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- This is only a rough draft - Megan 04/15/92
-
- IETF SMTP Extensions WG
- Minutes: San Diego IETF
- --------------------------
-
- Summary
- -------
-
- During the San Diego meeting, the WG reviewed several issues that had been
- settled earlier, but for which it appeared that new technical issues had
- been identified. The WG concluded that there were, in fact, no
- significant new technical issues being raised, and no significant changes
- to the working document were made. The WG did succeed in tying up the
- remaining loose ends in the document, including identifying locations
- where additional explanatory text was needed and providing exact keywords,
- syntax, and definition for concepts agreed upon some time ago.
-
- The present draft provides an extension model and compatible
- extensions to SMTP for mail transport of 8-bit characters. Using the
- same extension model, it provides some additional extensions to
- supplement SMTP and improve its efficiency, especially when very
- large files are being transmitted.
-
- It is expected that a new Internet Draft, reflecting agreements made in
- San Diego, will be produced shortly after IETF, reviewed quickly on the
- mailing list, and then submitted for processing as a proposed standard.
-
- The meeting contained an extended discussion of the issues raised the
- previous day, including a review of whether the WG's work and the RFC-ZZZZ
- model fit well into a "transition plan"/"final target" model. Several
- other issues were revisited, including the question of whether we might be
- better off with a new protocol on a new port. The assertion was made that
- the present model either constituted two separate services over the same
- port (in which case it was muddled and wrong) or some attempt at hidden
- gateways (in which case there was fear of other problems). It was pointed
- out that the two port model made it very difficult to distinguish between
- no service on the "new" port and temporary unavailability. The advocates
- of the two-port model felt that this was a non-problem unless one wanted
- to mix services or have implied gateways. It was pointed out that no
- gateway was implied if the originating system was prepared to send a
- message in either 8-bit or 7-bit form, but preferred 8 if that was
- available. There was a brief religious argument as to whether or not
- this case was interesting.
-
- The WG concluded that it did not want to revisit the "new port" issue.
-
- A second heated discussion over the CPBL command with a contention that
- the command would increase the number of round trips pitted against a
- contention that it would give intelligent clients the ability to reduce
- the actual number of round trips. The WG decided to retain CPBL.
-
- The issue of "SIZE" was reviewed, both with regard to the information to
- be returned by CPBL (redesignated as "LIMIT" after the meeting to reduce
- possible confusion) and with regard to the estimation and treatment of the
- value to be sent with the SIZE verb. The WG concluded that the capability
- limit should be reported in terms of two administrative values, the size
- that the implementation would try to provide in all cases and the size
- that would probably always be rejected. The editor was directed to
- provide some guidance in the document for estimating, in hosts with
- single-character newline conventions internally, the size to be
- transmitted. See the new version of the draft document for the results of
- these discussions.
-
-
- Details of Discussions and Decisions
- ------- -- ----------- --- ---------
-
- As discussed in the summary above, much of the two WG sessions at this
- meeting was devoted to a review of previously-settled issues, sometimes
- from a new point of view.
-
- Issues and proposals raised included:
-
- * Syntax and semantics for the response to the CBPL command/inquiry.
- The WG decided that this should list all capabilities of the server, on
- a one-verb-per-line basis, using the existing syntax for multiline
- responses. This is one of the options considered in Santa Fe and
- tentatively approved. The handling of the "message size" portion of
- the response was as agreed on in Santa Fe, i.e., providing the
- administrative limits.
-
- * Syntax and semantics of the SIZE command.
- The decisions made in Santa Fe were affirmed and refined.
-
- See the forthcoming version of the Internet Draft for additional
- details on the two features above.
-
- * Possible separation of a "transition model" from the "protocol" as it
- would exist in deployed form, e.g., creating two clearly separated
- documents.
- The WG concluded that this was neither necessary nor appropriate.
-
- * Possible replacement of the notion of capabilities inquiries with a
- clear "version" model with no optional features. The theory behind
- this was that the Internet has succeeded because of the small number of
- options (Telnet negotiation notwithstanding) and that few clients have
- really be designed to take advantage of optional features in any event.
- This discussion led to the insight that some confusion has been created
- by describing EMAL and related features in "negotiation" terms. They
- are really verification that particular expected capabilities are
- present.
- The next version of the Internet-Draft will been modified to reflect
- the "verification" terminology and to remove "negotiation". This does
- not affect the operation of the proposed protocol.
-
- After some discussion, the WG concluded that a "version" model was
- inappropriate. Different members saw different problems, but the most
- serious included the fact that SMTP already contains optional features
- (e.g., the interactive mail commands SEND FROM, SOML FROM, and SAML
- FROM) and that introducing strict "all or nothing at this level"
- versioning would require either requiring support for those verbs and
- concepts or deprecating them. The WG was unwilling to consider doing
- either; some members considered such tampering with the requirement
- level for existing features to be outside the WG's scope. There were
- also concerns about excessively raising the level of effort required
- for a minimal implementation of the new features, thereby defeating the
- WG's goal of providing as smooth and easy a transition path to existing
- (nonconforming) 8bit-sending implementations as possible.
-
-
- * There was interest expressed in "address streaming" and, in
- particular, return of sequence numbers in replies to RCPT TO commands.
- The WG concluded that this was not an extension it was willing to make
- to SMTP during the current round, especially since no concrete or
- specific proposal was on the table.
-
- John C. Klensin
- Chair
- IETF SMTP Extensions WG
-