Citrix Systems 9.2 Evaluation Order Within a Policy Bank, Format of Each Entry in a Policy Bank

20 Citrix NetScaler Policy Configuration and Reference Guide

The following table summarizes each entry in a policy bank.

Format of Each Entry in a Policy Bank

Policy Name	Priority	Goto	Invocation	Policy Bank to
		Expression	Type	be Invoked
The policy name, or a	An integer.	Optional.	Optional.	Optional.
“dummy” policy		Identifies the	Indicates that	Used with
named NOPOLICY.
		next policy in	an external	Invocation
The NOPOLICY
		the bank to	policy bank	Type. This is
entry controls
		evaluate, or	will be	the label for a
evaluation flow
		ends any	invoked.	policy bank or
without processing a
		further		a virtual server
rule. For more			This field
		evaluation.		name.
information, see			restricts the
				The NetScaler
“Evaluation Order			choices to a
Within a Policy			global policy	returns to the
Bank,” on page 20.			label or a	current bank
			virtual server.	after
				processing the
				external bank.

If the policy evaluates to TRUE, the NetScaler stores the action that is associated with the policy. If the policy evaluates to FALSE, the NetScaler evaluates the next policy. If the policy is neither TRUE nor FALSE, the NetScaler uses the associated Undef (undefined) action.

Evaluation Order Within a Policy Bank

Within a policy bank, the evaluation order depends on the following items:

•A priority. The most minimal amount of information about evaluation order is a numeric priority level. The lower the number, the higher the priority.

•A Goto expression. If supplied, the Goto expression indicates the next policy to be evaluated, typically within the same policy bank.. Goto expressions can only proceed forward in a bank. To prevent looping, a policy bank configuration is not valid if a Goto statement points backwards in the bank.

•Invocation of other policy banks. Any entry can invoke an external policy bank. The NetScaler provides a built-in entity named NOPOLICY that does not have a rule. You can add a NOPOLICY entry in a policy bank when you want to invoke another policy bank, but do not want to process any other rules prior to the invocation. You can have multiple NOPOLICY entries in multiple policy banks.

Values for a Goto expression are as follows: