Statewide 911 outage was caused by 911 vendor's malfunctioning firewall

Related: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=40720744">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=40720744</a><p>Press Release: <a href="https:&#x2F;&#x2F;www.mass.gov&#x2F;news&#x2F;massachusetts-state-911-department-determined-firewall-caused-statewide-911-disruption" rel="nofollow">https:&#x2F;&#x2F;www.mass.gov&#x2F;news&#x2F;massachusetts-state-911-department...</a>

That is a serious single point of success. What are the backups or alternatives to 911?