MODELING CALL HOLDING TIME DISTRIBUTIONS FOR CCS NETWORK DESIGN AND PERFORMANCE ANALYSIS

The message traffic offered to the CCS signaling network depends on an d is modulated by the traffic characteristics of the circuit switched calls supported by the CCS network. Most previous analyses of CCS netw ork engineering, performance evaluation and congestion control protoco ls generally assume an exponential holding time of circuit switched ca lls. Analysis of actual holding time distributions in conversations, f acsimile and voice mail connections revealed that these distributions radically differ from the exponential distribution. Especially signifi cant is the large proportion of very short calls in real traffic in co mparison with the exponential distribution model. The diversity of cal ls (partial dialing, subscriber busy, no answer) and services results in a multi-component call mix, with even larger proportion of short ti me intervals between message-generating events. Very short call holdin g times can have a significant impact on the traffic stream presented to the CCS network: for calls with short holding times, the different CCS messages arrive relatively close to each other, and this manifests as burstiness in the CCS traffic stream.