Why Branch Routers Take a Backseat to SD-WAN

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A road map will show you the shortest distance between two places, but there’s no guarantee it will be the safest or most efficient route. Construction zones, mountain passes, weather conditions, traffic patterns and other factors can all impact the journey.

That’s a rough approximation of the challenges inherent in traditional router-based wide-area networks (WANs).

WANs allow companies to extend the reach of their core networks by creating direct connections for delivering applications and services to branch offices. Designed long before the cloud era, these hardware-centric architectures were never meant to transport massive amounts of cloud, mobile and web traffic.

Instead, routers at each branch location backhaul Internet traffic across multiple intermediate network links to the backbone network for security inspection. The traffic jams, bottlenecks and delays caused by this “hairpin” routing scheme were acceptable when Internet usage was minimal, but they’ve become intolerable now that most companies are highly dependent on an array of cloud and web-based applications.

Software-defined WAN (SD-WAN) solutions effectively create expressways for Internet traffic. Using virtualized appliances and policy-based routing practices, SD-WAN can replace branch routers and move Internet- and cloud-bound traffic without backhauling.

In the Fast Lane

Almost half of organizations still using legacy WAN solutions report that they have experienced connectivity issues as they’ve become more dependent on cloud- and web-based applications and services to support remote and hybrid workforces, according to a recent global survey of more than 1,500 networking professionals. Slow-loading web pages, poor application response times and freezing video calls were among the biggest complaints.

To support today’s workloads, organizations need the ability to prioritize traffic and ensure that delay-sensitive applications such as voice and video get preference. That’s a big job in a conventional WAN where dozens or even hundreds of individual branch routers would require manual configuration changes. Because such changes require expertise with the router’s command line interface, but it is very time consuming to have to change on all the routers 1 at a time vs using the automation on SD-WAN technologies to change all at once.

SD-WAN eliminates this time-consuming and complex tasks by separating the data and control planes so that IT can make intelligent decisions for the whole network vs. relying on individual hardware. As a virtual overlay network, it uses software to control and orchestrate WAN services. That allows organizations to blend multiple transport types such as MPLS, broadband Internet, cellular and satellite to suit their connectivity requirements.

Changing Directions

An intelligent software layer manages all of those connectivity options and allows administrators to create routing policies based on a variety of application characteristics. Using those policies, the software chooses the optimal route and the most efficient connectivity option. For example, latency-sensitive voice and video applications that require predictable bandwidth might be routed across a dedicated MPLS connection while less-sensitive apps such as email are sent across commodity broadband circuits.

SD-WAN can also aggregate multiple connections to support real-time or near-real-time applications that have especially large bandwidth requirements. For example, VMware’s SD-WAN solution has a Dynamic Multipath Optimization feature that utilizes all available links to deliver all packets of a single flow to their destination. It automatically performs resequencing at the receiving end to ensure that the use of multiple transports doesn’t cause packets to be delivered out of order.

With its ability to optimize routing, reduce complexity and eliminate many hardware purchases, more organizations are looking to use SD-WAN to replace branch routers. Gartner analysts predict that by 2023, more than 90 percent of WAN infrastructure refreshes will be based on SD-WAN and virtualized hardware versus traditional routers.

Just as a road trip can be disrupted by unexpected hazards, application traffic can be severely impacted by unforeseen routing complications. If your existing WAN architecture is putting the brakes on your web and cloud traffic, give us a call. Our infrastructure experts can show you how to use SD-WAN to accelerate network improvements.

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