XDP

There is a lot happening on the XDP front in the Linux kernel these days. This presentation provides a good overview.

I love the idea that eBPF is becoming a policy language for the kernel.

BBR Congestion Talk is Online

A talk describing Google’s new TCP congestion control algorithm, BBR, is now online.

Such a beautiful and simple solution to a long standing problem. This one of those situations when you have to wonder why this wasn’t done before.

On a related note, it’s interesting how BBR separates the retransmission and congestion control (rate) logic. There is a section in An Engineering Approach to Networking where the author specifically calls out that it’s easier to solve both problems if they are considered separately vs. using the retransmission window size to control the rate as most TCP congestion control solutions do. This struck me as very interesting and I’m excited to see it demonstrated by sch_fq and BBR now.

History of SDN-like approaches

I stumbled across an interesting paper called The road to SDN: an intellectual history of programmable networks (ACM DL link) this morning. It’s good to place current trends in historical context especially while keeping RFC 1925 Rule 11 in mind.

The concept of active networking is particularly intriguing to me. Could eBPF be the instruction set for a revival in this area? This may not make sense on a per-packet basis but perhaps for larger PDUs/messages?