RE: PDM> Interfaces - needs work

From: Richard_Landau@Dell.com
Date: Fri Oct 26 2007 - 12:26:50 EDT

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    Ira, you are not the first person we've managed to confuse with a poorly
    chosen name and an insufficiently explicit description. We should
    probably rename it to the "Connector" group.

    The MIB2 Interfaces group is for network interfaces. The PDM group is
    for video and audio data-delivery interfaces. (Only two of them
    accidentally are also network interfaces, but there's not much
    network-ish about them in this application.) The group has two
    purposes:
    - Through which physical connector is the device currently (attempting
    to) receive its video signal? Same for audio signal?
    - From which physical connectors should the device look for video and
    audio signals?

    The only properties that these objects might share with the Interface
    group are Description, maybe Type, and maybe AdminStatus. All the other
    properties of Interface are for bit-byte-packet oriented interfaces,
    which almost all of these *analog* gezintas are not.

    To the extent that network interfaces (ethernet and wireless) might
    appear here at all, the only "extension" would be something like "don't
    listen to this interface for video signals." This is not very similar
    to prtChannel, either: we are not planning to enable/disable individual
    data paths. It's strictly physical. But neither does it turn off the
    whole connector, e.g., ethernet would still carry management traffic.
    This is an instruction to the video processor to listen to the gezinta
    or not.

    Since the network attributes are irrelevant to these connectors, and
    these functions are irrelevant to the network interfaces, I don't
    believe they ought to be combined.

    Shared properties? The intersection of the two sets of Types is almost
    empty. The AdminStatus has odd enum values that do not mesh with the
    way people think about these connectors, but could be used. And
    OperStatus is not reported by these devices. Not much fertile ground
    here, but maybe non-zero.

    If IANA has a registry of these connectors, well, I missed it. 99% of
    these connectors are not Internet anything, so it's not surprising that
    IANA doesn't collect them. They have a video *media* registry, but that
    doesn't help much. But VESA and CEA do define these connector types,
    though not quite up to the level of a formal registry. Nick is
    investigating the collection of those definitions.

    Seem reasonable?

    rick

    -----Original Message-----
    From: owner-pdm@pwg.org [mailto:owner-pdm@pwg.org] On Behalf Of Ira
    McDonald
    Sent: Thursday, October 25, 2007 20:29
    To: pdm@pwg.org; Ira McDonald
    Subject: PDM> Interfaces - needs work

    Hi,

    Comments on PDM Interfaces group:

    All SNMP Agents must implement the required groups in MIB-II (per the
    core SNMP protocol specs for all three versions), including the
    Interfaces group (which includes all local and network data interfaces
    but NOT memory, video, etc., like the PDM group).

    The PDM Interfaces group should *augment*, rather than attempt to
    replace the MIB-II required group for local and network data interfaces
    (802.11, 802.3 (aka Ethernet), etc.).

    I'll send a more detailed suggestion after I think about it a bit more,
    but we do NOT want to compete with the exstensive IANA registry of
    local/network data interface types - waste of time and effort.

    FWIW - Host Resources MIB (RFC 2790) treats as distinct device
    types: Network, Video, Audio, Disk Storage, Parallel, and Serial (among
    others).

    Cheers,
    - Ira

    --
    Ira McDonald (Musician / Software Architect) Chair - Linux Foundation
    Open Printing WG Blue Roof Music / High North Inc PO Box 221  Grand
    Marais, MI  49839
    work: +1-906-494-2434
    home: +1-906-494-2697
    email: blueroofmusic@gmail.com
    


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