Quick-Start for TCP and IP
RFC 4782
Document | Type | RFC - Experimental (January 2007; Errata) | |
---|---|---|---|
Authors | Pasi Sarolahti , Amit Jain , Sally Floyd , Mark Allman | ||
Last updated | 2020-01-21 | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4782 (Experimental) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Lars Eggert | ||
Send notices to | (None) |
Network Working Group S. Floyd Request for Comments: 4782 M. Allman Category: Experimental ICIR A. Jain F5 Networks P. Sarolahti Nokia Research Center January 2007 Quick-Start for TCP and IP 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 IETF Trust (2007). Abstract This document specifies an optional Quick-Start mechanism for transport protocols, in cooperation with routers, to determine an allowed sending rate at the start and, at times, in the middle of a data transfer (e.g., after an idle period). While Quick-Start is designed to be used by a range of transport protocols, in this document we only specify its use with TCP. Quick-Start is designed to allow connections to use higher sending rates when there is significant unused bandwidth along the path, and the sender and all of the routers along the path approve the Quick-Start Request. This document describes many paths where Quick-Start Requests would not be approved. These paths include all paths containing routers, IP tunnels, MPLS paths, and the like that do not support Quick- Start. These paths also include paths with routers or middleboxes that drop packets containing IP options. Quick-Start Requests could be difficult to approve over paths that include multi-access layer- two networks. This document also describes environments where the Quick-Start process could fail with false positives, with the sender incorrectly assuming that the Quick-Start Request had been approved by all of the routers along the path. As a result of these concerns, and as a result of the difficulties and seeming absence of motivation for routers, such as core routers to deploy Quick-Start, Quick-Start is being proposed as a mechanism that could be of use in controlled Floyd, et al. Experimental [Page 1] RFC 4782 Quick-Start for TCP and IP January 2007 environments, and not as a mechanism that would be intended or appropriate for ubiquitous deployment in the global Internet. Table of Contents 1. Introduction ....................................................4 1.1. Conventions and Terminology ................................5 2. Assumptions and General Principles ..............................6 2.1. Overview of Quick-Start ....................................7 3. The Quick-Start Option in IP ...................................10 3.1. The Quick-Start Option for IPv4 ...........................10 3.2. The Quick-Start Option for IPv6 ...........................13 3.3. Processing the Quick-Start Request at Routers .............14 3.3.1. Processing the Report of Approved Rate .............15 3.4. The QS Nonce ..............................................16 4. The Quick-Start Mechanisms in TCP ..............................18 4.1. Sending the Quick-Start Request ...........................19 4.2. The Quick-Start Response Option in the TCP header .........20 4.3. TCP: Sending the Quick-Start Response .....................21 4.4. TCP: Receiving and Using the Quick-Start Response Packet ..22 4.5. TCP: Controlling Acknowledgement Traffic on the Reverse Path ..............................................24 4.6. TCP: Responding to a Loss of a Quick-Start Packet .........26 4.7. TCP: A Quick-Start Request for a Larger Initial Window ....26 4.7.1. Interactions with Path MTU Discovery ...............26 4.7.2. Quick-Start Request Packets that are Discarded by Routers or Middleboxes ................27 4.8. TCP: A Quick-Start Request in the Middle of a Connection ..28 4.9. An Example Quick-Start Scenario with TCP ..................29 5. Quick-Start and IPsec AH .......................................30 6. Quick-Start in IP Tunnels and MPLS .............................31 6.1. Simple Tunnels that Are Compatible with Quick-Start .......33 6.1.1. Simple Tunnels that Are Aware of Quick-Start .......33 6.2. Simple Tunnels that Are Not Compatible with Quick-Start ...34 6.3. Tunnels That Support Quick-Start ..........................35 6.4. Quick-Start and MPLS ......................................35Show full document text