DR-TCP: Downloadable and reconfigurable TCP

Advances in communication technology allow a variety of new network environments and services available very rapidly. Appearance of various network environments tends to enable a user with a mobile terminal to access among different network simultaneously. However, since new network environment affects performance of communication protocols, terminal systems should provide adaptation schemes for the protocols in order to keep the quality of network performance high. A possible solution is to make the protocol reconfigurable to be adapted to current network environment. Unfortunately, because most existing network systems are implemented monolithically, they cannot support protocol reconfiguration dynamically at runtime. This paper proposes a new reconfigurable model that enables TCP functions to be adapted whenever network environment is changed. The proposed scheme also supports binary-level protocol upgrade for extensibility by downloading new TCP variants which the terminal does not have for new network environment, and it is more suitable for mobile hand-held devices than existing source-level solution. Our model is based on a recursive state machine. We re-implement TCP Reno from scratch using our proposed model. The new implementation of TCP Reno is named DR-TCP. To demonstrate the effectiveness of DR-TCP, dynamic reconfiguration is performed over Internet, which successfully converts DR-TCP to TCP Westwood at runtime.