On 2020-12-12 1:11 p.m., Rich Brown wrote:
Google Alerts for "bufferbloat" pointed to this talk at Stony Brook
University in New York State:
Dates: Thursday, December 17, 2020 - 12:30pm to 2:00pm (US EST: UTC-5)
Location: Zoom - contact [email protected] for Zoom info.
Abstract: BBR is a new congestion control algorithm and is seeing
increased adoption especially for video traffic. BBR solves the
bufferbloat problem in legacy loss-based congestion control algorithms
where application performance drops considerably when router buffers
are deep. BBR regulates traffic such that router queues don’t build up
to avoid the bufferbloat problem while still maintaining high
throughput. Though BBR is able to combat bufferbloat for sustained
steady traffic such as large file downloads, our analysis shows that
video applications experience significantly poor performance when
using BBR under deep buffers. In fact, we find that video traffic sees
inflated latencies because of long queues at the router, ultimately
degrading video performance.
In this talk, I will present our work on the interaction between BBR
and streaming video. We investigate the relationship between network
metrics such as delay and delivery rate during the video run and the
quality of subsequent video segments. However, we find only weak
correlations, suggesting that another factor is at play. Our empirical
investigation reveals that BBR under deep buffers and high network
burstiness severely overestimates available bandwidth and is slower to
converge to steady state, both of which result in BBR sending
substantially more data into the network, causing a queue buildup.
This elevated packet sending rate under BBR is ultimately caused by
the router’s ability to absorb bursts in traffic, which destabilizes
BBR’s bandwidth estimation and overrides BBR’s expected logic for
exiting the startup phase.
Original Notice:
https://www.cs.stonybrook.edu/Rebecca-Drucker-Research-Proficiency-Presentation-Investigating-BBR-Bufferbloat-Problem-DASH-Video
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Ms Drucker is in their PhD program, as you might guess, mentioned in
https://www3.cs.stonybrook.edu/~csgso/eboard.html#
Rebecca is a 3rd year PhD student working in the NetSys lab with
Professor Aruna Balasubramanian. Her research involves optimizing web
performance at the application and transport layers, particularly for
streaming video. She enjoys hiking, cross stitching, and watching true
crime television shows.
--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
[email protected] | -- Mark Twain
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