Empirical observations of traffic patterns in mobile and IP telephony

This paper provides recent empirical traffic data and observations of telephony traffic patterns in mobile and IP telephony. These are compared with old telephony patterns from Public Switched Telephone Networks (PSTN) to investigate potential evolution and impact on traffic characterisations due to technology changes from fixed to mobile phones, changes in quality from fixed phone to mobile and IP telephone, changes in tariffs from usage based to flat-rate subscriptions, and appearance of alternative message based communication means. The results show different daily and weekly traffic profiles compared to PSTN telephony. In particular, the profile of international calls is significantly changed. Furthermore, the average call holding times show significant variations over the day in flat-rate subscriptions. Finally, the results indicate that the Short Message Service (SMS) seems to serve as a supplement to phone calls, in particular in the evenings, which might change call holding time distribution and traffic intensities.