Modernizing a Public University’s Communications with a SIP-First Approach
CallTower’s SIP-First approach ensured compliance with strict E911 requirements, avoided academic disruptions, and addressed challenges like rising maintenance costs, limited integration, and hybrid work demands. The result was a seamless migration to a scalable, cloud-first communications strategy that enhanced operational efficiency and flexibility.
The Highlights
Challenge
- Aging Mitel PBX system with rising maintenance costs, hardware failures, and limited integration with modern tools.
- Increasing demand for hybrid work flexibility and strict campus safety/compliance requirements.
- High risk of service disruption, complex number porting, and stakeholder resistance with a traditional “rip-and-replace” migration.
Solution
- Parallel SIP Infrastructure: Deployed alongside the Mitel system to modernize connectivity without disrupting functionality.
- Decoupled DID Porting: Ported 25,000 DIDs into CallTower’s network while maintaining Mitel operations to avoid downtime.
- Phased Webex Activation: Migrated users in departmental waves aligned with the academic calendar for controlled rollouts and training.
Outcome
- Seamless migration of 25,000 DIDs with zero disruption to academic operations.
- Reduced maintenance costs, eliminated dependency on aging hardware, and improved infrastructure control.
- Enhanced hybrid work flexibility and a scalable, cloud-first communications strategy.
Large Public University
Size: Thousands of Students and Faculty
Industry: Education
Overview
A large public university serving thousands of students and faculty needed to modernize its aging on-premise Mitel phone system, which supported approximately 25,000 DIDs across academic, administrative, and campus safety operations. With fixed academic calendars, strict E911 requirements, and limited tolerance for downtime, the institution required a low-risk path to cloud calling.
Using CallTower’s SIP-First methodology, the university transitioned from Mitel to Webex Calling through a phased, risk-managed approach, modernizing its communications infrastructure without disrupting a single academic day.
The Challenge
The existing Mitel PBX was approaching end-of-life and created increasing risk due to:
- Rising maintenance costs and hardware failures.
- Limited integration with modern collaboration tools.
- Growing demand for hybrid work flexibility.
- Strict campus safety and compliance requirements.
A traditional “rip-and-replace” migration was deemed too risky, with concerns around service disruption, complex number porting, and stakeholder resistance. In a university environment, phone numbers are mission-critical access points, not just extensions.
The Solution: SIP-First Migration
CallTower implemented a phased migration designed to isolate risk and preserve continuity.
Phase 1: Parallel SIP Infrastructure
A parallel SIP trunk was deployed alongside the existing Mitel system, modernizing carrier connectivity while maintaining full system functionality and avoiding end-user disruption.
Phase 2: Decoupled DID Porting
Approximately 25,000 DIDs were ported into CallTower’s network while Mitel continued operating normally, eliminating downtime and removing number cutover from the high-risk go-live event.
Phase 3: Phased Webex Activation
Users were migrated to Webex Calling in controlled departmental waves aligned to the academic calendar, enabling training, pilot validation, and predictable rollouts.
Results And Business Impact
The university achieved:
- Successful migration of 25,000 DIDs with zero disruption.
- Elimination of aging Mitel hardware dependency.
- Reduced long-term maintenance and operational risk.
- Improved routing resiliency and infrastructure control.
- Enhanced hybrid work flexibility for faculty and staff.
Strategic Outcome
By separating infrastructure modernization from cloud activation, CallTower enabled the university to move from reactive telephony maintenance to a scalable, cloud-first communications strategy—modernizing confidently while preserving service continuity.
Key Takeaway:
SIP-First transforms complex PBX migrations from high-risk cutovers into controlled, phased modernization strategies; ideal for compliance-sensitive, distributed environments like higher education.
