What is Hybrid WAN?

What is Hybrid WAN, and How Does SD-WAN Digitally Transform it?

Zabrina Doerck
Jan. 16 2020

I’m often asked the question, “What is a hybrid WAN?” That query is usually followed by, “What is SD-WAN" or "How is that different from SD-WAN?”

What is Hybrid WAN?

So, What is Hybrid WAN? In a nutshell, a hybrid WAN consists of two separate WAN circuits that carry traffic between branches and data centers. If one circuit fails, or is slow because of congestion, traffic will be routed to a second WAN circuit. A Hybrid WAN design can have various network combinations, such as two separate MPLS circuits, an MPLS and Internet circuit; two different Internet circuits; or an Internet and LTE circuit. 

Enterprises deploy hybrid WANs to provide an additional layer of reliability and resiliency, to maintain business continuity for branch to data center connectivity. 

Hybrid WAN benefits

Now that you know the answer to "What is Hybrid WAN?", what are the benefits? A Hybrid WAN offers many benefits, including lowering bandwidth costs, by provisioning cost-effective broadband Internet and LTE. It can also provide more flexible and optimized bandwidth utilization. This is accomplished by using policies to steer non-critical applications over an Internet circuit, while freeing up the MPLS circuit to handle more mission-critical workloads. For non-critical applications, Internet traffic can be managed without having go through the data center, with the added latency that slows performance.  

For reliability and resiliency, a hybrid WAN can use path selection to manage traffic over the best performing WAN circuit. You can choose which circuit is the best path for certain traffic types, based on the underlying network characteristics. 

While a hybrid WAN has its advantages, it also has disadvantages. Today’s growing mobile workforce and cloud deployments, bring additional complexity and security risk, to an already complex network environment. Hybrid WANs are not well suited for managing these new requirements. 

SD-WAN brings intelligence to hybrid WAN

A hybrid WAN maintains the underlying properties and characteristics associated with each WAN circuit. For example; while MPLS has built-in security and control, like encryption, VPN, packet guarantees/prioritization, SLAs and traffic engineering; the Internet does not. Conversely, while Internet and wireless networks can beflexibly deployed, and low-cost circuits can be provisioned by different carriers and service providers; MPLS is expensive, rigid and controlled by a single service provider. 

There is very little operational intelligence within a hybrid WAN architecture. They always direct traffic over the same route, and only use a different path when the primary path is no longer available. SD-WAN brings operational intelligence to the hybrid WAN. All applications and distributed workloads, and all WAN circuits, can be highly engineered and controlled to ensure traffic always flows over the most appropriate and best performing WAN circuits. This is accomplished using business intent policies that match with dynamically changing network conditions and application performance requirements. Aggregated WAN circuits are virtualized through a software overlay that manages all SD-WAN-enabled circuits, applications and users. Everything is orchestrated, automated and controlled, to enhance application performance and deliver a more predictable and optimal user experience.

SD-WAN adds bandwidth efficiencies to the hybrid WAN

SD-WAN enables more efficient use of bandwidth, by directing traffic to the most appropriate connection, based on business policies. For example, an enterprise with an MPLS and broadband circuit, and branch offices accessing cloud apps, like Microsoft Office 365 and Salesforce, no longer needs to unnecessary route Internet traffic going to the cloud, through the corporate data center. SD-WAN enables them to send that traffic directly to the cloud portals over either circuit, while ensuring secure and optimized performance.  

Application-aware SD-WAN adds control to the hybrid WAN 

An SD-WAN that understands application SLA requirements, and enforces them using business intent policies, will ensure network connectivity aligns with application performance and business objectives. An application-aware SD-WAN controls user sessions, automatically adjusts traffic flows and incorporates quality of service (QoS). These capabilities help ensure application performance is met, even during dynamically changing network conditions.  

SD-WAN simplifies provisioning, deployment and management of distributed branch offices and remote locations. A central controller and orchestrator provide the operational intelligence and automated zero-touch deployment to remote locations. IT teams gain simplified policy-based management, through a single-pane-of-glass for all their distributed offices throughout the enterprise WAN. 

Learn more about how the right SD-WAN can solve user experiences problems and directly support the key strategic priorities of your business. Go to our SD-WAN solutions page for more details. 

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