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Consider the Ethernet option for primary SD-WAN connectivity

SD-WAN connectivity offers the ability to use a variety of links. While most enterprises opt to use cable or DSL as the primary link, Ethernet could be the better option.

The architecture used to build enterprise wide area networks hasn't changed fundamentally in more than 30 years. The traditional hub-and-spoke network design that uses MPLS was designed to support businesses where the majority of network traffic flowed from branch offices to the data center to support client-server applications. These legacy networks are long overdue for an overhaul for a number of reasons, including a lack of agility and centralized management and inefficient bandwidth utilization.

To address these challenges, enterprises have turned to software-defined WANs. SD-WAN connectivity is fundamentally different than a legacy WAN. As the term suggests, SD-WAN is software-centric, and the control plane has been decoupled from the data forwarding plane. These features allow network operations to be centralized, orchestrated and even automated, so changes can be made once and quickly propagated across the entire network.

One of the biggest benefits of SD-WAN connectivity is being able to replace high-cost MPLS circuits with lower-cost broadband connections. One challenge network professionals face is determining which type of broadband is best to use. Available options include DSL, cable, Ethernet, satellite, and 3G and 4G cellular.

Wireless services seem compelling, but they are typically metered services in which enterprises pay for the bandwidth they consume. These usually make great backup connections, but can be cost-prohibitive for use as primary circuits. That likely leaves the terrestrial services as the best choice. But even within these services, quality of service can vary. While cable and DSL are more widely adopted than Ethernet, ZK Research believes Ethernet may be a better SD-WAN connectivity choice for a number of reasons.

SD-WAN connectivity: Comparing Ethernet to DSL and cable

Ethernet offers the security and performance of private IP, but with broadband pricing that gives it the best of both worlds.

The first reason enterprises should consider Ethernet for primary SD-WAN connectivity is cable and DSL are shared services, which means the throughput can vary greatly based on time of day. ZK Research recently interviewed a large retail organization that was using cable to connect its stores. The retailer found that during the day, when most people were at work, the connection easily got bandwidth speeds that exceeded the 50 MB for which it was paying.

Later in the day, however, when consumers were using social media, Netflix and YouTube, the bandwidth speed dropped to under 10 MB, which sometimes crippled the company's ability to use any bandwidth-intensive services.

Ethernet, though, offers dedicated and private services to each customer to ensure businesses receive the allotted bandwidth they purchase. This is crucial in today's digital world, where the network determines the user experience of employee- and customer-facing applications. Shared broadband services that deliver inconsistent network speeds can lead to lost revenue and unhappy customers and employees. The predictability of Ethernet will lead to a more consistent user experience.

Another issue with DSL and cable services is limited agility. WAN bandwidth requirements continue to grow by leaps and bounds, so what's currently in place for bandwidth will likely need to be upgraded in two to three years. This requires a highly agile network in which bandwidth can be added on demand. Imagine the ability to bring cloud-like scaling to a network. DSL and cable can certainly do this, but only for a limited amount of bandwidth that typically caps out at 1 Gb or less.

Ethernet services, however, can start with smaller bandwidth and scale up to 10 Gb or higher. In fact, most Ethernet service providers have 40 Gb and 100 Gb speeds on their roadmaps, meaning Ethernet will be multiple orders of magnitude faster than its DSL and cable counterparts in a few years.

Finally, Ethernet is delivered as a private service, whereas cable and DSL are typically shared services. This makes Ethernet significantly more secure. One of the reasons businesses have stayed with MPLS despite its high price point is because its private nature gives security-minded companies more confidence their data won't be compromised. Ethernet can offer the same level of security as MPLS. 

The agility of SD-WAN connectivity is far too compelling to ignore, and ZK Research recommends IT leaders aggressively adopt this next-generation WAN architecture. It's important, however, to carefully choose broadband services that go with it. Shared services can perform unpredictability and create security risks. Ethernet offers the security and performance of private IP, but with broadband pricing that gives it the best of both worlds.

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