PMP Mail Archive: RE: PMP> PortMon Mib question

PMP Mail Archive: RE: PMP> PortMon Mib question

RE: PMP> PortMon Mib question

From: Ivan Pavicevic (ivanp@windows.microsoft.com)
Date: Tue Jun 28 2005 - 14:34:40 EDT

  • Next message: McDonald, Ira: "RE: PMP> PortMon Mib question"

    Regarding truncation our requirement is that the device Id has to have
    MANUFACTURER (or MFG) and MODEL (or MDL) fields in order to be able to
    calculate PnPId.

    I'm fine with Ira's suggestion about having a plain OCTET STRING with
    constrains we define.

    Thanks,
    Ivan

    -----Original Message-----
    From: pmp-owner@pwg.org [mailto:pmp-owner@pwg.org] On Behalf Of
    McDonald, Ira
    Sent: Tuesday, June 28, 2005 9:26 AM
    To: 'thrasher@lexmark.com'; pmp@pwg.org
    Subject: RE: PMP> PortMon Mib question

    Hi Jerry,

    I think we should change to 1023 octets for 'ppmPortIEEEDeviceID'
    with normative 'intelligent truncation' rules (strip whole key/value
    pairs) stated in the object and its OBJECT clause back in the
    MODULE-COMPLIANCE macro.

    Justification appears in the following note from the latest IETF
    "Guidelines for Authors and Reviewers of MIB Documents", page 34:

      "Note 2. DisplayString does not support internationalized text.
                It MUST NOT be used for objects that are required to
                hold internationalized text (which is always the case
                if the object is intended for use by humans [RFC2277]).
                Designers SHOULD consider using SnmpAdminString,
                Utf8String, or LongUtf8String for such objects."

    SnmpAdminString (which we have been using per Bert Wijnen) is defined
    in the SNMP Framework MIB (RFC 3411), but is _limited_ to 255 octets.

    LongUtf8String is defined in the System Application MIB (RFC2287)
    and is limited to 1024 octets (but IPP/1.1 limits strings to 1023,
    so for PWG Semantic Model coherence we should use 1023).

    I don't like importing from RFC 2287. I suggest make this one object
    plain ASN.1 'OCTET STRING' and constrain it in the DESCRIPTION clause
    to UTF-8 (with max length 1023 octets and an OBJECT clause allowing
    support for only 255 octets).

    Comments?

    Cheers,
    - Ira

    Ira McDonald (Musician / Software Architect)
    Blue Roof Music / High North Inc
    PO Box 221 Grand Marais, MI 49839
    phone: +1-906-494-2434
    email: imcdonald@sharplabs.com
    -----Original Message-----
    From: pmp-owner@pwg.org [mailto:pmp-owner@pwg.org]On Behalf Of
    thrasher@lexmark.com
    Sent: Tuesday, June 28, 2005 11:33 AM
    To: pmp@pwg.org
    Subject: RE: PMP> PortMon Mib question

    Ira,

    A 1284 ID length of 1023 octets would probably encompass the vast
    majority
    of strings in use today, and
    we(Lexmark) probably could live with 255 if that's what is decided,
    however
    we (PWG) would still need to explain the
    truncation rules regardless of the length we decide (simple truncation
    at
    the final byte, or truncation at the last full key/value
    pair before reaching the limit etc....).

    JT

    "McDonald, Ira" <imcdonald@sharplabs.com>
    Sent by: pmp-owner@pwg.org
    06/27/2005 11:23 PM
            
            To: "'thrasher@lexmark.com'" <thrasher@lexmark.com>,
    pmp@pwg.org
            cc:
            Subject: RE: PMP> PortMon Mib question

    Hi Jerry,

    The IETF SMIv2 and the IETF's best practices recommend that MIB string
    objects longer
    than 255 octets be avoided for interoperability reasons. There are some
    instances in
    some modern IETF MIBs of strings with max lengths of 1023 octets (and
    conformance
    statements allowing a short length such as 255 octets).

    We could certainly make the IEEE Device ID string longer. Should we do
    so?

    Cheers,
    - Ira

    Ira McDonald (Musician / Software Architect)
    Blue Roof Music / High North Inc
    PO Box 221 Grand Marais, MI 49839
    phone: +1-906-494-2434
    email: imcdonald@sharplabs.com

    -----Original Message-----
    From: pmp-owner@pwg.org [mailto:pmp-owner@pwg.org]On Behalf Of
    thrasher@lexmark.com
    Sent: Monday, June 27, 2005 9:05 PM
    To: pmp@pwg.org
    Subject: PMP> PortMon Mib question

    Question/Issue from one of our dev's

    For the variable ppmPortIEEE1284DeviceID, the MIB states:

    The value of this object MUST exactly match the IEEE 1284-2000
    Device ID string, except that the length field MUST NOT be
    specified. The value MUST be assigned by the Printer vendor
    and MUST NOT be localized by the Print Service.

    The definitition indicates that the size is 0-255. However, the actual
    1284
    device ID can be much longer.

    I think the length field of the 1284 string is two bytes (and the length
    includes the two bytes of length field).???

    Jerry Thrasher



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