The environment used by NSRC is mainly Cisco. We will discuss Cisco configuration essentials in the next few slides. We'll be talking about components of Cisco routers and switches running Cisco IOS. IOS is Cisco's internet operating system and it's the software used to control the router or switch. Cisco produces other equipment running other operating systems namely IOS-XR which is used on their high-end routers you also have IOS-XE which is a replacement for IOS. And you have NX-OS which is used on data center and enterprise switches. Equipment from other vendors use similar concepts. Where is the configuration saved? Cisco always has two configurations, namely running configuration and the static configuration. Running configuration is saved in the main memory of the router and it also shows you which parameters are currently in use. It can be modified by typing the command "configure terminal" and you can display the running configuration by typing "show running config" at the prompt. You also have the startup configuration which is stored in NVRAM. By NVRAM we mean non-volatile ram and it's loaded by the router the next time it boots. This is where the running configuration is saved and you can look at the startup configuration by typing the command "show startup config" How do you input information into the router? You can do so by using the management input sources of the Cisco router or switch. The first option is the console which gives you direct access to the device via the serial port. It is useful for configuring brand new devices or connecting to routers after you've lost access to the the network. The second option is the auxiliary port and it's similar to the console for its use for connecting modems and other serial devices. You can also use it for accessing other serial devices. The auxiliary port is useful as you can use it to connect the modem to give you out of band access. You also have the virtual terminals which is the vty which will give you telnet or ssh access to the router. This is the typical form of use as it allows you to get access via the ip network infrastructure. How do you change the configuration of a Cisco device? Please note that commands are implemented immediately so be very careful when typing. When working on serial console or via telnet or ssh commands can either be copied from a text file and pasted into the terminal or they can be copied by SCP or TFTP from a file prepared previously on an SCP or TFTP server. You have three different access modes in a router. The first one is the standard user access node which lets you see some of the device status. The standard user access mode is denoted by the prompt followed by the arrow key. You have the privileged user access node which also gives you full administrative view of the device. This mode can be accessed by typing the enable command when you're in standard user access mode you know you're in the privileged user access mode when you have the prompt immediately followed by the hash key you also have the configuration mode which can be accessed by typing the command "configure terminal" when you're in privileged user access mode as you can see on the screen. You have the router prompt with "config" in parenthesis followed by the hash key to tell you that you are in configuration mode. How do you exit configuration mode? You can exit configuration mode by typing the command "end" or using Control-Z. You can exit privileged mode by typing the command "disable" and you can log off the router by simply typing "exit" at the router prompt. How do you save your configuration? Remember it's very important to save your configuration to the device and NVRAM after it has been updated. The device does not do it automatically so you will have to do so by typing the command "write memory" in privileged mode. This command can be shortened by using the command "wr" but the actual full longhand form of the Cisco command to save the configuration is "copy running config startup config" There are many available options for saving the configuration. You can either save it locally on the device or you can save it to an external server using TFTP or SCP. To figure out the options available when using TFTP or SCP you can simply type the command "copy running config" followed by the question mark as you can see on the screen the different options available on saving configuration to the flash or TFTP server. You can also use secure copy to transfer to an external file or server. You can use the memory slots available on the device basically external memory slots 0 and slots 1 or you can copy the running config to the startup config as we had shown you previously this is to save it on the NVRAM of the router or you can copy the running configuration to a TFTP server. How do you get help on a router? Please note the question mark is used to obtain a list of commands available in your current configuration mode. As you can see on the screen when you're in configuration mode when you type the question mark it shows you all the different commands available. For example you see you have aaa which is the authentication authorization and accounting command, etc. How do you get online help? You can also use the question mark to see all the possible parameters to an incomplete command as you can see on the screen. When you're in configuration mode and you would like to add a user you simply type "user name" followed by the question mark. This will show you that you need to complete it with a word which is the actual username. So you would then type user name which is "cnd lab" followed by the question mark. This will show you that you need to specify the password for the user. You would continue by typing "username cnd lab password" followed by the secret password. You can also look at the different options available for the show command by typing "show" followed by the question mark. Remember question mark will show you all the lists of possible parameters to any incomplete command. How do you complete a command? You can use the Tab key to complete any command. As you can see on the screen when you type "int" followed by the Tab sign it's going to complete it with "interface" you can continue by typing "interface fa" followed by the Tab sign and this would do interface fast ethernet 0. If you want to type the ip address you can just simply type "ip add" followed by the Tab sign and it would complete it with the command ip address. At this point you would simply enter your ip address and the subnet mask. Please note that various short-hands to all the Cisco commands IOS understands. The shorthand complete command does not need to be typed as long as the initial characters are unique. As you can see on the screen there's this command "int fa0" followed by "ip add" and you have an ip address 192.12 followed by the subnet mask This is followed by the command "no sh" and it's followed by Ctrl-Z. You also see this command being typed show "sh ip int br" and you see the output as shown on the screen being showing you the details of the interface fast ethernet 0 on the screen so from the above commands you realize that the full commands of the first one is "int fa0" simply means "interface fast ethernet 0" and you're adding the ip address with its subnet mask to interface fast ethernet 0. "no sh" simply means no shutdown and Ctrl-Z gets you out of the configuration mode. "show ip int br" simply means "show ip interface brief" and in this case it's showing you the fast ethernet interface of that router how do you move faster around the command line the various options available are shown on the screen if you want to look at the command history you can simply type the up arrow key for previous command or the down arrow key for the next command when you're line editing you can simply move the arrow key to the left to move to the left within a line or to the right to move to the right within a line Ctrl-A will move to the beginning of a line Ctrl-E will move to the end of a line and ctrl a will delete till the end of a line. So those of you that are familiar with vi it's a bit similar to vi with some of the editing options.

© Produced by Philip Smith and the Network Startup Resource Center, through the University of Oregon.

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