ECE U629 Internetworking Design Lab, Northeastern University
Routing
Protocols Lab
RIP and OSPF
Name: ________________________________________
Date Experiment Performed: ______________________
Group Members:
______________________
______________________
______________________
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Objective
The goal of this exercise is to construct a six node TCP/IP network and analyze the use of
RIP vs. OSPF as the active routing protocols.
Equipment List
Routers: 6 Cisco 2600 series with Fast Ethernet and Serial interfaces
Switches: 1 Cisco Catalyst 2900 series with Fast Ethernet ports
Other: Terminal
Assorted cabling (Cat 5 straight-through, crossover and T1)
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Introduction and Background
Much like the highway infrastructure, the backbone construction of the Internet presents
an interesting problem: How do you get around? How does packetized data travel from A
to B? Does it get lost? How does it know where is the best or quickest path?
The technological answer behind these questions is called routing. Routing is a general
term used to describe the workings of routers, particularly their manipulation of
packetized data in transit. Routers, combined with hubs and switches, take the traffic of
the Internet, data packets, and attempt to direct it in the most efficient way possible. A
router is a device or software that determines the next network node (or the end node,
meaning the destination machine) to which a packet should be forwarded. The router is
almost always connected to at least two networks. Routers work by forming routing
tables, general tables of information on how the traffic should be directed, and sending
out this information to other routers on the network. (The exact method of sending is
implementation-dependant.)
A hub is a place where data arrives from one or more directions and is forwarded out in
one or more other directions. A hub usually includes a switch of some kind, or the switch
could be housed as a separate unit. The distinction seems to be that in the switch many
can talk at once, all at the same speed, while in the hub, only one can speak at a time. If
more than one node is speaking at a time, collisions occur. When using CSMA/CD,
backoffs are a method for avoiding these collisions. After a collision is detected, the one
of the colliding systems “backs off” from sending for a length of time (variable or fixed),
while the other sender attempts to resend.
These devices all work together to form our picture of the Internet, and in this
experiment, you will be manipulating some of these components to implement your own
network and form conclusions about how routing works in relation to this network. The
hardware we will be using in this lab includes Cisco routers, all 2600 series, and a Cisco
catalyst 2900 switch. The Cisco 2600 series of Ethernet and token ring routers provide
connectivity and routing for smaller enterprises. The 2900 switch connects the two, and
any other networking components, via software configurable virtual LANs on any of the
ports on the switch.
The software we will be using in this lab includes the Cisco Internetwork Operating
System (IOS), which is the text-based operating system for Cisco routers. We will be
dealing with the IOS, for the routers and the switches, which has a Unix- like command
line.
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Lab Procedures
The goal of this lab is to construct a 6- node IP network tha t will utilize two methods of
routing, RIP and OSPF. RIP (Routing Information Protocol) is a routing protocol that
utilizes regular broadcasts of the routing table to keep all routing nodes up to date.
Routing is determined by hop count. OSPF (Open Shortest Path First) is a more
encompassing solution, which utilizes any number of conditions (called metrics) to
determine which path to destination is the “open shortest path.” Examples of metrics
include cost and line speed.
Configuring the interfaces
First, we must use router commands to setup our chosen routes. You will be interfacing
with your devices and issuing commands that will establish routes on the network, with
each hop having a certain line speed, IP address, and port type associated with it.
In order to see the difference between the RIP and OSPF routing protocols, we will
monitor the routing update packets using an analyzer (FETEST LanXL) and analyze the
captured traffic.
To setup the logical links between the machines, a set of commands will be necessary for
each side of each link.
Establish a connection with the Cisco 2621 router by clicking on the cisco2621
HyperTerminal icon on the desktop. The router command prompt will appear.
Router>
2. Issue the following commands, replacing the parts in italics with appropriate values:
Router>enable
Password:cisco[CR]
Router#configure terminal [CR]
Router#hostname R2 [Replace “R2” with your router number i.e. R3, R4 etc]
Router(config)#interface FastEthernet 0/1 [CR]
Router(config-if)#ip address 192.168.50.2 255.255.255.0 [CR]
[Refer to diagram/table ]
Router(config-if)#[Ctrl -Z]
Router#write [very important! otherwise the router will not save the changes!]
