revised prtChannelInformation MIB object (was prtChannelMagicCookie)

revised prtChannelInformation MIB object (was prtChannelMagicCookie)

revised prtChannelInformation MIB object (was prtChannelMagicCookie)

David_Kellerman at David_Kellerman at
Sun Oct 20 03:11:54 EDT 1996

Here is the revised prtChannelInformation object definition  (previously
prtChannelMagicCookie).  I've tried to incorporated all the decisions
reached at the October 18th conference call.  Please let me know if
anything is missing or mis-stated, or if you have suggestions on
clarifying the language. 

Following the object definition are the specific semantics for a
handful of enum values.  Again, please speak up if you think different
information should be included, or if you can suggest improvements to
the exposition. 

There's one thing I'm confused about.  Randy recommended changing the
SYNTAX to DisplayString, and I thought I understood why this made sense. 
But RFC 1759 seems to use plain OCTET STRING throughout, not
DisplayString.  Explanation? 

::  David Kellerman         Northlake Software      503-228-3383
::  david_kellerman at Portland, Oregon        fax 503-228-5662

prtChannelInformation OBJECT-TYPE
    SYNTAX      DisplayString (SIZE(0..255))
    MAX-ACCESS  read-write
    MIN-ACCESS  read-only
    STATUS      current
        "Auxiliary information to allow a printing application to use
        the channel for data submission to the printer.  An application
        capable of using a specific prtChannelType should be able to use
        the combined information from the prtChannelInformation and
        other channel and interface group objects to 'bootstrap' its use
        of the channel.  prtChannelInformation is not intended to
        provide a general channel description, nor to provide
        information that is available once the channel is in use. 

        The encoding and interpretation of the prtChannelInformation
        object is specific to channel type.  The description of each
        PrtChannelType enum value for which prtChannelInformation is
        defined specifies the appropriate encoding and interpretation,
        including interaction with other objects.  For channel types
        that do not specify a prtChannelInformation value, its value
        shall be null (0 length).  

        When a new PrtChannelType enumeration value is registered, its
        accompanying description must specify the encoding and
        interpretation of the prtChannelInformation value for the
        channel type.  prtChannelInformation semantics may also be added
        to an existing PrtChannelType in the same manner as described in
        section 2.4.1 for type 2 enumeration values. 

        The prtChannelInformation specifies values for a collection of
        channel attributes, encoded according to the following rules: 

         1. The prtChannelInformation is a list of entries containing
            data values.  Each entry begins with a name, composed of
            alphabetic characters (A-Z, a-z), that identifies a channel
            attribute.  The name is followed by an equals sign (=), the
            data value, and a linefeed character.  No other characters
            (such as extraneous space characters) should be present. 

         2. If a channel attribute has multiple values, it is
            represented by multiple entries with the same name, each
            containing one value.  Otherwise, there should be at most
            one entry for each attribute. 

         3. Entries may appear in any order. 

         4. The prtChannelInformation value may contain information that
            is not normally coded in human-readable form.  In these
            cases, whatever symbolic representation is conventionally
            used for the information is used for encoding the
            prtChannelInformation.  (For instance, a binary port value
            might be encoded as a decimal number.) 

         5. For each PrtChannelType for which prtChannelInformation is
            defined, the descriptive text associated with the
            PrtChannelType enumeration value shall specify, at a
            minimum, the following: 
             a. The attributes specified by the prtChannelInformation,
                their identifying names, and how their data value is
                encoded if it is not normally human-readable. 
             b. For each attribute, whether it is mandatory or optional,
                and whether it may have multiple values. 

        Applications that interpret prtChannelInformation should ignore
        unrecognized entries, so they are not affected if new entry
        types are added. 
    ::= { prtChannelEntry 9 }

Here are proposed prtChannelInformation definitions for selected
PrtChannelType values: 

    chLPDServer(8),     -- ...
                        -- prtChannelInformation entries:
                        --   printer queue name
                        --     name: QUEUE, mandatory, single value
                        --     value is the ASCII queue name as
                        --     described in RFC 1179
    chDECLAT(32),       -- ...
                        -- prtChannelInformation entries:
                        --   port name
                        --     name: PORT, optional, single value
                        --   service name
                        --     name: SERVICE, optional, single value
                        -- Exactly one of port and service must be
                        -- specified. 
    chPortTCP(37),      -- ...
                        -- prtChannelInformation entries:
                        --   TCP port number
                        --     name: PORT, mandatory, single value
                        --     value is encoded as a decimal number
    chBidirPortTCP(38), -- ...
                        -- prtChannelInformation is same as chPortTCP

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