Current flow-control scheme for IMPSYS
A short BBN note saying RFC 442 on IMP flow control is mostly accurate but points to better official sources.
Walden, D.C., "Current flow-control scheme for IMPSYS", RFC 449, DOI 10.17487/RFC0449, January 1973, <https://www.rfc-editor.org/info/rfc449>.
@misc{rfc449,
series = {Request for Comments},
number = 449,
howpublished = {RFC 449},
publisher = {RFC Editor},
doi = {10.17487/RFC0449},
url = {https://www.rfc-editor.org/info/rfc449},
author = {D.C. Walden},
title = {{Current flow-control scheme for IMPSYS}},
pagetotal = 1,
year = 1973,
month = jan,
} RFC text
Network Working Group Dave Walden RFC # 449 BBN-NET NIC # 14133 Jan. 6, 1973 Updates RFC 442 The Current Flow-control Scheme for IMPSYS. While Vint's notes on IMPSYS flow-control from the March 16, 1972, meeting (RFC 442) seem reasonably accurate and while he does cite our Quarterly Technical Report #13, he might have done better to cite BBN's two formal publications 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 particularly important reading for NCP programmers - things have recently changed somewhat. The inter-IMP acknowledgement mechanism, described in the last section of Vint's RFC 442, is also described in reference 1 and an almost identical mechanism is described in Appendix F of reference 2. The acknowledgement is of only intellectual interest to most Hosts as it is transparent to network users. However, the description in reference 2 is of vital interest to so-called Very Distant Hosts. [ This RFC was put into machine readable form for entry ] [ into the online RFC archives by Alex McKenzie with ] [ support from GTE, formerly BBN Corp. 9/99 ]
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§1A Correction to RFC 442
RFC 449, by Dave Walden of BBN, comments on RFC 442, Vint's notes on IMPSYS flow control from the March 16, 1972 meeting. Walden says those notes are reasonably accurate and that they do cite BBN's Quarterly Technical Report #13.
He adds that he might have done better to cite BBN's two formal publications on the flow-control scheme.
The note says the earlier write-up was fine, but there are better official books to read.
§2The Two Publications
The two recommended sources are a paper by McQuillan et al., Improvements in the Design and Performance of the ARPA Network, in the AFIPS 1972 FJCC proceedings (pp. 741-754), and BBN Report 1822, Specifications for the Interconnection of a Host and an IMP, December 1972 Revision, section 3 (pp. 17-35).
The note calls the second one particularly important reading for NCP programmers, because things have recently changed somewhat.
Two official documents are named. The second one matters most for people writing the programs that talk to the network, because the rules changed a little.
§3The Inter-IMP Acknowledgement
The inter-IMP acknowledgement mechanism, described in the last section of RFC 442, is also described in the first publication. An almost identical mechanism appears in Appendix F of BBN Report 1822.
The note says this acknowledgement is of only intellectual interest to most Hosts, since it is transparent to network users. The description in Report 1822 is, however, of vital interest to so-called Very Distant Hosts.
Most computers never see the behind-the-scenes receipts between network boxes. A few far-away ones need to know about them.