What is SD-WAN?

Software-defined wide-area network (SD-WAN) is an automated, programmatic approach to managing enterprise network connectivity and circuit costs. It extends software-defined networking (SDN) into an application that businesses can use to quickly create a smart “hybrid WAN” – a WAN that comprises business-grade IP VPN, broadband Internet, and wireless services. Hybrid WAN architectures enable companies to manage their growing number of applications, particularly when using the cloud. Traffic is automatically and dynamically forwarded across the most appropriate and efficient WAN path based on network conditions, the security and quality-of-service (QoS) requirements of the application traffic at hand, and cost of the circuit. The enterprise customer sets the routing policies.

Benefits of SD-WAN

Companies are rapidly adopting SD-WAN technology because of the comprehensive financial and operational benefits it offers:

  • Lowers WAN OpEx and CapEx costs, and overall total cost of ownership
  • Provides greater business agility and responsiveness to keep pace with IT innovations
  • Supports multiple, secure, high-performance connections eliminating backhaul penalties imposed by MPLS networks
  • Allows for load sharing across connections and adjusts traffic flows based on network conditions to improve performance
  • Supports the automated provisioning of – and changes to – premium network services, such as VPNs, firewalls, security, WAN optimization, and application delivery control
  • Supports zero-touch provisioning (ZTP)
  • Improves network security by encrypting WAN traffic and segmenting the network to minimize damage if breaches occur

Problems Addressed by SD-WAN

Managing the WAN traditionally has been one of the most expensive and rigid aspects of running the enterprise network. SD-WAN eases that burden by making use of programmable network devices that you can modify remotely and through dynamic best-path routing, both of which improve cost, agility, and performance. SD-WAN is able to respond proactively to real-time network conditions.

SD-WAN Uses and Functions

When the SD-WAN is embedded in software running on virtual CPE (customer premises equipment), it monitors the conditions of all public and private-line services and determines how to route each type of application traffic accordingly. For instance, you might default to sending voice-over-IP (VoIP) traffic over an MPLS VPN service. However, if the MPLS connection were to become congested, the SD-WAN might switch that traffic over to a broadband Internet or 4G LTE wireless circuit. In this way, the SD-WAN enables automatic load balancing and network congestion management for best performance and least-cost effective routing.

SD-WAN’s Relationship to NFV

It’s possible to layer virtual network infrastructure services, such as VPN, firewalling, QoS, and WAN optimization, alongside the SD-WAN on the same virtual CPE (vCPE) platform. One way is to add virtual network functions (VNFs) to the SD-WAN using Network Functions Virtualization (NFV) technology. NFV incorporates cloud and virtualization technologies to drive rapid development of new network services with elastic scale and automation. SD-WANs and VNFs are both virtual services that can run adjacently to one another or independently of one another. Learn more