Classification Scripts Overview

The service activation engine (SAE) uses classification scripts to determine whether it manages router interfaces, to select default policies, to find subscriber profiles, and to choose Dynamic Host Configuration Protocol (DHCP) profiles. The SAE has three classification scripts:

How Classification Scripts Work

Classification scripts consist of targets and conditions.

Each script can have multiple targets, and each target can have multiple conditions. When an object needs classification, the script processes the targets in turn. Within each target, the script processes conditions sequentially. When it finds that the classification conditions for a target match, it returns the target to the SAE. If the script does not find any targets that can be matched, the classifier engine returns a no-match message to the SAE.

Because classification scripts examine conditions sequentially as the conditions appear in the script, you should put more specific conditions at the beginning of the script and less specific conditions at the end of the script.

Interface Classification Scripts

When a subscriber’s IP interface comes up on the router, the router sends the subscriber’s login and interface information to the SAE. For example, the router might send the following information:

IP address=0.0.0.0Virtual router name=default@erx5_ssp58 Interface name=FastEthernet3/1.1PPP login name (PPP)=pebbles@virneo.netUser IP address (PPP)=192.168.55.5Interface speed=100000000Interface description=P3/1.1Interface alias=1st pppoe intRADIUS class=null

The SAE invokes the interface classification script and provides to the script the information that it received from the router. The script engine matches the information sent from the router to the conditions in the interface classification script. The script examines each condition in sequential order to find a match.

Subscriber Classification Scripts

When the SAE begins managing an interface, it determines whether a subscriber is associated with the interface by running the subscriber classification script. The SAE also runs the subscriber classification script when certain login events occur. See Login Events for a description of login event types.

To find the matching subscriber profile, the SAE uses interface information that it received from the router when the interface became operational (for example, virtual router name, interface name, interface alias). It also uses login information that it received from the router or the portal application when the subscriber attempted to log in (for example, subscriber IP address, login name, or login event type).

When the SAE runs the subscriber classification script, the script engine matches the information sent from the router to the conditions in the subscriber classification script. The script examines each condition in sequential order to find a match.

DHCP Classification Scripts

DHCP classification scripts choose DHCP profiles. See Assigning DHCP Addresses to Subscribers for information about how DHCP classification scripts are used.

Sharing Information Among Classification Scripts

In many instances, the same classification rule may appear in different classification scripts. You can reuse the same information in different scripts by configuring the information in one script and including that information in another script. Interface, subscriber, and DHCP classification scripts all let you include another script.

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