Network Swapping

Wireless mobile terminals have limited storage memory due to weight, size and power constraints. Potentially unlimited virtual memory could be found on remote servers made accessible through a wireless link, but power hungry wireless network interface cards (WNIC) may reduce the battery lifetime if not efficiently exploited, actually limiting the practical interest of network virtual memory (NVM). On the other hand, when network memory is used for swapping, service performance can be an issue. In this tutorial we discuss the feasibility of network swapping for wireless mobile terminals. First, we perform extensive experiments to compare performance and energy of network swapping with those of local swapping on microdrives and flash memories. Our results show that remote swap devices made accessible through a power-manageable WNIC can be even more efficient than local microdrives. Second, we address the issue of mobility management by presenting an infrastructure providing efficient remote memory access to mobile terminals. We report experimental results obtained on a working prototype of the proposed infrastructure.