# Example: Configuring Hierarchical Policy Parameters

You configure policy parameters in Global Configuration mode. Only hierarchical policy parameters can have external parent group references. Each parameter has a single value, depending on the type of parameter. The hierarchical policy parameter can have a single numeric value or a keyword.

In Interface Configuration mode, you can override the value for a policy parameter for each interface. The value for a parameter configured in Interface Configuration mode supersedes the value configured for the parameter in Global Configuration mode. However, if a parameter is not configured in Interface Configuration mode, the value configured in Global Configuration mode is used.

Each reference to a policy parameter in a policy is substituted with its value for all attachments of this policy at the interface. The value can come from the interface or global configuration for the parameter. Therefore, the value configured for the parameters referenced in policies can be different for attachments at different interfaces. This enables you to have an attachment-specific configuration in a policy list that is deferred until the policy is attached.

There are two types of values that a hierarchical policy parameter can take: numeric and keyword. Keywords are resolved to numeric values during configuration of a policy parameter at the interface.

The following example assigns a value of 10 to policy parameter A in Global Configuration mode.

host1(config)#policy-parameter A hierarchical host1(config-policy-parameter)#aggregation-node 10 host1(config-policy-parameter)#exit

The following example assigns value 1 to policy parameter A and value 2 to policy parameter B in Interface Configuration mode. Also, the value configured for parameter A in interface fast3/0.1 overrides the value configured in the previous example.

host1(config)#interface fastEthernet 3/0.1 host1(config-interface)#ip policy-parameter hierarchical A 1 host1(config-interface)#ip policy-parameter hierarchical B 2 host1(config-interface)#exit

The following example assigns keyword vlan to parameter C in Global Configuration mode.

host1(config)#policy-parameter C hierarchical host1(config-policy-parameter)#aggregation-node vlan host1(config-policy-parameter)#exit

The following example assigns keyword atm-vc to parameter C in Interface Configuration mode. Policy parameter C is assigned with interface type atm-vc for IP interface at atm3/0.1. The keyword atm-vc is resolved to the identifier of the ATM minor interface on which the IP interface atm3/0.1 is stacked.

host1(config)#interface atm 3/0.1 host1(config-interface)#ip policy-parameter hierarchical C atm-vc host1(config-interface)#exit

The following keywords are supported: atm-vc, atm-vp, atm, ethernet, vlan, svlan, fr-vc, forwarding, and ppp-interface. Table 16 indicates the mapping of shorthand notation to actual value that are used internally.

Table 16: Shorthand Notation Mapping

Shorthand number | Shorthand | Value | Supported in
--- | --- | --- | ---
1 | ATM-VP vpi | Identifier constructed from slot, adapter, port, ATM VP id. | IP, IPv6, L2TP, and MPLS policies
2 | ATM-VC | Unique identifier of the ATM minor interface | IP, IPv6, and MPLS policies
3 | Ethernet | Unique identifier of Ethernet major interface | IP, IPv6, and MPLS policies
4 | VLAN | Unique identifier of VLAN interface | IP, IPv6, and MPLS policies
5 | SVLAN | Identifier constructed from slot, adapter, port, SVLAN ID. | IP, IPv6, L2TP, and MPLS policies
6 | FR-VC | Unique identifier of frame relay minor interface | IP, IPv6, and MPLS policies
7 | ATM | Unique identifier of ATM major interface | IP, IPv6, and MPLS policies
8 | Forwarding | Unique identifier of the forwarding interface where the parameter is configured. | IP, IPv6, L2TP, and MPLS policies
9 | ppp-interface | Identifier constructed from PPP interface. | IP, IPv6 policies