A cluster tree network formed by self-organization of a number of nodes. The method of self-organization includes processes for cluster formation, cluster network maintenance, intra-cluster communication. In the cluster formation process, each node discovers if any neighboring node is a cluster head or if any node is already a member of a cluster (thus making it a networked node), and if a cluster head or a networked node is discovered, each node establishes a communication link with the cluster head or the networked node. If no cluster head or networked node is discovered, the node itself becomes a cluster head. The network is maintained by each node periodically broadcasting a HELLO message to neighboring nodes, receiving responses to the HELLO message and updating a neighbor list in accordance with responses to the HELLO message. Multi-cluster networks are also provided using the processes of inter-cluster network formation, inter-cluster network maintenance, and inter-cluster communication. The resulting network has one or more clusters of nodes, each with a cluster head and a number of member nodes, each assigned a node identifier by the cluster head. In a multi-cluster network, a designated device assigns identifies to each cluster head in the network. Border nodes, which are members of at least two clusters, act as routers connecting the clusters and relaying information packets between the clusters.