When Seconds Count: SD-WAN Gives 911 Failsafe Last Mile

Did you know that 911 has only been available across the United States for the past 40 years? Thankfully since its implementation, 911 has served as the vital link between the American public and emergency services. In recognition of 911 awareness -- April was 911 education month -- let's take a look at how software-defined WAN technology can contribute to the effort of saving lives.

911 emergency services demand a failsafe last-mile network -- one that delivers high availability and reliable, predictable application performance. The network connecting public-safety answering points (PSAPs) and operations centers must be available every second of the day. The network must deliver constant, acceptable levels of capacity and coverage, as well as availability during routine maintenance and upgrades.

Traditionally, PSAPs eliminated potential points of failure with network path diversity. But in a traditional routed network, failing over to the backup network can take seconds -- and that delay certainly means the risk of dropped calls.

The solution now requires a migration to Next Generation 911 (NG911), which utilizes IP networks rather than the traditional circuit-switched TDM networks that have been in use for decades. 911 administrators need to evaluate strategies to increase network availability and resiliency as they move into an IP world.

With NG911, people can contact 911 via text or video messages from any device, as well as make calls the way they always have. Under NG911, the location of cellular callers will be more accurate. Callers can be pooled by the scene of the same emergency, which will aid rapid response. Life-saving data from notification systems, medical alerts, and sensors can be sent to 911 call center agents, as well as to dispatchers and first responders.

In addition, with NG911, call control can be distributed, which means a 911 outage can affect a greater number of PSAPs -- and people. As more regions and communities contract out 911 services, critical functions may be located farther from the PSAPs and the person in need, making network responsiveness and reliability even more critical.

Enter SD-WAN. With an SD-WAN in place, you can build a converged IP network that supports voice as well as new capabilities, while mitigating the risk of change.

An SD-WAN can deliver many benefits, including:

  • Continuous availability and predictable performance -- SD-WAN adapts in real time to actual network conditions and demand for bandwidth, ensuring that critical applications have priority at all times and regardless of network issues and that all applications take the best-quality path through the network. This is possible with the continuous unidirectional measurements of packet loss, latency, jitter, and bandwidth utilization for all paths between any pair of locations. When forwarding decisions are made on a per-packet basis, SD-WAN can deliver sub-second response to any network issues on that path.

  • Access all bandwidth across multiple links -- PSAPs are typically linked by two or even three connections for redundancy, but only the primary network is active until a link failure occurs. With SD-WAN, all circuits are active so locations have access to the full aggregated amount of bandwidth, which means an increase in network capacity for no additional spending. Policy-based prioritization ensures that real-time, quality-sensitive applications like VoIP get the highest priority and are securely transmitted over the best possible network -- whether that network is T1, MPLS, metro Ethernet, cloud, or broadband.

Whether improving a dispatch center or adopting NG911, an SD-WAN can play a critical role ensuring that when the worst happens, call takers can handle phone calls (and increasingly texts) promptly and first-responders get the detailed information they need to improve situational awareness. But not only is an SD-WAN a proven way to deliver continuous availability for the last-mile network, an SD-WAN also can help 911 call centers make the most of their IT infrastructure investments. And that delivers peace of mind for everyone.