This reports whether this virtual ring is a major (standalone) ring or a sub-ring attached to a major ring, per G.8032's interconnected-ring topology model. A sub-ring's protection behavior depends on how it terminates onto its major ring, so an admin troubleshooting a sub-ring's protection switching needs to know it's a subRing to look at the interconnection node's behavior rather than treating it as an independent ring. For example, a metro network with one large backbone ring and several smaller access rings hanging off it would configure the backbone as majorRing(1) and each access ring as subRing(2).