Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension
RFC 7301
| Document | Type |
RFC - Proposed Standard
(July 2014; Errata)
Updated by RFC 8447
|
|
|---|---|---|---|
| Last updated | 2017-11-03 | ||
| Replaces | draft-friedl-tls-applayerprotoneg | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Joseph Salowey | ||
| Shepherd write-up | Show (last changed 2014-02-02) | ||
| IESG | IESG state | RFC 7301 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Stephen Farrell | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) S. Friedl
Request for Comments: 7301 Cisco Systems, Inc.
Category: Standards Track A. Popov
ISSN: 2070-1721 Microsoft Corp.
A. Langley
Google Inc.
E. Stephan
Orange
July 2014
Transport Layer Security (TLS)
Application-Layer Protocol Negotiation Extension
Abstract
This document describes a Transport Layer Security (TLS) extension
for application-layer protocol negotiation within the TLS handshake.
For instances in which multiple application protocols are supported
on the same TCP or UDP port, this extension allows the application
layer to negotiate which protocol will be used within the TLS
connection.
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/rfc7301.
Friedl, et al. Standards Track [Page 1]
RFC 7301 TLS App-Layer Protocol Negotiation Ext July 2014
Copyright Notice
Copyright (c) 2014 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Application-Layer Protocol Negotiation . . . . . . . . . . . 3
3.1. The Application-Layer Protocol Negotiation Extension . . 3
3.2. Protocol Selection . . . . . . . . . . . . . . . . . . . 5
4. Design Considerations . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 8
1. Introduction
Increasingly, application-layer protocols are encapsulated in the TLS
protocol [RFC5246]. This encapsulation enables applications to use
the existing, secure communications links already present on port 443
across virtually the entire global IP infrastructure.
When multiple application protocols are supported on a single server-
side port number, such as port 443, the client and the server need to
negotiate an application protocol for use with each connection. It
is desirable to accomplish this negotiation without adding network
round-trips between the client and the server, as each round-trip
will degrade an end-user's experience. Further, it would be
advantageous to allow certificate selection based on the negotiated
application protocol.
Friedl, et al. Standards Track [Page 2]
RFC 7301 TLS App-Layer Protocol Negotiation Ext July 2014
This document specifies a TLS extension that permits the application
layer to negotiate protocol selection within the TLS handshake. This
work was requested by the HTTPbis WG to address the negotiation of
HTTP/2 ([HTTP2]) over TLS; however, ALPN facilitates negotiation of
arbitrary application-layer protocols.
With ALPN, the client sends the list of supported application
protocols as part of the TLS ClientHello message. The server chooses
a protocol and sends the selected protocol as part of the TLS
ServerHello message. The application protocol negotiation can thus
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