Can an OBJECT IDENTIFIER have only one component? - SNMP

This is a discussion on Can an OBJECT IDENTIFIER have only one component? - SNMP ; It says very clearly in the book "Understanding SNMP MIBs" that "an OID value must have at least two components" (2.7.10, page 48). Does that mean that an agent which is returning things like this SNMP-VIEW-BASED-ACM- MIB::vacmViewTreeFamilyStorageType."anonymousView000".1.1 = INTEGER: permanent(4) ...

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Thread: Can an OBJECT IDENTIFIER have only one component?

  1. Can an OBJECT IDENTIFIER have only one component?


    It says very clearly in the book "Understanding SNMP MIBs" that "an
    OID value must have at least two components" (2.7.10, page 48). Does
    that mean that an agent which is returning things like this

    SNMP-VIEW-BASED-ACM-
    MIB::vacmViewTreeFamilyStorageType."anonymousView000".1.1 = INTEGER:
    permanent(4)

    is in error? (1.1 here means the OID "1" - the first component is the
    length). The agent in question is a somewhat old version of NET-SNMP,
    and I can't see that this is configured anywhere - it probably makes
    up the "anonymousView" on the fly.

    Should a manager treat such a value harshly, and reject the element,
    or present it as the OID "1"?

    I suppose I am asking: do such values occur regularly, and will I
    break many things by letting my manager be harsh?

  2. Re: Can an OBJECT IDENTIFIER have only one component?

    Hi Arndt,

    I believe you're confusing things here: AFAICT "1" is not an OID.
    It rather seems to be an index value (or part of an index value) - which
    is only the trailing part of the full OID.

    1.1 does not mean the OID "1" and never will.

    Cheers,

    -- daniel
    http://blogs.sun.com/jmxetc

    Arndt Jonasson wrote:
    > It says very clearly in the book "Understanding SNMP MIBs" that "an
    > OID value must have at least two components" (2.7.10, page 48). Does
    > that mean that an agent which is returning things like this
    >
    > SNMP-VIEW-BASED-ACM-
    > MIB::vacmViewTreeFamilyStorageType."anonymousView000".1.1 = INTEGER:
    > permanent(4)
    >
    > is in error? (1.1 here means the OID "1" - the first component is the
    > length). The agent in question is a somewhat old version of NET-SNMP,
    > and I can't see that this is configured anywhere - it probably makes
    > up the "anonymousView" on the fly.
    >
    > Should a manager treat such a value harshly, and reject the element,
    > or present it as the OID "1"?
    >
    > I suppose I am asking: do such values occur regularly, and will I
    > break many things by letting my manager be harsh?


  3. Re: Can an OBJECT IDENTIFIER have only one component?

    Oops, sorry, I answered too fast - I should have looked at
    the MIB first :-(
    "1" is indeed the value of the vacmViewTreeFamilySubtree index which
    *is* an OBJECT IDENTIFIER

    Please disregard my previous answer - I apologise for *my* confusion.
    That will teach me to answer without thinking first :-(

    I could not find any explicit mention in the RFC of whether such
    a value should be allowed (given that vacmViewTreeFamilySubtree is
    not-accessible and therefore never returned as a single stand-alone
    OID).
    I'd say that a vacmViewTreeFamilySubtree of '1' is at least
    very suspicious.

    Once again I apologize for the confusion.

    -- daniel

    Daniel FUCHS wrote:
    > Hi Arndt,
    >
    > I believe you're confusing things here: AFAICT "1" is not an OID.
    > It rather seems to be an index value (or part of an index value) - which
    > is only the trailing part of the full OID.
    >
    > 1.1 does not mean the OID "1" and never will.
    >
    > Cheers,
    >
    > -- daniel
    > http://blogs.sun.com/jmxetc
    >
    > Arndt Jonasson wrote:
    >> It says very clearly in the book "Understanding SNMP MIBs" that "an
    >> OID value must have at least two components" (2.7.10, page 48). Does
    >> that mean that an agent which is returning things like this
    >>
    >> SNMP-VIEW-BASED-ACM-
    >> MIB::vacmViewTreeFamilyStorageType."anonymousView000".1.1 = INTEGER:
    >> permanent(4)
    >>
    >> is in error? (1.1 here means the OID "1" - the first component is the
    >> length). The agent in question is a somewhat old version of NET-SNMP,
    >> and I can't see that this is configured anywhere - it probably makes
    >> up the "anonymousView" on the fly.
    >>
    >> Should a manager treat such a value harshly, and reject the element,
    >> or present it as the OID "1"?
    >>
    >> I suppose I am asking: do such values occur regularly, and will I
    >> break many things by letting my manager be harsh?


  4. Re: Can an OBJECT IDENTIFIER have only one component?

    Daniel FUCHS wrote:

    > I'd say that a vacmViewTreeFamilySubtree of '1' is at least
    > very suspicious.


    The definition of vacmViewTreeFamilySubtree says that values are
    of syntax OBJECT IDENTIFIER (and ASN.1 base type) and hence all
    rules for OBJECT IDENTIFIER values apply. Hence, '1' is not a
    legal value for vacmViewTreeFamilySubtree.

    /js

    --
    Juergen Schoenwaelder Jacobs University Bremen gGmbH
    Phone: +49 421 200 3587 Campus Ring 1, 28759 Bremen, Germany
    Fax: +49 421 200 3103

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