Personal digital assistants and other mobile computing devices rely on synchronization protocols in order to maintain data consistency. These protocols operate in environments where network resources such as ban h, memory, and processing power are limited. In this article we examine a number of popular and representative synchronization protocols, such as Palm's HotSync, Pumatech's Intellisync, and the industry-wide SyncML initiative. We investigate the scalability performance of these protocols as a function of data and network sizes, and compare these protocols to a novel synchronization approach, CPISync, which addresses some of their scalability concerns. The conclusions of this survey are intended to provide guidance for handling scalability issues in synchronizing data on large, heterogeneous, tetherless networks.
