Engineering Task Force S . Floyd INTERNET - DRAFT ICIR

This document describes a possible congestion control mechanism for acknowledgement traffic (ACKs) in TCP. The document specifies an end-to-end acknowledgement congestion control mechanism for TCP that uses participation from both TCP hosts, the TCP data sender and the TCP data receiver. The TCP data sender detects lost or ECN-marked ACK packets, and tells the TCP data receiver the ACK Ratio R to use to respond to the congestion on the reverse path from the data receiver to the data sender. The TCP data receiver sends roughly one ACK packet for every R data packets received. This mechanism is based on the acknowledgement congestion control in DCCP’s CCID 2. This acknowledgement congestion control mechanism is being specified for further evaluation by the network community. Floyd Expires: 4 January 2010 [Page 2] INTERNET-DRAFT TCPM ACK CONGESTION CONTROL July 2009 Table of