Intra Domain Routing OSPF Single Area and Multi Area

This repository contains a Python script (ospf-lab.py) that simulates an OSPF (Open Shortest Path First) network using Mininet. The script creates a topology with multiple routers and hosts, demonstrating both single-area and multi-area OSPF configurations.

Requirements

• Python 3
• Mininet
• FRRouting (FRR)

Usage

To run the OSPF lab simulation:

sudo python3 ospf-lab.py

Topology

The script creates a network topology with three subnets, each containing a main router, a switch between the main router and two sub-routers, and two client hosts. The main routers are interconnected to form the backbone of the network.

Multi-Area OSPF

In multi-area OSPF, the network is divided into multiple areas, with Area 0 serving as the backbone. This configuration improves scalability and reduces the processing load on routers.

graph TB
    subgraph "Area 0 (Backbone)"
        R1((R1)) --- R2((R2))
        R2 --- R3((R3))
        R3 --- R1
    end
    
    subgraph "Area 1"
        R1 ---|eth0| S1{S1}
        S1 ---|eth0| R1_1((R1_1))
        S1 ---|eth0| R1_2((R1_2))
        R1_1 ---|eth1| C1_1[C1_1]
        R1_2 ---|eth1| C1_2[C1_2]
    end
    
    subgraph "Area 2"
        R2 ---|eth0| S2{S2}
        S2 ---|eth0| R2_1((R2_1))
        S2 ---|eth0| R2_2((R2_2))
        R2_1 ---|eth1| C2_1[C2_1]
        R2_2 ---|eth1| C2_2[C2_2]
    end
    
    subgraph "Area 3"
        R3 ---|eth0| S3{S3}
        S3 ---|eth0| R3_1((R3_1))
        S3 ---|eth0| R3_2((R3_2))
        R3_1 ---|eth1| C3_1[C3_1]
        R3_2 ---|eth1| C3_2[C3_2]
    end

    classDef switch fill:#f9f,stroke:#333,stroke-width:4px;
    class S1,S2,S3 switch;

Loading

Network Components

• R1, R2, R3: Main routers (Area Border Routers in multi-area configuration)
• R1_1, R1_2, R2_1, R2_2, R3_1, R3_2: Sub-routers
• C1_1, C1_2, C2_1, C2_2, C3_1, C3_2: Client hosts
• S1, S2, S3: Switches connecting routers within each subnet

Configuration

The script generates configuration files for each router using templates. These configurations are stored in the specified directory and are used to set up OSPF routing on the routers.

Customization

You can modify the OSPFLab class in the script to adjust the network topology, IP addressing, or OSPF areas as needed for your specific requirements.

Note

This lab is designed for educational purposes and may need additional configuration for production use. Ensure you have the necessary permissions and understanding of OSPF before deploying in a live environment.

ADDITIONAL CONFIGURATION !

sudo nano /etc/sysctl.conf

Uncomment this section :

net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1

And, config this too :

sudo modprobe bridge
sudo modprobe br_netfilter

The command :

lsmod | grep bridge

bridge                335872  1 br_netfilter
stp                    12288  1 bridge
llc                    16384  2 bridge,stp

example results when running the ospf-lab.py :

========================================
Warning: Linux bridge may not work with net.bridge.bridge-nf-call-arptables = 1
Warning: Linux bridge may not work with net.bridge.bridge-nf-call-iptables = 1
Warning: Linux bridge may not work with net.bridge.bridge-nf-call-ip6tables = 1
Finished initializing network in: 1.1319239139556885 seconds

Intra-domain Routing Task with OSPF Single Area and Multi-Area - Mininet

Experiment Scenario 1: All routers run OSPF in a single area.

Experiment Scenario 2: Run OSPF in a multi-area configuration.

IMPORTANT, READ THIS SECTION!

For Scenario 2, simply run this repository without making any changes.

