1. A distributed hierarchical registry for device discovery and communication, the distributed hierarchical registry comprising: a plurality of registry groups at a first level of the hierarchical registry, each registry group comprising a plurality of registry servers, wherein the plurality of registry servers in a registry group provide services comprising: receiving client update information from client devices; and responding to client lookup requests from client devices; wherein the plurality of registry servers in each of the plurality of registry groups provide the services using, at least in part, a quorum consensus protocol.