The eXplicit Control Protocol (XCP), which explicitly sends feedback information on the current network resource condition to end-hosts to control congestion, is a promising protocol for the network supported congestion control that will be needed in the future Internet. Because of its flexibility, XCP can provide relative bandwidth allocation service that is impossible with other protocols. However, with the existing version of this XCP service, the convergence time to network stability is long due to the gradual resource allocation. We have analyzed the existing allocation method and propose a new allocation method for use at XCP routers. The effectiveness of the proposed method has been evaluated through simulation and the results are discussed here.