case study
55,000 Users, Zero Disruption
A global Teams Phone success story
55,000 Users, Zero Disruption
A global Team Phone success story
A large, global enterprise engaged its trusted service provider to transition from Cisco to Microsoft Teams Phone. Working through a multi-layered delivery model, VOSS was brought in by a partner to lead the migration effort. Despite the environment complexity, the scale of the deployment, and the global footprint involved, the collective team delivered an exceptional outcome – on time, with zero disruption, and with significant cost savings.
The scenario
This project involved four major stakeholders: The end customer, their service provider, the partner delivering UC services, and VOSS as the migration specialist. The partner was newly engaged with the customer and had limited migration experience, so they relied heavily on VOSS to architect, manage, and execute a large-scale transformation spanning APAC, EMEA, LATAM, and North America. All migration work was performed outside business hours to minimize risk and maintain business continuity.
The challenge
This was the partner’s first major engagement with the customer, making flawless execution essential to build confidence and trust. The customer needed to migrate 55,000 employees from a Cisco voice platform to Microsoft Teams Phone across multiple regions, time zones, and regulatory environments.
Key elements included:
The solution
VOSS worked hand-in-hand with the partner, service provider, Microsoft, and the customer’s network and project teams to deliver a unified migration strategy. This included establishing a global framework with region-specific plans tailored to local technical, regulatory, and operational requirements, and executing highly structured off-hours migration waves to ensure zero end-user disruption. The teams collaborated closely with regional voice leads across APAC, EMEA, LATAM, and NA to navigate complex gateway and routing scenarios. Strong operational support, proactive troubleshooting, and day-1 automation, further strengthened the delivery. Technical engineers, project managers, operations teams, and partner leadership worked together to maintain momentum and quality throughout the 7-month project.
The value
At the conclusion of the project, the customer reported significant business impact:
55,000 users
migrated in 6–7 months with zero end-user disruption
$2M USD in savings
faster migration through automated provisioning, validation, and cutover sequencing
Seamless multi-region delivery
meeting diverse regulatory and technical requirements
Improved customer confidence
with the partner exceeding expectations in their first major engagement
A scalable, modern voice platform
enabling smoother operations and future UC innovation
This project demonstrates what is possible when global teams collaborate with clarity, dedication, and a shared commitment to excellence. Today, the customer is fully operational on the Microsoft Teams Phone platform, with a modern, scalable, and future-proofed voice environment that supports ongoing innovation and growth.
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