Learning How to Create Behavior Models - How to Use Alarm Scope in Behavior Models - What is Alarm Scope? -
How to Use Alarm Scope in Behavior Models      How to Use Alarm Scope in a Multi-alarm Behavior Model

What is Alarm Scope?

Each alarm has a scope, which is a setting that determines which triggers are applied to that particular alarm. An alarm scope can be one of the following:

• Enterprise Scope manages one alarm instance for all the applicable nodes (that is, all nodes with the alarm's property) in the enterprise.
• Node Scope manages only one alarm instance for a single node.
• SubObject Scope manages multiple alarm instances for a single node. One instance is managed for each occurrence of the managed object. A subobject scope alarm is limited by both the object and the instance. Each interface, port, or other managed object can cause an alarm instance.
• Instance Scope tracks alarm instances for each instance of any managed object, regardless of the base object polled. An instance scoped alarm is limited by the instance, but not the object being tracked.

Another way to describe scope is to illustrate which trigger components need to match in order for an alarm to advance to the next state, as shown in Properties Needed to Match Scope.The scopes are listed on the left and the properties required to match the scope are listed across the top.

Properties Needed to Match Scope

	Trigger Name	Property	Node	SubObject	Instance
Enterprise
Node
Subobject
Instance

For example, if you assign an instance scope to an alarm, the trigger name, property, node and instance must all match to advance the alarm to the next state. The subobject may vary.

Consider the following example: suppose a car rental company were to use NerveCenter to keep track of flat tires. Mid-size Car A and Mini-Van B have one flat and Compact Car D has two. How does varying the scope change the results?

A Car Rental Company Uses Alarm Scope to Keep Track of Flats

 
  Enterprise Scope (Fleet):

• Polls the Western or Eastern fleet to see if at least one flat tire exists.
• Does not care which car or which tire has a flat. Does not care how many flats exist.
• Notifies the tire repair company since the fleet contains at least one flat tire.

Enterprise Scope is not a good choice for monitoring flat tires, because you receive one notification whenever a tire is flat. If you are monitoring hundreds of cars, knowing that at least one car, but not which car or cars, has a flat tire is not helpful. However, Enterprise Scope is a good choice for monitoring car availability. If you were monitoring car availability, you would know that the Eastern Fleet has at least one car available.

 
  Node Scope (Car):

• Returns information that Mid-Sized Car A has at least one flat, Mini-Van B has at least one flat, and Compact Car D has at least one flat.
• Does not care how many or which tires are flat.
• Notifies the reservation system that it is down one compact car, one mini-van and one mid-size car.

Node Scope is also not a good choice for monitoring flat tires because it doesn't tell you what tire on the car is flat. However, Node Scope is useful for monitoring parts of the car of which there is only one, such as an engine or air conditioner. You could also poll to check if the insurance and registration for each car are valid.

 
  SubObject Scope (Tire):

• Returns information that Mid-Size Car A and Mini-Van B have one flat and Compact Car D has two flats.
• Notifies the inventory department, so it can keep track of the number of spare parts needed for each car.

SubObject Scope is the best choice for monitoring flat tires because it provides the information you need to order new parts and let you know which cars are unavailable.

 
  Instance Scope (Specific Tire and Specific Brake Pads):

• Returns information about the flat tires for Cars A, B and D, but can then monitor other conditions, such as wheel alignment, the condition of brake pads, or shocks.
• Notifies the service department of each condition detected.

Instance Scope is not a good choice for monitoring for flat tires, but it is very useful for seeing what else might be wrong if you have a flat tire.

As the above example illustrates, scope limits what an alarm monitors. The best scope depends on what information is important for your behavior model.