1. A method for mediating communication over a data network, comprising: receiving over the data network a registration request from a first network node and a registration request from a second network node; receiving a request over the data network to establish a mediated communication session between the first network node and the second network node over the data network; generating a specification of one or more interfaces for implementing the mediated communication session between the first network node and the second network node; transmitting a software component to each of the first network node and the second network node, the software component including the specification of the one or more interfaces; causing the establishment of the mediated communication session directly between the first network node and the second network node via at least one of the one or more interfaces, and transmitting a mediated communication of the mediated communication session via a communication link that is independent of a validation node.