High availability Consideration
In Cisco VVB there are two types of high availability models:
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Comprehensive
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Standalone
Comprehensive Model
Cisco Virtualized Voice Browser is a single node and there is no high availability inbuilt for active redundancy. In order to improve level of availability and to eliminate single point of failure, deploy additional Cisco VVB(s) to build passive redundancy by including the additional Cisco VVB(s) in the CVP SIP Server group.
When CVP detects failure of one of the Cisco VVB's in the SIP Server group, CVP will continue to route calls to remaining active Cisco VVBs, thereby, allowing new calls to be accepted.
Note |
All active calls on the failed Cisco VVB will disconnect and all the call data is lost. |
When the failed Cisco VVB recovers and is detected by CVP heartbeat mechanism, CVP will start routing calls to the recovered Cisco VVB. So by deploying redundant Cisco VVBs, you can manage unscheduled and scheduled downtime of one of the Cisco VVBs.
Standalone Model
For standalone call model, user can configure primary and secondary VXML servers for an application. On arrival of a new call, if the primary server fails to respond to new session request, Cisco VVB will attempt to establish new session with the secondary server. If VXML server goes down when a session is already established, Cisco VVB will play a critical error message as part of error handling.
In order to improve level of availability and to eliminate single point of failure, deploy additional Cisco VVB(s) to build passive redundancy. One of the methods by which this can be done is by including the additional Cisco VVB(s) in the Ingress GWs dial-peer configuration. For this create ‘voice class uri’ for ‘VVB’ and then add dial-peers for various VVBs which define destination session target for the uri ‘VVB’ (refer to IOS-GW documentation for more details). This way the Ingress GW will load balance between the various deployed VVBs and if any of the VVB serving standalone call model fails, then Ingress-GW will continue to route new calls to remaining active VVBs.
Note |
Survivability is currently unavailable for Standalone Model deployment. |