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Overview

Note

This configuration is not supported on ERE and is intended for use with an external PSX and/or ePSX only.

The SBC is enhanced to support a flexible policy mechanism to facilitate dynamic routing and policy decisions based on any SIP message information element whereby routing and policy selection criteria are provisioned by the operator. An information element can be anything in the message, such as the following examples:

  • SIP header value
  • Presence or absence of a header
  • String in a message body
  • Parameter value
  • Presence or absence of a parameter

The flexible policy process is summarized below:

  • Operator dynamically programs SBC using flexible policy rules for extracting SIP information elements and populating variables.
  • Operator provisions PSX’s flexible routing and policy framework to use those variables as criteria for selecting routes and policies.
  • When a message is received by the SBC, flexible policy adapter profile rules are applied to populate the variables. These variables are sent in the policy request to Policy Execution Server (PES).
  • PES matches the received information contained in these variables to provisioned criteria and returns routes and policies in policy response.
  • SBC applies policies returned in the policy response and routes the message using routes received in the policy response.

Figure : Flexible Policy Mechanism

Figure : Flexible Policy Mechanism on SBC-PSX

The SBC supports creating a SIP adaptor profile designated for the flexible policy mechanism. This flexiblePolicyAdapterProfile profile is provisioned and attached to either/both the ingress Trunk Group or Ingress Zone. If flexiblePolicyAdapterProfile is provisioned both at the trunk group and zone, the trunk group’s profile takes precedence. If inputAdapterProfile is configured, it is applied first to manipulate the PDU and then flexiblePolicyAdapterProfile rules are applied on the manipulated PDU.

Flexible Policy and Routing Enhancements for PSX

SBC applies flexible policy rules on received SIP messages to store information in variables. These variables are then passed to PSX over the Diameter+ interface in a policy request message.

The PSX uses the received information contained in these variables as a part of its enhanced Routing and Policy decision making. Refer to PSX documentation for additional details.

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