draft-ietf-httpbis-cache-digest-05.txt		draft-ietf-httpbis-cache-digest-latest.txt
	HTTP Working Group K. Oku		HTTP Working Group K. Oku
	Internet-Draft Fastly		Internet-Draft Fastly
	Intended status: Experimental Y. Weiss		Intended status: Experimental Y. Weiss
	Expires: January 3, 2019 Akamai		Expires: April 16, 2026 Akamai
	July 2, 2018		October 13, 2025
	Cache Digests for HTTP/2		Cache Digests for HTTP/2
	draft-ietf-httpbis-cache-digest-05		draft-ietf-httpbis-cache-digest-latest
	Abstract		Abstract
	This specification defines a HTTP/2 frame type to allow clients to		This specification defines a HTTP/2 frame type to allow clients to
	inform the server of their cache's contents. Servers can then use		inform the server of their cache's contents. Servers can then use
	this to inform their choices of what to push to clients.		this to inform their choices of what to push to clients.
	Note to Readers		Note to Readers
	Discussion of this draft takes place on the HTTP working group		Discussion of this draft takes place on the HTTP working group
	skipping to change at page 1, line 43 ¶		skipping to change at page 1, line 43 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on January 3, 2019.		This Internet-Draft will expire on April 16, 2026.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2025 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
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	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3		1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
	2. The CACHE_DIGEST Frame . . . . . . . . . . . . . . . . . . . 3		2. The CACHE_DIGEST Frame . . . . . . . . . . . . . . . . . . . 3
	2.1. Client Behavior . . . . . . . . . . . . . . . . . . . . . 4		2.1. Client Behavior . . . . . . . . . . . . . . . . . . . . . 4
	2.1.1. Creating a digest . . . . . . . . . . . . . . . . . . 4		2.1.1. Creating a digest . . . . . . . . . . . . . . . . . . 5
	2.1.2. Adding a URL to the Digest-Value . . . . . . . . . . 5		2.1.2. Adding a URL to the Digest-Value . . . . . . . . . . 5
	2.1.3. Removing a URL to the Digest-Value . . . . . . . . . 7		2.1.3. Removing a URL to the Digest-Value . . . . . . . . . 7
	2.1.4. Computing a fingerprint value . . . . . . . . . . . . 8		2.1.4. Computing a fingerprint value . . . . . . . . . . . . 8
	2.1.5. Computing the key . . . . . . . . . . . . . . . . . . 9		2.1.5. Computing the key . . . . . . . . . . . . . . . . . . 9
	2.1.6. Computing a Hash Value . . . . . . . . . . . . . . . 9		2.1.6. Computing a Hash Value . . . . . . . . . . . . . . . 9
	2.1.7. Computing an Alternative Hash Value . . . . . . . . . 9		2.1.7. Computing an Alternative Hash Value . . . . . . . . . 9
	2.2. Server Behavior . . . . . . . . . . . . . . . . . . . . . 10		2.2. Server Behavior . . . . . . . . . . . . . . . . . . . . . 10
	2.2.1. Querying the Digest for a Value . . . . . . . . . . . 10		2.2.1. Querying the Digest for a Value . . . . . . . . . . . 10
	3. The SETTINGS_SENDING_CACHE_DIGEST SETTINGS Parameter . . . . 11		3. The SETTINGS_SENDING_CACHE_DIGEST SETTINGS Parameter . . . . 11
	4. The SETTINGS_ACCEPT_CACHE_DIGEST SETTINGS Parameter . . . . . 12		4. The SETTINGS_ACCEPT_CACHE_DIGEST SETTINGS Parameter . . . . . 12
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 13		6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 13		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
	7.1. Normative References . . . . . . . . . . . . . . . . . . 13		7.1. Normative References . . . . . . . . . . . . . . . . . . 14
	7.2. Informative References . . . . . . . . . . . . . . . . . 14		7.2. Informative References . . . . . . . . . . . . . . . . . 14
	7.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 15		7.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 15
	Appendix A. Encoding the CACHE_DIGEST frame as an HTTP Header . 15		Appendix A. Encoding the CACHE_DIGEST frame as an HTTP Header . 15
	Appendix B. Changes . . . . . . . . . . . . . . . . . . . . . . 16		Appendix B. Changes . . . . . . . . . . . . . . . . . . . . . . 16
	B.1. Since draft-ietf-httpbis-cache-digest-04 . . . . . . . . 16		B.1. Since draft-ietf-httpbis-cache-digest-05 . . . . . . . . 16
