RFC 1 (rfc1) - Page 2 of 11
Host Software
Alternative Format: Original Text Document
RFC 1 Host Software 7 April 1969
IV. Initial Experiments
Experiment One
Experiment Two
Introduction
The software for the ARPA Network exists partly in the IMPs and
partly in the respective HOSTs. BB&N has specified the software of
the IMPs and it is the responsibility of the HOST groups to agree on
HOST software.
During the summer of 1968, representatives from the initial four
sites met several times to discuss the HOST software and initial
experiments on the network. There emerged from these meetings a
working group of three, Steve Carr from Utah, Jeff Rulifson from SRI,
and Steve Crocker of UCLA, who met during the fall and winter. The
most recent meeting was in the last week of March in Utah. Also
present was Bill Duvall of SRI who has recently started working with
Jeff Rulifson.
Somewhat independently, Gerard DeLoche of UCLA has been working on
the HOST-IMP interface.
I present here some of the tentative agreements reached and some of
the open questions encountered. Very little of what is here is firm
and reactions are expected.
I. A Summary of the IMP Software
Messages
Information is transmitted from HOST to HOST in bundles called
messages. A message is any stream of not more than 8080 bits,
together with its header. The header is 16 bits and contains the
following information:
Destination 5 bits
Link 8 bits
Trace 1 bit
Spare 2 bits
The destination is the numerical code for the HOST to which the
message should be sent. The trace bit signals the IMPs to record
status information about the message and send the information back to
the NMC (Network Measurement Center, i.e., UCLA). The spare bits are
unused.
Crocker