Hierarchical Path Metric in Multi-Hop Wireless Networks

In a large mobile ad hoc network, nodes may be organized by a hierarchical address system that reflects the organizational structure of the users within the network. This is typical for many mission-critical applications such as military networks. For such applications, it is important to keep cross-organization data transfer at the lowest possible level for minimal disruption of the traffic within each organization and for security reasons. To measure the degree that a multi-hop path conforms to this "level constraint", we propose a new link metric to quantify the "distance" between two neighboring nodes in terms of their hierarchical addresses. Using this metric, we discover that existing routing protocols that are not aware of the level preference in routing tend to find routes that violate the level constraint frequently. On the other hand, a direct adoption of the distance metric in existing routing protocols produces significant route detours. To deal with this situation, we need to design a new routing protocol to balance the level preference and the topological shortness of routes.