From: "Ralph Case" <[email-masked]>
Date: Mon, 9 Oct 95 13:06:19 EDT

MINUTES OF ARCHITECTURE REFERENCE SIG AT AIW8
 _____________________________________________

    This SIG discusses clarifications, fixes, and minor
    enhancements to the APPN architecture.  The focus is on
    improving the quality and interoperability of APPN
    Implementations.

    If we've missed something from the meeting, or if you
    have additional questions or comments, please post them
    here or send them directly to us.

    I'd like to thank everyone who participated in the
    discussions at the SIG meeting.  I'd especially like to
    thank those who took the time and effort to prepare
    presentations:

    o   Andy Barclay
    o   Roy Brabson
    o   Rich Daugherty
    o   Tim Hefel
    o   Ron Sanders
    o   Gary Schultz
    o   Ed Tremblay

 ARCHITECTURE UPDATES AND DISCUSSIONS
 ____________________________________

    This is a brief record of the discussions.  See the
    various mail logs for additional discussion on many of
    the topics.

 SNMP OVER SNA

    This was proposed at AIW 7 and documented in
    "aiw/snasnmp/snmpsna.txt".  It was approved
    electronically prior to AIW8 on 6/2/95.

 DLUR SIGNALLING FORMATS

    This was discussed at AIW 7.  Revisions were suggested
    and the final document is posted as "arch8304d.psbin".
    It was approved electronically prior to AIW8 on 8/3/95.

 ADD DLUR PROCESSING TO SEND PU NAME TO DLUS

    Requirements from several vendors have been submitted to
    allow the DLUR to send a PU name to the DLUS to be used
    there.  Multiple reasons have been provided also, for
    example, to allow the end user to provide a PU name
    instead of the DLUS-generated name when the PU is
    dynamically created at the DLUS; and to provide the DLUS
    with additional PU search criteria when the DLUR and DLUS
    are adjacent and two PUs have been defined at the DLUS.

    The proposed solution is to add CV X'0E' type X'F1' (PU
    name) to the FID2 Encapsulation (X'1500') GDS variable
    when it encapsulates the REQACTPU RU to allow the DLUR to
    send the PU name to the DLUS (just as currently the DLUS
    uses the same CV on ACTPU to send the PU name to the
    DLUR).

    This item is documented in "abs8294.txt" and
    "arch8294d.psbin".  There was a consensus on the
    solution.  This item is now APPROVED.

 CLARIFY DLUR TAIL VECTOR REGISTRATION PROCESSING

    Questions from DLUR implementers concerning DLUR EN tail
    vector registration procedures have pointed out a need to
    specify the algorithm for DLUR to use to decide which
    session (CP-CP or CP-SVR) session to use to send TDUs.

    VTAM handles the TDUs the same whether they are sent over
    the CP-CP session or the CP-SVR pipe.  Therefore, this
    item will also optionally allow the adjacent DLUR to not
    use the CP-CP session and only use the CP-SVR pipe for
    tail vector registration.

    This item is documented in "abs8296.txt" and
    "arch8296d.psbin".  There was a consensus on the
    solution.  This item is now APPROVED.

 ALLOW SIGNALLING INFORMATION DEFINITION AT DLUR

    DLUR signaling information is currently defined via
    DLCADDR at the DLUS.  While some users prefer centralized
    (at DLUS) signaling information definition, there are
    others who prefer distributed (at DLUR) definition.  The
    DLUS does not require DLCADDR to be defined, so some or
    all of the information currently defined via DLCADDR at
    the DLUS should be allowed to be optionally sysdefed at
    the DLUR instead.

    This item is documented in "abs8303.txt" and
    "arch8303d.psbin".  There was quite a bit of discussion
    on this item.  There was agreement on the general
    proposal, but there was not agreement on how to handle
    "error" cases where there is conflicting information
    defined at the DLUR and DLUS.  This discussion will
    continue on the mail exploder.

 ADDITIONAL APPN FR PVC SIGNALLING INFORMATION FORMATS FOR DLUR

    Formats are defined to support BAN connections between a
    DLUR and a downstream LAN-attached node.

    This item is documented in "arch8318d.psbin".  There was
    a consensus on the solution.  This item is now APPROVED.

 SUPPORT FOR ENCAPSULATED FID2 SEGMENTS ON CP-SVR PIPE TO DLUS

    Some messages sent by the DLUR on the CP-SVR pipe may
    have been received from the DLUR-serviced device in
    segments.  Currently, the DLUS only accepts encapsulated
    whole messages.

