RFC 21

RFC 21 🎀 Network Working Group Notes

Okay bestie, the header is giving: Network Working Group, Request for Comments 21, written by V. Cerf at UCLA, dated October 17, 1969. ✨ There's no category listed, and the title block doesn't say what it obsoletes or updates. 🌸

At UCLA on October 10, there was a network meeting. The people in the room were:

           SDC                             UCLA

        John Kreznar                    Vint Cerf
        Dick Linde                      Steve Crocker
        Marty Bleier                    Jon Postel
        Bob Long                        Michel Elie


           UCSB

        Ron Stoughton
        Nancy O'Hara
        George Gregg

The main topics on the agenda 💅:

1. Revisions to BBN memo 1822
2. Revisions to NWG/RFC 11
3. Transmission of multiple control messages

1. Changes to BBN Memo No. 1822 (underlined) 🦋

Okay so this one is about changes to BBN Memo No. 1822, which were informally shared by Dave Wa. The original text is shown below, and it's wild how many details matter here. 😭

p. 11 "The IMP program can handle up to 63 active transmit links
and 63 active receive links at a time.  If the Host attempts to
send a message on a new link when 63 active transmit links already
exist, a "Link Table Full" message will be sent from the IMP to
the Host, and the message will be discarded."

p. 11 "1.  Any link that is not used for a period of 26 seconds
   will have its entry automatically deleted by the IMP program."

Then there's a little debate between Cerf and Crocker about that deletion rule, and it's literally so good 🍿:

[Cerf:  How about deleting only if the transmit link table is full?

 Crocker:  No, because there is no other way for links to be deleted
           so they would always tend to accumulate.  Furthermore,
           the table at one site may be full while another site may
           not be.]

Next up, on p. 13 there's this entry:

p. 13  "5 Regular with discard."

This lets IMP systems generate traffic that never actually reaches any Hosts 🫠. It gets discarded when it reaches the top of the IMP-HOST queue in the destination Host's IMP. The Network Measurement Center is going to use this feature.

Also on p. 13, message type 6 is no longer assigned 🙈. Message type 10 is really in octal, so it's actually type 8. Types 9-15 are unassigned.

And p. 17 says the same thing again: Type 10 is really type 8. 💜

2. Revisions to NWG/RFC 11 🌈

This memo got obsoleted by developments at UCLA and by discussions with other nodes. NWG/RFC 22 has some of the major changes ✨. An updated version of NWG/RFC 11 is coming soon.

3. Transmission of Multiple Control Messages 🧚

George Gregg of UCSB is going to publish NWG/RFC 23 about the transmission of multiple control messages over control links. Iconic behaviour from George 👑.