IETF-Event-MIB-Draft pktcDevEvProgrammableEntry and pktcDevEvFixedEntry

Hi,
 We have common description for TWO MIBs. Need to undersand the
difference between the two.

pktcDevEvProgrammableEntry OBJECT-TYPE
    SYNTAX      PktcDevEvProgrammableEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Allows configuration of the reporting mechanisms for a
             programmable event, including level, report type, and
text."
    INDEX { pktcDevEvProgrammableId, pktcDevEvProgrammableEnterprise }
    ::= { pktcDevEvProgrammableTable 1 }

pktcDevEvFixedEntry OBJECT-TYPE
    SYNTAX      PktcDevEvFixedEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
            "Allows configuration of the reporting mechanisms for a
             fixed event, including level, and report type."
    INDEX { pktcDevEvFixedId, pktcDevEvFixedEnterprise }
    ::= { pktcDevEvFixedTable 1 }

Which events should be reported through  pktcDevEvFixedTable and which
events should be reported through  pktcDevEvProgrammableTable or can all
events be reported through either?

Comments please..

Thanks,
Satish