Designing and Managing Behavior Models - Using Trap Masks - Defining a Trap Mask -
Listing Trap Masks      Writing a Trigger Function

Defining a Trap Mask

This section outlines the procedure for creating a trap mask.

 
  To define a new trap mask:

1. From the client's Admin menu, choose Mask List.

   NerveCenter displays the Mask List window.

   

2. Select the New button.

   The Mask Definition window appears.

   

3. In the Name text field, type a unique name for the trap mask.

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      The maximum length for trap mask names is 255 characters.

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      A trap mask name should describe the type of trap the mask is looking for, for example, "ColdStart."

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4. From the Generic list box, select a generic trap type.

   Before a trap mask can fire a trigger, the value of this field must match the value of a trap's Generic trap field, which may contain any of the enumeration constants shown in Generic Trap Values:

   Generic Trap Values

   Constant	Meaning
   coldStart (0)	Signifies that the sending protocol entity is re-initializing itself such that the agent's configuration or the protocol entity implementation must be altered.
   warmStart (1)	Signifies that the sending protocol entity is re-initializing itself such that neither the agent configuration nor the protocol entity implementation is altered.
   linkDown (2)	Signifies that the sending protocol entity recognizes a failure in one of the communication links represented in the agent's configuration. The trap PDU of type linkDown contains as the first element of its variable bindings the name and value of the ifIndex instance for the affected interface.
   linkUp (3)	Signifies that the sending protocol entity recognizes that one of the communication links represented in the agent's configuration has come up. The trap PDU of type linkUp contains as the first element of its variable bindings the name and value of the ifIndex instance for the affected interface.
   authenticationFailure (4)	Signifies that the sending protocol entity is the addressee of a protocol message that is not properly authenticated.
   egpNeighborLoss (5)	Signifies that an EGP neighbor for whom the sending protocol entity was an EGP peer has been marked down and that the peer relationship no longer exists. The trap PDU of type egpNeighborLoss contains as the first element of its variable bindings the name and value of the egpNeighAddr instance for the affected neighbor.
   enterpriseSpecific (6)	Signifies that the sending protocol entity recognizes that some enterprise-specific event has occurred. The Specific trap field identifies the particular trap that occurred.

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      The definitions in Generic Trap Values are taken from RFC1157.

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   If you select EntSpecific = 6 (an enterprise specific trap), the Specific text field is enabled, and you must enter a vendor-specific trap number in that field.

   If you select AllTraps = -1, the mask will disregard the contents of each trap's Generic trap field when looking for traps of interest. That is, any generic trap type in the trap meets the trap mask's requirement.

5. If you want the trap mask to examine the contents of a trap's Enterprise field, follow these directions:
   1. Select the Filter on Enterprise scope checkbox.

      Controls in the Enterprise group box become enabled.

   2. Select one of the following radio buttons:
   • From -- specify that the trap's Enterprise field must contain an OID that either matches the OID in your mask's Enterprise field, or is subordinate to it.
   • From Only -- indicate that the trap's enterprise must match the mask's enterprise exactly.
   1. In the Enterprise text field, enter an OID, or a name that maps to an OID.
6. If the trap NerveCenter will process is an SNMP version 2c or 3 trap, select the v2C/v3 radio button.
7. For SNMP v1 traps, if your mask's generic trap type is 6 (enterprise specific), enter a vendor-specific trap number in the Specific text field.

   Before the mask can fire a trigger, the number you enter in the Specific field must match the value of a trap's Specific trap field.

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      To determine what enterprise specific traps an SNMP agent can produce, consult the vendor's ASN.1 files or other documentation.

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8. For SNMP v2c or v3 traps, enter the trap OID.

   You can select one of the OID values, choose All Traps, or type the value for a particular enterprise trap OID. SNMP v3 trap OID values map to generic traps as shown in SNMP v3 trap OID/Generic Value Mappings.

SNMP v3 trap OID/Generic Value Mappings

1. Select one of the Trigger Type radio buttons:
   • Simple Trigger -- if the values in your mask's Generic, Enterprise, and Specific fields are sufficient to define the trap you are looking for.
   • Trigger Function -- if you need to specify additional information: for example, the values of variable bindings.

     If you select the Simple Trigger radio button, the Simple Trigger combo box is enabled.

2. In step 9, if you selected:
   • Simple Trigger -- enter a trigger name in the Simple Trigger field. You can either type in the name of a new trigger or choose a trigger from the list of existing triggers.
   • Trigger Function -- select the Trigger function tab, and enter a trigger function on the Trigger Function page.

     This trigger function is a Perl subroutine that you can use to check the values of variable bindings or examine other pertinent information and to fire appropriate triggers. For complete information on writing trigger functions, see the section Writing a Trigger Function.

3. Select the Save button at the bottom of the Mask Definition window to save your mask.

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      Remember that you must enable the trap mask (by setting Enabled to On) before using it in a behavior model. While the mask is disabled, it is not used in the examination of any incoming traps. This means that any behavior models that use this trap mask as the sole source of triggers are also disabled.

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