CASE STUDY

32524 LANs and Routing

(Spring 2024)

Due Date:

IPv4 Addressing Milestone Submission (Tables A, B and C):

By Week 5 (Emailed to your Lab Instructor by 7am Mon 9 Sep 2024)

Video Demonstration Submission:

By Week 10 (Emailed to your Lab Instructor by 7am Mon 21 Oct 2024)

32524 LANs and Routing Spring 2024 Case Study

1. Preamble

   This Case Study offers students an opportunity to put into practice the network design, implementation, and troubleshooting skills they will have gained through studying LANs and Routing.

   The Case Study is structured to guide groups through the gradual completion of the entire project, enriching their learning journey. The Scenario provides a broad overview of the project, including the rationale behind network construction. Then, the Case Study is broken down into various tasks, each accompanied by detailed requirements to lead your group through successive steps. It is important to thoroughly read and comprehend each requirement, and complete the tasks on a weekly basis to advance your study.

2. Objectives and General Assessment Criteria

   Objectives

   • Design IPv4 addressing schemes that meet the addressing requirements.

   • Configure OSPFv2, including simple route redistribution, for IPv4.

   • Configure static, default static, summary static routing, and floating static routing for IPv4.

   • Configure switching networks for VLANs, 802.1q trunking, and inter-VLAN routing.

   • Configure static NAT and dynamic NAT with overloading.

   • Verify the network’s functionality and troubleshoot it as needed.

     General Assessment Criteria

   • Requirements met.

   • Correctness of the design.

   • Functionality of implementation.

   • Justification of design and implementation.

   • Verification of functionality.

3. Assessment

   The case study is intended to be completed as a group activity with 75 percent of its total marks being awarded individually. The Case Study’s assessment consists of the following two-stage submissions:

1. Part A: IPv4 Addressing Milestone Submission (25%; due by Week 5)

   Each group as a whole is required to Email their IPv4 subnetting and addressing scheme (including Tables A, B, and C on Page 10 of the book) to their lab instructor by the end of Week 5. Feedback on this milestone submission will be provided during the following week’s lab class.

2. Part B: Packet Tracer based Video Demonstration (75%; individually assessed; due by Week 10): By the end of Week 10, students as groups are required to submit a recorded video showing each member orally present their Packet Tracer (PT) network, explaining how each part of their network was designed and implemented to meet the specified requirements.

Additionally, the group must submit a copy of their completed PT file for reference. PS. The marking is purely based on students’ presentation in their submitted video.

For further information about the demonstration, please refer to Section 7 on Page 9 of this Case Study book.

1. Suggestions and General Requirements for Case Study Completion

   It is expected that each student needs to spend approximately six hours to complete this Case Study.

   Students as groups are encouraged to plan and work on the Case Study on a weekly basis, as the relevant topics covered in class, as outlined below. This strategy guarantees comprehensive completion of all tasks and ensures students derive the utmost advantage from this task. However, only two submissions are required and marked.

   Weeks 4&5: complete Task One – IPv4 Addressing (Part A submission due by Week 5) Week 6&7: complete Task Two – Static and OSPF Routing

   Week 8: complete Task Three – Switching

   Week 9&10: prepare PT Video Demonstration (Part B submission due by Week 10)

   Please note, postponing the Case Study until the last week or day(s) could potentially lead to a poorly designed network and restrict the advantages it offers for your final assessments. Hence, we strongly suggest adhering to the recommended weekly plan to secure a successful outcome.

2. Scenario

   The objective of this Case Study is to present a scenario in which the Arcadia Institute of Technology (AIT), a training organisation, has procured and relocated to a new training centre in the city. This move necessitates a comprehensive network overhaul and implementation. Your group has been engaged as AIT’s ICT consultants for this endeavour. Your mission is to design and deploy a new network, a prototype of which will be evaluated through a Packet Tracer-based demonstration.

   AIT’s campus network encompasses diverse networks, as illustrated in the partial logical Topology Diagram shown in Fig. 1. Your task involves designing and implementing these networks, including a simulated ISP, utilising the interfaces/ports of your preference. AIT expects a network prototype before full deployment to ensure its alignment with their requirements.

   To help your group organise the Case Study, it is divided into four tasks, each with specific requirements. Upon accomplishing all tasks, the network prototype is anticipated to be realised using Packet Tracer, followed by a demonstration of its operational capabilities in a recorded video.

   The AIT, which you are tasked with designing a network for, operates across two campuses. The City Campus encompasses three key locations: Main Building, West Tower, and East Tower. In contrast, the Branch Campus is situated in a suburban area and will be linked through a leased line serial connection, due to cost considerations.

   • The Thomas and Jones Street buildings serve primarily as the AIT Teaching and Learning hub. Various employee groups are situated in these two buildings. Due to the size and complexity of LANs, the company wants to create VLANs to control broadcasts, enhance security and logically organise user groups because these VLANs are essential for the organisation’s operations.

   • The Main Building site features one exit link, offering Internet access and external service connectivity. Leased Line serial connections link the Main Building to both the West Tower and East Tower sites.

