NWG/RFC#469                             Michael D. Kudlick MDK (SRI-ARC)
NIC 14798                               8-MAR-73

                      Network Mail Meeting Summary

Introduction

   The purpose of this RFC is to briefly summarize, from the NIC's
   viewpoint, the principal conclusions reached at the Network Mail
   Meeting held Friday, February 23 1973, at SRI-ARC.

      Please refer to RFC #475 (NIC 14919) for Abhay Bhushan's
      comprehensive summary of the issues discussed at the meeting.

      There is no major disagreement between the present RFC and RFC
      #475.

      RFC #453 (NIC 14317) contains background information on the
      meeting.

      RFC #479 (NIC 14948) describes what the NIC would like to see
      included in the File Transfer Protocol for Network Mail purposes,
      and also describes briefly how the NIC would use the information.

   The present RFC is organized as follows:

      Conclusions
      Discussion
      Attendees

Conclusions

   Additional FTP mail requirements were decided upon.  These would be
   implemented as a new mail command, with the following subcommands:

      TO

         This field is explicitly allowed to contain multiple
         addressees, with a standard syntax:  user@host.

      FROM

         This field provides a return-address for notification of
         undeliverable mail, as well as a clearcut identification of the
         sender for the recipient's information..

      AUTHOR

         This field denotes the author of the mail.  There may be
         multiple authors

      TITLE
         The "title" (i.e. subject) of the mail is to be terminated by
         period carriage return.

      ACKNOWLEDEGMENT  success / failure (time out) / normal

         For use by the intermediate host, probably the NIC in most
         cases, to tell the sender what happened to his attempt to send
         mail.  (Note:  "normal" wasn't defined.)

      RECORDED  jnumber / null

         Note: "jnumber" is the pre-assigned accession number (NIC
         number), to be used when known.

         The "RECORDED" subcommand provides for the option of having the
         mail recorded.  Information given with this subcommand would be
         recognized at the NIC. Options are:

            to be recorded (in NIC journal) only,
            to be recorded and distributed,
            to be distributed only.

         This field would also be used to inform the recipient that the
         mail has been recorded.

            (In retrospect, it may be preferable to have a separate
            command to inform the recipient of this fact, but no
            decision on this was made at the 23-Feb-73 meeting.)

      TYPE  long / urgent / ordinary

         This allows the recipient site to take whatever action it
         thinks appropriate in storing the mail.

      TEXT / FILE / CITATION

         TEXT

            This field is for the text of the mail message.

      FILE

         The purpose of the field is unclear to me.  Does it contain a
         machine readable pointer to the file that the sender wishes the
         recipient to read?

      CITATION

         This field is a person-readable pointer to the file that the
         sender wishes the recipient to read.  When the citation command
         is used, no mail is sent other than the citation.


Discussion

   Introduction

      The key aspects in the solution are:

         1) It is based on FTP.

         2) It uses the NIC without requiring direct use of NLS.

         3) There is a mechanism for uniformity in the use of
         user identifications.

         4) There is a mechanism for recording the mail for
         later reference.

      These issues are covered in the discussion that follows.

New FTP Mail Subcommands

   TO

      Addressee Format

         The standard form of the address is:  user@host

         "User" may be an individual's last name; or it may be whatever
         other identification the recipient has chosen AND has made
         known to the rest of the network.

            If the intended host doesn't recognize the intended
            recipient's identification, then it sends back an
            "undeliverable" mail message to the sender's host.  It is up
            to the individual to keep the NIC informed of his wherabouts
            [sic]; otherwise, he may not get his mail on time.

      NIC Role

         The NIC need have no role at all for mail sent from point A to
         point B, whenever that mail is not to be recorded at the NIC.

         For mail that is to be recorded at the NIC, the RECORDED
         subcommand is to be used.

         Also, when the sender does not know the standard address of the
         recipients, he may use the NIC to obtain this information.

      Idents and Addresses

         The NIC will modify its identification files to include the
         "user@host" standard address for each individual.

            Sites may ask the NIC to translate from NIC Ident, or from a
            user's last name, to the standard address.  A query facility
            will be made available at the NIC to do the translation on
            request.  The translation service will also be available for
            "group idents".