For Scenario 1, make changes to each router's frr-config. The change required is to set all areas to area 0 (Single Area). Make the changes using VS Code.

frr.conf R1

frr version 8.5.4
frr defaults traditional
hostname R1
service integrated-vtysh-config
!
interface R1-eth0
 ip ospf network broadcast
 ip address 10.11.1.1/24
exit
!
interface R1-eth1
 ip address 10.10.1.1/24
exit
!
interface R1-eth2
 ip address 10.10.2.1/24
exit
!
router ospf
 ospf router-id 1.1.1.1
 network 10.11.1.0/24 area 0
 network 10.10.1.0/24 area 0
 network 10.10.2.0/24 area 0
exit
!
line vty

frr.conf R1_1

frr version 8.5.4
frr defaults traditional
hostname R1_1
service integrated-vtysh-config
!
interface R1_1-eth0
 ip ospf network broadcast
 ip address 10.11.1.2/24
exit
!
interface R1_1-eth1
 ip address 172.16.1.1/24
exit
!
router ospf
 ospf router-id 1.1.1.2
 network 10.11.1.0/24 area 0
 network 172.16.1.0/24 area 0
exit
!
line vty

frr.conf R1_2

frr version 8.5.4
frr defaults traditional
hostname R1_2
service integrated-vtysh-config
!
interface R1_2-eth0
 ip ospf network broadcast
 ip address 10.11.1.3/24
exit
!
interface R1_2-eth1
 ip address 172.16.2.1/24
exit
!
router ospf
 ospf router-id 1.1.1.3
 network 10.11.1.0/24 area 0
 network 172.16.2.0/24 area 0
exit
!
line vty

frr.conf R2

frr version 8.5.4
frr defaults traditional
ipv6 forwarding
hostname R2
service integrated-vtysh-config
!
interface R2-eth0
 ip address 10.12.1.1/24
exit
!
interface R2-eth1
 ip address 10.10.1.2/24
exit
!
interface R2-eth2
 ip address 10.10.3.2/24
exit
!
router ospf
 ospf router-id 2.2.2.1
 network 10.12.1.0/24 area 0
 network 10.10.1.0/24 area 0
 network 10.10.3.0/24 area 0
exit
!
line vty

frr.conf R2_1

frr version 8.5.4
frr defaults traditional
ipv6 forwarding
hostname R2_1
service integrated-vtysh-config
!
interface R2_1-eth0
 ip address 10.12.1.2/24
exit
!
interface R2_1-eth1
 ip address 172.17.1.1/24
exit
!
router ospf
 ospf router-id 2.2.2.2
 network 10.12.1.0/24 area 0
 network 172.17.1.0/24 area 0
exit
!
line vty

frr.conf R2_2

frr version 8.5.4
frr defaults traditional
ipv6 forwarding
hostname R2_2
service integrated-vtysh-config
!
interface R2_2-eth0
 ip address 10.12.1.3/24
exit
!
interface R2_2-eth1
 ip address 172.17.2.1/24
exit
!
router ospf
 ospf router-id 2.2.2.3
 network 10.12.1.0/24 area 0
 network 172.17.2.0/24 area 0
exit
!
line vty

frr.conf R3

frr version 8.5.4
frr defaults traditional
hostname R3
service integrated-vtysh-config
!
interface R3-eth0
 ip address 10.13.1.1/24
exit
!
interface R3-eth1
 ip address 10.10.2.2/24
exit
!
interface R3-eth2
 ip address 10.10.3.1/24
exit
!
router ospf
 ospf router-id 3.3.3.1
 network 10.13.1.0/24 area 0
 network 10.10.2.0/24 area 0
 network 10.10.3.0/24 area 0
exit
!
line vty

frr.conf R3_1

frr version 8.5.4
frr defaults traditional
hostname R3_1
service integrated-vtysh-config
!
interface R3_1-eth0
 ip address 10.13.1.2/24
exit
!
interface R3_1-eth1
 ip address 172.18.1.1/24
exit
!
router ospf
 ospf router-id 3.3.3.2
 network 10.13.1.0/24 area 0
 network 172.18.1.0/24 area 0
exit
!
line vty

frr.conf R3_2

frr version 8.5.4
frr defaults traditional
hostname R3_2
service integrated-vtysh-config
!
interface R3_2-eth0
 ip address 10.13.1.3/24
exit
!
interface R3_2-eth1
 ip address 172.18.2.1/24
exit
!
router ospf
 ospf router-id 3.3.3.3
 network 10.13.1.0/24 area 0
 network 172.18.2.0/24 area 0
exit
!
line vty

Project Report (in Indonesian)

For more detailed information on the project setup, configuration, and results, refer to the full report:

Intra-domain Routing.pdf