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toke

Toke Høiland-Jørgensen

New blog post: The Big FIFO in the Cloud

I was recently made aware of an interesting issue, which appears to be a pretty fundamental property of the departure time-based traffic shaping that is used by BPF-based data planes, such as in the Cilium Bandwidth Manager.

It’s one of those things that seem really obvious in hindsight, but that no one thought about beforehand (apparently; or at least I didn’t). So I thought I’d write up an analysis to explain what’s going on and why it is a problem.

https://blog.tohojo.dk/2023/12/the-big-fifo-in-the-cloud.html

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dermoth@noc.social

Thomas Guyot-Sionnest

Reply to @toke

@toke Nice read. Many years ago I hand-configured hfsc on my home router with very good results. The base concepts for traffic shaping were confusing to me then, and I haven't looked much into it since.

I need to understand things from the bottom up, understand from the lower level. Is there documentation you'd recommend to understand how traffic shaping is implemented in Linux. All the guides I read back then focused more on the configuration than core concepts.

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