TCP-CM: A Transport Protocol for TCP-friendly Transmission of Continuous Media

We propose a new TCP-friendly transport protocol, called TCP-CM, for the continuous media applications over the Internet. TCP-CM is a direct modification of the TCP to support continuous media applications without compromising the congestion control feature of the TCP, which is critical to the stable functioning of the Internet. We design TCP-CM API to be compatible to the BSD socket interface, which requires minimum changes for the applications to adopt TCP-CM. Continuous media applications that adopt TCP-CM as the transport protocol can be relieved from the burdens such as rate control and scheduling for timely delivery, and hence can focus solely on advanced coding or compression techniques for adapting the content according to the available network bandwidth. We implement the TCPCM in Linux 2.2.15 TCP/IP protocol stack, and run extensive experiments on TCP-CM using emulated video flows. Our experiments show that TCP-CM can be used for the timely delivery of continuous media data within the constraints of the available network bandwidth, and can compete with TCP connections fairly.