   • Also, at the Main Building site, AIT houses its private Servers and intranet services, catering to both internal and external users.

   • To avoid single-point failure and allow certain levels of redundancy, users in the switching network on the City Campus have two exit points, i.e., via West (default) and East, respectively.

   • Furthermore, AIT’s internal network has two exit links for accessing the Internet and external services: one via Main and the other via Branch. The link from Main is the primary path and the backup path through the Branch will only become used when the primary Main-ISP link becomes unavailable.

     Fig. 1. Basic network topology

     AIT has agreed to use OSPF for its entire internal networks. At this stage, only IPv4 is considered. AIT also wants to use private IPv4 addresses for the entire internal network and appreciates efficiency and address conservation in their design. NAT for IPv4 will also be implemented on the border routers.

3. Requirements in Tasks

   In order to help your group organise this Case Study, the scenario has been broken into four tasks and detailed requirements are listed for each task. A prototype of the network is expected to be implemented using Packet Tracer to demonstrate its functionality when all tasks are completed.

   Discussion questions are provided at the end of each task for students to consider when justifying their design and implementation. However, there is no requirement to submit these discussions.

   Task One: Addressing the Network

   The ISP links:

   The ISP has allocated one of the following public IPv4 address spaces for your group. A ‘/30 address space’ will be used for each of the two ISP links:

   • Group A (or 1): 209.165.199.80/29

   • Group B (or 2): 209.165.199.88/29

   • Group C (or 3): 209.165.199.96/29

     The Internal Network:

     • Group D (or 4): 209.165.199.104/29

     • Group E (or 5): 209.165.199.112/29

     • Group F (or 6): 209.165.199.120/29

       As part of the network redesign, the AIT has allocated one of the following private address spaces for your group for addressing the internal network:

       • Group A (or 1): 172.17.80.0/21

       • Group B (or 2): 172.17.88.0/21

       • Group C (or 3): 172.17.96.0/21

       • Group D (or 4): 172.17.104.0/21

       • Group E (or 5): 172.17.112.0/21

       • Group F (or 6): 172.17.120.0/21

         The expected numbers of users for each of the user groups are:

         For the West switching network (this will be implemented in VLANs):

         • 500 hosts for Students

         • 120 hosts for Staff

           On the Main site:

         • 10 hosts on the Server Farm LAN. On the Branch site:

         • 200 hosts in Students (as shown in Appendix: Partial Topology Diagram)

         • 300 hosts in a spare LAN

     The AIT requires that:

     • The use of VLSM design to maximise the use of IPv4 addresses.

     • All networking devices (including switch SVIs) must have IPv4 addresses and the PC hosts’

       gateways will use the first usable address(es) in their subnet.

     • Each of the ISP links will be allocated a subnet mask of /30.

     • The Management VLAN for the switching networks will have an extra host (referred to as the “Network Admin Host” as shown in the Topology Diagram) for network administration usage.

     At this stage, AIT agrees that it is sufficient to assign all hosts with an IPv4 address statically.

     Milestone Submission: Tables A, B and C

1. IPv4 Network subnetting Table A, which shows possible subnets that meet the design requirements; Subnets that are not used are to be clearly identified in each table (‘not in use’).

2. Detailed IPv4 addressing tables (Tables B and C) showing all networking devices’ names and their interface details. Note that, the gateways of the VLANs will be implemented as sub- interfaces, e.g., Fa0/0.10 as the gateway of VLAN10.

Discussion Questions: Consider how you do subnetting so as to meet each of the requirements.

Task Two: Routing the Network

Routing to and from ISP

The AIT network has purchased two ISP links to access the Internet and external services, i.e., via the Main and Branch respectively. AIT’s policy requires that the backup ISP link via Branch is only used when the primary Main-ISP link becomes unavailable.

Since the ISP also serves many other customers, routing to and from ISP will use static routing only, and a standard static route should be used on ISP to forward traffic to the AIT internal network only when needed.

When correctly implemented, all hosts within the AIT network must be able to reach all external addresses, via the Main-ISP link, or the Branch-ISP link when the Main-ISP link is unavailable, in both directions.

Note that, for the demonstration purpose, use a loopback interface with the address of 1.1.1.1/32, on ISP to simulate the Internet. Also, NAT at both border routers will be considered in Task Four.

Routing the Internal Network

• AIT’s policy is that OSPFv2 routing will be used internally.

Your design and implementation of static routing should be in a most efficient manner.

Fig. 3. Routing the network dynamically and statically

Discussion Questions:

Consider how you implement and verify the following functions:

1. OSPF routing for the internal networks.

2. Static routing and failover routing via the two ISP links.

   Task Three: Switching Network at City and Branch Campuses

   Because of the size and complexity of LANs, AIT wants to use VLAN technologies to control broadcasts, enhance security and logically organise its user groups. 802.1Q trunk-based Inter-VLAN routing is to be implemented to advertise all VLAN networks.

   Fig. 2. The switching networks at the City Campus (left) and the Branch Campus (right).

