Happy Eyeballs: Success with Dual-Stack Hosts
RFC 6555
| Document | Type |
RFC - Proposed Standard
(April 2012; Errata)
Obsoleted by RFC 8305
|
|
|---|---|---|---|
| Last updated | 2020-01-21 | ||
| Replaces | draft-wing-v6ops-happy-eyeballs-ipv6 | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized with errata bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Fred Baker | ||
| IESG | IESG state | RFC 6555 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Ron Bonica | ||
| IESG note | Fred Baker (fred.baker@cisco.com) is the document shepherd. | ||
| Send notices to | (None) | ||
Internet Engineering Task Force (IETF) D. Wing
Request for Comments: 6555 A. Yourtchenko
Category: Standards Track Cisco
ISSN: 2070-1721 April 2012
Happy Eyeballs: Success with Dual-Stack Hosts
Abstract
When a server's IPv4 path and protocol are working, but the server's
IPv6 path and protocol are not working, a dual-stack client
application experiences significant connection delay compared to an
IPv4-only client. This is undesirable because it causes the dual-
stack client to have a worse user experience. This document
specifies requirements for algorithms that reduce this user-visible
delay and provides an algorithm.
Status of This Memo
This is an Internet Standards Track document.
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). Further information on
Internet Standards is available in 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/rfc6555.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Wing & Yourtchenko Standards Track [Page 1]
RFC 6555 Happy Eyeballs Dual Stack April 2012
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Additional Network and Host Traffic . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Hostnames . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Delay When IPv6 Is Not Accessible . . . . . . . . . . . . 5
4. Algorithm Requirements . . . . . . . . . . . . . . . . . . . . 6
4.1. Delay IPv4 . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Stateful Behavior When IPv6 Fails . . . . . . . . . . . . 8
4.3. Reset on Network (Re-)Initialization . . . . . . . . . . . 9
4.4. Abandon Non-Winning Connections . . . . . . . . . . . . . 9
5. Additional Considerations . . . . . . . . . . . . . . . . . . 10
5.1. Determining Address Type . . . . . . . . . . . . . . . . . 10
5.2. Debugging and Troubleshooting . . . . . . . . . . . . . . 10
5.3. Three or More Interfaces . . . . . . . . . . . . . . . . . 10
5.4. A and AAAA Resource Records . . . . . . . . . . . . . . . 10
5.5. Connection Timeout . . . . . . . . . . . . . . . . . . . . 11
5.6. Interaction with Same-Origin Policy . . . . . . . . . . . 11
5.7. Implementation Strategies . . . . . . . . . . . . . . . . 12
6. Example Algorithm . . . . . . . . . . . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . . 13
Wing & Yourtchenko Standards Track [Page 2]
RFC 6555 Happy Eyeballs Dual Stack April 2012
1. Introduction
In order to use applications over IPv6, it is necessary that users
enjoy nearly identical performance as compared to IPv4. A
combination of today's applications, IPv6 tunneling, IPv6 service
providers, and some of today's content providers all cause the user
experience to suffer (Section 3). For IPv6, a content provider may
ensure a positive user experience by using a DNS white list of IPv6
service providers who peer directly with them (e.g., [WHITELIST]).
However, this does not scale well (to the number of DNS servers
worldwide or the number of content providers worldwide) and does
react to intermittent network path outages.
Instead, applications reduce connection setup delays themselves, by
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