Enterprise networks are the final frontiers undergoing significant transformations ushered in by computer virtualization and adoption of cloud delivery models.  This is significant because virtualization and cloud technologies provide new levels of IT flexibility, efficiency and cost benefits while leaving underlying networks unchanged.

As mobile devices and new application requirements are impacted by enterprise workloads, networks struggle to meet the demands placed upon them. Inevitably, network bottlenecks occur based on hardware-centric, proprietary and outdated technologies.

Software-Defined Networking (SDN) promises to provide solutions for many of these problems by using a software-based solution on commercial off-the-shelf (COTS) hardware platforms. Sophisticated hardware platforms enable a transition from proprietary hardware devices to software-defined networks that are programmable, agile and decoupled to keep pace with innovations in enterprise IT.

Software-Defined WAN (SD-WAN) is an extension of SDN that transforms the enterprise branch office. With SD-WAN, the advantages of SDN are no longer limited to just the data center. SD-WAN abstracts network hardware into a control plane and multiple data planes that can be used with cloud-based management and automation to simplify the delivery of services to the branch office.  This work can be done with manageability, performance and reliability assurances that enterprises expect and need.

SD-WAN is the latest big thing, and it is rapidly gaining popularity in the IT world. With any new disruptive technology, existing incumbents and related solution providers are demanding a larger share of the market. This activity is part of the IT hype cycle. However, vendors who provide solutions with real benefits often emerge as industry leaders and eventually move on to define the technology space.

Defining SD-WAN and Understanding Its Significance

SD-WAN is a new, revolutionary way to architect, deploy and operate corporate WANs, as it provides a simplified way of deploying and managing remote office connectivity in a cost-effective manner.  It uses software and cloud-based technologies to simplify delivery of WAN services to branch offices. Software-based virtualization enables network abstraction that results in a simplification of network operations. SD-WAN enables IT and business managers to deploy Internet-based connectivity with several advantages, including:

Ubiquity; High bandwidth; Affordability; Ease and Speed; Quality; Reliability; and

SD-WAN provides attributes typically associated with Software-Defined Networking (SDN) in data centers except for wide area network solutions for enterprise branch offices.  Both SDN and SD-WAN virtualize resources that leads to accelerated service delivery, better performance and improved availability by automating network deployment and management while improving ROI and reducing the total cost of ownership. SDN in general applies to any networking environment. Web-scale Internet companies has supported its adoption, primarily in massive data centers and in the links between them, followed by telecom service providers in a variety of scenarios, including radio access.

Changing Traffic Patterns: SaaS, Cloud, Mobile, and Video

The evolution of IT technologies has altered traffic flows within distributed organizations.  Not only do remote users require more bandwidth (the most popular example being video), but they also need direct access to SaaS/cloud-based applications such as Salesforce, Office 365, Lync and off-premise storage (such as Dropbox, Evernote, and so on). Traditional MPLS networks, which transmit traffic from a branch location to a more centralized data center are unable to offer low latency/high performance access to cloud applications.  In addition, the security and management requirements associated with disparate traffic flows has added to the complexity of managing branch operations, and thus increasing staffing costs for many IT organizations.

SD-WAN Benefits

SD-WAN provides a wide range of benefits for distributed organizations, including:

Business agility.  Rapid deployment of WAN services (such as bandwidth and firewall) to distributed branch operations allows you to keep your IT personnel on-site.

Internet economics. Internet connectivity (including cable, DSL and ethernet) is widely available, quick to deploy and more economical than equivalent MPLS circuits. SD-WAN provides the benefits of reliable, secure WAN service at competitive Internet price points.

Optimized cloud architecture. SD-WAN eliminates the backhaul penalties of traditional MPLS networks and leverages the Internet to provide secure, high-performance connections from the branch to cloud. With SD-WAN, remote users will see significant improvements in their experience when using the cloud/SaaS-based applications.

SD-WAN: Networking Technical Perspective

In terms of networking, SD-WAN provides these advantages over SDN:

Optimizes and simplifies the use of multiple public and private links; Separates data, control and orchestration planes with programmatic APIs; Reduces recurring and capex costs of wide area networking; Simplifies WAN with zero-touch deployment; Delivers network-wide policy and security; Provides additional services; WAN Transport Virtualization Centralized Management of Services; and App-centric & Policy-based Orchestration

SD-WAN Management Portals

In terms of Management Portals, SD-WAN provides these advantages:

Single-pane of glass for configuration network management that is cloud-hosted and on-premises; Zero-touch provisioning; Portals where user defines global policies; Aggregated visibility on application performance

SD-WAN Controllers

In terms of SD-WAN Controllers, they provide the following advantages:

Establishes and manages Secure Virtual Overlay to sites; Interprets the Global Policy according to the knowledge collected from the network; Defines service chains to enable policy goals; and Manages distribution of interpreted Policy to individual elementsVirtual WAN Fabric

These advantages are offered through SD-WAN:

Secure Fabric Overlay; Transport Independence; and etwork Segmentation

Virtual WAN Fabric

These advantages are offered through SD-WAN:

Secure Fabric Overlay; Transport Independence; and Network Segmentation

SD-WAN Gateways

These advantages are offered in terms of SD-WAN Gateways:

Local Policy Enforcement; WAN Path Selection, Network QoS, Firewall, Service Chaining; and Telemetry feedback loop to/from SD-WAN Controller

SD-WAN:  Enhancing Buying Considerations

If you’re an IT or business manager, consider the following criteria when evaluating SD-WAN deployments:

Ease of adoption and management. A key benefit of SD-WAN is that it makes deploying WAN services at the branch fast and simple. SD-WAN solutions must be ready to deploy, and they leverage centralized provisioning to eliminate the need for trained personnel to visit remote sites.

Ability to migrate to hybrid WAN. The majority of distributed organizations already have MPLS deployed to their branch offices. Organizations should be able to seamlessly deploy SD-WAN solutions (Internet circuits) without changing the existing MPLS network. Those organizations can, over time, migrate traffic growth toward cost-effective Internet bandwidth.

Automation – traffic steering. SD-WAN gives organizations the ability to prioritize traffic. The key is success is providing managers with easy-to-use tools for setting priorities and with features that automatically changes traffic flows according to current network conditions.

Conclusions and Making Recommendations

The increased deployment of Cloud, SaaS, Video and Mobile Applications has challenged IT business managers to provide high-quality WAN services to their branch. Deploying and managing the WAN has become more challenging and costly as traffic flows decentralize.  SD-WAN offers compelling advantages for distributed organizations with critical branch operations, including the benefits of business agility, improved application performance and lower costs of bandwidth. Distributed organizations should consider SD-WAN solutions on the basis of their ease of use and management, ability to integrate with their existing MPLS network and the intelligence to automatically adjust traffic flows to current network conditions. By the end of 2019, 30% of enterprises will use SD-WAN products in all their branches, up from less than 1% today.