WISP Access Point Oversubscription Ratio Insights

Title image for WISP Access Point Oversubscription Ratio blog

by | March 2, 2020 | Networking

Access Point Oversubscription Ratio Insights from the Fixed Wireless Network Report

Welcome to the fifth and final entry in Preseem’s Know Your WISP Network blog series! Based on Preseem’s Fixed Wireless Network Report, the blogs in this series present the real-world experience of fixed wireless subscribers, networks, and equipment in an easy-to-comprehend format.

Our previous installment looked at WISP access point (AP) latency, examining rates experienced across the overall AP market while also comparing rates of latency across individual AP models. Over the past few weeks the Know Your WISP Network blogs have also examined a variety of fixed wireless topics, including insights on subscribers, the overall AP market, and AP throughput.

An important metric that we’ve yet to explore is access point oversubscription ratio. So let’s dive in!

Today’s analysis will look at WISP access point oversubscription insights that answer the following questions:

  • How is oversubscription ratio calculated?
  • What is the oversubscription ratio of access points across the entire WISP market?
  • How does the oversubscription ratio compare between individual AP models?

Calculating the WISP Access Point Oversubscription Ratio

Before we begin analyzing the results of our investigation, it’s important to know how we got these results. This requires understanding what metrics were collected in order to calculate the oversubscription ratio of numerous access points.

We begin by taking a look at the formula used in order to calculate the ratio of access point oversubscription:

Formula for access point oversubscription ratio

Now that we know the formula to calculate the oversubscription ratio of an AP, we can see how it’s applied in practice by using the following example: If a WISP has sold twenty 10Mb/s plans on an access point that typically achieves 50Mb/s, what is its oversubscription ratio?

Calculation of AP oversubscription ratio for specific access point

In this case, the oversubscription ratio is 4. Now that we know this, let’s move on to analyzing the findings of the latest Fixed Wireless Network Report.

WISP Access Point Oversubscription Ratio: Overall Market

In most networks, some amount of oversubscription is normal. For example, a wiring closet switch may have twenty 1G ports with a single 10G port to the core network. This results in a 2:1 (sum port rates/uplink port rate) oversubscription ratio. Internet provider networks are no different in this regard. No ISP can afford to provision enough bandwidth from the edge to the transit point for every subscriber to use their entire plan rate at the same time. The business model simply does not work. We’ve summarized our findings in the figure below, showing the percentage of APs that fall within various oversubscription ratios.

Graph showing access points by oversubscription ratio

By segmenting access points this way, the most typical oversubscription ratios become apparent. For instance, the graph above shows that over 44% of access points are between 1 and 2 times oversubscribed.

WISP Access Point Oversubscription Ratio: Individual Models

To narrow our focus, we also explored how oversubscription ratios compare across different AP models. Accordingly, the following figures demonstrate the variability of oversubscription between access point models.

Graph showing AP oversubscription ratio across Cambium and Ubiquiti models

As seen in the model-specific graphs, oversubscription distribution is relatively stable across many AP models, with the PMP 450m being an outlier. These results suggest that the 450m supports a much higher level of oversubscription compared to the other AP models studied.

While oversubscription in and of itself is not bad, it’s important to recognize that higher oversubscription ratios generally lead to lower subscriber throughput during peak. As a result, a higher oversubscription ratio normally leads to a poorer subscriber experience.

See how organizations within the fixed wireless industry are already using the insights contained in this year’s report. Read the Telecompetitor article here!

Do you want to know more about our method of data collection? Are you interested in seeing other fixed wireless insights?

Preseem’s Fixed Wireless Network Report contains 30 key fixed wireless stats spanning 26 pages. Best of all, it’s free!

Preseem is a one-of-a-kind Quality of Experience (QoE) monitoring and optimization platform, designed specifically for fixed wireless networks. Learn more or sign up for a free 30-day trial by booking a demo with us today!

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