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-
- CURRENT_MEETING_REPORT_
-
- Reported by Peter Furniss/Consultant
-
- Minutes of the Minimal OSI Upper-Layers Working Group (THINOSI)
-
- This was our first meeting as a Working Group. Most of the time was
- spent reviewing the first draft of the bytestream cookbook and
- especially the technical choices of what OSI upper-layers features
- should be included.
-
- Some guiding principles emerged:
-
-
- o Interworking with ``full'' OSI implementations was a key purpose of
- the thinosi approach and must be maintained, even at the cost of
- some complexity.
-
- o Inclusion or exclusion of features is determined by (and
- determines) the set of application protocols that can be supported.
-
- o It will be little trouble to add additional features (thus widening
- the application range) once the basic format and style is worked
- out - these could be alternatives in the same document or in
- separate ones.
-
- o If at all possible the set of supported application protocols
- should include the DAP and X.400 P7 protocol. (These are not
- actually byte-stream in the sense we have now, but at least DAP
- should be possible with only a two octet change. P7 to be
- investigated. PRF)
-
-
- A number of conclusions were reached (most of these are confirmations of
- what is in the first draft).
-
- o Expect to receive any of the various allowed encodings of lengths,
- etc.
-
- o Describe sending of one application abstract-syntax and transfer
- syntax name (in addition to the ACSE as & ts), but also describe
- how, as responder, to locate and reply when these are one of a
- number of offered abstract syntaxes and/or transfer syntaxes (how
- to send and use multiple as and ts is one of the extension
- possibilities).
-
- o Do not use the invocations ids or the responding AP-title,
- AE-qualifier (ignore happily on receipt).
-
-
- 1
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-
-
-
-
- o Do not use the userdata field on ACSE A-ASSOCIATE or A-RELEASE
- exchanges.
-
- o Do allow the user data on the ACSE user abort to be used by the
- application (typically to carry application- or
- implementation-specific error/explanation messages).
-
- o Use Session version 2 (with the Common Upper-Layer Requirements
- limits on userdata).
-
- o Include the correct procedure to follow when a release collision
- occurs (this is different for the association initiator and
- responder).
-
- o Identify more clearly where the cookbook is taking advantage of a
- CULR part 1 restriction.
-
- o Do not include re-use of transport (although this can improve
- efficiency, it is always *additional* to starting with new
- T-connections, and thus makes the implementation more complex.)
-
- o Do not shorten the explanatory text at the beginning or move it to
- another document (clarify it by all means).
-
- o Change the layout of the octet sequences to a more rigid
- tag-length-value column format, with the datatype of primitive
- values in a fourth column. Indent to show the nesting if feasible.
- e.g.,
-
- 30 80 {4 . list of transfer syntaxes
- 06 02 5101 oid . BER transfer syntax
- 00 00 }4 . e-o-c for ts list
-
-
-
- The Group was uncertain on whether the lengths of constructed elements
- should all be indefinite, all definite, or follow a pattern of whatever
- is convenient. For interworking all possibilities must be understood on
- receipt, but various performance payoffs are possible. The views of the
- mailing list will be sought.
-
- There was also some discussion of related work in other circles.
-
-
- o A profile for ``minimal OSI functionality'' is being developed in
- the OIW and EWOS regional workshops (these are the OSI profiling
- bodies for North America and Europe). This is intended to be part
- three of Common Upper-Layer Requirements. The mOSI profile and
- thinosi work have a common origin. At present, the upper-layer
- facilities supported in mOSI and in thinosi are not quite the same.
- It will be highly desirable for there to be one single selection of
- features for both. Attempts will be made to align these - in
-
- 2
-
-
-
-
-
- particular the new draft of the cookbook should be made available
- to the EWOS technical liaison group (TLG) in time for their next
- meeting in April.
-
- o Within X/Open, a new appendix for the XTI interface is being
- developed that defines the use of this interface for minimal OSI.
-
-
- The Group will meet in Amsterdam.
-
- Attendees
-
- John Boatright bryan_boatright@ksc.nasa.gov
- Kevin Carosso kvc@innosoft.com
- George Chang gkc@ctt.bellcore.com
- Peter Furniss p.furniss@ulcc.ac.uk
- Sylvain Langlois Sylvain.Langlois@exp.edf.fr
- Mark Needleman mhn@stubbs.ucop.edu
- Geir Pedersen Geir.Pedersen@usit.uio.no
- Jim Romaguera romaguera@cosine-mhs.switch.ch
- Keith Sklower sklower@cs.berkeley.edu
- Klaus Truoel truoel@gmd.de
- William Warner warner@ohio.gov
- Les Wibberley lhw24@cas.org
- Charles Young Charles.E.Young@att.com
-
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