SDN Mininet Ryu Controllers

This repository contains implementations of multiple Software-Defined Networking (SDN) controllers using Ryu and Mininet, as part of COL334/672 coursework (IIT Delhi, Diwali 2024).
The focus is on understanding OpenFlow-based flow rules, network efficiency, and routing algorithms.

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🚀 Features

1. Hub Controller

• Floods packets to all ports except incoming one.
• Installs only a table-miss rule.
• Inefficient due to high broadcast traffic.

2. Learning Switch

• Dynamically learns MAC-to-Port mappings.
• Installs flow rules to reduce broadcast traffic.
• Efficient packet forwarding.

3. Spanning Tree Controller

• Implements Minimum Spanning Tree (MST) using Kruskal’s Algorithm.
• Prevents broadcast loops in cyclic topologies.
• Maintains optimized forwarding rules.

4. Shortest Path Routing (SPR)

• Uses LLDP (Link Layer Discovery Protocol) to measure link delays.
• Computes optimal paths using Dijkstra’s Algorithm.
• Ensures minimum-delay routing and loop prevention.

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🛠️ Tech Stack

• Python 3
• Ryu Controller
• Mininet
• OpenFlow
• Algorithms: Learning Switch, Kruskal’s MST, Dijkstra’s Shortest Path

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📂 Repository Structure

├── p1_hub.py # Hub controller ├── p1_learning.py # Learning switch controller ├── p2_spanning_tree.py # MST spanning tree controller ├── p3_spr.py # Shortest Path Routing controller ├── Assignment_3_Mininet_SDN.pdf # Assignment description ├── Assignment3_Report.pdf # Detailed implementation report

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⚙️ How to Run

1. Start Mininet with the desired topology:

   sudo mn --custom p1_topo.py --topo mytopo --controller remote --switch ovsk --mac
   
   

Run Ryu controller (example for Learning Switch):

ryu-manager p1_learning.py

Test connectivity:

mininet> pingall mininet> iperf h1 h2

📊 Observations

Controller	Flow Rules Installed	Traffic Handling	Broadcast Traffic	Efficiency
Hub Controller	Only table-miss	Floods all packets	High	Low
Learning Switch	Table-miss + MAC-to-Port	Direct forwarding	Low	High
Spanning Tree	MST-based flow rules	Loop-free broadcast forwarding	Medium	High
Shortest Path	Delay-weighted Dijkstra’s routing	Optimized unicast + loop-free broadcast	Low	Very High

📌 Key Takeaways

Demonstrates SDN concepts: Hub, Learning, Spanning Tree, and Shortest Path controllers.

Uses Ryu framework to implement OpenFlow rules dynamically.

Hands-on with network topology discovery, LLDP delay measurement, and routing algorithms.

Builds strong foundations for Network Security, Distributed Systems, and Cloud Infrastructure roles.

👨‍💻 Authors

Rohit Patidar (2024JCS2042)

Jitesh. (2024JCS2043)