Unified Communications as a Service (UCaaS)

is a managed PBX environment in the cloud that provides phone services to end users. It replaces on-prem PBXs as well as SIP, PRIs, and POTS lines.

is an evolutionary approach to the WAN that offers simplified management, quick turn-up, better application performance, improved resiliency, and cost savings when compared to traditional approaches. It can replace or work with MPLS, and is delivered directly, via carriers, or via managed service providers.