Both Bungie and 343 have done an admirable job (well, compared to other devs) about explaining their network infrastructure etc. Back in the day they did a big talk about how their matchmaking in Halo2/3 worked that I think to this day is still one of the best methods of learning when you're not in the industry yet. I can't recall what it was called though: might be the "Chris Butcher - Recreating the LAN Party Online: The Networking and Social Infrastructure of Halo 2" GS talk but I can't listen right now to check
Along these lines is the venerable TRIBES Engine Networking Model whitepaper. It was so good, it was shipped as part of the XDK for a decade. I believe Bungie even leaned on it quite a bit when creating their networking stack.
https://www.gamedevs.org/uploads/tribes-networking-model.pdf
Disclaimer: I work at Microsoft Game Studios, but this comment reflects my own opinions.
Only semi-related, but there was a recent excellent, short podcast interview series with one of Halo 2's multiplayer designers: https://smarturl.it/H2Pod
And similar to my sibling comment, mostly for anyone else browsing through - the comments on this recent HN post have a lot of resources about game dev stuff in general, which might be of interest (though I also cannot promise directly related X) ): https://news.ycombinator.com/item?id=31084779