[NetDev-People] 0x14: nutsnbolts, Evaluation of TCP Congestion Control Algorithms over mmWave (5G) Mobile Networks

Jamal Hadi Salim jhs at mojatatu.com
Wed Feb 5 13:51:26 UTC 2020

As the commercials say - 5G(Fifth Generation) networking is here.
Why is that a big deal?
One appealing aspect: How do you like getting multi-gigabit
bandwidth to your mobile device(s)?

How does that work?
For the first time in commercial mobile networking history
a vast untapped spectrum has been made available for mass user
consumption in the millimeter wave length range; in the 5G world
it is refered to as "mmWave".
The spectrum in mmWave links makes possible the multi-Gbps data rates
on the 5G cellular networks.

The problem with mmWave links is they are, like most high-frequency
signals, susceptible to blockage. Basic obstructions like trees, snow,
rain, buildings, etc interfere with the signal. A technique called
beamforming helps but doesnt solve the problem entirely.

To put this in context:
Think of having a link that is very high speed but is constantly
fluctuating in capacity. Then the question is: "How does TCP congestion
control work in this kind of setup?"

In this talk Feng Li, Jae Won Chung and Jamal Hadi Salim[1]
will present results of a study to evaluate how various Linux TCP
congestion control algorithm implementation fare over mmWave links.
The authors claim this is _the first ever_ such study on a real
commercial 5G network! The study was carried on the Verizon 5G
deployment network.

Feng et al will present data on comparing popular TCP congestion
control algorithms, including NewReno, Cubic, BBR and BBRv2
(prepatch) etc. The results show that the performance of TCP on
mmWave links is still highly dependent on the combination of TCP
algorithm and socket buffer sizes.

Without a doubt mmWave links impose new challenges on future transport
layer design and the authors hope this talk will incentivize
more discussions in the community.

[1] Refered to in the third person.

More info:

Reminder, registration is now open and early bird is still in effect.


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