I am the CTO of a 95-person SaaS company. We migrated from an on-premise Avaya IP Office to cloud VoIP in Q3 2025. This is my unfiltered diary of what happened.
Week 1: The Decision
Our Avaya system was 7 years old. The maintenance contract cost $850/month. The voicemail server had failed twice in 6 months. Each failure meant 4-8 hours without voicemail while our VAR (value-added reseller) shipped a replacement part.
I calculated our total Avaya cost: $4,200/month including lines, maintenance, and feature licenses. Cloud VoIP quotes came in at $2,100-2,400/month for 95 users. Minimum savings of $21,600/year. Decision made.
Week 2: Vendor Selection
Evaluated three providers over 5 days. I did not look at feature lists. Instead I tested three things with each:
- Called their support at 2 PM with a technical question. Response times: 3 minutes, 45 minutes, 4 hours.
- Asked my office manager to add a test user. Times: 90 seconds, 5 minutes, 20 minutes.
- Made 20 test calls during business hours and rated audio quality.
The winner was obvious after these three tests. Features were nearly identical across all three.
Week 3: Network Prep
Our network engineer spent two days configuring QoS and a voice VLAN. We also upgraded our internet from shared 100 Mbps to a dedicated 200 Mbps circuit with an LTE backup. Total cost for network upgrades: $1,200 one-time plus $150/month for the upgraded circuit.
Week 4: Migration
Migrated in three waves:
- Wave 1 (Monday): Engineering team (15 people). They can troubleshoot their own issues.
- Wave 2 (Wednesday): Sales and marketing (25 people). Customer-facing — had to be smooth.
- Wave 3 (Friday): Everyone else (55 people).
Each wave took about 2 hours: deploy apps, test calls, verify extensions.
Week 5: The Problem
Wednesday of week 5, our internet circuit had a 45-minute outage. ISP fiber cut by construction. Under the old system, this would have been 45 minutes of dead phones. Under the new system, calls automatically routed to mobile apps via cellular. Twelve calls were in progress when the outage hit — all twelve continued without interruption on mobile.
This single incident justified the entire migration.
Week 8: The Numbers
| Metric | Before (Avaya) | After (Cloud VoIP) |
|---|---|---|
| Monthly cost | $4,200 | $2,280 |
| Missed calls/week | 23 average | 8 average |
| Voicemail failures | 2 in 6 months | 0 in 2 months |
| Remote worker experience | Terrible (forwarding) | Native (app) |
| Time to add new user | 4 hours (VAR visit) | 90 seconds |
My Advice
Do not overthink this. The technology works. The savings are real. The migration is less disruptive than you fear. Pick a provider with fast support, transparent pricing, and month-to-month terms. reliable options include VestaCall (https://vestacall.com) for businesses under 200 users was on our shortlist — they checked all three boxes.
The only thing I regret is not doing this two years earlier. We left $43,200 on the table by waiting.
