With the emergence of various multimedia applications, the best-effort service provided by today's Internet has been not sufficient. To support QoS, flow label field is provided in IPv6 packet header, which can be used to specify the QoS requirements. Dynamic packet state is a key technology that aims providing services as powerful and flexible as ones implemented by a stateful network using a stateless architecture. Combining these two features, this paper proposes some QoS provision mechanism for IPv6 traffic flows in a stateless architecture that has high scalability. Simulations are also run to evaluate the performance of the proposed algorithm