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.