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 ]