Protocol Implementation - see W Rich Steven's very excellent series of books, TCP/IP Illustrated (especially volume 2!). As well as a structured walk through of Berkeley Unix kernel source code, there's lots of useful lessons in there - the Linux code is "interesting", but less transparent as to purpose in my opinion (e.g. see my book on the Linux code from a while back).
Other useful protocol implementation ideas (in terms of managing concurrency, buffering, and other patterns) are distributed throughout lots of papers. Some early RFCs cover tricks used to do small fast data structures for various things. Model checking protocol implementations was an important contribution from groups here, notably the Network Semantics project, which did a full scale model of TCP and the socket layer!
In terms of the huge protocol TLA (Three Letter Acronym) soup out there, wikipedia is probably your best friend! basically, if a million monkeys typed for a million year,s they'd still not have all the ISO, ITU, IETF acronyms, even if they had shakespeare down pat.