What is SD-WAN ?

SD-WAN (Software-Defined Wide Area Network) is an approach to managing and optimizing a wide area network by decoupling the networking hardware from its control mechanism. This is achieved through software-based technology that allows more flexible, efficient, and secure connectivity, particularly for distributed enterprises and remote locations. Here’s a detailed overview of what SD-WAN is and how it works:

Key Components of SD-WAN

1. Centralized Control:
   • SD-WAN separates the control plane from the data plane. The control plane is centralized, allowing administrators to manage network policies and configurations from a single, unified interface.
2. Transport Independence:
   • SD-WAN can use a variety of connection types, including MPLS, broadband internet, LTE, and more. This flexibility allows organizations to leverage cost-effective connections without compromising performance.
3. Dynamic Path Selection:
   • Traffic is dynamically routed over the best available path based on real-time network conditions and application requirements. This helps ensure optimal performance and reliability.
4. Application Awareness:
   • SD-WAN can identify and prioritize traffic for critical applications, ensuring they receive the necessary bandwidth and low-latency paths. This is particularly useful for applications that are sensitive to latency, such as VoIP and video conferencing.
5. Enhanced Security:
   • SD-WAN often includes built-in security features such as encryption, firewalls, and secure tunneling, which protect data as it travels over the internet.
6. Scalability and Flexibility:
   • SD-WAN can easily scale as business needs change. New sites can be added quickly without the need for extensive reconfiguration of hardware.

Benefits of SD-WAN

1. Cost Efficiency:
   • By using a combination of MPLS and cheaper broadband connections, SD-WAN can significantly reduce the overall cost of WAN connectivity.
2. Improved Performance:
   • Dynamic path selection and application-aware routing ensure that critical applications have optimal performance, reducing latency and improving user experience.
3. Increased Agility:
   • Centralized control and simplified management allow for faster deployment and easier changes to network configurations.
4. Enhanced Security:
   • Integrated security features provide robust protection for data traveling over public and private networks.
5. Better Cloud Integration:
   • SD-WAN is designed to support cloud applications, providing direct, optimized paths to cloud services and improving access speeds and reliability.
6. Resilience and Reliability:
   • With multiple connection options and automatic failover capabilities, SD-WAN ensures high availability and reliability.

How SD-WAN Works

1. Deployment:
   • SD-WAN appliances or virtual instances are deployed at each site, including branch offices, data centers, and cloud environments. These devices connect to a central SD-WAN controller.
2. Policy Configuration:
   • Network administrators use the SD-WAN controller to define policies based on business needs, such as prioritizing certain applications, ensuring security, and optimizing traffic paths.
3. Traffic Management:
   • The SD-WAN devices continuously monitor network conditions, such as bandwidth, latency, jitter, and packet loss. Based on these metrics and the defined policies, the devices dynamically route traffic across the best available paths.
4. Security Enforcement:
   • Data is encrypted, and security policies are enforced as traffic passes through the SD-WAN devices. This ensures that data remains secure even when traveling over less secure public internet connections.
5. Monitoring and Analytics:
   • The centralized controller provides real-time visibility into network performance, application usage, and security events, enabling proactive management and troubleshooting.

Summary

SD-WAN revolutionizes traditional WAN by using software-based technologies to create a more flexible, efficient, and secure network. It enables organizations to reduce costs, improve performance, increase agility, enhance security, and better support cloud applications. By centralizing control and management, SD-WAN simplifies network operations and provides greater visibility and control over the entire network infrastructure.

Cisco SDWAN

Cisco Viptela SD-WAN solution provides the following improvements over the traditional WAN design:

• Connecting any edge in a fast, secure, and highly available manner using Zero-Touch Provisioning (ZTP) or Cisco Plug and Play (PnP).
• Establishing a carrier-independent WAN using any type of underlying transport. 
• Abstracting the underlying WAN infrastructure away from the services side and applications that run over the network such as WAN Routing, Segmentations, Analytics, IaaS, and Multitenancy. 
• Providing end-to-end security from remote sites to the Internet, Cloud, and SaaS applications.
• Providing a single pane of glass (SPOG) for management, analytics, and configuration policy across the enterprise WAN.
• Providing REST APIs that enable enterprises to create their own unique services and meet any niche requirements.

Cisco SDWAN Architecture

Below figure summarizes the key architectural components of Cisco SDWAN

This Cisco SDWAN solution consists of four main components and one optional analytics component:

1. vManage (management)

2. vBond (orchestrator)

3. vSmart (controller)

4. vEdge or cEdge (routers)

5. vAnalytics (analytics)