Updating TCP to Support Rate-Limited Traffic (RFC7661)
Original Publication Date: 2015-Oct-01
Included in the Prior Art Database: 2016-Feb-05
Internet Society Requests For Comment (RFCs)
G. Fairhurst: AUTHOR [+3]
TCP is used for traffic with a range of application behaviours. The TCP congestion window (cwnd) controls the maximum number of unacknowledged packets/bytes that a TCP flow may have in the network at any time, a value known as the FlightSize [RFC5681]. FlightSize is a measure of the volume of data that is unacknowledged at a specific time. A bulk application will always have data available to transmit. The rate at which it sends is therefore limited by the maximum permitted by the receiver advertised window and the sender congestion window (cwnd). The FlightSize of a bulk flow increases with the cwnd and tracks the volume of data acknowledged in the last Round-Trip Time (RTT).
Internet Engineering Task Force (IETF) G. Fairhurst Request for Comments: 7661 A. Sathiaseelan Obsoletes: 2861 R. Secchi Category: Experimental University of Aberdeen ISSN: 2070-1721 October 2015
Updating TCP to Support Rate-Limited Traffic
This document provides a mechanism to address issues that arise when TCP is used for traffic that exhibits periods where the sending rate is limited by the application rather than the congestion window. It provides an experimental update to TCP that allows a TCP sender to restart quickly following a rate-limited interval. This method is expected to benefit applications that send rate-limited traffic using TCP while also providing an appropriate response if congestion is experienced.
This document also evaluates the Experimental specification of TCP Congestion Window Validation (CWV) defined in RFC 2861 and concludes that RFC 2861 sought to address important issues but failed to deliver a widely used solution. This document therefore reclassifies the status of RFC 2861 from Experimental to Historic. This document obsoletes RFC 2861.
Status of This Memo
This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation.
This document defines an Experimental Protocol for the Internet community. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7661.
al. Experimental [Page 1]
RFC 7661 New CWV October 2015
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