VoIP – from UC to SIP Trunking – offers businesses more flexibility, cost savings, and scalability than traditional phone systems, but these advantages don't matter if the call quality is poor. Choppy audio and dropped calls are more than just annoying technical glitches; they’re business disruptors.
Delivering consistently great VoIP call quality requires a combination of proper monitoring, network optimization, and a proactive strategy. This guide covers how to measure VoIP quality, what causes common issues, and seven proven strategies to improve your VoIP network’s performance.
VoIP call quality refers to the stability and clarity of a voice conversation carried over IP networks. VoIP relies on the internet and its network infrastructure, making it more flexible than traditional phone systems but also more vulnerable to issues like latency, jitter, and packet loss.
For example, ECG worked with a retail bank chain with a large Cisco-based VoIP PBX platform. The PBX worked fine, but the underlying network meant that calls were often difficult to understand. When you're talking to your mortgage banker, you want to be sure he knows when you said to lock in the rate.
Several factors play a part in determining VoIP call quality, including:
These technical elements translate directly into human experiences. A dropped word, a moment of static, or an unexpected delay can undermine the trust and professionalism your organization works hard to maintain.
Whether you're an enterprise running a large contact center or a service provider supporting thousands of endpoints, maintaining strong VoIP quality of service (QoS) is business-critical. Enterprises simply cannot use a service provider with questionable VoIP call quality.
To meet this need, many voice service providers offer SLA-backed VoIP services where call quality and uptime aren’t just features but contractual commitments.
Before you can improve your VoIP quality, you'll need to measure it. A VoIP quality test can offer a diagnostic window into your network's performance that reveals potential issues before they become problems for your users. But beware: these tests can take real effort and planning!
There are several ways to run a VoIP quality test, including:
Many voice engineering teams use tools like Wireshark, PRTG, and dedicated VoIP monitoring platforms such as VoIP Monitor or Oracle Communications Operations Monitor (OCOM) to maintain visibility into their VoIP environments.
Once you’ve identified your VoIP performance issues, it’s time to take action. Here are seven strategies to boost VoIP call quality across your network:
Voice packets are time-sensitive since the timeline from when they are transmitted to when they are received matters. However, they can experience delays when competing with large data transfers, like file downloads or video streaming.
Implementing VoIP quality of service policies ensures voice traffic is prioritized across your network routers and switches. You can also use DSCP (Differentiated Services Code Point) tagging to mark VoIP packets for priority handling and avoid performance issues during high-traffic periods. This can work well for parts of the network you directly control but has limited success across the public internet.
If you depend on the internet, you don't have the option of using prioritization – as in, you can't insist that every ISP enforces your requests. You have to use other techniques, like traffic engineering, to choose which ISP to use for a particular customer.
Sometimes, QoS packet prioritization in your network isn't the challenge: it's packet performance in your client's network. ECG once worked with a service provider who had a client with a large multi-branch network architecture. The internal network between sites had substantial packet loss, but the service provider had no visibility to fix that problem. As a VoIP service provider, your role may be simply to advise clients in proper QoS design.
When it comes to bandwidth, it isn’t just about having more – it’s about using it efficiently. Effective bandwidth management can transform your VoIP network from a bottleneck into a high-performance communication platform.
Limited bandwidth is a common cause of degraded VoIP quality, so be sure to evaluate your usage patterns and ensure your network can support data and voice traffic simultaneously. For organizations experiencing congestion during peak hours, consider increasing your network or internet capacity or limiting bandwidth-heavy apps during business hours, such as scheduling backups to off-hours.
Traffic engineering (TE) is the practice of choosing links for certain network paths, such as routing traffic to client A over GTT and traffic to client B over Lumen. But you need to analyze the traffic flows – through traceroute and BGP data – to assess which links are best for each path.
Jitter is one of the most subtle and disruptive challenges in VoIP communication. This phenomenon creates audio experiences that feel disconnected and robotic. Reduce jitter by:
Addressing jitter can help you create smoother, more reliable communication experiences. Larger jitter buffers aren’t always the way to go, as they increase latency. We have seen VoIP service providers fix their echo problems by reducing the size of jitter buffers in key VoIP devices.
Latency is the delay between sending and receiving a voice packet. Even minor delays – as low as 150ms – can disrupt the natural flow of conversation and undermine professional interactions. To minimize latency, consider:
In global deployments, using regional SIP trunks and distributed SBCs (Session Border Controllers) can also help reduce latency for international calls.
Sometimes, VoIP issues aren’t with the network but with the endpoint. Old headsets, outdated firmware, or insufficient system resources can create poor audio experiences. In BYOD environments, some phones may be Android devices running software from a VoIP provider, and these devices can be overloaded if software is installed.
Make sure to regularly update firmware on desk phones and softphone applications, and verify that all your endpoints meet minimum hardware specs for VoIP. Device-level monitoring tools can alert you to performance bottlenecks before users start complaining.
VoIP codecs determine how voice data is compressed and transmitted. Common options include G.722/AMR-WB (high definition), G.711 (legacy uncompressed), and G.729 (compressed). While G.729 saves bandwidth, it can reduce call clarity – especially if mobile carriers or other intermediate networks apply additional compression.
Codec compatibility requires all parties to cooperate; service providers and enterprises rarely have the freedom to adopt a particular codec unilaterally. While G.711 is the most common option on VoIP networks, those integrating with cellular networks should consider AMR-WB and other codecs. Keep in mind that using an SBC to transcode audio never improves the audio quality.
For high-value interactions, use less compression to maximize clarity and adjust codec settings based on your network conditions.
Maintaining VoIP quality requires continuous monitoring. Alerting systems can notify your IT or voice engineers whenever packet loss exceeds a defined threshold, MOS scores fall below acceptable levels, or issues like jitter or latency spikes occur.
Popular monitoring approaches include:
Proactive monitoring gives your teams time to fix issues before they escalate and affect users. Plus, analyzing these trends over time can help you identify areas for long-term improvement.
At ECG, we work with service providers, universities, and large enterprises to ensure they deliver consistent, reliable VoIP quality at scale. From call monitoring and network design to QoS configuration and SBC integration, we offer the engineering expertise and hands-on support you need to keep your voice services performing at their best.
Our teams specialize in solving real-world VoIP performance issues, whether they involve SIP signaling, network bottlenecks, or misconfigured endpoints. We can also help you run comprehensive VoIP quality tests and build long-term monitoring strategies that evolve with your infrastructure.
Want better VoIP call quality across your network? Reach out to ECG today to find out how we can help you ensure every call is crystal clear.