Abstract-Is it possible to migrate TCP/IP flows between different networks on modern mobile devices without infrastructure support or protocol changes?To answer this question, we make three research contributions. (i) We report a comprehensive characterization of IP traffic on 27 iPhone 3GS users for three months. (ii) Driven by these findings, we devise two simple, effective, and easily deployable system mechanisms to support seamless flow migration without network support, and extensively evaluate their effectiveness using our field collected traces of real-life usage. Wait-n-Migrate leverages the fact that most flows are short lived. It establishes new flows on newly available networks but allows pre-existing flows on the old network to terminate naturally. Resumption Agent takes advantage of the resumption functionality of modern protocols to securely resume flows without application intervention. Combined, they provide an unprecedented opportunity to immediately deploy policies that leverage multiple networks to improve the performance, efficiency, and connectivity of mobile devices. (iii) We report an iPhone based implementation of these system mechanisms and demonstrate their overhead to be negligible. Furthermore, we employ a sample switching policy, AutoSwitch, to demonstrate their performance. Through traces and field measurements, we show that AutoSwitch reduces user disruptions by an order of magnitude.Index Terms-Mobile Computing, Network Architecture and Design, User/Machine Systems ---------- ----------

Abstract-In this paper we present MultiNets, a system which is capable of switching between wireless network interfaces on mobile devices in real-time. MultiNets is motivated by the need of smartphone platforms to save energy, offload data traffic, and achieve higher throughput. We describe the architecture of MultiNets and demonstrate the methodology to perform switching in Linux based mobile OSes such as Android. Our analysis on mobile data traces collected from real users shows that with real-time switching we can save 27.4% of the energy, offload 79.82% of the data traffic, or achieve 7 times more throughput on average. We deploy MultiNets in a real world scenario and our experimental results show that depending on the user requirements, it outperforms the state-of-the-art Android system either by saving up to 33.75% energy, or achieving near-optimal offloading, or achieving near-optimal throughput while substantially reducing TCP interruptions due to switching.

In this poster we describe initial findings regarding Internet usage characteristics, in particular TCP flows from a field study with 27 iPhone 3GS users. We present details regarding their usage characteristics, and provide a solution for migrating flows between different networks and/or network interfaces without requiring infrastructure support or changes to current applications and protocols, with minimal impact to the user.

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