Key Takeaways

  • Clearspan: Enterprises evaluating UCaaS platforms must account for a market that reached 117.1 million global UCaaS seats in 2025, according to Metrigy’s current market study.
  • A standard proof of concept should test Session Initiation Protocol interoperability, emergency calling, contact-center routing, identity management, and service behavior during a wide-area network failure.
  • Deployment contracts should specify targets for call-quality mean opinion score, failed-call rates, provisioning time, contact-center transfers, and carrier-incident resolution.

Define the Communication Problem Before Comparing Vendors

A multinational employee cannot reach a support queue because one office uses four-digit dialing, another relies on full E.164 numbers (the international telephone-numbering format) and the contact center maintains a separate routing table. That is the type of operational problem a UCaaS program should solve. Replacing desk phones is only one part of the assignment.

The scale of adoption makes structured planning more important. Metrigy’s UCaaS Market Size and Forecast: 2025–30 counted 117.1 million global UCaaS seats in 2025, up 6.9% year over year, and valued the market at $23 billion. The study also found that 58.6% of surveyed businesses used UCaaS exclusively, while 32.7% still operated multiple phone-system types.

For a large enterprise, the problem statement should identify which systems create friction. Typical examples include aging private branch exchanges (PBXs) connected through Primary Rate Interface (PRI) circuits, separate video platforms, duplicate voicemail services, manually maintained direct inward dialing (DID) inventories, and contact-center queues that cannot transfer context into an employee collaboration client.

Buyers should document dependencies at the protocol level. That means cataloging Session Initiation Protocol (SIP) trunks, session border controllers that secure and manage voice traffic between networks, analog adapters, fax lines, paging systems, E911 or local emergency-calling requirements, call-recording repositories, and Web Real-Time Communication (WebRTC) applications. A spreadsheet of office locations is not enough.

Build an Evaluation Around Workflows, Not Feature Counts

A practical request for proposal starts with representative call flows. Buyers can ask each provider to demonstrate an inbound customer call entering an interactive voice response (IVR) system, moving into a skills-based queue, escalating to a subject-matter expert, and returning to the agent without losing caller context.

Platform choices may include Microsoft Teams Phone, Zoom Phone, Cisco Webex Calling, RingCentral, and 8x8. The comparison should examine deployment model, geographic coverage, carrier relationships, administrative controls, application programming interfaces (APIs), and contact-center integration rather than treating every calling license as equivalent.

Providers such as Clearspan can be assessed against a technical scorecard covering unified cloud communications, conferencing, messaging, and contact-center requirements. The proof of concept should include SIP signaling traces, identity provisioning through System for Cross-domain Identity Management (SCIM) or Microsoft Entra ID, single sign-on using Security Assertion Markup Language 2.0 (SAML 2.0), and call-detail-record export through a representational state transfer (REST) API or scheduled CSV file.

Buyer interest in combined services is increasing. An Omdia enterprise communications study commissioned by Sippio reported that 67% of 450 enterprise decision-makers were willing to replace their UCaaS or contact center as a service (CCaaS) platforms, while 37% planned to adopt a combined MultiCaaS model within 12 months in 2026. MultiCaaS means managing multiple cloud communications services through a coordinated operating model. The finding makes cross-platform administration and data portability relevant evaluation criteria.

The Metrigy and Omdia figures measure different subjects and should not be treated as competing forecasts. Metrigy measures global UCaaS seats and market value, whereas the Omdia study measures stated purchasing intentions among 450 enterprise decision-makers.

Plan Migration in Operational Phases

During discovery, the project team should create a current-state inventory of DIDs, extensions, hunt groups, auto attendants, toll-free numbers, devices, carrier contracts, and regulatory recording policies. Roles commonly include a communications architect, network engineer, identity administrator, contact-center owner, security reviewer, procurement lead, and regional IT representatives.

A controlled pilot can then test office workers, remote users, receptionists, contact-center agents, and employees who depend on shared lines or call delegation. Relevant test cases include browser calling over WebRTC, SIP failover between session border controllers, emergency-location updates, mobile-client handoff, and calls traversing a high-latency network path.

Regional constraints deserve separate treatment. The IDC found in 2025 that 28% of EMEA organizations were more likely to use regionally based network providers, 27% were increasing sovereign-network use, and 26% were diversifying providers. These regional sourcing preferences are not directly comparable with Metrigy’s global seat data or Omdia’s platform-replacement findings. A global design may therefore require local number hosting, in-country media processing, region-specific retention, or more than one carrier.

During broader rollout, platforms like Clearspan must be evaluated on number-porting coordination, administrative delegation, SIP interoperability, analytics access, and escalation paths for carrier incidents. Buyers should also define rollback criteria before moving a site, such as failed emergency-call validation, unacceptable packet loss, or incomplete number transfer.

Decide Which Outcomes to Measure

The measurement plan should be agreed before migration. Otherwise, teams may end up reporting licenses activated rather than communication quality.

For voice, track mean opinion score (MOS), a one-to-five measure of perceived call quality, along with jitter, latency, packet loss, failed-call percentage, and one-way-audio incidents. For administration, monitor the elapsed time required to provision a user, assign a number, change a call queue, and remove access after an employee departure.

Contact-center measures can include transfer frequency, abandoned calls, queue time, first-contact resolution, and the percentage of escalations that preserve customer relationship management (CRM) context. Collaboration teams should examine meeting-join failures, room-system compatibility, and external-participant access.

Because vendors do not uniformly disclose customer-specific performance metrics, buyers should request reference architectures, sample service reports, incident-response targets, and anonymized performance distributions rather than relying on isolated success claims.

Turn Pilot Findings Into Contract Requirements

The most actionable pilot finding is often an exception. If a warehouse paging adapter cannot negotiate the selected codec (the algorithm used to encode and decode audio) the contract should identify a supported gateway or retain a local SIP path. If SCIM provisioning fails to map location attributes, the identity schema should be corrected before bulk activation.

Granted, number porting looks administrative until a rejected letter of authorization delays a site cutover. Buyers can reduce that exposure by validating business names, service addresses, account numbers, and number ownership against carrier records during discovery.

Service terms should cover more than uptime. Ask how the provider measures availability, whether planned maintenance is excluded, which party owns last-mile troubleshooting, how call-detail records can be exported, and how quickly administrators can retrieve recordings in WAV or MP3 format.

Apply the Model Across Different Enterprise Environments

A mid-market company can narrow the same playbook to a single collaboration client, one SIP carrier, and a smaller pilot group. A multinational enterprise may need regional session border controllers, country-specific emergency calling, multiple contact-center instances, and centralized policy management.

Frequently Asked Questions

How long does an enterprise UCaaS migration take?

Duration depends on number portability, site count, analog dependencies, and contact-center scope. Buyers should organize the work into discovery, pilot, regional rollout, and stabilization phases, with exit criteria such as validated E911 routing, acceptable MOS, and completed DID reconciliation.

What should a UCaaS proof of concept include?

Test real workflows rather than basic dial tone. Include SIP failover, WebRTC browser calls, SAML authentication, SCIM provisioning, CRM screen pops, call recording, mobile handoff, and a simulated wide-area network outage.

Is one UCaaS provider enough for a multinational enterprise?

It can be, but regional regulation and carrier availability may favor a mixed model. Evaluate whether the provider supports local number hosting, sovereign media paths, centralized analytics, and consistent APIs across every required country.