Byte Caching in Wireless Networks

Abstract

The explosion of data consumption has led to a renewed interest in byte caching. With studies showing potential reductions in network traffic of 50%, this fine grained caching technique looks like a very good and attractive solution for mobile wireless operators. However, properties of wireless networks actually present new challenges. We first show that a single packet loss, re-ordering or corruption -- all common conditions over the air interface -- can result in circular dependencies and cause existing byte caching algorithms to loop endlessly. To remedy the problem, we then explore a new set of encoding algorithms. Third, we assess the impact of packet losses on byte caching performances, both in terms of byte savings and delay reduction. We found that a mere 1% packet loss can already nullify any delay reduction and instead cause significant increases that users may not be willing to tolerate. Finally, we shared several insights, including interactions between transport layer protocol's mechanisms (e.g., TCP window congestion) and byte caching operations that can cause sophisticated encoding algorithms to perform poorly. We believe that these insights are important for designing more efficient and robust byte caching encoding algorithms.