Introducing a Software-Defined WAN (SDWAN)
The software-defined wide-area network (SD-WAN or SDWAN) is a specific application of software-defined networking (SDN) technology applied to WAN connections such as broadband internet, 4G, LTE, or MPLS. It connects enterprise networks — including branch offices and data centers — over large geographic distances.
A WAN might be used, for example, to connect branch offices to a central corporate network, or to connect data centers separated by distance. In the past, WAN connections often used technology that required special proprietary hardware. SD-WAN, on the other hand, utilizes the internet or cloud-native private networks. SD-WAN decouples the network from the management plane and detaches the traffic management and monitoring functions from hardware. It relies on four central components:
- Edge Connectivity Abstraction
- WAN Virtualization
- Policy-Driven, Centralized Management
- Elastic Traffic Management
Source: Nemertes Research
SD-WAN (SDWAN) Business Drivers
Enterprise customers are demanding more flexible, open, and cloud-based WAN technologies, rather than installing proprietary or specialized WAN technology that often involves expensive, fixed circuits, or proprietary hardware.
Many of the new software-defined WAN offerings, for example, can be used to improve and secure internet connectivity, making it more competitive with more expensive legacy WAN technologies such as T-1 or MPLS. However, according to a Nemertes study, “78 percent of organizations deploying SD-WAN have no plan to completely drop MPLS from their WAN.” In some cases, software-defined WAN technology uses internet broadband connections to replace more expensive solutions. Virtualization technology can apply security and virtual private networking (VPN) technology to broadband Internet connections, making them more secure.
A noticeable trend in the networking arena is the rising adoption of the multi-cloud in enterprise networking. The multi-cloud is a mix of private and public clouds. Common combinations are several public clouds or a public cloud and a private cloud — with each cloud serving a specific business application. SD-WAN is often integrated in a multi-cloud strategy as it improves connectivity and boosts security in the multi-cloud. Its scalability across numerous locations and its centralized management for both the public and private cloud ease the management of the multi-cloud. Several SD-WAN products encrypt data across the connectivity points and provide firewalls and application-based security. Learn more about the benefits of SD-WAN for the multi-cloud in this research brief, Networking for Multi-Cloud — An SD-WAN Perspective.
Customer Focus: Cost, Reliability, Security
An SDxCentral Research Brief, Secure SD-WAN: Seeking the Holy Grail, emphasizes that “in survey after survey (including those at SDxCentral), enterprises and service providers alike rank security capabilities among the top 3 for SD-WAN requirements.” The main goal of SD-WAN technology is to deliver a business-class, secure and simple cloud-enabled WAN connection with as much open and software-based technology as possible. This can be used to deliver basic WAN connectivity, or it can be used for premium business services such as VPN, WAN optimization, and applications delivery control (ADC).
Many new startups are going after the potential in the software-defined WAN market, and established enterprises are pursuing the market as well. According to the IDC, the SD-WAN market “will grow at a 40.4% compound annual growth rate from 2017 to 2022 to reach $4.5 billion.”
Gartner identifies the key players in SD-WAN technology in its 2018 Magic Quadrant for WAN Edge Infrastructure Report. It named three leaders: Silver Peak, Cisco, and VMware The firm also acknowledged that Riverbed, Citrix, Fortinet, Aryaka, and Huawei are strong contenders in the market as well.
Many of these vendors have slightly different approaches to the market. For example, Silver Peak focuses on accelerating Software-as-a-Service (SaaS) applications in the cloud. VMware enfolded the VeloCloud product into its own line of products, the VMware NSX SD-WAN by VeloCloud, after it acquired VeloCloud in December 2017. The product contains edge applications, orchestration, and cloud-resident gateways. Aryaka built a global network so that companies can use WAN as a Network-as-a-Service (NaaS) anywhere, even outside of its point of presence (POP) area.
Incumbent WAN technology vendors such as Cisco and Riverbed, which make specialized appliances for WAN connectivity, are now focusing more on WAN optimization and the edge WAN offerings.
Expect the trend to accelerate over the next few years. What started as a solution for branch-office and data-center WAN connectivity requiring less proprietary equipment appears to be expanding into a wide range of SD-WAN (SDWAN) offerings and technologies including VPN, security, edge, WAN optimization, NaaS, and application policy control.
Updated April 2019