Call State Replication for VoIP Session Continuity
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Solution Overview
Problem
In Next Generation Networks (NGNs), communication faults lead to the inability to process service requests due to a lack of call state information, resulting in the termination of active communication sessions when a network element fails, causing disruptions and service outages.
Innovation Solution
A method involving the transmission of specific SIP messages to establish and maintain communication sessions, allowing for seamless failover and the creation of new VoIP bearer communication paths while maintaining active sessions, ensuring continuous communication by resolving call state information deficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If call state information is replicated between active and standby call processors, then service continuity is preserved after failover, but device complexity increases
Solution Approach 1:
The patent creates a copy of the call state information from the active call processor to the standby call processor. This copying mechanism ensures that when failover occurs, the standby processor already possesses the necessary call state information to continue service without interruption, thus resolving the contradiction between maintaining service continuity and avoiding complex replication mechanisms.
Solution Approach 2:
The patent performs call state information replication in advance, before the actual failover event occurs. By pre-populating the standby processor with call state data during normal operation, the system eliminates the need for complex real-time synchronization mechanisms during failure scenarios, thereby maintaining reliability while controlling device complexity.
2Reliability
If a network element fails without call state information, then service outage occurs, but maintaining redundant call state information increases information storage requirements
Solution Approach 1:
The patent applies local quality by storing call state information specifically at the standby network element where it is needed for failover, rather than replicating it universally across all network elements. This targeted approach ensures service availability at the critical failover point while minimizing unnecessary information storage throughout the broader network infrastructure.
3Reliability
If new VoIP bearer paths are established during active sessions, then communication continuity is maintained, but device complexity increases due to multiple concurrent paths
Solution Approach 1:
The patent implements a dynamic path management mechanism where the system can transition from an original VoIP bearer path to a new VoIP bearer path while maintaining active communication sessions. The dynamic nature of this mechanism allows the system to adapt to network conditions and failover scenarios, ensuring communication continuity while managing the complexity of concurrent paths through automated path selection and switching.
Data Source
AI summary
A system that incorporates teachings of the present disclosure may utilize, for example, a method involving receiving from a first communication device a service request while providing back-up services to an out-of-service network element, detecting a deficiency in call state information to process the service request, transmitting to the first communication device an error message that prevents termination of an active Internet Protocol (IP) communication path between the first communication device and a second communication device, and receiving from the first communication device a request for an alternate IP communication path for communicating between the first and second communication devices which resolves the deficiency in call state information. Additional embodiments are disclosed.