I should implement a QoS Concept in a given network. The main components are Access - cat 4500, Distribution and Core - 6509 The first QoS step is to configure for VoIP. I would like to implement the 'conditionally-trusted IP Phone with Scavenger-Class QoS(Basic) Model The configuration in the Cat 4506 is ok because it is possible to cfg it via class-map and policy maps and place it to the incoming Interface where the IP phone and pc connected is. So what is the next step ? Should I cfg queuing in the downstream interface to the distribution switches ? And what about this cfg in the cat 6509 ? It is not possible to cfg the 'conditionally-trusted IP Phone with Scavenger-Class QoS(Basic) Model' with the cisco IOS ? The cisco model for the distribution means : trust dscp, interfacegroup line card dependent queuing and dropping !!?? For me it means I cfg in the distribution/core trust dscp in the upstream interfaces to the access/distribution router ?! but where shoud i implement queuing and dropping ? and what strategy ??