During this lab time you will configure the routing protocol OSPF with IPv4 addresses.

Lab 2: OSPF

During this lab time you will configure the routing protocol OSPF with IPv4 addresses. It is your responsibility to create an appropriate IPv4 subnet plan and address plan.

To ensure a timely lab time this part of the lab must be presented to the lecturer ONE day prior to the lab. Failure to send this part will lead to an extradiction of the lab and therewith a failure to complete the course.

Also, please consider that during the second part of the lab you will interconnect all groups. So please plan for

• What IP addresses will be used for the interconnect

• Which router must change it's IP address

• Which group will configure for ABR

The network:

Be aware that the routers in the lab may have different names for their interfaces. I.e.instead of FastEthernet 0/0 it might be GigabitEthernet 0/0 or instead of Serial0/0 it might be Serial0/0/0. It is advised to examine every router for the correct interface names. This can be done with the command „show ip interface brief“.

But this should be known from the first lab.

Address layout

Router A

Interface IP Adresse

Subnetzmaske Default Gateway

Fa0/0

N/A

Fa0/1

N/A

S0/1

N/A

Router B

Fa0/0

N/A

S0/0

N/A

S0/1

N/A

Router C

Gi0/0

N/A

S0/0

N/A

S0/1

N/A

Router D

Gi0/0

N/A

S0/0

N/A

Fa0/1

N/A

PC A

NIC

PC B

NIC

PC C

NIC

PC D

NIC

You must make your address layout with the following constraints:

Every group has it's onw class-b network in the format 172.2x.0.0/16 with <x> as the group number (group 1 has the addresses 172.21.0.0/16, group 2 has 172.22.0.0/16 and so on).

The 172.2x.0.0/16 IP network must be subnetted with: • The LAN of router D requires 8000 addresses

• The LAN of router B requires 4000 addresses • The LAN of router A requires 2000 addresses • The LAN of router C requires 2 addresses

• The connection between the routers do require 2 addresses

Task 1: Answer the following questions.

How many subnets do you need when configuring as stated above? ________

What subnet mask do you need for the LAN of router B? ________________________ What is the highest usable IP address in this network? __________

What subnet mask do you need for the LAN of router A? ___________________ What is the highest usable IP address in this network? __________

Task 2: Create a correct address layout and write it down in the table above. Please answer the following questions::

1. What is the network address of the LAN of router D? _________________

2. What is the network address of the LAN of router C? ______________________ 3. What is the network address of the LAN of router B?______________________ 4. What is the network address of the LAN of router A? ___________________________ 5. What is the network address of the interconnect between router A and router B?

___________________________

6. What is the network address of the interconnect between router C and router D? ____________________

Interface addresses:

Assign the correct IP addresses to the router interfaces and PCs with the following rules

1. the first possible address in the LAN should be used as the address for the router interface. 2. The last possible address in the LAN should be used as the address for the PC.

Preparations before the lab time

Use the program “PacketTracer” from Cisco Systems (available over the Internet or

„https://www.fbi.h-da.de/labore/netze.html“) to create your network in this simulation program.. In the simulator, check for errors, failures etc. and correct them if required. Send the resulting PacketTracer file to the lecturer. This file contains your preparation and will decide if you are able to enter the lab or not. It is sufficient if the lecturer receives ONE file per group but with the recording of all the participants.

Use the address

[email protected]

Lab time

Basic configuration

Task 1: cable your routers if not already done (check that!). Task 2: remove any old configuration, as known in lab 1.

Router#copy flash:start0-cfg startup Router#reload

Task 3: configure the basic configuration for routers and PCs as known from lab 1:

1. Router hostname 2. disable DNS lookup 3. EXEC mode password 4. Console password 5. Telnet (VTY) password

Task 4: configure and activate all required interfaces.

Task 5: test the connectivity between PCs and their router interface.

The connection between the individual PCs should not work at that time. But is is mandatory that the PC must reach their next hop gateway (the router LAN interface). If not, check for errors and correct them.

Task 6: test the connection between the routers.

Every router must be able to ping it's direct neighbor router. If not, find the error and correct it. Configure the OSPF protocol

Task 1: figure which interfaces must participate in the OSPF processes. Task 2: Answer the following questions:

Which commands do you need to confgure the OSPF process on a router?

Are there any interfaces which do not need to send OSPF updates? If yes, name them here.

What command do you use to disable updates on a specific interface?

Task 3: configure OSPF on all routers.

When done, answer the following question:

When configuring the “NETWORK” command, do you need the netmask or the wildcard?

Task 4: distribute a default route

The router A should distribute a default route to all other routers via OSPF. Which commands are required? Implement this then.

Task 5: Check your configuration

Every PC in your group must be able to ping every other PC in the group. If not, check for errors and correct them.

Which OSPF-type routes are in the forwarding table of router D?

What is the default route of router D?

Which OSPF-type routes are in the forwarding table of router A?

Why is this path chosen?

Interconnect all groups together:

In this work you will interconnect all groups into one large network. This must be done by creating different OSPF areas.

Every group is assigned a OSPF area id as  all routers in group 1 are in AREA 1  all routers in group 2 are in AREA 0  all routers in group 3 are in AREA 2  all routers in group 4 are in AREA 2  all routers in group 5 are in AREA 3

Every group need a specific interface to the neighboring groups. There are two free ethernet interfaces in every group on the routers B and C. Interconnect (cable them!) the groups as follows::

 Group 1 connects their router B (GigabitEthernet 0/1) to router C (GigabitEthernet 0/1) of group 2

 Group 2 connects their router B (GigabitEthernet 0/1) to router C (GigabitEthernet 0/1) of group 3

 Group 3 connects their router B (GigabitEthernet 0/1) to router C (GigabitEthernet 0/1) of group 4

 Group 4 connects their router B (GigabitEthernet 0/1) to router C (GigabitEthernet 0/1) of group 5

 Group 5 connects their router B (GigabitEthernet 0/1) to router C (GigabitEthernet 0/1) of group 1

Choose suitable IP addresses for these interconnects.

Please remember that with this interconnect you have to configure either router B or router C as ABR (AreaBorderRouter).

After cabling and configuring (check that the interconnect works before creating OSPF

Is the given configuration valid and correct?

If not, what do you need to do to change that?

At this point, every PC in the lab should be able to ping every other PC. If not, find the fault and correct it.

Question: could you configure one or more areas as STUB/totally STUB?