3. Now setup the rest of the links. The entries that come after the interface command will
change, as well as the IP address that comes after the ip address command, and so these
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are given for each link to be created in the following table (note the link we just setup is
included for completeness):
Device Interface IP address
R1 FastEthernet 0/0 192.168.50.1/24
FastEthernet 0/1 192.168.5.30/24
Serial 0/0 192.168.99.2/24
R2 FastEthernet 0/0 192.168.24.3/24
FastEthernet 0/1 192.168.50.2/24
R3 FastEthernet 0/0 192.168.24.1/24
FastEthernet 0/1 192.168.25.30/24
Serial 0/0 192.168.26.2/24
R4 FastEthernet 0/0 192.168.30.1/24
FastEthernet 0/1 192.168.45.30/24
Serial 0/0 192.168.26.1/24
R5 FastEthernet 0/0 192.168.20.1/24
FastEthernet 0/1 192.168.30.2/24
R6 FastEthernet 0/0 192.168.20.2/24
FastEthernet 0/1 192.168.65.30/24
Serial 0/0 192.168.99.1/24
You may type “show running-config” any time to view the current configuration of the
router.
Since some routers are plugged into a Catalyst switch, we now want to put those two
links on their own virtual LAN (VLAN) so that they are logically linked and can reach
one another.
Look for a PC labeled “Switch Console”. Log in to the catalyst switch IOS and enter the
commands:
Switch# show running configuration
The following commands will create an empty vlan 2 (named VLAN2):
Switch# vlan database
Switch(vlan)# vlan 2 name VLAN2
Switch(vlan)# exit
The following commands will add Fast Ethernet interface 0/1 to vlan 2:
Switch# configure terminal
Switch(config)# interface FastEthernet 0/1
Switch(config-if)# switchport access vlan 2
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Note: The interfaces (or ports) on the Catalyst 2900XL switch are numbered
FastEthernet 0/1
.
FastEthernet 0/24
The switch ports, along with their VLAN numbers are listed below:
VLAN 2: FastEthernet 0/1 – 0/4
VLAN 3: FastEthernet 0/5 – 0/8
VLAN 4: FastEthernet 0/9 – 0/12
VLAN 5: FastEthernet 0/13 – 0/16
VLAN 6: FastEthernet 0/17 – 0/20
VLAN 7: FastEthernet 0/21 – 0/24
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Configuring RIP Routing
Now we will enable RIP routing on each device we have just configured. To do this,
issue the following commands:
R2>configure terminal [CR]
R2(config)#router rip [CR]
R2(config-router)#network network-number [CR]
R2(config-router)#network network-number [CR]
R2(config-router)#network network-number [CR]
.
You can add as many networks as you want using this method. Now add the networks
that are given in the table below:
Device Networks to add
R1 192.168.99.0
192.168.5.0
192.168.50.0
R2 192.168.50.0
192.168.24.0
R3 192.168.24.0
192.168.25.0
192.168.26.0
R4 192.168.26.0
192.168.45.0
192.168.30.0
R5 192.168.30.0
192.168.20.0
R6 192.168.20.0
192.168.65.0
192.168.99.0
Now execute the “traceroute” command on the IP addresses of the end nodes to
determine transmit time and speed, and fill in the following tables. This table will ensure
that the entire setup is configured and working. This is essential for capturing and
monitoring the routing update traffic. The syntax for this command is:
R2> traceroute IP-address [CR]
Traceroute to Average Time (ms) Hop Count
R1
R2
R3
R4
R5
R6
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Afterwards, view the routing table for your router by executing the “show ip route”
command at the router console, and fill in the following table:
Routing Table:
Destination Interface Source of Protocol Metric
IP Address Information
To view the decoded IP packets on LanXL, use the following instructions:
1. Click on the LanXL icon
2. Make sure the 802.3 module is loaded and it is in “capture and monitor” mode.
3. Switch to detail view (Click the detail view icon)
4. Click on Monitor Views à Packet Summary, and start capturing traffic.
5. Once you have gathered sufficient data, and have observed a few routing update
packets, stop the traffic capture and click Capture Views à Capture view
Scan the captured traffic for routing update packets (RIP broadcasts in this case). Always
check the source address of the packet to check if it was broadcast by your router.
