Abstract: In some embodiments, the present invention provides a distributed monitoring, evaluation and routing (“DiMER”) system that provides active management of a data-network based telephony networks. Such a system, and data-network-based telephony networks incorporating the same, advantageously route calls to meet call-quality standards and/or cost goals, among other targets. To meet such quality standards, the system periodically obtains call-related data, analyzes the data, and revises call routing, as appropriate, by shifting or reallocating call traffic between available terminating gateways (based on their performance).