TCP-CM: a transport protocol for TCP-friendly transmission of continuous media

We propose a new TCP friendly transport protocol, called TCP-CM, for continuous media applications over the Internet. TCP-CM is a direct modification of TCP to support continuous media applications without compromising the congestion control feature of TCP, which is critical to the stable functioning of the Internet. We design TCP-CM API to be compatible with the BSD socket interface, which requires minimum changes for applications to adopt TCP-CM. Continuous media applications that adopt TCP-CM as the transport protocol can be relieved from 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 TCP-CM 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.