OCS Load Balancing in SIP Cluster

Starting with release 8.1.522.05, when operating in SIP Cluster deployments with multiple SIP Cluster nodes, OCS supports load distribution in the following dialing modes: Progressive, Predictive, Progressive with Seizing, Predictive with Seizing, Progressive GVP, Predictive GVP, and Power GVP. OCS distributes the load by issuing requests to dial outbound and engaging calls to multiple SIP Cluster nodes. OCS uses one of the SIP Cluster nodes (called the prime node) to subscribe and receive all DN-related events.

See the Configuring Outbound Contact topic about configuring OCS in the SIP Cluster environment.

Regular (non-ASM) Dialing Modes (Progressive, Predictive, Progressive GVP, Predictive GVP, Power GVP)

When load balancing is enabled, in the regular (non-ASM) dialing modes, OCS evenly distributes TMakePredictiveCall requests for outbound calls between all SIP Cluster nodes in round-robin fashion. OCS maintains a list of active (connected) primary/backup SIP Cluster nodes and sends each new TMakePredictiveCall request to the subsequent active node. OCS checks the state of an inactive node on the next round and attempts to send a TMakePredictiveCall request to it when it becomes active.

OCS receives all DN-level T-Events from the prime SIP Cluster node.

OCS attempts to reconnect to a backup SIP Server Application if a connection with the primary SIP Server is lost. OCS considers a SIP Cluster node inactive if connections to both the primary and backup SIP Server Applications are lost. OCS stops dialing if a connection is lost to the prime SIP Cluster node (both the primary and backup SIP Server Applications are disconnected).

ASM Dialing Modes (Progressive with Seizing, Predictive with Seizing)

In ASM dialing modes, OCS balances the load per Campaign Group, where each Campaign Group can use a different SIP Cluster node for dialing. OCS always uses the same SIP Cluster node to dial outbound and engaging calls for the same Campaign Group. You designate a SIP Cluster node to be used for dialing for a Campaign Group in the Agent Group level option sip-cluster-asm-dial-node. OCS sends TMakePredictiveCall (for outbound calls) and TMakeCall (for engaging calls) requests to that SIP Cluster node. If this option is not configured or a SIP Server Application with the configured DBID is not present in the OCS Application connections, OCS uses the prime SIP Cluster node for dialing for that Campaign Group.

OCS attempts to reconnect to a backup SIP Server Application if a connection with the primary SIP Server is lost. OCS considers a SIP Cluster node inactive if connections to both the primary and backup SIP Server Applications are lost. OCS stops dialing for a Campaign Group if a connection is lost to the prime SIP Cluster node or to the dialer node that is used for the Campaign Group.

Enabling Load Balancing Mode

To enable load balancing mode:

1. Add primary SIP Server Applications of the SIP Cluster nodes (all that will be included in load balancing) to the Connections tab of the primary OCS Application object. OCS can be connected to T-Controller ports (TCport) or Smart Proxy ports (SmartProxy) of SIP Cluster nodes.
2. Designate one SIP Custer node as the prime node to distribute DN-related events to OCS.
3. (For ASM modes only) Designate a SIP Cluster node for each Campaign Group to use as a dialer node. Genesys recommends distributing Campaign Groups equally between SIP Cluster nodes, so that the final load on SIP Cluster is balanced.
4. Configure the following configuration options:
   • sip-cluster-lb-mode—Set this option to round-robin.
   • sip-cluster-prime-node—Set this option to the valid DBID of the primary SIP Server Application object of the SIP Cluster node that is designated as the prime one for outbound dialing.
   • sip-cluster-asm-dial-node—(For ASM modes only) Set this option to the valid DBID of the primary SIP Server Application object of the designated dialer SIP Cluster node at the Agent Group object that is associated with the Campaign Group. This option must be set for every Agent Group associated with Campaign Groups which will run in ASM modes.
5. Restart OCS for the configuration changes to take effect.