VPN-Related Configuration Commands

Configuring the CNA system to work with an IP-routed VPN is essentially no different than configuring the device to optimize web traffic, except that there are some configuration commands that allow you to focus the CNA configuration to apply specialized policies for a much smaller number of predetermined destinations:

• tunnel optimization--using the outbound-bgp-community (discontinued) command, you can define BGP community values to force traffic through a predetermined interface, such as a tunnel connecting your enterprise headquarters with a remote location
• prefix specialization--using the route-assert-filter command, you can configure the CNA system to assert routes for prefixes that are not contained in the BGP tables, which would allow you to assert a route to any prefix, such as a single /32 prefix (an interface at your remote location, for example); any prefix associated with a policy by the set-decision-policy command will be created in the database, whether it is in a BGP table
• preferential decision-making--using the priority-prefix command, you can designate your remote-location VPN interfaces for preferential treatment, which means the CNA decision-maker process will always evaluate them first
• targeted policies--using the decision-policy commands, you can have one set of decision-making parameters such as winner-set width and link penalties for individual prefixes or small groups of prefixes (such as your VPN endpoints) and another set of policies of all other prefixes

See Chapter 6: Decision Policies and Application Models in the CNA Basic Monitoring Guide for information about configuring decision policies and designating prefixes for preferential treatment.