Contact Expert v7.5

Behavior of Contact Expert and OnCall IVR in High-Availability Cases

Overview

This article describes how redundantly deployed CE and IVR systems operate after a failover situation.

IVR Server Failure

OnCall IVR relies on the Microsoft telephony platform's load balancing / redundancy services, therefore when deployed in multiple instances and any one of these fail, the telephony system figures out which of the remaining IVR instances are available and re-routes subsequent calls to it automatically.

The next calls immediately following an IVR failure – though will be rerouted – might suffer some delays as the telephony system needs to confirm such a failure happened, which takes some time.

CE Server Failure

OnCall IVR in Frontend

When the first treatment a calling customer receives is performed by an IVR solution, then that IVR is acting as a "frontend" of the contact centre. These sections describe the configuration options at play during failover scenarios in this setup.

CE Integration Link Redundancy in Frontend Mode – IVR Component Service

To add integration link resiliency, this component needs to be configured to connect to more than one CE Core Host computer. If one of the links times out, the IVR takes the next URL in line, and so on.

CE Campaign Endpoint Redundancy – Call Transfer Resiliency

When the IVR transfers a call to a SIP or TEL URI – defined as service endpoints within the affected CE system – the affected CE queue receives it and runs all affected business logic defined as Dialing Rules, etc. If however the target CE system is down while the relevant endpoint is up and running, the call will be handled by the telephony platform.

OnCall IVR can be configured to perform endpoint status checks before attempting to transfer a call, however this must be explicitly set in the Component Server's configuration file, and also an additional Node need to be added to the IVR tree to trigger this before a transfer (see below for details).

Read more about how to configure OnCall IVR to handle endpoints in the Endpoint Service setup article.

Custom Nodes

The following Custom Nodes need to be enabled so that the IVR can serve the call requests.


`CEFailingOver`	If this option is enabled, the IVR can check whether the failover/failback procedure is in progress. It is done with the use of management service requests.
`EndpointAvailable`	If this option is enabled, the IVR can check whether the specified SipURI is responding to requests. The EndpointStateCheck node needs to be enabled in CompSrv web.config file for this to work.

OnCall IVR in Backend

When the IVR is used to automate certain agent tasks, then it is acting as a "backend" service within the contact center. On top of the standard integration link provided via its Component Service the IVR also needs to maintain its 'agent channel' communication with CE.

CE Integration Link Redundancy in Backend Mode – IVR Component Service

Read more about OnCall IVR's Component Server.

IVR Agent Channel Resiliency

In backend mode, the IVR needs to maintain an additional connection with CE – this time with CE's IVR Connector Service – to be able to signal its readiness to CE. Assuming a HA CE, the IVR uses its Component Service integration link to discover which CE server is active, and attempts to maintain this agent channel connection with that.

Read more about the details of setting up an IVR solution in backend mode in the How to set up IVR scripts to act as CE IVR channels article.

Co-locating IVR and CE

The failover configuration options outlined in this article should be applied in this co-locating scenario without change.