Network administrators and IT managers need to understand Mean Opinion Score metrics to ensure optimal VoIP communication quality. A poor MOS value can indicate network problems like high network latency, jitter, or packet loss that directly impact business communications, customer experience, and end-user satisfaction in contact center and telephony environments.
Maybe you haven't considered your network's Mean Opinion Score yet. If you already have a Voice over Internet Protocol PBX or contact center infrastructure, you should monitor the MOS value to ensure high-quality voice calls and optimal audio quality for your end-users.
The Mean Opinion Score (MOS) has been introduced to provide quantitative assessment of the quality of VoIP communications. Wikipedia defines the MOS score as follows:
Mean opinion score (MOS) is a measure used in the domain of Quality of Experience and telecommunications engineering, representing overall quality of a stimulus or system. It is the arithmetic mean over all individual values on a predefined scale that a subject assigns to his opinion of the performance of a system quality. Such ratings are usually gathered in a subjective quality evaluation test, but they can also be algorithmically estimated using objective measurement algorithms that analyze voice signal characteristics and network conditions.
MOS is a commonly used measure for video, audio, and audiovisual quality evaluation, but not restricted to those modalities. ITU-T has defined several ways of referring to a MOS in Recommendation P.800.1, depending on whether the score was obtained from audiovisual, conversational, listening, talking, or video quality tests. (Wikipedia)
Basically, the MOS score is somewhere between the values of 1 and 5. A MOS value of 5.0 certifies excellent quality for voice calls. As a comparison: Public Switched Telephone Network (PSTN) telephony achieves a high MOS between 4 and 5, where 5 represents the absolute optimum case for perceived quality and quality of experience.
The following table provides an initial overview of the different quality levels of the Mean Opinion Score:
| MOS | Quality | Impairment |
|---|---|---|
| 5 | Excellent | No effort required to understand |
| 4 | Good | Slight effort required to understand |
| 3 | Fair | Moderate effort required to understand |
| 2 | Poor | Considerable effort required to understand |
| 1 | Bad | Despite great effort, impossible to understand |
VoIP MOS measurements vary in precision. Human-based assessments typically provide scores to one decimal place. Specialized VoIP monitoring equipment and software can deliver more precise measurements up to 2-3 decimal places, enabling better troubleshooting and network optimization. MOS testing can be affected by various factors including codecs, bandwidth usage, and routing configurations.
PRTG Network Monitor provides Quality of Service (QoS) monitoring through specialized QoS sensors that measure the network performance metrics affecting VoIP call quality in real-time across data centers and enterprise networks. The QoS (Quality of Service) Round Trip sensor measures critical network performance metrics including jitter, packet loss, and round-trip time that directly impact voice quality and audio quality for voice packets traveling end-to-end through your network infrastructure.
Important Performance Note: QoS sensors have high performance impact. PRTG recommends using no more than 200 QoS sensors per probe to maintain optimal monitoring performance.
PRTG's QoS Round Trip sensor provides these specific measurement channels:
The Cisco IP SLA sensor monitors Voice over IP (VoIP) network parameters using IP service level agreements (SLA) from Cisco routers and network devices via SNMP. This integration provides enterprise-grade VoIP monitoring capabilities for Cisco network environments, enabling service providers to track voice signal quality across their telecommunications infrastructure.
Key PRTG Features for VoIP Quality Monitoring:
Ready to monitor your network's VoIP quality parameters with PRTG? Start your PRTG trial and gain visibility into the network factors that affect your voice communications.
Network problems that commonly affect MOS scores include:
Monitoring these factors provides complete end-to-end visibility into VoIP performance issues and quality degradation. Professional network monitoring helps identify root causes before they impact business communications and customer experience in contact center and telephony operations.
While MOS value provides an overall quality assessment for voice calls, comprehensive VoIP monitoring requires tracking additional telecommunications metrics:
PRTG's advantage lies in correlating QoS parameters (jitter, network latency, packet loss) with broader network performance metrics, helping you identify root causes rather than just symptoms. This integrated approach provides comprehensive network visibility beyond isolated voice quality monitoring, enabling you to optimize network conditions for high-quality voice communications across your entire infrastructure.
Prioritize voice traffic over less critical data to ensure consistent call quality. Configure traffic shaping and bandwidth allocation specifically for VoIP applications.
Use automated network monitoring tools to track network latency, jitter, and packet loss in real-time. Set up proactive alerts to address network conditions before they affect call quality and create quality degradation for end-users.
Conduct periodic MOS testing assessments across different network paths and times of day to identify patterns and potential improvements in voice signal quality.
"Poor voice quality costs businesses an average of 30% longer phone call times and significantly impacts customer experience in contact centers. Proactive network monitoring prevents these costly communication breakdowns and maintains high-quality voice calls for improved user experience."
QoS parameter monitoring provides immediate feedback on network changes and helps troubleshoot VoIP issues faster. Real-time alerting on jitter, latency, and packet loss enables proactive problem resolution before users experience call quality problems.
Executive dashboards showing network quality trends help demonstrate IT performance to business stakeholders. Historical QoS metrics support infrastructure investment decisions and capacity planning for telecommunications and data center environments.
Understanding and monitoring MOS values is essential for maintaining professional communication standards in today's business environment. With the right network monitoring tools and best practices, you can ensure consistently high-quality voice calls and excellent quality user experience that supports your organization's productivity, customer experience, and telephony objectives.
Discover how PRTG's QoS monitoring can help you track the network performance metrics that affect audio quality and voice signal integrity across your entire telecommunications infrastructure, from data centers to end-user devices. Download PRTG free trial and see the difference professional network monitoring makes.