Quick-Start TCP was codified in an Experimental RFC (RFC 4782) in 2007. Based on explicit feedback from the network, it can use a large Initial Window
, with the goal to speed up the initial phase of transfers over underutilized paths. The approach was later extended to DCCP in RFC 5634.
The protocol roughly works as follows: The sender asks the network for its desired sending rate, by putting an IP option in its first packet (containing the SYN TCP segment) to a receiver. Routers on the path can then accept the request, refuse it, or accept it with a reduced rate. The resulting rate is then echoed back by the receiver. The protocol must detect the case where there are Quick-Start-agnostic routers in the path. Since it requires explicit router support that current routers don't have, it is not likely to be seen used in the Internet today.
- RFC 4782, Quick-Start for TCP and IP, S. Floyd, M. Allman, A. Jain, P. Sarolahti, January 2007
- RFC 5634, Quick-Start for the Datagram Congestion Control Protocol (DCCP), G. Fairhurst, A. Sathiaseelan, August 2009
- 18 Aug 2010