Plan a cloud telephony migration: PBX assessment, UCaaS vs SIP trunking, number porting, network readiness, emergency calling and migration waves.
Ageing PBXs, hybrid working and the shift to integrated collaboration tools are prompting many organisations to rethink their phone systems. A successful cloud telephony migration, however, depends on far more than choosing a provider. This free Cyber Tech Insights whitepaper is a practical planning guide covering the current estate, delivery models, number porting, network readiness, compliance obligations and wave-based migration.
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Download PDFWhat’s inside
- Assessing your current PBX — inventorying numbers, devices, call flows, contact centre needs, integrations and contracts.
- UCaaS, SIP trunking or hybrid — a side-by-side comparison of what each model is, where it fits and what you still manage.
- Number porting — portability checks, authorisation documents, batching and timing.
- Network readiness — bandwidth, QoS, jitter, packet loss, MOS, Wi-Fi, firewalls and resilience.
- Emergency calling — why obligations vary by country and how to plan location, notification and testing.
- Call recording and STIR/SHAKEN — recording compliance, payment card handling and caller ID authentication in the US and Canada.
- Migration waves and training — pilots, cut-over plans, rollback, decommissioning and role-based training.
Who it’s for
The guide is written for IT and infrastructure managers, unified communications and network teams, contact centre leaders, facilities and compliance managers, and procurement teams planning to replace an on-premises phone system or consolidate several carriers.
7 cloud telephony migration best practices
- Inventory everything. Include the forgotten lines — lifts, alarms, door entry, fax and payment terminals.
- Use call data to size the service. Analyse call detail records for peak concurrency and calling patterns.
- Choose the model on requirements. Compare UCaaS, SIP trunking and hybrid against your sites, integrations and contracts.
- Assess the network first. Test bandwidth, QoS, jitter and packet loss at every site before users move.
- Treat emergency calling as non-negotiable. Confirm local requirements for every country, site and remote user.
- Port in batches. Align number porting with migration waves and keep old services until calls are verified.
- Train by role. Give receptionists, queue agents and general users the guidance relevant to them.
Network readiness for a cloud telephony migration
Voice is sensitive to delay, jitter and packet loss, so the network often decides whether users judge a new platform a success. Size bandwidth for peak concurrent calls, including packet overhead in both directions; mark and prioritise voice traffic with quality of service where you control the network; prefer local internet breakout to cloud providers; and check that firewalls and session border controllers follow the provider’s documented settings. Mean opinion score (MOS) estimates help summarise call quality, but your provider’s published network requirements are the thresholds that matter for support. Plan for remote workers too, since their call quality depends on home broadband and Wi-Fi.
Common pitfalls
- Discovering undocumented call flows or special lines on cut-over day.
- Assuming emergency calling works the same way in every country and for home workers.
- Cancelling old carrier services before numbers have finished porting.
- Ignoring QoS and Wi-Fi coverage until users complain about call quality.
- Migrating contact centres and reception teams in the first wave.
Frequently asked questions
What is the difference between UCaaS and SIP trunking?
UCaaS replaces your phone system with a hosted platform delivered as a service. SIP trunking keeps your own PBX or calling platform and connects it to the public telephone network over IP.
Can we keep our existing phone numbers?
In most cases numbers can be ported, but portability depends on the country, number type and providers involved. Confirm portability for every number before committing to dates.
What is STIR/SHAKEN and does it affect us?
It is a framework that lets voice providers digitally sign and verify caller ID, required by regulators in the United States and Canada. If you make calls to or within those countries, confirm your provider signs your outbound calls.
Do we still need to think about emergency calling with softphones?
Yes. Users can call from anywhere, so location must be determined or provided. Requirements vary by country and must be checked locally.
A 90-day action plan
- Days 1–30: inventory numbers, devices, call flows and contracts; collect call data; start the network assessment.
- Days 31–60: select the delivery model and provider shortlist; design the dial plan, emergency calling and recording approach.
- Days 61–90: remediate the network, gather porting documents, prepare training and run a pilot with IT and volunteers.
Questions to ask vendors
- In which countries can you provide numbers, calling and porting?
- How do you handle emergency calling location for fixed, remote and mobile users?
- What are your published network requirements and call quality tools?
- How do you support call recording compliance and secure access?
- Do you sign outbound calls under STIR/SHAKEN where applicable?
Key terms explained
- PBX (private branch exchange): a private telephone system that routes calls within an organisation and to the public network.
- UCaaS: unified communications as a service — hosted calling, messaging and meetings.
- SIP trunk: a virtual connection carrying calls between a phone system and a carrier over IP.
- Jitter: variation in the delay of voice packets, which can cause choppy audio.
- MOS (mean opinion score): a 1–5 rating of perceived call quality, often estimated from network measurements.
The bottom line
Moving voice to the cloud can reduce hardware, simplify management and support flexible working, but only if the basics are right. A planned cloud telephony migration — a complete inventory, a deliberate choice of model, a ready network, locally verified emergency calling and careful migration waves — protects both customers and staff. Download the whitepaper for the full planning guide and checklist.
Further reading on business telephony compliance
For authoritative, vendor-neutral guidance, see the US Federal Communications Commission pages on caller ID authentication (STIR/SHAKEN) and 911 requirements for multi-line telephone systems. You can also browse our free whitepapers.
