Case Study
Routing & Switching
Cisco Networking Academy
Routing and Switching:
Scaling Network Case Study
Overview and Objectives
This case study allows students to build and configure a complex network using
skills gained throughout the course. This case study is not a trivial task. To
complete it as outlined with all required documentation will be a significant
accomplishment.
The case study scenario describes the project in general terms, and will explain
why the network is being built. Following the scenario, the project is broken into a
number of phases, each of which has a detailed list of requirements. It is important
to read and understand each requirement to make sure that the project is
completed accurately.
The following tasks are required to complete this case study:
n Set up the physical layout of the network using the diagram
and accompanying narrative
n Correctly configure multi-area OSPF with MD5 authentication
n Correctly configure VLANs and 802.1q trunking
n Correctly configure RSTP
n Correctly configure Etherchannel when required
n Correctly configure routing
n Correctly configure HSRP
n Correctly configure DHCP
n Correctly configure NAT
n Create and apply access control lists (ACL’S) on the appropriate
routers and interfaces
n Verify/test and document that all devices are operational and
functioning according to the scenario guidelines
n Provide detailed documentation in a prescribed form as listed in
the deliverables sections
2-2
CCNA 2: WAN Technologies v3.1
Copyright ~ 2003, Cisco Systems, Inc.
Scenario
A company needs a network to be designed and implemented; the company has
locations in four cities. All of the locations will be connected using leased-line serial links.
The company has previously used RIP version 2; however, all four locations will use
OSPF routing process. Also, default static route must be used to access the internet.
One location, Belfast, has a large and complex LAN. Due to the size and complexity,
the company wants to create VLANs to control broadcasts, enhance security, and
logically group users. The company also wants to use private addresses throughout
the Autonomous System, DHCP over most of the LAN segments, and NAT
implemented for Internet connectivity. The company also wishes to limit Internet
access to Web traffic while allowing multiple protocols (not all) within its own WAN.
Although private addresses (RFC 1918) will be used, the company appreciates
efficiency and address conservation in design. To minimize wasted address space,
they have requested VLSM to be used when appropriate.
Copyright ~ 2003, Cisco Systems, Inc.
Case Study: WANs 3-9
Phase 1: Addressing the WAN & LAN
Use the following instructions to complete Phase 1:
n Use 172.16.0.0/20 for internal addressing with IP subnet zero enabled.
n Apply /30 subnets on all serial interfaces, using the last available subnet.
n Assign an appropriately sized subnet for the Belfast LAN, which has about 900 devices:
- VLAN 99: 40 devices (Management VLAN)
-
VLAN 2: 120 hosts
-
VLAN 3: 250 hosts
-
VLAN 4: 500 hosts
n Assign the appropriately sized subnet to the Limerick LAN, which has 200 hosts.
n Assign an appropriately sized subnet for the Galway’s 2 LANs, which have 400 devices.
n Assign the appropriately sized subnet to the Cork LAN, which has 100 hosts
n Document all of the addressing in tables.
DHCP POOL
Configure DHCP services on the Cork router. DHCP should provide services to the following
LANs hosts:
 Belfast’s VLAN 2, VLAN 3 and VLAN 4
DHCP should pass the following parameters to the hosts:
 IP address, Subnet Mask, Default Gateway and DNS (10.0.0.4)
4-4
CCNA 4: WAN Technologies v3.1
Copyright ~ 2003, Cisco Systems, Inc.
Phase 2: Configuring Default Routes, OSPF
Routing and HSRP
Use the following instructions to complete Phase 2:
n Configure each router with a hostname and required passwords.
n Configure each interface on all routers documented in Phase 1.
n Configure Multi-area OSPF on Routers (Galway, Cork, Limerick, and Belfast).
n Configure a summary (type 3) for area 1.
n Configure a Default on Belfast and redistribute the route into the OSPF process.
n Configure MD5 authentication between OSPF routers across all WAN links
n Adjust the Hello timer to 40 sec and Dead timers to 160 sec on the link between
Cork and Galway
n Verify that the Limerick, Belfast, Galway, and Cork routers have connectivity through
Layers 1-7.
Provide the ability of the network to dynamically recover from the failure of a device acting as a
default gateway to ISP. Use first-hop redundancy protocol (HSRP) to provide the mechanism.
n
Capture and save the four router configuration files. Edit the text files, and include
comments at the top of each file documenting the following:
– Your name – The date – CCNA4 Case Study – Phase 2
This documentation will serve as the deliverable item for Phase 2.
Copyright ~ 2003, Cisco Systems, Inc.
Case Study: WANs 5-9
Phase 3: Configuring VLANs
Internet
Area 1
S0/0
Galway
200
200
Hosts Hosts
(Use a PC and a switch
to simulate 10.0.0.4/29)
DCE
G0/0
10.0.0.2/29
S0/0
Cork
G0/0
10.0.0.1/29
S0/0
S0/1
S0/0
G0/0
Belfast2
Belfast1
G0/1
HSRP
S0/0
G0/1
G0/1
Limerick
G0/1
G0/0
Etherchannel
S2
100 Hosts
OSPF 10
area 0
Nat Outside
200.10.10.64/26
Nat Inside
172.16.0.0/20
S1
200 hosts
S3
VLA
N
2
VLAN
3
VLAN
4
N
VLA
99
Belfast VLANs
900 hosts (total)
Use the following instructions to complete Phase 3:
1. Apply the basic switch configuration
-
Hostname and passwords
- Root Bridge (PVST +)
- VTP Server (S1)
2. Configure the Belfast’s LAN (2 routers and 3 switches) as follows:

