RFC 21

Network Working Group                                            V. Cerf
Request for Comments: 21                                            UCLA
                                                        October 17, 1969

At UCLA on October 10, there was a network meeting attended by:

           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

Topics discussed:

        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)
    As informally communicated by Dave Wa

    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."

[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.]

    p. 13  "5 Regular with discard."

    This allows IMP systems to generate traffic which never actually
    reaches any Hosts since it will be discarded when it reaches the 
    top of the IMP-HOST queue in the destination Host's IMP.  The
    Network Measurement Center will make use of this feature.

    p. 13  Message type 6 is no longer assigned, and message type 10
    is really in octal so is actually type 8.  Types 9-15 are unassigned.

    p. 17   Type 10 is really type 8.

2.  Revisions to NWG/RFC 11

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

3.  George Gregg of UCSB will publish NWG/RFC 23 concerning the
    transmission of multiple control messages over control links.