How Do I Use Access Point Shaping?

Preseem Access Point shaping enables operators to maintain a high quality of experience (QoE) when an Access Point is overloaded.

When network elements such as Access Points reach their capacity, the subscriber quality of experience (QoE) degrades greatly. This occurs because these devices implement buffering with simple FIFO queues which increase latency and eventually loss when the outgoing link reaches capacity. Preseem's shaping makes use of modern active queue management (AQM) techniques which do not have this behavior and deliver a great subscriber experience even when the link is busy. Preseem's traffic management can be deployed on one or both of the subscriber plan and the Access Point levels.

On the subscriber level, we refer to this QoE optimized plan enforcement. This feature ensures that a subscriber hitting the limit of their own plan continues to get a good experience. Concretely, this solves problems like games or VoIP calls not working when other members of the household watch streaming video or do a big download.

A subscriber hitting the limit of their own plan is probably the most common bottleneck in the network. Another common location is at the Access Point itself. Preseem's Access Point shaping enables the operator to set a bandwidth limit for the Access Point as a whole and within that apply the intelligent AQM algorithms and share the traffic between subscribers. The rate to shape to can be configured directly in Preseem when viewing at an individual Access Point.

When first enabling Access Point shaping Preseem recommends one of two approaches:

  1. If the Access Point is congested, set the rates to 10% below the observed peak rates. This should bring the capacity below the pain threshold as measured by latency and other metrics such as TCP retransmisions. If no improvement is observed, further reduce the limits another 10%.
  2. If the Access Point is not currently congested, the Access Point comparisons as displayed by the orange line on the charts provide the best starting point. The Access Point comparisons are built from data collected from hundreds of customers and tens of thousands of Access Points and provide a very robust indication of what the Access Point should be capable of in the real world (vs marketing numbers). For more real world Access Point performance information, see our Fixed Wireless Report.

Requirements

Access Point shaping requires Preseem 1.6 or greater (preferably the newest release) configured with the TwoLevelMQ policy. This has been the default for new installs for some time. Preseem support can verify that your node is ready for Access Point shaping if you have any concerns.