Create and name three Data VLANs and one Management VLAN
-
VLAN
VLAN
VLAN
VLAN
99: Management (Native)
2: HR
3: R&D
4: Production.

Configure G0/0 ports as trunks (802.1Q) on S1 and S2

Configure switches S1, S2 and S3; assign:
-
ports 1-4 as trunks (802.1Q)

Configure access layer switch S3; assign:
- Port 6 to VLAN 99
- Ports 7-10 to VLAN 2
- Ports 11-14 to VLAN 3
- Ports 14-20 to VLAN 4
- Disable all unused ports

Connect G0/0 of the Belfast’s 2 routers to G0/0 of S1 and S2

Connect one workstation per VLAN.
This documentation will serve as the deliverable item for Phase 3
6-6
CCNA 3, R & S: Scaling Network
Cisco Systems, Inc.
Phase 4: Configuring ACLs
Use the following instructions to complete Phase 4:
1. Configure a Reflexive ACL On the Belfast Router.
The ACL should:

Allow IP traffic for TCP and ICMP sessions originating from the inside
(established sessions) while denying IP traffic for sessions originating
outside the network.
2. Use an ACL to control VTY access on the Limerick router only.
The ACL should:

Allow telnet session to the Limerick router from the Management VLAN
(VLAN 99) only; telnet from other networks should be denied
Document the ACL configuration a chart. This will serve as the deliverable item for Phase 4.
Copyright ~ 2003, Cisco Systems, Inc.
Case Study: WANs 7-9
Phase 5: Configuring DHCP
Internet
Area 1
S0/0
Galway
200
200
Hosts Hosts
DCE
G0/0
10.0.0.2/29
S0/0
Cork
(Use a PC and a switch
to simulate 10.0.0.4/29)
S0/1
G0/0
G0/0
10.0.0.1/29
S0/0
S0/0
Belfast2
Belfast1
G0/1
HSRP
S0/0
G0/1
G0/1
Limerick
G0/1
G0/0
Etherchannel
100 Hosts
Nat Outside
200.10.10.64/26
Nat Inside
172.16.0.0/20
S2
OSPF 10
area 0
S1
200 hosts
S3
VLA
N
2
VLAN
3
VLAN
4
N
VLA
99
Belfast VLANs
900 hosts (total)
DHCP Services
DHCP should provide services to the following LANs hosts:
 Belfast’s VLAN 2, VLAN 3 and VLAN 4
DHCP should pass the following parameters to the hosts:
 IP address and Subnet Mask
 Default Gateway
 DNS address (10.0.0.4)
The Cork router will perform the DHCP services. Configure Cork using the
DHCP pools documented in Phase 1.
Configure DHCP services on the Cork router as follows:


