Introduction to Cisco Router

1. Introduction
This paper aimed at the beginner level readers learn new
networking. Therefore, the criticism-criticism that were presented here only
understanding of basic router configuration and the basic course.
2. Definitions Router
Router is a device that serves to forward packets from a
network to another network (either LAN to LAN or LAN to WAN) so that
hosts are on a network can communicate with hosts that have
network on the other. Router connecting the network-network on
network layer of the OSI model, so that technically is a Layer 3 Router Gateway.
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Router can be a device designed to function as a router
(dedicated router), or can also be a PC as a router is enabled.
In this paper, I will only write about the Cisco Router, which is a
dedicated router made by the Vendor named Cisco (http://www.cisco.com). By
Therefore, every word in any posts Router will be defined as Cisco
Router.
3. Network Interface
Network Interface is an interface that serves to connect the
a host to the network. Network Interface is the hardware that works on
1 layer of OSI Model. Needed by the Network Interface for Router
connect the Router with a LAN or WAN. Because Router duty
connect the network-network, a router must have a minimum of 2 network
interface. With this minimal configuration, the router can connect 2
network, because each network requires a network interface that
connected to the Router.
4. Configure Router
Router does not have a screen to interact with the network
administrator, therefore, we need a PC to set up a
router.
PC must connect to the router with one of the following ways:
• through the console port
• Network through
4.1. Men-configuration through the Router Console Port
Console port is a port on the router that is provided to connect the
router on the "outside world". A cable is required to Roll Over
connect the serial interface on the PC and the Console port on the router. After
Router connected to the PC, the Router can be configured to run application
HyperTerminal of PC.
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4.2. Men-through configuration Router Network
In this way, Router can be configured with a PC connected to the Router
through the network. This can only be used to view configuration and
modify the configuration on the router. Why? Because a router will only
connected to the network if the Network Interface is terkonfigurasi properly. In
the other hand, it also has advantages. In this way, the network administrator
more liberal place PC-to modify its configuration router. Network
administrator can place it on the PC anywhere, as long as your PC can be
connected to the router via the network. In this way, Network administrator
need to configure the telnet application is Router.
Here are the steps to use telnet on a PC with Operating System
Windows:
• Run the command prompt (or MS DOS prompt in Windows 9x)
• Type the following command in the command prompt:
C: \> telnet IP-address-Router
Example:
C: \> telnet 172.16.148.1
4.3 initialisation Router Configuration
Router configuration is stored in a memory on a special router called
nonvolatile random-access memory (NVRAM). If no configuration
stored in NVRAM, the operating system will run on a Router
routine that will provide the questions that the answer will be
used to configure the router. This routine vocabulary in Windows
known as the Wizard. However, the Cisco Router, this routine is called with
the system configuration or setup dialog dialog.
The setup is designed to make only minimal configuration, because the goal
main mode of this setup is just to make the configuration quickly and
easy. For a complex configuration, the network administrator must do so
manually.
Setup dialog can also be called even if NVRAM already contains a configuration.
Administrators simply type setup at the CLI command (Command Line Interface)
Setup dialog and will be executed.
Here is an example of the CLI Setup Dialog.
4.4 Level access command
For the purpose of keamaan, commands can be run from the CLI is divided into
2 levels of access, namely:
• User Mode
• Privileged Mode
User mode is to see the router. Commands are allowed in the
this mode can not change the router configuration, so that the mode is more secure when
a network administrator only want to see the status of the router and do not want to
change the configuration.
Privileged Mode has access level is higher. With this mode, the network
configurasi administrator can change the router. Therefore, this mode should
used with caution to avoid changes that are not desired
on the router.
When you log on to the router the first time, you will be entered in the user mode, with the prompt
a sign (>).
To move from user mode to priviledge mode, you must execute the command
enable the prompt. Prompt will change to a sign (#) when you are on the
Privilged mode.
To return to user mode from priviledge mode, you must execute the command
disable the command prompt.
Example 4.4-1:
con0 router is now available
Press RETURN to get started
router>
router> enable
router # disable
router>
router> logout
4.5. Changing the Router Configuration
As disinggung in chapter 4.4, Setup Dialog is not designed to modify
Router Configuration Router Configuration and create a complex. Because
that, for this purpose, must be done manually by entering the Mode
Configuration. Changing this configuration can be done directly through the console or
through a remote network such as has been reviewed in Chapter 4.1 and 4.2. After the PC
connected to the router, the network administrator must first enter Privileged Mode
as has been disinggung in Chapter 4.4.
Finally, the configuration can be changed with the configure terminal command to
enter the global configuration mode, which was then followed with a line-line
configuration. After these lines configurasi written, the exit will be required
to exit global configuration mode.
Example 4.5-1: change the router configuration
con0 router is now available
Press RETURN to get started
router>
router> enable
router # configure terminal
router (config) # interface ethernet 0
router (config-if) # description LAN IT Department
router (config-if) # exit
router (config) # exit
router #
5. Securing the Router Password
To make people who do not have the right to change configuration and stir
router, the router must be protected with a password (password).
5.1 Password for console
If a password is enabled on the console, the user can not simply get
access to the router through the console without the console write a password first.
To do this, you need line console 0 command followed by the command
login and password in the router configuration.