1. A peer-to-peer processing node for participating in multi-party voice-over-IP services, the peer-to-peer processing node comprising: a distribution tree processor that: establishes a peer-to-peer distribution tree to broadcast a composite audio signal from a root mixing node to a plurality of participating nodes, wherein a subset of the participating nodes are originating nodes that provide a respective audio stream output received by the root mixing node to produce the composite audio signal; establishes overlay mesh interconnections among the participating nodes; constructs a respective distribution tree from the respective node to every other node within the participating nodes; distributes a respective performance characteristic for each respective distribution tree to each node within the participating nodes; and performs an election protocol to determine an optimal root mixing node; a mixing tree processor that identifies, independently of the distribution tree, a first intermediate mixing node from within the plurality of participating nodes; and a mixer that provides to the root mixing node a mixing of respective audio stream outputs provided by a first subset of originating nodes to the mixer.