Ratio attempts and the total number of PDP context activation attempts. Equation: ETSI TS 102 250-2 V2.2.1 (2011-04) PDP Context Activation Time Definition:The PDP context activation time describes the time period needed for activating the PDP context. Equation: Note 5: While determining the average PDP context activation time only successful activation attempts are included in the calculations ETSI TS 102 250-2 V2.2.1 (2011-04) PDP Context Cutoff Ratio Definition: The PDP context cut-off ratio denotes the probability that a PDP context is deactivated without being initiated. Equation: Note 6: Precondition for measuring this parameter is that a PDP context was successfully established first ETSI TS 102 250-2 V2.2.1 (2011-04) FIXED NETWORKS Call Setup Success Rate Definition: Call Setup success rate is defined as the ratio of successful calls to the total number of call attempts in a specified time period. (CSSR) Equation: Where: Note 7: An unsuccessful call is a call attempt to a valid number, properly dialled following dial tone, where neither called party busy tone, nor ringing tone, nor answer signal, is recognized at the access of the calling user within 30 seconds from the instant when the last Regulations for Quality of Service of Cellular Mobile and Fixed Networks Services (Voice, SMS and 3G Data) 14