            This service would be FTP-like, in term of the prootocol
            [sic] it accepts, but would not be within FTP itself.  A
            different server process would handle Ident translation
            requests.

            Translation will also be done at the NIC when the NIC is
            used as an intermediate point on the delivery route.

               The NIC could be an intermediate point for recording the
               mail as a NIC journal item, and for forwarding the mail
               to its ultimate destinations.  During this process, the
               NIC would translate from NIC idents to standard
               addresses.

      In the NIC ident files, provision already exists to specify
      hardcopy or on-line delivery of recorded (NIC Journal) mail.

            This provision will be extended to include a "network"
            attribute, which means "deliver the mail to the host of this
            person".

            The network attribute may be qualified by restricting all
            mail to be kept at the sender, with only a notification
            message actually mailed.

            Notification would be in the form of a citation giving "to",
            "from", "title", "date of submission", and "location of
            mail".

      TIP Users

         To enable TIP users to have access to the mail system, both for
         sending and receiving mail, it was suggested that some hosts
         will have to be the "home" site for these users (but no more
         than one "home" site per user).

         That is, an account that allows a TIP user to send and receive
         mail will have to be established at such a host.

            For the present, any TIP user can use the SRI-ARC system for
            his mail requirements.

         An alternate solution, that TIP's be equipped with a hardcopy
         device that is continuously available for printing mail, was
         discarded in favor of the above approach.

   FROM

      The "FROM" command in FTP, identifies the sender in "standard
      address" form.

         This will allow "undeliverable" mail notices to be sent back to
         the originator.

            The default condition is that the sender's host must retain
            the mail until it is "delivered" to the recipient's host.

               "Delivered"  means that the recipient's host has accepted
               the mail. It does NOT mean that the recipient has READ
               the mail.

            Alternatively, the sender may designate that an intermediate
            host store the mail.  Then the intermediate host has the
            responsibility of storing the mail until it is "delivered"
            to all intended recipients.

         The "ACKNOWLEDGEMENT" command will allow an optional, positive
         acknowledgement to be given to the originator of the mail (the
         "FROM" addressee), stating that the mail was delivered.

   AUTHOR

      The AUTHOR may be several persons. For recorded documents the
      authors appear separately in the index of authors, to facilitate
      searching for mail when an author is known, but the title and
      location of the mail are unknown.

   TITLE

      The TITLE field is especially useful for recorded mail, since
      indexes on key words in the title can be produced relatively
      easily, and facilitate searching for mail.

      For this reason, the title should be a succinct indicator of the
      contents.

   ACKNOWLEDGEMENT

      Acknowledgement of failure to deliver should be given to the
      sender.

         An optional, positive acknowledgement of successful delivery to
         the recipient's sitename will be given on request of sender
         (like U.S. CERTIFIED mail).

         No acknowledgement that the recipient actually saw the mail
         will be given (comparable to not having U.S. REGISTERED mail).

   RECORDED

      The concept of "recorded" mail is that a permanent record of the
      mail is kept centrally, to allow future references and re-readings
      of the mail to be made.

         For example, in the NIC Journal system, a record is kept of all
         the items entered into the Journal.  From this record, author,
         title-word, and NIC number indexes are produced to allow for
         references and re-readings.

         The key to retrieval of recorded Journal items is the use of an
         accession number (the NIC number).  This essentially removes
         the possibility of duplicate filenames being used.

      The basic aspect of recorded mail which was discussed at the mail
      meeting is the assignment of an "accession" number.

         It was decided to get the accession numbers from the NIC on an
         as-needed basis, without pre-assignment and without local
         assignment of numbers.

         This subject may be reviewed in the future.  Local assignment
         may be desirable to prevent the NIC from becoming a bottleneck
         in the mail process.

         It was pointed out that local assignment of numbers would be
         un-ambiguous if the numbers included some information such as
         sitename, date, and time.

      One other problem exits [sic], namely "where is the recorded
      document?".

         Initially the document should be in the NIC, but ultimately it
         could be anywhere on the Network, provided only that there is a
         central mechanism for indexing and cataloging all the recorded
         documents.

         The pathname to the recorded document would then include
         filename and sitename.

