Opportunistic mobility with multipath TCP

Host mobility has traditionally been solved at the network layer, but even though Mobile IP has been standardised for 15 years, it hasn't been supported by operators. IP's double role as a location identifier and communication endpoint identifier brings a number of functional and performance problems. We argue that the best place to handle mobility is at the transport layer. While this is not a new argument, we believe that the emerging standard of Multipath TCP (MPTCP) can be used to solve many issues related to mobility. MPTCP naturally implements make-before-break, can be incrementally deployed, is backwards compatible with TCP, and could even ease incremental adoption of IPv6. Using simulations and indoor experiments with WiFi and 3G, we show that MPTCP gives better throughput, achieves smoother handoffs, and can be tuned to lower energy consumption.