Communications Reimagined
Industry insights for 5G evolution and transforming digital experience.

SD-WANs Provide a Fast Path to Next-Gen 911 Services

Zeus Kerravala
Founder and principal analyst with ZK Research

Most of the technology industry has evolved at a blistering pace over the past decade.  One area that has not kept pace is the 911 service on which most cities rely to provide emergency services to its citizens.  Most 911 systems were built using legacy, analog phone systems rather than digital technologies, which means most public safety answering points (PSAPs) across the country need to be upgraded to modernized IP-based systems—something commonly referred to as next-generation 911 (NG911).

The modernization of 911 will greatly improve the reliability of the service as the new platforms will be built on modernized infrastructure.  This will allow voice, pictures, video and SMS to be sent from the public switched telephone network (PSTN) to the 911 network. Another benefit of NG911 is that the calling capacity can be increased by transferring calls to alternate PSAPs in the event of a disaster, thus eliminating any overload on one PSAP.  

Something that’s just as important as the calling infrastructure is the network. Because one of the fundamental tenets of NG911 is agility, and PSAPS cannot be agile without an agile network, it’s important to modernize a network when planning for NG911. Legacy networks use a combination of MPLS, frame-relay and leased lines, often with IP VPN providing the backup.  

While these types of network services are fairly reliable, the failover time when switching from the active connection to backup can often take some time, often up to a minute. While this might not seem like much to many businesses, it’s an eternity with 911, as a dropped call, or the service being unavailable even for a few seconds, could mean the difference between life and death.

What’s the Answer?
A software-defined wide area network (SD-WAN) – at least one that offers technology for high reliability and high quality of experience (QoE) – is much better aligned to meet the needs of NG911. SD-WANs have seen significant uptake in general enterprises, however city organizations should be looking at SD-WAN as a way of improving services like 911. Below are the top ways that SD-WANs can improve NG911 services:

  • More uptime. Legacy WANs were built on a concept of “active-passive” connectivity where the backup connection could only turn active if the primary failed. As noted above, the challenge is the length of time it takes to switch from the failed circuit to backup. SD-WANs operate in “active-active” mode where all circuits can send traffic all the time. If one circuit is unavailable or performing poorly, the packets that represent the call will be directed down better-performing connections. Through a combination of wired and wireless network types, 100 percent can be achieved;
  • Better call quality. SD-WAN appliances constantly micromanage each packet through the network for latency, packet loss and jitter. If a circuit is experiencing congestion, 911 packets can be distributed across better-performing links. Some SD-WAN offerings can even replicate call flows on two different paths, using different WAN connections at each end, suppressing the duplicate packet at the other end. This ensures the highest levels of call quality all the time, regardless of network outages or even network congestion incidents causing high packet loss or jitter;
  • End-to-end visibility.  Some of the SD-WAN vendors have integrated performance, fault and configuration management tools, which can make troubleshooting network problems much faster. Today, networks are built to be redundant enough that an actual outage is rare. The bigger problem is poor performance, which can be hard to identify as the network dashboards often show all nodes as “up” even if applications are performing poorly due to packet loss and/or jitter in the network.  An advanced, self-healing SD-WAN that does continuous unidirectional measurement of all traffic can even fix the problem, sub-second, so that end users and existing applications sessions and voice flows are not affected, allowing administrators more time to make sure the underlying network provider issue is addressed, since end users are not impacted. The end-to-end visibility can make troubleshooting much fasters.  Also, trending information can be used to predict when network connections will reach saturation and network teams and upgrade before there is a problem.

NG911 services will be game changing for many communities as they promise to bring digital technologies to a service that is long overdue for an upgrade.  As IT leaders go through the planning phase, it’s important that the network be considered a key component of the infrastructure and modernized.

Be sure to view The Economist Intelligence Report on the “Network Highway of Tomorrow,” here and read more SD-WAN blogs.

Also check out the ZK Research home page, here.


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