RFC 17 (rfc17) - Page 1 of 4
Some questions re: Host-IMP Protocol
Alternative Format: Original Text Document
Network Working Group J. Kreznar
Request for Comments: 17 SDC
Category: Informational 27 August 1969
Some Questions Re: HOST-IMP Protocol
1. Automatic deletion of links, as indicated in BBN 1822, page 11,
seems bad:
a) Link use may be dependent upon human use of a time share
terminal - indefinite time between messages.
b) Program using link may be slow due to:
i) Busy HOST (many jobs)
ii) Much local I/O and/or CPU time between messages - is it
that, if a HOST's user fails to use a link for 15 seconds,
the HOST network program must generate a dummy message
merely to keep the link open?
2. Steve Crocker, HOST Software, 1969 Apr 7, asks on page 2: "Can a
HOST, as opposed to its IMP, control RFNM's?" BBN, Report No. 1837,
1969 Jul, says on page 2: "The principal function of the (IMP)
program...includes...generating of RFNM's..." What if an IMP
generates an RFNM and then discovers it cannot, for some reason,
complete timely delivery of the last received message to its HOST?
This seems especially pressing since I don't recall seeing anywhere an
IMP constraint upon HOSTs that they must accept incoming messages
within some specified maximum time.
3. A HOST has to be prepared to repeat transmissions of a message
into network (see, e.g., Page 17, BBN 1822) therefore why the
special discardable NOP message (Page 12, BBN 1822).
4. "Arbitrary delays," middle paragraph, page 23, BBN 1822, seems
inconsistent with automatic link deletion questioned in 1 above.
Normally the times involved differ by many orders of magnitude but a
high priority non-network HOST responsibility could delay next bit for
a long time.
1. Abhi Bhushan, Proj. MAC 10. Sal Aranda, SDC
2. Steve Crocker, UCLA 11. Jerry Cole, "
3. Ron Stoughton, UCSB 12. John Kreznar,"
4. Elmer Shapiro, SRI 13. Dick Linde, "
5. Steve Carr, Utah 14. Bob Long, "
6. John Haefner, RAND 15. Reg Martin, "
Kreznar & Kahn