Site Survivability in UCaaS: What It Is and Why It Matters 

Unified Communications as a Service (UCaaS) gives businesses flexibility and scalability, but it depends on reliable internet. When a Wide Area Network (WAN) or Internet Service Provider (ISP) fails, cloud-only UCaaS platforms stop working. Almost every team has felt this disruption — calls stop, coworkers can’t reach one another, and critical updates stall until the connection comes back 

That’s where site survivability comes in. It keeps your business talking even when the cloud connection breaks. 

What site survivability means in UCaaS 

Site survivability is a local failover system that keeps essential voice services running during outages. On its own, survivability allows internal communications to continue, employees can still call extension to extension even if the upstream connection is down. 

When a failover option is added, inbound and outbound calling, including emergency dialing (911), can also continue.  

Survivability and failover together are what make UCaaS a reliable choice when uptime is critical. 

Why survivability matters for business continuity 

Businesses can’t afford downtime. Site survivability keeps employees connected internally, even if the upstream internet connection is lost. With survivability in place, teams can still communicate extension to extension and maintain core internal workflows during an outage. 

This continuity is especially important for industries where internal communication is critical to safety and operations, such as healthcare, education, retail, and manufacturing. Survivability provides a baseline layer of resilience, ensuring your business is never left completely silent. 

(Pro tip: sometimes a simpler option than survivable branch appliances is connecting a few emergency analog phones directly to a VoIP gateway. That way, key phones keep working even if the internet or UCaaS goes down.) 

How hybrid UCaaS keeps businesses online 

Sangoma’s Hybrid UC, powered by Business Voice Plus, combines the scalability of the cloud with the reliability of on-site systems. At the center is the StarBox appliance, which provides local call control and survivability even if your WAN or ISP connection fails. 

Hybrid UCaaS gives you: 

• Local survivability: phones stay active during WAN or ISP failures 

• Multiple failover options: backup via 4G/5G LTE or POTS (plain old telephone service) lines 

• Multi-location flexibility: built for campuses, branch offices, and distributed businesses that need consistency everywhere 

• Enterprise-grade reliability: designed for 99.999% uptime to keep your business connected 

With this model, businesses get UCaaS site survivability for business continuity without sacrificing the reach and flexibility of the cloud. 

Why on-premises UC still matters 

Some organizations prefer to keep everything on-site. With Sangoma’s On-Prem UC powered by Switchvox, call control and survivability are built directly into the system. Voice traffic stays local, so communications keep moving regardless of the state of the internet. 

Key benefits of on-prem systems include: 

• Full control: businesses manage communications directly on-site 

• Built-in survivability: with no cloud dependency, local connectivity stays live 

Side note: few UC providers still offer true on-premises systems. Sangoma does, giving businesses freedom to choose their UC type instead of forcing them into cloud-only models. 

How survivability supports different industries 

• Healthcare: staff can still reach one another internally, which is critical for patient safety and coordination during an outage 

• Education: teachers and administrators stay connected through internal extensions, keeping classrooms and offices in touch 

• Retail and hospitality: employees can communicate across departments or locations inside the building, even if external lines are down 

• Manufacturing: workers on the floor and supervisors remain connected internally to keep production and safety communication moving 

In each case, site survivability ensures that when the internet goes down, internal communications keep going. 

If you need five-nines reliability, look no further 

Whether hybrid or on-premises, Sangoma ensures your communications don’t go offline. From disaster recovery and failover in UCaaS platforms to UCaaS high availability and disaster avoidance, survivability is the foundation of uptime. 

If you need site survivability in your UCaaS, we’ve got you. Send us a message to get in touch with a Sangoma team member today.