The Internet relies on the cooperation of competitive network operators that typically administrate their networks unilaterally and autonomously to interconnect people and companies in different locations. Recent work calls for extending this organizational model with augmented interactions between network operators, to provide a higher level of end-to-end quality of service and to ease certain aspects of traffic management in backbone networks. This chapter presents the emerging collaborative network management models as well as related technologies. In particular, it describes recent techniques for inter-domain traffic engineering and for quality of service aware routing. The detailed methods are of great interest for network operators and permit the development of new types of commercial relationships between them, ranging from simple interconnection agreements to collaborative traffic management and automated provisioning.