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Configuring and binding a traffic rate policy

You implement rate-based application behavior by configuring a policy in an appropriate NetScaler feature. The feature must support Advanced policies. The policy expression must contain the following expression prefix to enable the feature to analyze the traffic rate:

sys.check_limit(<limit_identifier>)
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Where limit_identifier is the name of a limit identifier.

The policy expression must be a compound expression that contains at least two components:

  • An expression that identifies traffic to which the rate limit identifier is applied. For example:
    http.req.url.contains("my_aspx.aspx").
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  • An expression that identifies a rate limit identifier, for example, sys.check_limit(“my_limit_identifier”). This must be the last expression in the policy expression.

To configure a rate-based policy by using the command line interface

At the command prompt, type the following command to configure a rate-based policy and verify the configuration:

add cache|dns|rewrite|responder policy <policy_name> -rule expression && sys.check_limit("<LimitIdentifierName>") [<feature-specific information>]
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Following is a complete example of a rate-based policy rule. Note that this example assumes that you have configured the responder action, send_direct_url, that is associated with the policy. Note that the sys.check_limit parameter must be the last element of the policy expression:

add responder policy responder_threshold_policy "http.req.url.contains("myindex.html") && sys.check_limit("my_limit_identifier")" send_direct_url
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For information about binding a policy globally or to a virtual server, see “Binding Advanced policy Policies.”

To configure a rate-based policy by using the configuration utility

  1. In the navigation pane, expand the feature in which you want to configure a policy (for example, Integrated Caching, Rewrite, or Responder), and then click Policies.

  2. In the details pane, click Add. In Name, enter a unique name for the policy.

  3. Under Expression, enter the policy rule, and make sure that you include the sys.check_limit parameter as the final component of the expression. For example:

    http.req.url.contains("my_aspx.aspx") && sys.check_limit("my_limit_identifier")
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  4. Enter feature-specific information about the policy.

    For example, you may be required to associate the policy with an action or a profile. For more information, see the feature-specific documentation.

  5. Click Create, and then click Close.

  6. Click Save.

Configuring and binding a traffic rate policy