SNMP Polling Results

SNMP polling operation status is presented by SNMP (snmp) variable with the following fields:

SNMP polling results are presented as Device setting variables according to the following rules:

• If a group of OIDs represent SNMP Table, one tabular device setting variable is created for them.

• In all other cases, one device setting variable is created per OID.

Device setting variable names for SNMP variables are constructed by the following rules:

• If a MIB symbol is found for a certain OID, device setting name equals to MIB symbol name (ex.: sysDescr, hrStorageTable).

• If no MIB data is found for an OID, device setting name equals to OID itself. Dots are substituted by underscores to make a valid name (ex.: 1_3_6_1_2_1_5_27_1_5_2_0).

Device setting variable descriptions for SNMP variables are constructed by following rules:

• If a relevant MIB file is found for an OID, description constructed in accordance with Variable Descriptions setting defined for this MIB file.

• If full MIB data is not found, variable description includes symbolic name for recognized part of OID followed by numeric unrecognized part. Full variable OID is also included in parentheses. For example: iso.org.dod.internet.mgmt.mib-2.icmp.27.1.5.1.0 (1.3.6.1.2.1.5.27.1.5.1.0)

Device setting variables are grouped by MIB filed the corresponding OIDs are defined in. Setting variables corresponding to OIDs not found in MIB directory are put into Unrecognized SNMP OIDs group.

Some SNMP metrics may be augmented depending on the MIB file or files being used. If a metric in an MIB file includes an AUGMENTS component, than it will be augmented by the metric indicated by the AUGMENTS component whenever it is retrieved. For example, considering the following object definition:

ifXEntry OBJECT-TYPE
    SYNTAX      IfXEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    INDEX   { ifIndex }
    DESCRIPTION
        "An entry containing additional management information
        applicable to a particular interface."
    AUGMENTS    { ifEntry }
    ::= { ifXTable 1 }  

The above example indicates that the metric ifEntry will be used to augment ifXEntry. The retrieval method used to retrieve ifXEntry will depend on the specific SNMP settings. When ifXEntry is read, the augmenting metric ifEntry will be read with either a bulk or walk request, and the results of ifXEntry will be augmented, or extended, with the results from ifEntry, and presented as a single response.

When a column in one metric does not have a counterpart column in the other metric, the records for that metric will be filled with NULL values for that column. This behaviour could be considered roughly analogous to a LEFT JOIN operation in SQL.

SNMP types are converted to Iotellect types, as described in the following table:

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