SNMP Agent Trap Send Rule Edit

Rule Number – Used as a reference in the rule list for ordering the rules.

Branch – Specifies which branch in the MIB that this trap rule applies to, and primarily provides the means to look up the local object number that should be evaluated.

Index – Specifies the index or row number in the given branch for looking up the local object nubmer.

Test – Defines the test that should be performed to determine if the trap send rule state is true or false. Trap state is considered “true” when this condition is met

Test label	Test performed on object versus threshold
GT	Object greater than threshold
GE	Object greater than or equal threshold
LT	Object less than threshold
LE	Object is less than or equal threshold
EQ	Object is equal threshold
NE	Object is not equal threshold
DEV	Object deviates from threshold by hysteresis amount
DELTA	Object has changed by threshold amount

For most tests, the object is simply compared to the threshold value. The delta test is a special case. The threshold specifies an amount by which the local object needs to change before the rule test will be flagged as true. However, this “true” state is only temporary. Once the trap is sent, the new object value is now saved for subsequent tests of “changed by”. Every time the local object changes by the threshold amount, a new trap will be sent.

Test type delta with threshold of zero is a special case within the special case. If the test type is delta and the threshold value is zero, then the trap will be sent any time the local object (found by looking it up in the MIB) has been updated or changed by some other action in the system, without any regard for what the actual value of the object is.

Threshold Value (CSV "CondVal") – Provided no threshold object number is given, this becomes the threshold value for test purposes.

Threshold Object (CSV "CondObj")– Overrides the threshold value when given (non-zero), and provides the local object from which a test threshold should be retrieved.

Hysteresis (CSV "Hyst") – Specifies the hysteresis value to be applied in the test process. Hysteresis is used to prevent a flood of trap messages when the object is hovering near the threshold but fluctuating frequently. For ‘greater than’ type tests, once the rule state becomes true, the object value must fall below the threshold by the hysteresis amount before the rule state will return to false. For ‘less than’ type tests, once the rule state becomes true, the object value must rise above the threshold by the hysteresis amount before the rule state will return to false. For example, if the rule threshold is 10, and the test is ‘greater than’, then the rule state will become true when the object value exceeds 10. If the hysteresis value is 2, then the object value must now fall below 8 before the rule state will return to false.

The hysteresis value takes on a special role when the test type is “deviates by”. The rule state will be true when the difference between object value and threshold exceeds the hysteresis amount in either direction, high or low.

SendOnTrue – Enter “N” to disable, or “Y” to enable the sending of a trap when the condition specified by this rule tests “true”.

SendOnFalse – Enter “N” to disable, or “Y” to enable the sending of a trap when the condition specified by this rule tests “false”.

DevMask – A 32-bit bit mask that allows sending the same trap to multiple devices. Both the trap send rules and the trap devices have a “device mask” (devMask). This effectively creates device groups in a very simple manner. The bit mask found in the trap send rule is logically ANDed with the bit mask in the device table entry. If the result is non-zero, then the trap is sent to this device.

SendInform – Enter “N” to send the message as an SNMP Trap, or “Y” to send the message as an SNMP Inform.

OnTime – Specifies a minimum amount of time in seconds that the “true” state must exist before the trap state will be fully regarded as true and “true” trap sent. If the condition tests true, and within this time period returns to false, no “true” trap will be sent.

OffTime – Specifies the minimum amount of time in seconds that the “false” state must exist before the trap state will be fully regarded as false and the “false” trap sent. If the condition tests false, and within this time period returns to true, no “false” trap will be sent.

TrueMsg – Provides a user defined message that will be delivered as one of the varbinds in any “true” Trap or Inform message sent.

FalseMsg – Provides a user defined message that will be delivered as one of the varbinds in any “false” Trap or Inform message sent.

RepTrue – Used only with SNMP v1 or v2, and generally only with Trap messages (not Inform messages) to repeat the trap this number of times when true. Traps are not acknowledged, so this provides a means of repeating the same Trap message to better ensure delivery.

RepFalse – Used only with SNMP v1 or v2, and generally only with Trap messages (not Inform messages) to repeat the trap this number of times when false. Traps are not acknowledged, so this provides a means of repeating the same Trap message to better ensure delivery.

RepTime – Specifies the amount of time in seconds to wait in between repeated sending of the same Trap message as indicated by the repeat count attributes above.