FLIP: A Flexible Interconnection Protocol for Heterogeneous Internetworking

Abstract

This paper describes the Flexible Interconnection Protocol, or FLIP, whose main goal is to allow interconnection of heterogeneous devices with varying power, processing, and communication capabilities, ranging from simple sensors to more powerful computing devices such as laptops and desktops. The vision is that FLIP will be used to interconnect such devices forming clouds in the farthest branches/leaves of the Internet, while still providing connectivity with the existing IP-based Internet infrastructure. Through its flexible, customizable headers FLIP integrates just the functions required by a given application and that can be handled by the underlying device. Simple devices like sensors will benefit from incurring close to optimal overhead saving not only bandwidth, but, more importantly, energy. More sophisticated devices in the cloud can be responsible for implementing more complex functions like reliable/ordered data delivery, communication with other device clouds and with the IP infrastructure.

FLIP is designed to provide a basic substrate on which to build network- and transport-level functionality. In heterogeneous environments, FLIP allows devices with varying capabilities to coexist and interoperate under the same network infrastructure. We present the basic design of FLIP and describe its implementation under Linux. We also report on FLIP's performance when providing IPv4 and IPv6 as well as transport-layer functionality a la TCP and UDP. We show FLIP's energy efficiency in different sensor network scenarios. For example, we use FLIP to implement the directed diffusion communication paradigm and obtain an improvement of 50% in energy savings over an existing directed diffusion implementation. Finally, we showcase FLIP's flexibility by demonstrating its ability to incorporate new protocol functions seamlessly. In particular, we add data aggregation functionality onto FLIP and show that it significantly increases the system's energy efficiency.