1. A system comprising: an overlay network linking a plurality of publishers, a plurality of subscribers, and a plurality of brokers, the overlay network including a first computer network having a first network protocol carried by a second computer network having a second network protocol; and an agent carried by each of the publishers, the subscribers, and the brokers that adjusts the network's topology based upon collected runtime data of at least one of condition of each link within the network and broker availability to any publisher and subscriber.