Programming The Router And Connecting The Networks

Finally, the time has come to logically connect yours and Hermione’s networks to Ron’s network so that you can transfer packets around.

Please download the Cisco 3900 Series and Cisco 2900 Series Hardware Installation Guides for a higher-resolution version of this image. The installation guide also contains additional information about the routers. Giving detailed information about routers is beyond the scope of this tutorial.

We only need three ports on the Cisco 2911 router. Ports 4,5, and 6 are required.

To program a router, follow the steps below.

Connecting Networks: Configuring a Router to Transfer Packets

The commands used below are for a Cisco router. Most routers will have very similar commands. To learn more, read the documentation for your router.

1 Connect a serial cable from a computer to the router.

A serial cable can be used to connect to most routers. Nowadays, you can buy a USB to serial cable and then use a terminal program to type commands into the router.

2 Navigate to the router's enable or programming mode.

Routers can operate in several modes. The first is typically a read-only mode. To program it, you must first put it into programming mode. That usually entails typing a command such as enable to enter privileged mode, followed by configuring terminal to actually program it.

3 Select the interface to setup

You must now select the interface that you want to configure. This refers to the physical connection, which could be Ethernet or serial. To route anything, a router must have at least two interfaces. The command interface GigabitEthernet0/0 in Cisco IOS will select the first or “zero” GigabitEthernet port on the first or “zero” GigabitEthernet card.

4 Configure the address and launch the interface

The first command, ip address IP_ADDRESS_OF_THE_INTERFACE SUBNET_MASK, configure the interface’s IP address and subnet mask.

The no shutdown command informs the router that the interface is in use.

5 Choose the second interface.

Enter the command exit, followed by the command interface GigabiEthernet0/1. This will switch us to the other interface so we can configure it as well.

6 Configure the address and launch the second interface.

The first command, ip address IP_ADDRESS_OF_THE_INTERFACE SUBNET_MASK, configure the second interface’s IP address and subnet mask.

The no shutdown command informs the router that the interface is in use.

7 Exit programming mode and save our configuration 

By typing exit twice, then writing me, we can save our configuration to nonvolatile memory. Our router is now set up to route traffic between the connected networks.

Setting up IP Addresses for End Devices in Cisco Packet Tracer

In the following section, we will show you how to program a Cisco 2911 router.

Cisco Packet Tracer includes both a graphical user interface(GUI) and a command line interface(CLI) for programming the router. The Config tab lets you program the router using GUI. To program the router using a terminal use the CLI. In this tutorial, we will program the router using the CLI. It is worth noting that while configuring the router via the GUI, you will see the equivalent commands listed in the following “Equivalent IOS Commands” box.

The end devices’ IP addresses must first be configured. You do not need to assign an IP address to the switches in this tutorial. To configure the IP Addresses of the end devices in Cisco Packet Tracer you have to follow the following steps:

Click on the end device

We will be assigning IP Addresses to the end devices using the GUI. To do this you have to select Desktop in the menu. And then select IP Configuration from the options available in the Desktop. You will see the following window.

Make sure that the static is selected. Then assign IP Address, Subnet Mask, and Default Gateway for the end device. The IP addresses, subnet masks, and default gateways that we used are listed in the table below.

Yours and Sam’s Network

Network Address: 192.168.100.0/24

Subnet Mask: 255.255.255.0

Ron’s Network

Network Address: 192.168.200.0/24

Subnet Mask: 255.255.255.0

Assign ip addresses to all the devices to transfer packets. If you properly configure the end devices, you will see the following when you place the cursor in one of them.

Configuring a Cisco Router using the Command Line Interface (CLI)

Router’s Configuration

Enter the following command in the CLI:

Router>enable
Router#configure terminal
Router(config)#interface GigabitEthernet0/0
Router(config-if)#ip address 192.168.100.1 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config)#interface GigabitEthernet0/1
Router(config-if)#ip address 192.168.200.1 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#exit
Router(config-if)#exit
Router#write mem

The diagram above further explains the command we entered. You’ll see something like this in the CLI.

