Networked Systems

In the (n,M)-renaming problem, there are n processes, each with an initial name known only from itself, and these processes have to compute new names from the set {1, ...,M}, despite asynchrony and any number of process crashes, such that no two processes have the same new name. If M = n, the renaming is said to be perfect. If M is only on function on the number n of the processes in the system, the renaming is said to be non-adaptive. In contrast, if M is on function on the number of processes that actually participate in a given execution, renaming is adaptive. The consensus number of a concurrent object is an integer which measures its synchronization power in presence of any number of process crashes. This paper investigates the consensus number of non-adaptive perfect renaming objects. It shows that, while a non-adaptive perfect renaming object for two processes (ports) has consensus number 2, its consensus number decreases to 1 when the number of processes which can access it increases beyond 2.