A dynamic protocol stack configuration model for adaptation to communications environments

Differences in the quality of communication occur based on the conditions of the network and the position where the client is connected when the client is communicating with a server distributing continuous media over a network. In this paper the authors propose a DPC (Dynamic Protocol stack Configuration) to dynamically change the protocol stack for each flow based on the reliability and throughput of the data transfer when a client connected to a network is starting or maintaining communications with a server. In addition, the authors define dsocket, an expanded socket based on the DPC model, and DPCP (Dynamic Protocol stack Configuration Protocol) as a protocol to change the protocol stack through coordination between the client and the server. The authors demonstrate the validity of the DPC model by using it for dynamic changes between TCP and UDP for changes in network load in a system in which computers running this model under FreeBSD are connected via a wireless LAN or the Internet.