A First Look at Mobile Hand-held Device Traffic Gregor Maier, Fabian Schneider, and Anja Feldmann TU Berlin / Deutsche Telekom Laboratories Ernst-Reuter-Platz 7, 10589 Berlin, Germany {gregor|fabian|anja}@net.t-labs.tu-berlin.de Abstract. Although mobile hand-held devices (MHDs) are ubiquitous today, lit- tle is know about how they are used—especially at home. In this paper, we cast a first look on mobile hand-held device usage from a network perspective. We base our study on anonymized packet level data representing more than 20,000 resi- dential DSL customers. Our characterization of the traffic shows that MHDs are active on up to 3 % of the monitored DSL lines. Mobile devices from Apple (i. e., iPhones and iPods) are, by a huge margin, the most commonly used MHDs and account for most of the traffic. We find that MHD traffic is dominated by multi- media content and downloads of mobile applications. Key words: Mobile Devices, iPhone, Traffic Characterization 1 Introduction Today advanced mobile hand-held devices (MHDs, e. g., iPhones and BlackBerrys) are very popular. MHDs have evolved rapidly over the years—from pure offline devices, to cell phones with GSM data connectivity, to 3G devices, and universal devices with both cellular as well as WiFi capabilities. Their increased graphics and processing power makes these devices all-in-one PDAs and media centers. Today’s MHDs can be used to surf the Web, check email, access weather forecast and stock quotes, and navigate using GPS based maps—to just name some of the prominent features. This increase in flexibility has caused an increase in network traffic. Indeed, cellular IP traffic volume is growing rapidly and significantly faster than classic broadband volume [15]. We, in this paper, cast a first look at Internet traffic caused by mobile hand-held devices. We use anonymized residential DSL broadband traces, spanning a period of 11 month, to study MHD behavior and their impact on network usage. We are thus able to observe the behavior of MHDs when they are connected via WiFi at home and com- pare their traffic patterns to the overall residential traffic characteristics. Some devices (most notably iPod touch and iPhone) require WiFi connectivity rather than cellular connectivity for some services. Other services are more likely to be used via cellular connectivity due to user mobility, e. g., looking up directions on Google Maps, while walking around town or driving. Although, we in this paper only focus on residential MHD usage and not MHD usage in cellular networks, our analysis gives first insights into what kind of services users are interested in when they are at home and have access to all services. This information is crucial for 3G cellular providers to anticipate usage patterns and future traffic growths.