Fa0/0 and sub-interfaces with the first useable address.
Exclude the first 10 IP addresses from each pool (to be used for
printers and servers)
 Configure Workstations to obtain its IP address automatically.
Have one host connected to Fa0/0 on Cork and one host per
VLAN connected to VLANs 2-4 on the Belfast’s access layer
switch.
Recapture and save the Galway router configuration file. Edit the text file, and include
comments.
This documentation will serve as the deliverable item for Phase 5
12-8 CCNA 4: WAN Technologies v3.1
Copyright ~ 2003, Cisco Systems, Inc.
Phase 6: NAT
Internet
Area 1
S0/0
Galway
200
200
Hosts Hosts
DCE
G0/0
10.0.0.2/29
S0/0
Cork
(Use a PC and a switch
to simulate 10.0.0.4/29)
S0/1
G0/0
G0/0
10.0.0.1/29
S0/0
S0/0
Belfast2
Belfast1
G0/1
HSRP
S0/0
G0/1
G0/1
Limerick
G0/1
G0/0
Etherchannel
100 Hosts
S2
OSPF 10
area 0
Nat Outside
200.10.10.64/26
Nat Inside
172.16.0.0/20
S1
200 hosts
S3
VLA
N
2
VLAN
3
VLAN
4
VLAN
99
Belfast VLANs
900 hosts (total)
Use the following instructions to complete Phase 6:
1. The Cork routers will perform NAT. Configure the Cork routers as follows:

Define the NAT pool. The pool consists of public network address
200.10.10.64/26. Exclude first 10 addresses from this pool (to be use
for servers, when required).

Define an access control list, which will translate for all internal
(172.16.0.0/20) addresses, and deny all other traffic.

Establish dynamic source translation, specifying the NAT pool and the ACL
defined in the previous steps.

Specify the inside and the outside NAT interfaces.

Change the default NAT timeout value to 120 seconds.
Document NAT configuration in a chart; it will serve as the deliverable item for Phase 6.
2. Connect a workstation to Belfast’s Fa0/0 port to simulate an ISP server.


Configure this workstation as follows:
Configure the IP address and subnet mask as 10.0.0.2/8.

Configure the default gateway.
3. Configure the workstation to act as a web server. Create a simple web page that
will tell users that they have reached the ISP.
Recapture and save the Belfast’s routers configuration file. Edit the text file, and include
comments.
This documentation will serve as the deliverable item for Phase 6
12-9 CCNA 4: WAN Technologies v3.1
Copyright ~ 2003, Cisco Systems, Inc.
Phase 7: Verification and Testing
Use the following instructions to complete Phase 7:
1.
Verify communication between various hosts in the network. Troubleshoot
and fix any problems in the network until it works properly. Document the
results of the tests in a table.
2.
Recapture and save the router configuration files for all four routers. Edit the
text files, and include comments at the top of each file documenting the
following:
– Your name
– The date
– CCNA4 Case Study – Final Router Configuration
– The router name that corresponds to each file.
This documentation, along with the completed tables from Phase 1, Phase 2, Phase 3,
Phase4, Phase 5, Phase 6, and Phase 7, will serve as the final deliverable item for the
case study.
12-10 CCNA 4: WAN Technologies v3.1
Copyright ~ 2003, Cisco Systems, Inc.
Phase 8: Documentation & Presentation
The final task in this case study is to deliver a 20 minutes presentation of the main features
of the design decisions and recommendations. A formal written report should also be
provided that contains all of the design documents as well as all the supporting worksheets
(see the case study requirements; Overview and Objectives on page 1).
The design documentation should include: device configurations, a list of the number and
types of networking devices selected for this design, logical and physical diagrams,
subnetting scheme, and network testing verifications. The completed tables from Phase 1,
Phase 2, Phase 3, Phase 4, Phase 6, Phase 6, and Phase 7, should be included with the final
deliverable items.
The documentation should be complete and should contain enough information to allow a
third party to properly install and configure or troubleshoot the network without requesting
additional information.
12-11 CCNA 4: WAN Technologies v3.1
Copyright ~ 2003, Cisco Systems, Inc.