Moshe

Abstract

We present Moshe, a novel scalable group membership algorithm built specifically for use in wide area networks (WANs), which can suffer partitions. Moshe is designed with three new significant features that are important in this setting: it avoids delivering views that reflect out-of-date memberships; it requires a single round of messages in the common case; and it employs a clientserver design for scalability. Furthermore, Moshe's interface supplies the hooks needed to provide clients with full virtual synchrony semantics. We have implemented Moshe on top of a network event mechanism also designed specifically for use in a WAN.In addition to specifying the properties of the algorithm and proving that this specification is met, we provide empirical results of an implementation of Moshe running over the Internet. The empirical results justify the assumptions made by our design and exhibit good performance. In particular, Moshe terminates within a single communication round over 98% of the time. The experimental results also lead to interesting observations regarding the performance of membership algorithms over the Internet.

Specification, Implementation and Verification of Dynamic Group Membership for Vehicle Coordination

“…Transis [2] was the first system that allowed partitions to continue with independent groups. It has been followed by several other such as Totem [18], Moshe [14], Relacs [5], Jgroups [6], Newtop [10], and RMP [13]. For a comprehensive comparison of different group communication services, we recommend the paper by Chockler et al [9].…”

Cliff-Edge Consensus: Agreeing on the Precipice

“…Deciding on a view in our protocol can be seen as the equivalent of installing a view. The link is particularly true with partitionable group membership (PGM) services [1,11,16], which look at how successively installed views should evolve to ensure that both reachability and unreachability between nodes are reflected in their installed views.…”

Quicksilver Scalable Multicast (QSM)

“…A region is a set of nodes that are members of the same multicast groups. The system is partitioned into regions ( Figure 2) by a global membership service (GMS [15]). Nodes contact the GMS to join groups, and it monitors their health.…”