Once you have observed a couple of such RIP broadcasts, we will bring down one of the
serial links and observe the convergence time for RIP. At this stage, ask the TA for
further instructions, but keep the monitor running in capture and monitor mode.
You will be informed when the serial link is down and now you have to allow your router
to find alternate routes and update its routing table. Observe the RIP broadcasts until they
stop changing anymore. Count the number of updates it took to arrive at the new routing
table. Copy the new routing table in the following page.
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Number of update packets before the new routing table was built:____________
New Routing Table :
Destination Interface Source of Protocol Metric
IP Address Information
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Configuring OSPF Routing
Now, turn off RIP, turn on OSPF, configure, and view the routing table. The following
sequence of commands gives the proper syntax:
R2>configure terminal [CR]
R2(config)#no router rip [CR]
R2(config)#show process [CR] [pick a free process id number ]
R2(config)#router ospf process-id [CR]
R2(config-router)#network network-number mask area area-id [CR]
R2(config-router)#[CTRL-Z]
R2# write
Use the table shown below for information specific to your router. The network-
number identifies the network using ospf, the mask tells which bits to use from the
network- number, and the area- id is used for determining the different ‘areas’ in an ospf
configuration. (use: 0.0.0.0). Execute this sequence of commands at your device using the
settings given in the table below
Device Network Mask Area-id
R1 192.168.99.0 255.255.255.0 0.0.0.0
192.168.50.0 255.255.255.0 0.0.0.0
192.168.5.0 255.255.255.0 0.0.0.0
R2 192.168.24.0 255.255.255.0 0.0.0.0
192.168.50.0 255.255.255.0 0.0.0.0
R3 192.168.24.0 255.255.255.0 0.0.0.0
192.168.26.0 255.255.255.0 0.0.0.0
192.168.25.0 255.255.255.0 0.0.0.0
R4 192.168.26.0 255.255.255.0 0.0.0.0
192.168.30.0 255.255.255.0 0.0.0.0
192.168.45.0 255.255.255.0 0.0.0.0
R5 192.168.20.0 255.255.255.0 0.0.0.0
192.168.30.0 255.255.255.0 0.0.0.0
R6 192.168.99.0 255.255.255.0 0.0.0.0
192.168.20.0 255.255.255.0 0.0.0.0
192.168.65.0 255.255.255.0 0.0.0.0
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Now execute the “ping” command on multiple IP addresses to make sure that the setup is
working and to determine transmit time and speed, and fill in the following table.
R2>ping ip-address [CR]
Ping interface on Average Time (ms)
R1
R2
R3
R4
R5
R6
From the console, type “show ip route ospf ” command and fill in the following tables:
Routing Table:
Destination Interface Source of Protocol Metric
IP Address Information
To view the decoded IP packets on LanXL, use the following instructions:
1. Click on the LanXL icon
2. Make sure the 802.3 module is loaded and it is in “capture and monitor” mode.
3. Switch to detail view (Click the detail view icon)
4. Click on Monitor Views à Packet Summary and start capturing traffic.
5. Once you have gathered sufficient data, and have observed a few routing update
packets, stop the traffic capture and click Capture Views à Capture view
Scan the captured traffic for routing update packets (Link State Updates in this case).
Once you have observed a couple of such LSUs, we will bring down the same serial link
and observe the convergence time for OSPF. At this stage, ask the TA for further
instructions, but keep the monitor running in capture and monitor mode.
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You will be informed when the serial link is down and now you have to allow your router
to find alternate routes and update its routing table. Observe the LSUs until they stop
changing anymore. Count the number of updates it took to arrive at the new routing table.
Copy the new routing table.
Number of update packets before the new routing table was built:____________
New Routing Table
Destination Interface Source of Protocol Metric
IP Address Information
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Review and Questions
1. Based on the information contained in the RIP broadcasts and the Link State
Updates, comment on the number of updates required to converge in RIP vs.
OSPF. Give a brief explanation.
2. In OSPF, you will notice a lot of “hello” packets. Briefly explain their function.
3. If an IP address is written as: 192.168.24.44/20
a. What does the “/20” mean?
b. What is the subnet mask for such a network?
c. Write down the network ID and the host ID
d. Calculate the maximum number of hosts this network can have
4. List the metrics used by RIP and OSPF. (hop count, bandwidth etc)
5. Give an example of a situation where VLANs can be used.
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