How Preseem Identifies Problems


Preseem’s existing Quality of Experience (QoE) monitoring and optimization metrics, like TCP Round Trip Time and Retransmision, have proven to provide excellent value in helping to identify where problems occur in the networks of Wireless ISPs (WISPs). Since using Preseem, hundreds of WISPs have been able to understand where and when bottlenecks occur in their networks.

The next step in Preseem’s evolution is figuring out why these problems occur in the first place. To accomplish this, Preseem relies on the billions of metrics captured in its dataset and advanced algorithms. And the first step of this process is already underway!

Prefer watching a video? If so, click here to watch Gerrit Nagelhout, CEO of Preseem, walk you through the evolution of Preseem in just 10 minutes.


The Preseem QoE Monitoring Evolution


In October, Preseem released it’s real-world Access Point (AP) Comparisons feature, which allows WISPs to see how their APs are performing relative to their peers. This comparison combines real-world performance metrics from Preseem’s customer base, allowing WISPs to identify under-performing or overloaded APs.

Then, in February, Preseem began collecting and analyzing metrics directly from APs via SNMP and other management interfaces. The introduction of these AP metrics has made it even easier for WISPs to identify the root cause of AP-related QoE problems. These metrics include Frame Utilization, Multiplexing Gain, RF Packet Drop, and RF Packet Retransmitted for Cambium APs; and Airtime, AirMax Capacity/AMC, and AirMax Quality/AMQ for Ubiquiti APs.

To see a full list of AP models and the corresponding metrics that Preseem collects from them, click here.


How Preseem Explains Overloaded APs, Backhaul Issues,

Interference, and More

Evolution of Preseem - Ubiquiti Rocket 5AC PTMP AP Graphs
The diagram above displays some of the metrics that Preseem collects from APs. In this case, we’re looking at a Ubiquiti Rocket 5AC PTMP AP.

The top chart shows the average latency of all subscribers on the sector, the middle chart displays the airtime, and the bottom chart shows the downstream bitrate. The orange line on the bottom chart indicates the typical downstream bitrate that Preseem expects from this AP, based on the performance data that Preseem has collected from other Ubiquiti Rocket 5AC PTMP APs. When looking at the downstream bitrate, we can see that there is room for improvement as the AP appears overloaded.

Referring to the middle chart, while airtime generally follows throughput, the data we see here is not indicative of any issues. Instead, where the problem becomes apparent is in the top chart, showing latency. Here, the sharply increased latency, together with reduced throughput, immediately indicates that the AP is underperforming. As a result, we can conclude that interference was the cause of the spike in latency.

In this case, knowing why the problem occurred allowed the WISP operator to make an informed decision about how to combat it. For instance, simply changing the channel and upgrading to an AP that could better handle noise, like the Ubiquiti Rocket Prism 5AC Gen2, resolved the issue.

Evolution of Preseem -  Cambium ePMP 1000 AP Graphs
The above graphs show some of the metrics Preseem collected on a Cambium ePMP 1000 AP, and will help us understand why subscribers are experiencing a poor QoE on this network.

Starting with the graph on the top left, we can see that latency is elevated. The chart on the lower left shows downstream bitrate, with an orange line that indicates the typical downstream bitrate of other Cambium ePMP 1000 APs. In this case, the downstream bitrate levels initially appear close to the orange line, indicating fine performance. However, the chart on the top right shows frame utilization to be at 100%! Moreover, on the bottom right, the chart shows that the AP is dropping packets.

Now let’s take a look at the vertical, yellow line on each graph. This line indicates the point at which there were network backhaul issues for about an hour. Furthermore, you can see that during this time latency increased significantly, whereas downstream bitrate, frame utilization, and RF packet drop all decreased substantially.

Taken all together, these metrics indicate that the an underlying backhaul problem was the root cause of this network’s poor QoE performance.


Looking Ahead: The Next Step in the Evolution of Preseem


Preseem’s QoE monitoring and optimization metrics have long enabled WISPs to detect and correct problems in their networks. Moreover, Preseem’s real-world AP comparisons, alongside Preseem’s ability to collect and analyze metrics directly from APs, have now made it even easier for WISPs to not only recognize issues, but figure out why these problems are occurring in the first place. And yet there’s still more to come from Preseem!

We expect to make Preseem even better by pulling in subscriber module information and presenting it in an easily comprehensible, actionable format. In addition, we’re looking at expanding the existing AP Score we provide by including more factors in it for consideration—saving you the time of having to figure out all of the details by yourself. And that’s not all! We’re also planning on creating a Subscriber Score, giving you proactive insights into subscribers that are experiencing issues on your network. With these upgrades, and even more in the pipeline, Preseem will continue to be the premier QoE monitoring and optimizations solution for WISPs!


Interested in adding Preseem’s QoE Monitoring and Optimized Shaping to your network?
Try Preseem today for free!

Still not sure that Preseem is right for you? Talk to a QoE specialist to see Preseem in action and learn more about how it can help your business. Book a call here!


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Preseem + Sonar SoftwareAPI Screenshot