Improvements in failure detection for emergency service centers in IMS network

Migration of customers from PSTN to IMS network brings challenges in replacing the existing services with equal services on the IMS network. Emergency service centers are special types of customers that require high availability of the service and fast responses to potential failures. Differences in technology require different approaches for handling same requirements. This paper describes the method for detection of failures on emergency service centers in IMS network that we have implemented in our network. The method is based on charging events for the detection of alternative call routing cases in the situations of unavailability. In the paper we describe the motivation for such approach and analyze the results and types of failures we encountered. In addition, the paper provides wider aspects of the implementation of the emergency service centers in IMS network.