RFC 449

The Current Flow-control Scheme for IMPSYS ✨

okay so the title block first 🎀: this is RFC 449, written by Dave Walden from BBN-NET (NIC # 14133) for the Network Working Group, dated Jan. 6, 1973. It updates RFC 442 💅

Vint's notes on IMPSYS flow-control from the March 16, 1972, meeting (RFC 442) honestly seem reasonably accurate 🌸 and while he does cite our Quarterly Technical Report #13, he could have done even better by citing BBN's two formal publications that are actually relevant to the IMPSYS flow-control scheme 📚:

1. McQuillan et al, Improvements in the Design and Performance of the ARPA Network, Proceedings AFIPS 1972 FJCC, pp. 741-754.
2. BBN Report 1822, Specifications for the Interconnection of a Host and an IMP, December 1972 Revision, section 3, pp. 17-35.

Reference 2 is seriously required reading for NCP programmers 🫶 because things have recently changed somewhat. 👀

The inter-IMP acknowledgement mechanism, described in the last section of Vint's RFC 442, is also covered in reference 1, and an almost identical mechanism shows up in Appendix F of reference 2 ✨. Honest tea: the acknowledgement is mostly of intellectual interest to most Hosts, since it's transparent to network users 🙈. But the description in reference 2 is of vital interest to so-called Very Distant Hosts 🧚💜

bestie, don't skip reference 2 if you're a Very Distant Host. it's giving main character energy 👑

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