TCP-Friendly Rate Control (TFRC) is a congestion control mechanism designed for unicast flows operating in an Internet environment and competing with TCP traffic. The goal is to compete fairly with TCP traffic on medium timescales, but to be much less variable than TCP on short timescales.
TCP congestion control works by maintaining a window of packets that have not yet been acknowledged. This window is increased by one packet every round trip time if no packets have been lost, and is decreased by half if a packet loss is detected. Thus TCP's window (and hence throughput) is a function of the losses observed in the network and the round trip time experienced by the flow.
The idea behind TFRC is to measure the loss probability and round trip time and to use these as the parameters to a model of TCP throughput. The expected throughput from this model is then used to directly drive the transmit rate of a TFRC flow.
RFC 5348 - TCP Friendly Rate Control (TFRC): Protocol Specification
Famous quotes containing the words friendly, rate and/or control:
“The friendly cow, all red and white,
I love with all my heart:
She gives me cream with all her might,
To eat with apple tart.”
—Robert Louis Stevenson (1850–1894)
“All of us failed to match our dreams of perfection. So I rate us on the basis of our splendid failure to do the impossible.”
—William Faulkner (1897–1962)
“The child knows only that he engages in play because it is enjoyable. He isn’t aware of his need to play—a need which has its source in the pressure of unsolved problems. Nor does he know that his pleasure in playing comes from a deep sense of well-being that is the direct result of feeling in control of things, in contrast to the rest of his life, which is managed by his parents or other adults.”
—Bruno Bettelheim (20th century)