The Internet is not run by a single organization; indeed, this is a key characteristic of the Internet architecture, and a key reason behind its success as a platform for innovation in communications. Instead, the management, safety, and trustworthiness of each domain of the network are the responsibility of that domain; cooperation among these domains is largely done on a personal, and somewhat informal, basis.However, the growing complexity of the network leads to complex, emergent threats that challenge the ability of current cooperative efforts to respond. Large-scale network "accidents", such as routing failures or software faults on widely distributed endpoints, are not confined within a single domain, and therefore difficult to react to. More troubling, organized criminal enterprises leverage vulnerabilities within the network across multiple domains to build "botnets", which are essentially large-scale coordinated infrastructures applied to a range of nefarious activities, from sending spam, to extortion scams through denial of service attacks, to the theft of personal financial information. There are societal challenges, as well, as growing awareness of privacy issues leads to unease with the traditional measurement approach of centralized storage and analysis of traffic information.Attempts to further centralize the response to these threats will simply not work. Therefore, network traffic monitoring and measurement must be made effective across domain boundaries in order to meet the challenges of this environment. Cooperative threats and distributed failures call for a distributed, cooperative detection and mitigation infrastructure. Specifically, DEMONS aims to design and demonstrate the operation of a network for cooperative monitoring. We will apply innovative measurement, analysis and data protection techniques across a network of flexible monitoring nodes in multiple domains to accomplish cooperation, resiliency, and scalability in measurement, and confidentiality of measured traffic.DEMONS will significantly advance the ability to detect and respond to large-scale threats while preserving citizens' right to privacy, thus increasing societal acceptance of the need for "being monitored". The project will demonstrate the trustworthiness of the proposed network monitoring and management infrastructure in a cooperative operational environment across several major network operators.