The Difference Between QoE and QoS (and Why it Matters)

The difference between quality of service and quality of experience is immediately clear during a videoconference that garbles words or pixelates a PowerPoint slide to the point of illegibility. The video transmission might technically hit quality of service level agreement minimums over the span of the call, but the overall experience still is an epic fail. This is the difference between Quality of Experience (QoE) and Quality of Service (QoS).

While QoS measures key network performance metrics, QoE focuses on the actual individual user experience: did the network actually deliver a sufficient end-user experience? During a video conference, if communication is impeded or a streaming video starts and stops, clearly the network failed. Was this noticed? Did the QoS metrics indicate that there was degradation that could impact QoE?

Let’s take a deeper dive into the difference between QoE and QoS, and why businesses should be focused on both network QoS and end-user QoE today.

Quality of Service Defined

The standard for measuring network performance is QoS. This is largely a holdover from the days when network management leaned on distributed, probe-centered architectures that used the CLI and SNMP protocols for monitoring the performance of individual networking components such as routers, switches, and load balancers.

QoS has its roots in old-school telephony performance monitoring and the earliest days of network performance management, and focuses on network characteristics such as latency, jitter, packet loss, R factor and MOS. All of which are still relevant today, but with the added complexity brought on by newer services today a new generation of QoS is needed.  One that goes beyond the traditional SNMP and round-trip measurements of the past. Accuracies in the milliseconds and measurements in the minutes are no longer sufficient to detect the nuance changes that can significantly impact next generation network performance.

The introduction of video and real-time bi-directional communications on the network requires that QoS measurement techniques evolve. The limitation of QoS is that it doesn’t account for the relationship between the end user and the technology. QoS, alone, simply cannot factor for end user satisfaction, including the effect of large audio or video level variations.

QoS is useful for measuring technical performance, but it only tells part of the network performance story.

Enter Quality of Experience

Just as marketers have moved away from simple technical metrics such as open rate and embraced the more holistic approach of monitoring the overall customer experience, IT teams are doing the same by focusing on QoE.

With QoE, the end user’s overall happiness or frustration with the network service experience is the litmus test for successful network performance. QoE looks at the impact of the network behavior on the end user, a fuzzier domain where certain network imperfections go unnoticed but others may render an application essentially useless. For example, a 5% packet loss might have a negligible impact on a cloud-based CRM system, while 0.5% packet loss can result in a data throughput reduction of >30%. A 100 millisecond delay could destroy the utility of a connected device operating in the field, such as a car sensor and 500 micro-seconds is the maximum delay for ultra-low latency services on 5G.

QoE achieves its goal by looking at the information within the data sent over the network, not just the efficiency of data transport across the network itself. For a VoIP call, for instance, QoE might look at echo, conversational quality, audio level and imperfections.

This level of quality control requires better network traffic analysis, with increased efficiencies and metadata collection algorithms that gather the key performance indicators while minimizing the amount of data that has to be stored. Advances in automation and artificial intelligence have made that attainable.

How to use QoE

Effective QoE management requires a combination of active and passive network traffic monitoring mixed with automation and real-time analysis.

First, IT teams should actively monitor traffic injected into the network that can test a large number of packets for key performance indicators. This should be combined with passive monitoring that analyzes every packet, looking at overall traffic characteristics.

This trove of network performance data then should be fed through platform that can analyze both passive and active data regardless of the source to detect for network behavior and troubleshoot performance variables on-the-fly. With this feedback loop, IT teams can respond to performance degradations that affect end user QoE.

While technically complex, the good news is this technology already exists. Accedian’s Skylight is a cloud-native networking and performance management platform that provides the granular, end-to-end traffic monitoring needed for QoE management, as well as the AI-driven analytics required for real-time network adjustment. It monitors and analyzes traffic from Layers 2 to 7, and across all application components.

So while QoS is gold standard for network performance management, it must be combined with QoE – and with good reason. The combination of QoS and QoE takes a much more holistic look at network performance and the end user, focusing on real world network outcomes. Bringing QoS and QoE together is truly the best of both worlds.