TCP Emulation at Receivers

This is the official TEAR page. It contains information about the description of TEAR protocol, its source codes (simulation and real codes), and experimental results.

TEAR is a protocol that runs at receivers to estimate TCP-friendly rates. The estimated rates can be used to control the rate of a non-TCP flow. TEAR is suitable for Internet-based multimedia streaming because (1) its rate adjustment is very smooth, and (2) it is TCP-friendly. We can find its application in congestion, and flow control for multicast because most of functionalities are performed at receivers and it is thus very scalable. TEAR is also designed for use in a symmetric networks such as wireless networks (e.g., satellite), ADSL, and Cable modems. In this page, we report some of preliminary results we got from our NS simulation experiments.

Hot Links

TEAR Technical Report (draft)
Injong Rhee, Volkan Ozdemir, and Yung Yi, "TEAR: TCP emulation at receivers -- flow control for multimedia streaming", Technical Report, Department of Computer Science, NCSU. ( HTML , PS , PDF )

From this report, you can find a detailed description on a unicast version of TEAR and discussion on simulation results and comparison with an equation-based flow control TFRC .

TEAR Power Point Presentation Power Point )

Issues on equation-based flow control ( PS , PDF )

This report analytically shows that model-based flow control (such as TFRC ) may not converge to the fair share, and can actually result in over-allocation or under-allocation.

TEAR NS scripts

TEAR NS Simulation Result

TEAR source codes (available soon)

TEAR NS Internet experimental results (My students in CSC591E Multimedia Networking are conducting Internet experiments comparing TCP, TEAR, and TFRC. Their results will be posted here).