   TYPE

      The TYPE subcommand was a result of a discussion on the
      problems of large mail files, and the associated
      question of who would pay for the processing and storing
      of these files.

      The main decisions made were:

         a) The processing, transmittal, and storage costs of
         sending mail should be borne at the sender's host.

         b) The processing and storage costs of receiving
         mail should be borne at the recipient's host
         initially, as a default.

      Information to enable the recipient host to make an
      intelligent decision about where to store the incoming
      mail are passed along via the TYPE command.

         The recipient host will have the local option of
         providing either of the following services:

            a) free use of system to send mail;
            b) free use of system to receive mail, i.e. login
            not required for delivery over the Network.  (A
            possible alternative is use of a "mail" account,
            or use of the recipient's account, for processing
            and storage of the incoming mail.

   TEXT / FILE / CITATION

      TEXT

         This field is for the text of the mail message.

      FILE

         The purpose of this field is unclear to me.  Does it contain a
         machine readable pointer to the file that the sender wishes the
         recipient to read?

      CITATION

         The citation is a person-readable pointer to the file that the
         sender wishes the recipient to read.

         An alternative to sending entire messages or files over the
         Network is to use the "CITATION" mechanism. With this, the
         sender sends a short message (the citation) saying, in effect,
         "please read file X at site Y".

            This alternative would be especially useful for

            a) mail that is distributed with group idents (to all
            liaisons, for example), and

            b) "long" files (size not defined) that the recipient may
            not be immediately interested in.

            However no method of enforcing use of this alternative was
            discussed.  It will be up to the recipients to devise a
            scheme satisfactory to them.

Other General Discussion

   Bob Kahn placed on the floor the following question (I paraphrase):

      Can't the design of a mail system be made to include alternative
      sources of data and alternative modes of operation, unless
      exclusion of these alternatives can be quantitatively defended?

      Particular aspects of this question are:

      1) What is the desirability and difficulty of admitting different
      data sources into the mail system?

         What are the "boundaries" that divide permitted from prohibited
         data sources?

         What is the quantitative distinction between deferred and
         realtime mail?

         Will the design we come up with allow such things as

            a) handling a calendar that reflects the known and
            anticipated whereabouts of people so that meetings can be
            scheduled sensibly?

            b) formatting the mail contents for later query and other
            information handling?

      2) Whatever primitives we implement, can't they be designed so as
      not to preclude things like Tenex "linking"?

         This requires two-way data communication paths.

         How do we specify and get the attention of a "sink" for the
         data stream?

            e.g., for interprocess communication, and for Tenex-type
            "linking".

   The general reaction to this discussion was one of perspective:

      In the scheme of things that could be considered "point-to-point
      communication", mailbox-type of communication is not the most
      general kind.

      AKB listed several types of communication problems:

         program-program communication
         people-people real-time communication,  e.g.
         Tenex-type "links"
         computer teleconferencing
         mailbox communication: cataloging, storage
         protocols: host-host, telnet, file transfer

      A design for a mailbox-type system won't be required to encompass
      the problems of, say, a computer teleconferencing system, which
      has attributes (real-time, video, very large volume of data to be
      transferred, to name some) that are not attributes of a mail box
      system.

Attendees at the Network Mail Meeting 2/23/73 at SRI-ARC

           Nancy Mimno             BBN
   ACB     Alan Bomberger  AMES-67
   AKB     Abhay Bhushan   MIT-DMOG
   AWH     Wayne Hathaway  AMES-67
   CHI     Charles Irby            SRI-ARC
   DHC     Dave Crocker            UCLA-NMC
   JBP     Jon Postel              UCLA-NMC
   JDH     Dave Hopper             SRI-ARC
   JEW     Jim White               SRI-ARC
   LPD     Peter Deutsch           PARC-MAXC
   MCK     Mark Krilanovich        UCSB-MOD75
   MDK     Mike Kudlick            SRI-ARC
   REK2    Bob Kahn                ARPA
   RKK     Rajendra Kanodia        MIT-MULTICS
   RST     Ray Tomlinson   BBN-TENEX



         [ This RFC was put into machine readable form for entry ]
         [ into the online RFC archives by Joseph Marshall 9/97  ]