—Video traffic, which represents an increasing fraction of the Internet traffic, requires end-to-end quality of service (QoS) guarantees for inter-domain routing. However, providing such guarantees remains a challenge essentially because it requires a strong and fair cooperation among the different network operators or Autonomous Systems (ASes), crossed by the traffic. Having a single AS on the path that does not meet its QoS engagement is sufficient to violate the end-to-end QoS guarantees. Unfortunately, the client is not capable of distinguishing unfair ASes from honest ones at the time it selects its path. Reputation mechanisms turn out to be very efficient tools to estimate how trustworthy and reliable entities can be without requiring the help of any central authority. They are effective to foster cooperation by remedying selfishness. In this position paper, we identify the main properties a reputation mechanism should meet to improve inter-domain QoS routing, and we provide a coarsed-grain vision of the design of such a mechanism.