the control plane signalling can be inspected and details from it collected and stored to the database in that case i a the gtp teid mobile phone 39 s ip address imsi imei are recorded and stored to call details fig7 depicts an example of the qos measuring application 406 this comprises a qos agent 802 qos analyser 804 and qos user interface 806 the qos agent 802 collects packet time stamp info and performs qos measurements among others the delay in a network and its throughput are measured and the signal jitter is calculated the qos agent 802 makes the measurements on grounds of the commands which come through the qos user interface 806 and are based on the external control from a monitoring person the commands include addresses for data collecting such as ip source destination addresses tcp udp ports and gtp teids the measuring targets and measurement start stop controls measurements in all can be done in all layers in case of s1 are traced the packets made by protocols udp ip and ethernet below gtp and u2018 tunnelled u2019 protocols ap tcp or udp and ip above gtp gtp itself included the qos agent 802 returns periodically the measurement results and collected packet time stamp information to the qos analyser 804 the interface 808 between the qos agent and analyser is preferably a tcp ip socket there can be several qos agents 802 connected to one qos analyser 804 in which case the qos analyser can calculate correlation results for instance for delay and packet drops between the nodes to which the agents are.