HPF: a transport protocol for supporting heterogeneous packet flows in the Internet
We present a new transport protocol called HPF for effectively supporting heterogeneous packet flows in the Internet environment. The following are the key features of HPF: HPF supports packet flows where different packets in the same transport connection have different quality-of service requirements in term of reliability, priority, and deadlines. HPP supports application-level framing, and provides APIs for applications to specify the priority, reliability and timing requirements of each frame. HPF enables the use of application-specified priorities as hints for network routers to preferentially drop low-priority packets during congestion. This ensures that 'important data' gets through preferentially during congestion. HPF decouples the congestion control and reliability mechanisms in order to support congestion control for unreliable and heterogeneous packet flows. Preliminary performance measurements in our experimental testbed show that HPF can provide effective support for heterogeneous packet flows in the presence of dynamic network resources.