    This change allows the DLUR to encapsulate PIU segments
    in separate GDS X'1500's.  The segments will be
    reassembled at the DLUS.

    This item is documented in "abs8321.txt" and
    "arch8321d.psbin".  There was a consensus on the
    solution.  This item is now APPROVED.

 DLUR SEGMENTATION SUPPORT FOR SHORT RSP(BIND) LUS

    The DLUR and NCP both assume that such a SLU cannot
    handle segments (indicating WBRI set on).  However, when
    a PIU too large to be sent on the downstream link to the
    SLU is received, the DLUR will UNBIND the LU-LU session
    while the NCP will segment the message.  This is a
    mismatch of function putting the DLUR at a disadvantage
    (even though it is doing the right thing).  For easier
    migration, the DLUR should follow the NCP's procedure.

    This item is documented in "abs8322.txt" and
    "arch8322d.psbin".  There was a consensus on the
    solution.  This item is now APPROVED.

 GENERALIZED ODAI USE

    This proposal was documented at AIW7.  A few minor
    changes to this documentation had been suggested, and
    were incorporated.  There was a concensus that the
    documentation is now complete.  It is contained in the
    files "odairoot.psbin", "arch8128f.psbin",
    "archno8128.psbin", "archcs8128.psbin",
    "archam8128.psbin", "archpc8128.psbin", and
    "archbo8128.psbin".  This item is now APPROVED.

 XID3 BYTE 27

    This was discussed at AIW 7.  Specific architecture
    changes were documented and distributed in
    "arch8299f.psbin" and "arch8299.psbin".  There was
    general agreement on the details, and the SIG was asked
    for final approval by 9/13.  This item is now APPROVED.

 LOCATE SEARCH CLEANUP AS THE RESULT OF A CP SESSION OUTAGE

    This item reviews a discussion from the mail exploder.
    It was noted that the APPN architecture reference
    contains an incomplete description of this processing.
    An update to the book will need to be created.

 TOPOLOGY NONVERIFY BYPASS

    Topology nonverify can prevent a Locate message from
    reaching the destination LU.  While this can result is a
    reduction of network control flows, there are some cases
    where information carried as payload on the Locate must
    reach the DLU for successful session setup.  This change
    allows an OLU to indicate that topology nonverify must be
    bypassed for a given Locate.

    There was agreement on this function.  A document will be
    distributed for approval.

 ENHANCEMENT OF APPN DIRECTORY SERVICES TO SUPPORT RESOURCE TYPES OTHER THAN LUS

    This is a proposal for a new addition to APPN directory
    services.  It is documented in "locsrvc1".  There was a
    lot of discussion about the proposal, focusing on the
    technical problems to be solved and the alternatives.  It
    became clear that the members have different priorities
    and requirements.  It was difficult to evaluate the
    solution choices without a clearer definition of the
    requirements.  Discussion will continue on the mail
    exploder.

 VERIFYING SESSION REACHABILITY WHEN PERFORMING TOPOLOGY NONVERIFY

    ("Modifications to Session Route Building" or
    "Improvement to Topology Nonverify Algorithm")

    The discussion on the mail exploder was reviewed and it
    was agreed that all concerns are now adequately covered
    by the current submission.  This item is now APPROVED.

 DETECTING DUPLICATE CP NAMES WHEN ONE NODE IS A VRN

    Several issues were raised on the mail exploder and were
    discussed further.  There was agreement on the main
    points - that the primary goal is to detect and report
    the case, but not all the issues were resolved.  More
    discussion is needed about what level of toleration is
    appropriate while the case still exists.

 NEW NOF COMMAND TO ALLOW NETWORK NODES TO IGNORE COS SUPPLIED BY CLIENT NODES

    Issues raised on the mail exploder were discussed.  It
    was agreed that this proposal was not a complete and
    effective solution to any of the requirements.  This item
    was withdrawn, but additional contributions to address
    these requirements were solicited.

 DOCUMENTATION
 _____________

    All references to the "architecture repository" in these
    minutes refer to the /pub/standards/aiw/appn/architecture
    directory on the networking.raleigh.ibm.com host.  Files
    are available via anonymous FTP.  Most files were also
    included in the binder for easy reference at the meeting.

    I will update the architem file to reflect these new
    status changes to the architecture items.

Ralph Case                    [email-masked]    (919)254-1882
AIW APPN Reference SIG Chair
IBM Networking Hardware Division