[rfc-i] What obsoletes what?

[Brian E Carpenter <[e-mail]>]

A few days ago I wanted to find out if there are precedents for an Informational RFC obsoleting a standards track RFC.

TL;DR: RFC 6248 obsoleted a BCP (RFC 4148), and RFC1574 and RFC1575 *both* obsoleted a PS (RFC 1139).

In the course of discovering this, I wrote a bit of code to extract the data from the RFC index, and here's a summary if anyone is interested.

The index contains 1330 obsoleted RFCs.

In 741 cases, the obsoleting RFC has the same status as the obsoleted RFC.

For the others, here are the details. For example, there are 13 Internet Standard documents that obsoleted an RFC of status Unknown. (The diagonal is intentionally zero.)

     UNK HIS PS  DS  IS  BCP EXP INF   <-- new status
UNK 000 011 007 007 013 000 002 003
HIS 001 000 019 000 002 003 001 027
PS  000 006 000 100 028 003 000 001
DS  000 001 010 000 035 000 000 000
IS  000 000 002 001 000 000 000 000
BCP 000 000 000 000 000 000 000 001
EXP 000 007 061 001 000 002 000 006
INF 000 004 032 001 001 018 000 000
|
|___old status


The code is at https://github.com/becarpenter/misc/blob/main/obsol.py

Regards
    Brian Carpenter