Due to cost factors, companies are now more inclined to implement MPLS-like performance using inexpensive broadband links. One option is to use overlay tunnels on heterogeneous WANs and add the ability to control traffic steering on these links. Traffic steering rules can be used to control the behavior of different types of traffic on each site. This way, companies can use any available WAN link based on business needs.
The SD-WAN is part of the WAN Edge Technology Suite, which can process packets at wire speed according to the template rules provided by the central SD-WAN controller. Therefore, SD-WAN has similarities to the SDN concept. As in SDN, the control plane (defined traffic steering rules) is moved to the centralized controller and the data plane (executing traffic steering rules) stays on the customer edge device. Therefore, a centralized SD-WAN controller is used to control SD-WAN devices installed in customer premises or sites. Since SD-WAN does not require routers to be configured in the WAN (this is required in MPLS for resource reservation on each label) and the development of a fast packet processing engine based on content addressable storage, SD-WAN Both device cost and execution cost are an order of magnitude cheaper than MPLS.
How does SD-WAN help?
More and more companies are deploying SD-WAN solutions to address the challenges of MPLS. The SD-WAN is opaque on the transmission path, so SD-WAN coverage tunnels can be established on any WAN link (MPLS, Internet, LTE, 4G) at the enterprise site.
To save bandwidth consumption of the MPLS link, the SD-WAN moves less critical applications over the SD-WAN tunnel of the alternate WAN link (Internet). Enterprises can define flow control rules for each application. Using a centralized SD-WAN controller, these flow control rules pass the loop back to the SD-WAN unit. All types of data traffic pass through this SD-WAN device and are processed according to the configured rules. For example, an SD-WAN controller might configure a site to use MPLS for VoIP connections, while an O365 application uses the Internet to connect.
To support faster access to applications executing in the cloud, SD-WAN can configure traffic steering rules to use the Internet connection for these applications. As a result, cloud traffic is transferred directly from the branch office to the Internet rather than backhaul to the headquarters. Some SD-WAN operators can directly access cloud data centers (such as AWS or Microsoft Azure) from their gateways to improve the performance and reliability of applications hosted on these clouds.
In addition, SD-WAN provides WAN optimization features such as data replication, data compression and forward error correction. These optimizations reduce WAN bandwidth requirements and provide better QoS. These WAN optimizations are value-added services in most SD-WAN solutions.