Uncovering Cellular Network Characteristics : Performance , Infrastructure , and Policies

Mobile Smart Devices (Smartphones and tablets) have become increasingly popular especially in IT based service management companies. According to IDC, more than 70% of executives and sale managers are replacing their PCs with tablets. This is in part due to the agility flexibility and the availability of diverse network-based and support applications. Thus network characteristics directly affect user-perceived performance and a deep understanding of the properties of contemporary cellular networks for commonly used platforms is important for smartphone application and platform optimization. In this work, we carry out the largest study to date of cellular networks in terms of users, time duration, location, and networks to understand the performance, infrastructure, and policy characteristics. With the data set collected from around 100K users across the world over 18 months, MobiPerf, a smartphone network measurement tool we developed and publicly deployed, enables us to analyze network performance along several new dimensions, previously not examined. Our results indicate that with better infrastructure support, large cities appear to have better performance than rural areas. Our case study on packet size’s effect on RTT uncovers a surprising pattern for AT&T’s uplink RTT. We also show that Internet-based CDN service provides very limited latency improvement in today’s cellular networks. We further examine how local DNS servers are assigned to mobile users. In addition, we scrutinize the carriers’ policy towards different types of traffic and successfully identify some middlebox behavior of today’s cellular carriers.