Happy Eyeballs Version 2: Better Connectivity Using Concurrency
RFC 8305
| Document | Type |
RFC - Proposed Standard
(December 2017; No errata)
Obsoletes RFC 6555
|
|
|---|---|---|---|
| Last updated | 2017-12-21 | ||
| Replaces | draft-pauly-v6ops-happy-eyeballs-update | ||
| Stream | IETF | ||
| Formats | plain text pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Ron Bonica | ||
| Shepherd write-up | Show (last changed 2017-10-06) | ||
| IESG | IESG state | RFC 8305 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Warren Kumari | ||
| Send notices to | Ron Bonica <rbonica@juniper.net> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | No IANA Actions | ||
Internet Engineering Task Force (IETF) D. Schinazi
Request for Comments: 8305 T. Pauly
Obsoletes: 6555 Apple Inc.
Category: Standards Track December 2017
ISSN: 2070-1721
Happy Eyeballs Version 2: Better Connectivity Using Concurrency
Abstract
Many communication protocols operating over the modern Internet use
hostnames. These often resolve to multiple IP addresses, each of
which may have different performance and connectivity
characteristics. Since specific addresses or address families (IPv4
or IPv6) may be blocked, broken, or sub-optimal on a network, clients
that attempt multiple connections in parallel have a chance of
establishing a connection more quickly. This document specifies
requirements for algorithms that reduce this user-visible delay and
provides an example algorithm, referred to as "Happy Eyeballs". This
document obsoletes the original algorithm description in RFC 6555.
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 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8305.
Schinazi & Pauly Standards Track [Page 1]
RFC 8305 Happy Eyeballs v2 December 2017
Copyright Notice
Copyright (c) 2017 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
(https://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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Hostname Resolution Query Handling . . . . . . . . . . . . . 4
3.1. Handling Multiple DNS Server Addresses . . . . . . . . . 5
4. Sorting Addresses . . . . . . . . . . . . . . . . . . . . . . 6
5. Connection Attempts . . . . . . . . . . . . . . . . . . . . . 7
6. DNS Answer Changes during Happy Eyeballs Connection Setup . . 8
7. Supporting IPv6-Only Networks with NAT64 and DNS64 . . . . . 8
7.1. IPv4 Address Literals . . . . . . . . . . . . . . . . . . 8
7.2. Hostnames with Broken AAAA Records . . . . . . . . . . . 9
7.3. Virtual Private Networks . . . . . . . . . . . . . . . . 10
8. Summary of Configurable Values . . . . . . . . . . . . . . . 10
9. Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1. Path Maximum Transmission Unit Discovery . . . . . . . . 11
9.2. Application Layer . . . . . . . . . . . . . . . . . . . . 11
9.3. Hiding Operational Issues . . . . . . . . . . . . . . . . 11
10. Security Considerations . . . . . . . . . . . . . . . . . . . 12
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
12.1. Normative References . . . . . . . . . . . . . . . . . . 12
12.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Differences from RFC 6555 . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
Schinazi & Pauly Standards Track [Page 2]
RFC 8305 Happy Eyeballs v2 December 2017
1. Introduction
Many communication protocols operating over the modern Internet use
hostnames. These often resolve to multiple IP addresses, each of
which may have different performance and connectivity
characteristics. Since specific addresses or address families (IPv4
or IPv6) may be blocked, broken, or sub-optimal on a network, clients
that attempt multiple connections in parallel have a chance of
establishing a connection more quickly. This document specifies
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