The SBC can be configured to operate with up to 40 active policy servers (as of Release 7.2.1) for load sharing and/or redundancy in a Centralized PSX routing scenario.

Policy requests are distributed among active PSXs via the round robin process. When an active PSX becomes congested, the SBC applies call-gapping to distribute any overflow traffic to an uncongested active server in the pool, or else to an uncongested standby server. For example, if a PSX becomes congested such that only three out of four transactions get through, then one out of four transactions skip the server and overflow to another server in the 'Active' state.

The SBC promotes a standby PSX to 'Active' status whenever one of the currently-active PSX goes out-of-service or becomes unreachable.

Procedure

This section provides examples of the steps an administrator uses from CLI and EMA to configure the SBC to communicate with external PSX policy servers in 'Active', 'Standby' or 'Alternate' modes.

When configuring external PSXs for Centralized PSX routing, it is highly recommended to put the local policy server (ERE) out-of-service.

The external PSX pool maximum is increased to 40 as of Release 7.2.1. 

  1. Set the local policy server mode to "outOfService".

    1. CLI:

      % set system policyServer localServer PSX_LOCAL_SERVER mode outOfService 
% show system policyServer localServer PSX_LOCAL_SERVER
   state            disabled;  
   mode             outOfService;  
   action           dryUp;  
   transactionTimer 2500;  
   keepAliveTimer   5;  
   retryTimer       2500;  
   retries          1;

    2. On SBC main screen, navigate to Configuration > System Setup > Policy Server > Local Server. The Local Server window is displayed.
      Figure 1: Local Server




  2. Set the global configuration.

    1. CLI:

      % set system policyServer globalConfig reconnectTimeout 10 switchOverMode automatic congestionControl enabled type mgmt mgmtInterfaceGroup mgmtGroup 
% show system policyServer globalConfig  
	reconnectTimeout    10;  
	switchOverMode      automatic;  
	congestionControl   enabled;  
	type                mgmt;
	mgmtInterfaceGroup  mgmtGroup

       

    2. On SBC main screen, navigate to Configuration > System Setup > Policy Server > Global Config. The Global Config window is displayed.

  3.  To configure an external PSX as an Active remote policy server, use settings similar to the example below:

    1. CLI:

      % set system policyServer remoteServer PSX1-A ipAddress 10.20.123.12 state enabled mode active 
% show system policyServer remoteServer PSX1-A  
   ipAddress 10.20.123.12;  
   state enabled;  
   mode active;

    2. On SBC main screen, navigate to Configuration > System Setup > Policy Server > Remote Server. The Remote Server window is displayed

  4. To configure an external PSX as a Standby remote policy server, repeat step 3 except set Mode to "standby".

    1. CLI:

      % set system policyServer remoteServer PSX1-B ipAddress 10.20.123.13 state enabled mode standby 
% show system policyServer remoteServer PSX1-B  
   ipAddress 10.20.123.13;  
   state enabled;  
   mode standby;

    2. On SBC main screen, navigate to Configuration > System Setup > Policy Server > Remote Server. The Remote Server window is displayed

  5. To optionally configure SBC to communicate with a remote policy server that will not receive any query messages from the SBC but can still send messages to it, set the remote policy server mode to "alternate".

    This deployment model is intended for networks where PSXs are interacting with an SCP which may generate and deliver unsolicited mid-call action events to the SBX via the PSX. In other words, this model connects SBC to PSXs not directly used by the SBC to route calls so that it may receive SCP-generated mid-call action events from those PSXs. 

    1. CLI:

      % set system policyServer remoteServer PSX2-A ipAddress 10.20.123.14 state enabled mode alternate  
% show system policyServer remoteServer PSX2-A  
   ipAddress 10.20.123.14;  
   state     enabled;  
   mode      alternate;

    2. On SBC main screen, navigate to Configuration > System Setup > Policy Server > Remote Server. The Remote Server window is displayed.

For a complete list of commands and parameters, please refer to either the CLI Reference Guide or EMA User Guide. 


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