In this paper, we present a protocol that allocates resources in communication networks in order to assure specific QoS characteristics as requested by new connections. The design takes into consideration the possibility for the network allocation to adapt to application requirements.The proposed protocol uses a Bandwidth Preemptive Algorithm that permits adaptive bandwidth allocation in multicast, multi-stream environments. This design has been inspired by the one proposed by Sakate [1] where a centralized methodology is used. In our approach, we use a distributed methodology where we change the behavior of the communication service and allow the continuation of the service under more severe conditions. In other words, when there is a lack of bandwidth for a new connection, the communication service will try to find the missing bandwidth within the existent connections (or streams) when looking for a feasible path on a hop-by-hop basis, starting from the destination to an a on-tree node.