UNIT-1

1. UNIT-1
SDN: INTRODUCTION

2. Evolving Network Requirements
•Increased Network Complexity: Traditional networks face scalability and management challenges.
•Diverse Application Needs: Rise of cloud computing, IoT, and high-bandwidth applications.
•Need for Flexibility: Dynamically changing network demands require better control.
•Network Automation: Manual configuration and management lead to inefficiencies.
•Security Demands: Rising need for better security protocols to combat increasing cyber threats.
•Cost Efficiency: Networks must optimize resource utilization to reduce costs
The SDN Approach
•Software-Defined Networking (SDN): A network architecture that decouples the control plane from the data
plane.
•Centralized Control: Centralized control enables easy management and programming of network devices.
•Programmable Networks: SDN allows applications to program the behavior of the network dynamically.
•Abstraction: SDN abstracts the underlying network infrastructure, making management simpler and more
flexible.
•Openness & Innovation: SDN promotes an open ecosystem with standardized protocols like OpenFlow,
encouraging innovation.

3. SDN Architecture Overview
•Three Main Planes:
• Data Plane (Forwarding Plane):
• Responsible for forwarding network traffic.
• Managed by network devices (switches, routers) under the control of SDN.
• Contains the flow tables that define how packets are forwarded.
• Control Plane:
• Centralized entity that makes decisions about where and how traffic is forwarded.
• Software-based (SDN Controller).
• Provides global network visibility and policies.
• Application Plane:
• Top layer, where network applications reside (e.g., traffic monitoring, load
balancing).
• Interacts with the SDN controller to specify network policies and behavior.

4. SDN Data Plane
•Functionality:
• Directs the flow of packets based on flow rules set by the control plane.
• Hardware devices (switches, routers) implement forwarding.
• Implements low-level packet forwarding.
•Key Components:
• Flow Tables: Store forwarding decisions.
• Match Fields: Criteria used to decide how to forward packets.
• Actions: Operations such as forward, drop, or modify packets.
SDN Control Plane
•SDN Controller: The "brain" of the network.
• Manages and programs network devices.
• Provides centralized visibility and control of the entire network.
• Ensures network policies and configurations are consistently applied
across devices.
•Protocols Used:
• OpenFlow: A standard protocol for communication between the
controller and network devices.
• REST APIs: To communicate with applications for dynamic
configuration

5. SDN Application Plane
•Network Applications: Applications running on top of the SDN architecture.
• Traffic Engineering: Optimizing traffic paths in real-time.
• Security Applications: Intrusion detection, DDoS protection, firewall
management.
• Network Monitoring: Collecting network metrics for analysis and optimization.
•Interfacing with SDN Controller: Applications interact with the control plane to
make real-time decisions and updates.
Key Benefits of SDN
•Centralized Network Management: Simplified and unified control
of network devices.
•Scalability: Easy to add new devices and scale the network.
•Programmability: Network behavior can be customized and adjusted
dynamically.
•Flexibility & Agility: SDN allows networks to quickly adapt to
changing requirements.
•Cost Efficiency: Reduces hardware reliance and operational overhead.

6. Conclusion
•SDN Evolution: Moving from hardware-based to software-based networking
solutions.
•A Step Toward the Future: SDN enables better performance, security, and agility
in modern networks.
•Transforming Network Management: SDN is paving the way for more
automated, efficient, and secure network infrastructures.