Dynamic decision policies

Dynamic decision policies are policies that the CNA system automatically assigns to subnets. Instead of manually assigning a decision policy to particular subnet (as in the previous examples), you can give CNA general guidelines for making these assignments.

For example, if you configure an active measurement group to probe endpoints involved in VoIP traffic that the EFC module is tasked to find, you can configure the CNA system to use a decision policy that will optimize VoIP traffic for the endpoint’s entire subnet (not just the endpoint found by EFC). The policy is considered to be dynamic because the subnet is automatically associated with the policy when the endpoint is first measured. This eliminates the need for you to specifically configure which prefixes require a specific policy.

Decision policies are automatically assigned to subnets in the following circumstances:

• Active measurements: When CNA attempts to measure an endpoint in an active measurement group, then its subnet is associated with the decision policy that you assigned to the active measurement group (by using the set-decision-policy command). If you did not assign a decision policy to the group, then the default, global decision policy is used.
• Single-pixel .gif measurements: If auto-creation of subnets is enabled, the decision policy that is assigned to a newly detected endpoint (using the set-decision-policy command) is assigned to its subnet. If no decision policy is assigned, then the default, global policy is assigned to the subnet.

When auto-creation of subnets is enabled, every time CNA detects a new endpoint, it creates a more-specific subnet (if one does not already exist).