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HighSpeed TCP for Large Congestion Windows (RFC3649)

IP.com Disclosure Number: IPCOM000020736D
Original Publication Date: 2003-Dec-01
Included in the Prior Art Database: 2003-Dec-11
Document File: 35 page(s) / 80K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

S. Floyd: AUTHOR

Abstract

The proposals in this document are experimental. While they may be deployed in the current Internet, they do not represent a consensus that this is the best method for high-speed congestion control. In particular, we note that alternative experimental proposals are likely to be forthcoming, and it is not well understood how the proposals in this document will interact with such alternative proposals.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 5% of the total text.

Network Working Group S. Floyd

Request for Comments: 3649 ICSI

Category: Experimental December 2003

HighSpeed TCP for Large Congestion Windows

Status of this Memo

This memo defines an Experimental Protocol for the Internet

community. It does not specify an Internet standard of any kind.

Discussion and suggestions for improvement are requested.

Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

The proposals in this document are experimental. While they may be

deployed in the current Internet, they do not represent a consensus

that this is the best method for high-speed congestion control. In

particular, we note that alternative experimental proposals are

likely to be forthcoming, and it is not well understood how the

proposals in this document will interact with such alternative

proposals.

This document proposes HighSpeed TCP, a modification to TCP's

congestion control mechanism for use with TCP connections with large

congestion windows. The congestion control mechanisms of the current

Standard TCP constrains the congestion windows that can be achieved

by TCP in realistic environments. For example, for a Standard TCP

connection with 1500-byte packets and a 100 ms round-trip time,

achieving a steady-state throughput of 10 Gbps would require an

average congestion window of 83,333 segments, and a packet drop rate

of at most one congestion event every 5,000,000,000 packets (or

equivalently, at most one congestion event every 1 2/3 hours). This

is widely acknowledged as an unrealistic constraint. To address this

limitation of TCP, this document proposes HighSpeed TCP, and solicits

experimentation and feedback from the wider community.

Floyd Experimental [Page 1]

RFC 3649 HighSpeed TCP December 2003

Table of Contents

1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . 2

2. The Problem Description.. . . . . . . . . . . . . . . . . . . . 3

3. Design Guidelines.. . . . . . . . . . . . . . . . . . . . . . . 4

4. Non-Goals.. . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5. Modifying the TCP Response Function.. . . . . . . . . . . . . . 6

6. Fairness Implications of the HighSpeed Response

Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7. Translating the HighSpeed Response Function into

Congestion Control Parameters . . . . . . . . . . . . . . . . . 12

8. An alternate, linear response functions.. . . . . . . . . . . . 13

9. Tradeoffs for Choosing Congestion Control Parameters. . . . . . 16

9.1. The Number of Round-Trip Times between Loss Events . . . . 17

9.2. The Number of Packet Drops per Loss Event, with Drop-Tail. 17

10. Related Issues . . . . . . . . . . . . . . . . . . . . . . . . 18

10.1. Slow-Start. . . . . . . . . . . . . . . . . . . . . . . . 18

10.2. Limiting burstiness on short time scales. . . . . . . . . 19

10.3. Other limitations on window size. . . . . . . . . . . . . 19

10.4. Implementation issues.. . . . . . . . . . ....