UNIVERSITY OF WEST ATTICA
SCHOOL OF ENGINEERING
DEPARTMENT OF COMPUTER ENGINEERING AND INFORMATICS

University of West Attica · Department of Computer Engineering and Informatics

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Computer Networks II

OSPF Routing

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

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Supervision

Supervisor: Adonis Bogris, Professor

UNIWA Profile · LinkedIn

Co-supervisor: Rania Garofalaki, Laboratory Teaching Staff

UNIWA Profile · LinkedIn

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Athens, May 2022

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README

OSPF Routing

The primary objective of this project was to establish full IP connectivity within Autonomous System (AS) 20 using the OSPF routing protocol.
The network architecture was designed using multiple OSPF areas:

• Area 0 (Backbone Area)
• Area 10
• Area 20

These areas are interconnected through Area Border Routers (ABRs), ensuring proper inter-area routing and adherence to OSPF hierarchical design principles.

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Table of Contents

Section	Folder / File	Description
1	assign/	Assignment material
1.1	assign/OSPF - homework_NetworksII.pdf	Assignment description in English
1.2	assign/OSPF - homework_ΔίκτυαΙΙ.pdf	Assignment description in Greek
2	docs/	Project documentation
2.1	docs/OSPF_Routing.pdf	OSPF routing analysis and configuration (English)
2.2	docs/OSPF_Δρομολόγηση.pdf	OSPF routing analysis and configuration (Greek)
3	src/	Source files
3.1	src/OSPF.pkt	Cisco Packet Tracer topology and OSPF configuration
4	README.md	Project documentation
5	INSTALL.md	Usage instructions

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1.Network Configuration Details

1.1 OSPF Process Configuration

OSPF was configured on each router by defining:

• A process ID
• A unique Router ID
• The participating subnets and their corresponding OSPF areas

Router IDs Used

• R1: 1.1.1.1
• ABR2: 2.2.2.2
• ABR3: 3.3.3.3
• R4: 4.4.4.4
• R5: 5.5.5.5

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2. Implementation Steps

The following Cisco IOS CLI commands were used during router configuration:

• router ospf <process-id>
  Initiates the OSPF routing process.

• router-id <address>
  Assigns a unique identifier to the router.

• network <ip-address> <wildcard-mask> area <area-id>
  Specifies which interfaces and subnets participate in OSPF and assigns them to the appropriate area.

• passive-interface <interface>
  Configured on R4 and R5 (interface FastEthernet0/1) to prevent the transmission of OSPF updates toward non-router end devices.

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3. Route Summarization

To improve routing efficiency and reduce the size of routing tables, inter-area route summarization was implemented on the ABRs.

3.1 Summarized Routes

• Area 10 Summary:
  172.16.32.0/23
  (Summarizes 172.16.32.0/24 and 172.16.33.0/24)

• Area 20 Summary:
  174.18.30.0/23
  (Summarizes 174.18.30.0/24 and 174.18.31.0/24)

• Area 0 Summary:
  173.17.36.0/22
  (Summarizes 173.17.37.0/24, 173.17.38.0/24, and 173.17.39.0/24)

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4. Verification Commands

The following commands were used to verify the correct operation of OSPF:

• show running-config
  Confirms the applied OSPF configuration.

• show ip route
  Displays the routing table and verifies inter-area (O IA) routes.

• show ip ospf neighbor
  Examines OSPF neighbor relationships and adjacency states (e.g., FULL/DR, FULL/BDR).

• show ip ospf database
  Inspects the Link State Database (LSDB) and the different LSA types.