The type of events that will be sent to this trap
receiver.  This filter is mainly used for limiting
'system event' traps that will be sent to a specific
receiver.

This filter is specified as a sum of values, where
each value specifies a classification of traps that
will be sent to this trap receiver.  The value for a
particular trap class C is computed as 2 raised to
a value representing C.  The trap classes are
defined as follows:

C (bit#)   Trap class
-----------------------------------------------
0          SNMP traps
1          informational events
2          warning events
3          critical events
4          debug events (HP internal use only)

For example, to specify that this trap receiver
should receive SNMP traps and critical event traps,
this object should be set to a value of 9 (2^0 +
2^3).

Note that some agents may not support
trap filtering.  Those agents may either implement
this object as read-only, or with a restricted
write syntax.