QoS monitoring and failure detection

This paper deals with two algorithms for monitoring the QoS and based on it to detect failures in voice communication systems. These algorithms are based on the analysis of data stored in Call Detail Records (CDR). For each call one CDR or ticket is generated. These tickets contain data related to the call describing the system elements involved, such as time and duration of the call, phone types and numbers, SS7 signaling, trunks, time slots, what happen to the call, etc. The tickets are generated in PSTN switches or over VoIP gateways, for the case of Internet Protocol Detail Record (IPDRs). These tickets can be used to monitor the QoS and to detect faults focusing in different aspects related to the call, such as technical, economic, or social. Our main goal is to analyze and classify these algorithms according to their performance and use.