's going to designate what the mode that I'm in is. The host name of this device is just switch, so it's pretty simple and straightforward, and then I see a greater than sign. The greater than sign is actually showing that this is in user exec mode right now.

The user exec mode is really just to get on and do some real basic troubleshooting of these devices. You really don't do much configuration within the user exec mode. It's just to get on, do some troubleshooting, test for some connectivity. So you really don't do much in the user exec mode. Most of the time you're going to have to get into privileged exec mode in order to do what you need to do on these devices.

So let's learn how to get into the privileged exec mode. We're going to type in enable, and that brings us in there. There's not going to be often that you need to go back to the user exec mode, but just so you know how to do that, you type in disable and that brings you back to the user exec mode. So you can go between the two.

Notice the difference between these two specifically in the prompt. You have a greater than sign for the user exec mode, and you've got a number sign or a pound sign for the privileged exec mode. So that's how you know which mode that you're in.

Global Configuration Mode

Now I did mention that there's a lot of sub modes also, so let's take a look at that. There's a lot of sub modes to the privileged exec mode. When you are in the privileged exec mode, maybe we need to do some configuration. There's not really much configuration that happens here at the privileged exec mode at the base level. Here we need to actually take it a step further to the sub mode called global configuration mode.

To get into global configuration mode you type in configure terminal. I hit configure terminal, and then we can see my prompt has changed now and it says config here, and so that lets me know now that I'm in the global configuration mode.

In this mode, the idea behind it is that I am going to be doing configurations for the switch as a whole. So anything that's global or switch wide happens in here. If I'm making specific changes to maybe some interfaces or routing protocols or something a little more specific than that, I have to go into a sub mode of this to change those interfaces or change those consoles. But for now just know that at this level, generally speaking, the commands that we issue at this level are going to affect the switch as a whole, not those specific interfaces, not those specific elements.

Sub Modes: Lines and Interfaces

Let's say we want to dig a little deeper and we want to configure a specific interface or something on the switch. Then I need to go into one of these sub modes. So for instance, maybe I want to do the line console. I type in line console and the line console number, so in this case zero. Now I can see that I am now configuring the line console here, and it's by dash line. I can see that it's one of the lines that I'm configuring here now.

Let's get into how do we exit out of a mode. You just type in exit. Exit brings us back to the global configuration mode. Maybe I need to get into one of the VTY lines, so I'm going to do line vty 0. Quite often we do 0 through 15 at the same time. I'm just going to type in 0 for this case, and you can see that I get into the line. There's not anything really that specifies between the fact this is the VTY line and this is the console line, so you'll just have to be cognitive of what you have gone into and what you're configuring, because you don't want to make an assumption here and then end up configuring the wrong interface or the wrong line.

All right, so now I'm going to exit out of that, and maybe I want to go into one of the interfaces. So I type in interface FastEthernet, maybe I'm going into 0/14. I type that in there, and now I'm in 0/14. Once again, it's letting me know that I'm in one of the interfaces, but it doesn't let me know which interface I'm in, so I'm going to have to know what I got into and what I'm programming.

Once again, I could hit exit to get out of this. You don't actually need to go back to the global configuration mode to get into the next interface. If I want to go from interface to interface, or maybe I want to go back to the line console right from here, I can type in line console 0 and it'll actually take me back to my line console. Let me put a space in there, and it'll take me back to my line console. We can see that I've gone from the interface to the line console.

Let me do that one more time, because I'm in the interface and now I want to go to the line console, and you can see that I've jumped directly from the interface to the line console.

Here again, maybe I want to go back a level. I can hit exit and go back a level. Maybe I want to hit exit again, go back a level again. If I type exit at this point, then it'll actually take me out of this switch, and so now I'm out of the switch.

Jumping Straight Back to Privileged Exec Mode

One other thing that I want to show you. I'm going to get into the enable mode, I'm going to go into global configuration mode, so configure terminal. Maybe I'm in one of the interfaces, so I'm going to go into interface FastEthernet, and now I'm inside that interface. If I hit, it's going to bring me all the way back to the privileged exec mode, so that way I don't have to hit exit and then type exit again.

I'm going to get into there again, so get into the global configuration mode, I'm going to go into interface FastEthernet 0/14, so I'm in with the interface. The other thing I can do is I can do a control Z, and then it's going to bring, that's a little shortcut, so that shortcut can bring me back as well.

So there are some ways that you navigate in and out of these different modes, and it's going to be important for you to understand how you navigate in and out of these different modes, because we'll be doing it quite a bit throughout this course.