Student Name
Date
DT021/4
COMMUNICATIONS NETWORKS 2
Laboratory 7
Objective
The objective of this exercise is to set up and test a small internetwork consisting of two
interconnected networks using 2 Cisco routers, and 3 PCs, using the OSPF routing protocol.
You should work in teams of 3 students.
Log in as “netengineer” on the PCs, and make sure that the firewalls are disabled. You should reenable the firewall at the end of the laboratory session.
Download this document from the web, and complete it as you progress. Print it at the end of the
laboratory session. Only one report is required per group. Complete the report on PC that you use to
open the hyperterminal to facilitate copy and paste.
Network set up
Each group will use 2 Cisco routers, and 3 PCs. Set up the Test Network as shown in the figure below
(use straight through cables with Hub).
Use the following network addresses.
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Net 1: 10.0.0.0/8
Net 2: 172.16.0.0/16
Net 3: 192.168.100.0/24
List the IP configuration of the PCs you have selected in the table below:
Network/Node
Net 1/Node A
Net 2/Node B
IP Address
Subnet Mask
Gateway IP Address
After configuring the PCs, check that the parameters have been included (ipconfig).
List the IP parameters to be used to configure the router interfaces.
Router 1
Fa0/0
IP Address
Mask
Fa0/1
IP Address
Mask
Router 2
Fa0/0
IP Address
Mask
Fa0/1
IP Address
Mask
The PC on Network 3 (Node E) will allow you to observe OSPF messages sent between routers.
See Appendix to start the Cisco Router.
Configuration of the routers interfaces
1) When in privileged mode, to configure any feature of the router, it is necessary to enter
configuration mode. This is done by issuing the command configure terminal.
Router# configure terminal
Router(config)#
2) Configure the interfaces you are using with IP address and subnet mask.
Router# configure terminal
Router(config)# interface fa0/0 (or fa0/1)
Router(config-if)# ip address ipaddress subnetmask
Router(config-if)# no shutdown
After completing the configuration of the interfaces, you may exit the configuration mode, after turning
on the routing function with the command ip routing.
Router(config-if)# exit
Router(config)# ip routing
Router(config)# exit
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Note: the router ID will be taken as one of the router interface addresses, usually the highest
numerical value. You could also configure a loopback interface (interface loopback0), which would
then be taken as the router ID.
Use the following commands to display the destination networks that each router has in its routing
table (directly connected networks).
Router# show ip route
What routes are displayed in each router:
Router 1
Router 2
We will now turn on the OSPF protocol to allow router 1 to learn a route for Network 2, and router 2 to
learn a route for Network 1.
Start the Wireshark analyser on Node E.
OSPF Routing single area
In this test, you should use Wireshark to observe the OSPF traffic (Hello packets towards networks).
Now configure both routers to use a single area OSPF.
Router# configure terminal
Router(config)# router ospf 1
Router(config-router)# network network mask area 0.0.0.0
Router(config-router)# network network mask area 0.0.0.0
Router(config)# exit
Note: the mask in statements above is called a wildcard mask, and is used to identify the range of
interfaces of the router on which OSPF will run; it is different of the subnet mask as in a wildcard
mask a 1 means “don’t care”, instead of 0, in the subnet mask . 0.0.0.31 is the wildcard mask
corresponding to the subnet mask 255.255.255.224.
/8 => subnet mask = 255.0.0.0
=> wildcard mask = 0.255.255.255
/16 => subnet mask = 255.255.0.0 => wildcard mask = 0.0.255.255
/24 => subnet mask = 255.255.255.0 => wildcard mask = 0.0.0.255
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What routes are displayed in each router:
Router 1
Router 2
Observe the traffic captured by Wireshark.
How frequently are the OSPF Hello packets sent ?
Observe the 2 last LSA updates, one from each router. Identify the links advertised.
Check the router database:
Router# show ip ospf database qualifier
Qualifier can be:
-
router to look at router LSA,
-
summary to look at network summary LSA,
-
network to look at declaration of Designated Router in Transit networks.
Summarize the links here, per LSA type (router, Summary, network,…). Give:
- advertising router
- link type (stub, point to point,..),
- link ID (router ID, Network Id,…),
- metrics.
Note: The 100 Mbps Ethernet link has a cost calculated as: 100000000/100000000=1.
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Appendix: Cisco router
The routers used in this lab will be Cisco 2800 series. They have various I/O connections possible.
 Console Port: Connection to a terminal or PC's serial port for local configuration.
 Serial Port: Used to make a direct connection between two adjacent routers with a serial cable.
 10/100 Ethernet: Ethernet port supporting 10/100 Mbps Ethernet.
The 10 or 100 Base Ethernet should be used to connect the routers to the Nets.
Connecting a management PC to the Switch
1. Connect the router’s console port using a roll-over cable to the serial (COM) port on PC,
Rollover cable
2. Open “Hyper terminal” by clicking: Start > Programs > Accessories > Communication > Hyper
terminal.
3. Enter connection name, e.g.: Cisco
4. Select COM3 (or COM1, whichever is available)
5. Under “bits per second” select 9600 and leave all other fields.
Bits per second: 9600
Data bits: 8
Parity: None
Stop bits: 1
Flow Control: None
6. Switch on power to router when main Hyper terminal window appears.
7. Enter password if prompted (passwords given during laboratory).
Note: When first connecting to the router, the lowest access mode, called the EXEC mode is entered.
From this mode, the user can only use a limited numbers of unprivileged commands.
It is necessary to enter privileged mode to configure the router. This is done using the command
enable. Privileged mode will usually be password protected.
8. Type enable and enter the password (if needed) to enter Privileged mode (passwords given
during laboratory).
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It is ALWAYS best practice to begin with a clean RAM configuration. Otherwise, stale configuration
commands may have unintended consequences:
Erase the Non Volatile RAM configuration file:
Router# erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue?
[confirm] <ENTER>
[OK]
Erase of nvram: complete
Reload the router:
Router# reload
System configuration has been modified. Save? [yes/no]: no
Proceed with reload? [confirm] <ENTER>
Would you like to enter the initial configuration dialog? [yes/no]: n
Would you like to terminate autoinstall? [yes]:y
When the router reboots, enter privileged mode:
Router> enable
Router#
Note: When in privileged exec command mode, any misspelled or unrecognized commands will
attempt to be translated by the router as a domain name. Since there is no domain server configured,
there will be a delay while the request times out. This can take between several seconds to several
minutes. To terminate the wait, simultaneously hold down the <CTRL><SHIFT>6 keys then
release and press x:
Router>enabel
Translating "enabel"...domain server (255.255.255.255) %
Briefly hold down the keys <CTRL><SHIFT>6, release and press x
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