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Comment by Aromasin | Hacker News Reader

I took a strange career jump recently into FPGA engineering with a focus on Ethernet. It's been a fun journey, which culminated in me finally designing my own Hard MAC IP and sending a packet over some custom PHY IP. I'd highly recommend it for those looking to try a "Hard Mode" version of this challenge. I feel like networking is very abstracted from users, so understanding how Ethernet cards, modems and switches put together and pull apart sections of packets, and how the PHY/PCS recovers signals over a link was really valuable.

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A while ago (about a decade, oh no) I was involved in a project which did direct TCP from an FPGA. As part of debugging and verification, I made it so you could hook up the simulated version from Verilator to the Linux TUN/TAP device, enabling you to connect directly into it from the developer machine without tying up the physical hardware (which we only had one of). Fun project.

Renode offers a similar approach, one could even route all stimulated packets into Wireshark. It's really powerful when it works

Sounds fun! Were you already familiar with networking/Ethernet when you started? If not, which resources - if any - did you use to get a broad overview of everything involved? My knowledge of networking ends at a very basic understanding of the OSI model, and I am very interested in taking a deep dive into the networking world.

Wireshark, plus a book about using Wireshark. I have "Wireshark Network Analysis", which looks to be shockingly expensive right now - to be fair, it's worth whatever price, but maybe not while you're speculativey getting your toes wet - and there are others out there. I am nowhere near an expert (I've only worked through about 1/3 of that book - just enough to solve the problem I had at the time!), but that's what's taught me what I know, and I know can take me further.

I'll tell you how I learned, I got thrown head-first into a network switch design. I knew almost nothing about networking.

The most useful resource while I was learning was RFC1812 "Requirements for IPv4 Routers" [1]

Its an ancient document written the same year I was born detailing how future routers should be built on this relatively new thing called the internet. The language is highly approachable and detailed, often explaining WHY things are done. It is an awesome read.

To be honest you don't need to finish it. I only read the first few chapters, but I googled EVERYTHING I did not understand. The first few paragraphs took several hours. Talk to LLM's if you need a concept explained. Take notes. In a few days you'll have a very solid grasp.

[1] https://datatracker.ietf.org/doc/html/rfc1812

I wasn't at all, to be honest. I joined a multidisciplinary team and they were short an Ethernet SME. I said I'd be happy to just in feet first and learn, as I was desperate to get into anything and everything FPGAs at the time, having become bored by the CPU world I resided before. Mostly I learnt everything through building stuff using our User Guides. Everything else was just reading; the Ethernet spec, random Cisco stuff online, Wikipedia, etc. I just searched for any word or acronym I didn't understand, and read up on it (meaning of 64/66b encoding, PCS vs PHY vs MAC, PTP, OTN, FlexE, FEC, ANLT, and so on). Once you get passed the TLAs, it's actually pretty simple (except for PTP - that's the bane or my working life at the moment).

Are you me? This is exactly my job at the moment. Send me an email if you'd like to compare notes

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