	B.2. Since draft-ietf-httpbis-cache-digest-03 . . . . . . . . 16		B.2. Since draft-ietf-httpbis-cache-digest-04 . . . . . . . . 17
	B.3. Since draft-ietf-httpbis-cache-digest-02 . . . . . . . . 17		B.3. Since draft-ietf-httpbis-cache-digest-03 . . . . . . . . 17
	B.4. Since draft-ietf-httpbis-cache-digest-01 . . . . . . . . 17		B.4. Since draft-ietf-httpbis-cache-digest-02 . . . . . . . . 17
	B.5. Since draft-ietf-httpbis-cache-digest-00 . . . . . . . . 17		B.5. Since draft-ietf-httpbis-cache-digest-01 . . . . . . . . 17
	Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 17		B.6. Since draft-ietf-httpbis-cache-digest-00 . . . . . . . . 17
			Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 17
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
	1. Introduction		1. Introduction
	HTTP/2 [RFC7540] allows a server to "push" synthetic request/response		HTTP/2 [RFC7540] allows a server to "push" synthetic request/response
	pairs into a client's cache optimistically. While there is strong		pairs into a client's cache optimistically. While there is strong
	interest in using this facility to improve perceived Web browsing		interest in using this facility to improve perceived Web browsing
	performance, it is sometimes counterproductive because the client		performance, it is sometimes counterproductive because the client
	might already have cached the "pushed" response.		might already have cached the "pushed" response.
	skipping to change at page 16, line 42 ¶		skipping to change at page 16, line 46 ¶
	transmitted using a single HTTP/2 connection.		transmitted using a single HTTP/2 connection.
	Also, due to the fact that any header that is supplied to Fetch is		Also, due to the fact that any header that is supplied to Fetch is
	required to be end-to-end, there is an ambiguity in what a Cache-		required to be end-to-end, there is an ambiguity in what a Cache-
	Digest header respresents when a request is transmitted through a		Digest header respresents when a request is transmitted through a
	proxy. The header may represent the cache state of a client or that		proxy. The header may represent the cache state of a client or that
	of a proxy, depending on how the proxy handles the header.		of a proxy, depending on how the proxy handles the header.
	Appendix B. Changes		Appendix B. Changes
	B.1. Since draft-ietf-httpbis-cache-digest-04		B.1. Since draft-ietf-httpbis-cache-digest-05
			o None yet.
			B.2. Since draft-ietf-httpbis-cache-digest-04
	o Remove ETag from the digest key calculations.		o Remove ETag from the digest key calculations.
	o Add SETTINGS_ prefix to parameter names.		o Add SETTINGS_ prefix to parameter names.
	B.2. Since draft-ietf-httpbis-cache-digest-03		B.3. Since draft-ietf-httpbis-cache-digest-03
	o Yoav becomes an author; Mark steps down.		o Yoav becomes an author; Mark steps down.
	B.3. Since draft-ietf-httpbis-cache-digest-02		B.4. Since draft-ietf-httpbis-cache-digest-02
	o Switch to Cuckoo Filter.		o Switch to Cuckoo Filter.
	B.4. Since draft-ietf-httpbis-cache-digest-01		B.5. Since draft-ietf-httpbis-cache-digest-01
	o Added definition of the Cache-Digest header.		o Added definition of the Cache-Digest header.
	o Introduce ACCEPT_CACHE_DIGEST SETTINGS parameter.		o Introduce ACCEPT_CACHE_DIGEST SETTINGS parameter.
	o Change intended status from Standard to Experimental.		o Change intended status from Standard to Experimental.
	B.5. Since draft-ietf-httpbis-cache-digest-00		B.6. Since draft-ietf-httpbis-cache-digest-00
	o Make the scope of a digest frame explicit and shift to stream 0.		o Make the scope of a digest frame explicit and shift to stream 0.
	Appendix C. Acknowledgements		Acknowledgements
	+{:numbered="false"}
	Thanks to Stefan Eissing for his suggestions.		Thanks to Stefan Eissing for his suggestions.
	Authors' Addresses		Authors' Addresses
	Kazuho Oku		Kazuho Oku
	Fastly		Fastly
	Email: kazuhooku@gmail.com		Email: kazuhooku@gmail.com
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	22 lines changed or deleted		25 lines changed or added
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