A survey and comparison of multi-ring techniques for scalable battlespace group communications

Ring-based network overlays have attractive characteristics for group communications such as inherent reliability and single fault-tolerance. However, ring networks also generally have longer paths and thus higher delay and delay jitter. In order to provide scalability as the number of group members grows, large single rings may be broken into smaller multi-rings interconnected together at the same level or interconnected in a multi-level hierarchy of rings. In this paper we consider different approaches to providing scalable battlespace group communications using multi-ring techniques -- classifying the techniques according to the primary military requirements of security and survivability. For multi-rings at the same level, an optimal number of rings to cover the group members may be approximated and these rings may then be interconnected at end systems or bridged via network devices. For hierarchical rings the number of levels and the number of rings per level may both be approximated. These results are dependent on application QoS demands and the underlying network infrastructure in terms of topology (dense versus sparse) and link bandwidths (bottleneck capacities). Network-centric warfare is not simply a combination of communication, intelligence, and signals, but rather warfare that leverages off a common network to support different purposes. While group communications based on a single virtual ring overlay may satisfy the most important requirements for survivability and security, scalability may force redesign. Thus comparing the characteristics of different multi-ring techniques provides an insight into which battlespace applications may be supported via virtual rings.