System Bootstrap, Version 15.1(4)M4, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 2010 by cisco Systems, Inc.
Total memory size = 512 MB - On-board = 512 MB, DIMM0 = 0 MB
CISCO2911/K9 platform with 524288 Kbytes of main memory
Main memory is configured to 72/-1(On-board/DIMM0) bit mode with ECC disabled
 
Readonly ROMMON initialized
 
program load complete, entry point: 0x80803000, size: 0x1b340
program load complete, entry point: 0x80803000, size: 0x1b340
 
IOS Image Load Test
___________________
Digitally Signed Release Software
program load complete, entry point: 0x81000000, size: 0x3bcd3d8
Self decompressing the image :
######################### [OK]
Smart Init is enabled
smart init is sizing iomem
TYPE MEMORY_REQ
Onboard devices &
buffer pools 0x022F6000
-----------------------------------------------
TOTAL: 0x022F6000
Rounded IOMEM up to: 36Mb.
Using 6 percent iomem. [36Mb/512Mb]
 
Restricted Rights Legend
 
Use, duplication, or disclosure by the Government is
 subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.
 
cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706
 
Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.1(4)M5, RELEASE SOFTWARE (fc2)Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Wed 18-Jul-07 04:52 by pt_team
Image text-base: 0x2100F918, data-base: 0x24729040
 
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
 
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
 
If you require further assistance please contact us by sending email to
[email protected].
 
Cisco CISCO2911/K9 (revision 1.0) with 491520K/32768K bytes of memory.
Processor board ID FTX152400KS
3 Gigabit Ethernet interfaces
DRAM configuration is 64 bits wide with parity disabled.
255K bytes of non-volatile configuration memory.
249856K bytes of ATA System CompactFlash 0 (Read/Write)
 
Press RETURN to get started!
 
 
 
Router>enable
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface GigabitEthernet0/0
Router(config-if)#ip address 192.168.100.1 255.255.255.0
Router(config-if)#no shutdown
 
Router(config-if)#
%LINK-5-CHANGED: Interface GigabitEthernet0/0, changed state to up
 
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up
 
Router(config-if)#exit
Router(config)#interface GigabitEthernet0/1
Router(config-if)#ip address 192.168.200.1 255.255.255.0
Router(config-if)#no shutdown
 
Router(config-if)#
%LINK-5-CHANGED: Interface GigabitEthernet0/1, changed state to up
 
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
exit
Router(config)#exit
Router#
%SYS-5-CONFIG_I: Configured from console by console
write
Building configuration...
[OK]
Router#write mem
Building configuration...
[OK]

You just created the following router configuration file!

Routers can obtain configuration files from network file servers such as tftp servers. You can also use a text editor to create a configuration file, which you can then upload to the router using the same service.

So is your network up and running?

Use the ping program to see if you can reach an end device in another network. Write the following command in your Packet Tracer PC Command line: ping 192.168.200.102. 

You can use the Packet Tracer PC Command line by clicking an end device(PC0) and then selecting the Command Prompt option below the Desktop.

What Is A Ping?

A ping (Packet Internet or Inter-Network Groper) is a simple Internet program that allows a user to test and confirm whether a specific destination IP address exists and can accept requests in computer network administration. The acronym was devised to correspond with the term used by submariners to describe the sound of a returned sonar pulse. Ping is also used for diagnostic purposes to ensure that a host computer that the user is attempting to reach is operational. Ping can be used by any operating system (OS) that supports networking, including most embedded network administration software.

Ping operates by sending an Internet Control Message Protocol (ICMP) Echo Request to a specific network interface and waiting for a response. When a ping command is issued, a ping signal is sent to the address specified. The target host responds to the echo request by sending an echo reply packet.

Ping commands, by default, send multiple requests (usually four or five) and display the results. The echo ping results indicate whether or not a specific request received a successful response. It also includes the number of bytes received as well as the time it took to receive a response, also known as the time-to-live.