What's about ETSI event?

[Trompo]

Hi everyone, i'm post procesing using Nemo Analize and I need to get "drop call" and "Call Setup Fail", but I don't know what is the difference between "Call Failures" and "Call Attempt Failure ETSI" and the difference between "Call Dropped" and "Call Dropped ETSI". What is ETSI?

Please help me.
BR