Internet Speed, Network Requirements & The Hidden Factors Behind Great Call Quality
VoIP is no longer a buzzword—it’s the backbone of modern business communication. But here’s the problem: many companies blame VoIP when the real issue is their network.
Whether you’re switching from a traditional PBX or setting up a new cloud phone system, this guide will help you understand exactly what’s required for VoIP to work flawlessly.
Key Questions Answered:
- What internet speed do I need for VoIP?
- How do I avoid choppy audio or dropped calls?
- What are the minimum network requirements for VoIP?
Let’s break it down.
First, What Impacts VoIP Call Quality?
VoIP (Voice over IP) uses your internet connection to make and receive calls. That means your call quality depends on:
- Your internet speed
- Your network setup and configuration
- The quality of your router, switches, and firewall
- How well your traffic is prioritised (QoS)
- The number of simultaneous users or devices
- Whether your connection is fibre, LTE, ADSL, or wireless
Even a top-tier VoIP system will underperform if your network isn’t ready. So let’s dig in.
What Internet Speed Is Required for VoIP?
Here’s the truth: VoIP doesn’t use as much bandwidth as you think. One VoIP call only requires around:
📞 100 kbps (0.1 Mbps) per call – for high-quality, G.711 codec audio
📞 As low as 30 kbps per call – with compressed codecs like G.729
So theoretically, a 10 Mbps line could support up to 100 simultaneous calls.
But that’s theory. In practice, your network handles much more than VoIP—browsing, streaming, file sharing, cloud apps—and this traffic competes for bandwidth.
So, how fast should your internet be for Cloud PBX?
We recommend:
| Number of Users | Minimum Upload/Download Speed |
|---|---|
| 1–5 | 5 Mbps |
| 6–15 | 10–20 Mbps |
| 16–50 | 20–50 Mbps |
| 51+ | 50 Mbps+ or dedicated fibre |
Pro Tip: It’s not just about speed. Stability, low latency, and minimal jitter are more important than raw Mbps.
What Are the Minimum Network Requirements for VoIP?
To ensure best VoIP quality, make sure your network meets these technical standards:
| Requirement | Recommended Value |
|---|---|
| Latency | < 150 ms (one-way) |
| Jitter | < 30 ms |
| Packet Loss | < 1% |
| Bandwidth per call | 100 kbps (G.711 codec) |
| Connection type | Fibre or business-grade LTE |
⚠️ Avoid shared or throttled lines, and always test during peak hours to simulate real-world conditions.
Does VoIP Work Over Wi-Fi?
Yes, but wired connections are always better. VoIP over Wi-Fi can suffer from:
Interference from other devices
Signal degradation over distance
Fluctuations in bandwidth availability
If using Wi-Fi, ensure:
Strong signal (use mesh if needed)
5 GHz band is preferred over 2.4 GHz
Limited congestion on the channel
⚠️ Still, for mission-critical VoIP (like call centres), use Ethernet wherever possible.
Quality of Service (QoS): Your Secret Weapon
QoS (Quality of Service) is a feature on your router or firewall that prioritizes VoIP traffic over everything else.
Why it matters:
Imagine uploading a large file while on a call—without QoS, your voice packets could be delayed, causing robotic audio or call drops.
With QoS enabled:
Voice traffic is marked and prioritised
Call quality remains stable, even with heavy network use
Jitter and latency are minimized
✅ Ask your IT provider or VoIP partner to configure QoS on your router and switches.
Network Tips for Best Quality VoIP
Here’s how to build a VoIP-ready environment:
Use business-grade fibre, not home broadband
Separate voice and data traffic on different VLANs (virtual networks)
Invest in a quality router with VoIP and QoS support
Avoid double NAT (when two routers create IP conflicts)
Disable SIP ALG, which can interfere with VoIP packet flow
Run regular speed and jitter tests to catch problems early
What About Firewalls and Security?
VoIP systems are often blocked or throttled by overly strict firewalls. Make sure:
SIP and RTP ports are open
The provider’s IP addresses are whitelisted
VoIP traffic is not being shaped or delayed
Your VoIP provider should give you a network readiness guide—make sure your IT team follows it closely.
The Bottom Line: VoIP Works Brilliantly—When Set Up Right
VoIP delivers unbeatable value, flexibility, and call features. But if your internet connection or internal network isn’t optimised, you’ll experience call drops, lag, and frustrated users—and wrongly blame your VoIP provider.
Checklist for Best VoIP Quality:
✅ Fibre or stable LTE
✅ Business-grade router with QoS
✅ Low latency and jitter
✅ Wired connections where possible
✅ VoIP-friendly firewall and ports open
✅ VoIP traffic prioritised or on its own VLAN
Need Help Setting Up VoIP?
We work with South Africa’s top VoIP providers who can:
Test your network readiness
Recommend the right connection speed
Help you configure your router and firewall
Deliver a VoIP system that just works
👉 Compare VoIP providers now
👉 Read our FAQ on VoIP phone systems