   The switching networks at the City and Branch Campus:

   • Create VLANs with the following VLAN IDs and Names for the required networks:

     • VLAN 10 – Students

     • VLAN 20 – Staff

     • VLAN 30 – Spare (if applicable)

   • For the purpose of demonstrating network functionality, allocate five ports to each user VLAN on each switch.

   • Create VLAN 99 as the Management VLAN and allocate one port to this VLAN on each switch.

     Use VLAN 555 as the native VLAN ID.

   • Do NOT allow traffic of the default VLAN 1 and unknown VLANs onto the trunk link(s).

Discussion Questions:

Explain, in detail, how you implement (e.g., show the corresponding commands used from the device’s running-configure outputs) and use specific tools/commands to verify the following functions:

1. Creating VLANs and assigning ports.

2. SVI configuration and verification.

3. Inter-VLAN routing configuration and verification.

   Task Four: IP Addressing Services

   The company has been allocated one of the following blocks of public IPv4 addresses for the NAT pools:

   • Group A (or 1): 209.165.199.160/28

   • Group B (or 2): 209.165. 199.176/28

   • Group C (or 3): 209.165. 199.192/28

   • Group D (or 4): 209.165. 199.208/28

   • Group E (or 5): 209.165. 199.224/28

   • Group F (or 6): 209.165. 199.240/28

Requirements on NAT for IPv4:

 All devices and only these devices in the internal network are expected to have Internet connectivity using the available addresses from the public address pool with overloading. This connectivity should be maintained regardless of whether the Primary or Secondary ISP links are used.

 For demonstration purposes, define a static NAT for the Server host (PC3) using an available address from the pool(s).

 Adjust the static routing configuration on the ISP so that returning traffic from the Internet and external services can return to the internal network.

Fig. 4. IP Addressing Services

Discussion Questions:

1. Show the details of your design, such as NAT pools for IPv4, and partial configuration scripts specific to this task that justify your solution.

2. Explain how the static routing over the two ISP links has changed with the implementa- tion of NAT.

3. Discuss how you verify that the functionality of your design meets all requirements.

1. Packet Tracer-based Video Demonstration

The company now wants a demonstration of the prototype network. To do this, you need to set up the network that you have designed and configure devices in Packet Tracer to demonstrate all the required functions.

The demonstration requires basic settings on all routers and switches including hostname, passwords, MOTD banner, management address and SSH access, detailed as follows:

 Configure basic device settings for routers and switches:

• Configure hostnames as per the partial Topology Diagram.

• Configure password cisco for console connections.

• Encrypt the privileged EXEC mode using the password class.

• Disable Domain Name Server (DNS) lookup.

• Enable logging synchronous for console connections and all virtual terminal lines.

 Configure the interfaces of routers and hosts as per the Topology Diagram and your Addressing Tables B&C.

 Configure static and OSPF routing on all routers according to the requirement and your design.

 Configure VLANs according to your Switch and VLAN tables.

 Configure the Management VLAN SVI interface on the switches.

• Configure the following host PCs based on your addressing:

  • PC1 as the Network Admin Host in Management VLAN on Thomas.

  • PC2 as the Staff Host on Jones.

  • PC3 as the Server connected to the Main router.

  • PC4 as a Student Host on George.

PS. The Company has a plan to implement DHCPv4 service and use ACLs to control network traffic. At this stage, statically assigning IPv4 addresses is sufficient for the demonstration purpose.

The Company requires the following network verification to be assessed:

• Verification of the devices’ basic configuration.

• Verification of the correctness and functionality of the interface configuration.

• Verification of dynamic routing for IPv4.

• Verification of static routing for IPv4.

• Verification of the VLANs and inter-VLAN routing.

• Verification of NAT (including Overloaded NAT and static NAT).

• Verifying end-to-end connectivity of all hosts to each other and the ISP’s loopback addresses.

• Verification of the redundant links.

Discussion Questions:

1) Discuss how to verify each of the above functions (the commands, expected outcomes, and explanation on the device outputs).

32524 LANs and Routing Spring 2024 Case Study

Sample Partial Tables:

Table A – IPv4 Subnetting Table

Subnet Number*	Subnet Address	Subnet Mask	Hosts Required	Maximum Hosts in Subnet	In Use (Yes or No)	Network Name

*“Subnet Number” is the index (starting from 0) of the subnet as the result of subnetting.

Table B Device Interface IP Addressing Table

Device	Interface	IPv4 address	Subnet Mask
ISP	Fa0/0
	Fa0/0
West
…
Thomas	SVI
…

Table C Host Addressing Table

Host	IPv4 Address	Subnet Mask	Gateway
PC1
PC2
PC3
PC4

Table D Switch Table

Switch Name: Switch Management IP Address:

Interface type & Port Number	Description of Purpose	Port Bandwidth	Network Name	Subnet Address	Subnet Mask	VLAN ID & Name	Switch Port Mode	Layer 2 Encapsulation

Table E VLAN Table

Switch Name	Number of Ports	Location	IP Address	Gateway	VLAN ID & Name

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