  During the COVID-19 pandemic the Comcast network performed well in response
to unprecedented changes in Internet usage and video communications
applications that are sensitive to network latency have exploded in popularity.
However, in today's typical networks-such as a home network-those applications
often degrade if they are sharing a network link with other network traffic.
This is a problem caused by a network design flaw often described using the
term 'buffer bloat'. Several years ago, Comcast helped to fund research and
development in the technical community into new Active Queue Management (AQM)
techniques to eliminate this issue and AQM was later built into Data Over Cable
Service Interface Specification (DOCSIS) standards.
  Just prior to the pandemic, Comcast also deployed a large-scale network
performance measurement system that included a latency under load test. In
addition, Comcast happened to deploy two otherwise identical cable modems; one
with upstream AQM enabled, and the other without. This fortuitous confluence of
events has enabled Comcast to perform a comparative analysis of the differences
between cable modem gateways using AQM with those that lack that enhancement,
at a unique level of scale across many months of time and millions of devices.
  The data reveals significantly better upstream latency under load performance
when AQM is used. For the device with AQM, most of the latency under load tests
resulted in 15-30 milliseconds of latency. In comparison, the device without
AQM averaged roughly 250 milliseconds of latency, between 8-16 times higher, a
highly significant difference to the end user quality of experience. These
large-scale measurement comparisons should provide additional data to justify
accelerated deployment of AQM in DOCSIS and other Internet Service Provider
networks and user-purchased home network equipment.

Networking and Internet Architecture