Integrating Mobility into Groups

Some form of migrating process, i.e., a process that can change the node during its execution, is being frequently proposed as a basic component for designing distributed applications. Similarly to distributed applications based on static processes, applications based on processes that can migrate also need forms of reliable cooperation between processes. In order to fulfil part of this requirement, we present the concept of mobile groups. Analogously to traditional group systems [5,6,14,16,18], mobile groups also provide message delivery guarantees and a sort of virtual synchrony. However, mobile groups provide these guarantees despite the mobility of its members. Furthermore, they make process mobility not only visible for the group, but also consistently ordered with other group actions (such as crashes, joins, leaves, and other migrations). In this paper, we discuss the motivations for the mobile groups, define their properties, and outline a membership protocol for such groups.