draft-ietf-httpbis-p5-range-23.txt		draft-ietf-httpbis-p5-range-24.txt
	HTTPbis Working Group R. Fielding, Ed.		HTTPbis Working Group R. Fielding, Ed.
	Internet-Draft Adobe		Internet-Draft Adobe
	Obsoletes: 2616 (if approved) Y. Lafon, Ed.		Obsoletes: 2616 (if approved) Y. Lafon, Ed.
	Intended status: Standards Track W3C		Intended status: Standards Track W3C
	Expires: January 16, 2014 J. Reschke, Ed.		Expires: March 29, 2014 J. Reschke, Ed.
	greenbytes		greenbytes
	July 15, 2013		September 25, 2013
	Hypertext Transfer Protocol (HTTP/1.1): Range Requests		Hypertext Transfer Protocol (HTTP/1.1): Range Requests
	draft-ietf-httpbis-p5-range-23		draft-ietf-httpbis-p5-range-24
	Abstract		Abstract
	The Hypertext Transfer Protocol (HTTP) is an application-level		The Hypertext Transfer Protocol (HTTP) is an application-level
	protocol for distributed, collaborative, hypertext information		protocol for distributed, collaborative, hypertext information
	systems. This document defines range requests and the rules for		systems. This document defines range requests and the rules for
	constructing and combining responses to those requests.		constructing and combining responses to those requests.
	Editorial Note (To be removed by RFC Editor)		Editorial Note (To be removed by RFC Editor)
	Discussion of this draft takes place on the HTTPBIS working group		Discussion of this draft takes place on the HTTPBIS working group
	mailing list (ietf-http-wg@w3.org), which is archived at		mailing list (ietf-http-wg@w3.org), which is archived at
	<http://lists.w3.org/Archives/Public/ietf-http-wg/>.		<http://lists.w3.org/Archives/Public/ietf-http-wg/>.
	The current issues list is at		The current issues list is at
	<http://tools.ietf.org/wg/httpbis/trac/report/3> and related		<http://tools.ietf.org/wg/httpbis/trac/report/3> and related
	documents (including fancy diffs) can be found at		documents (including fancy diffs) can be found at
	<http://tools.ietf.org/wg/httpbis/>.		<http://tools.ietf.org/wg/httpbis/>.
	The changes in this draft are summarized in Appendix E.4.		The changes in this draft are summarized in Appendix E.5.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 http://datatracker.ietf.org/drafts/current/.		Drafts is at http://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 16, 2014.		This Internet-Draft will expire on March 29, 2014.
	Copyright Notice		Copyright Notice
	Copyright (c) 2013 IETF Trust and the persons identified as the		Copyright (c) 2013 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 3, line 17		skipping to change at page 3, line 17
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1. Conformance and Error Handling . . . . . . . . . . . . . . 4		1.1. Conformance and Error Handling . . . . . . . . . . . . . . 4
	1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 4		1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 4
	2. Range Units . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Range Units . . . . . . . . . . . . . . . . . . . . . . . . . 4
	2.1. Byte Ranges . . . . . . . . . . . . . . . . . . . . . . . 5		2.1. Byte Ranges . . . . . . . . . . . . . . . . . . . . . . . 5
	2.2. Other Range Units . . . . . . . . . . . . . . . . . . . . 7		2.2. Other Range Units . . . . . . . . . . . . . . . . . . . . 7
	2.3. Accept-Ranges . . . . . . . . . . . . . . . . . . . . . . 7		2.3. Accept-Ranges . . . . . . . . . . . . . . . . . . . . . . 7
	3. Range Requests . . . . . . . . . . . . . . . . . . . . . . . . 7		3. Range Requests . . . . . . . . . . . . . . . . . . . . . . . . 7
	3.1. Range . . . . . . . . . . . . . . . . . . . . . . . . . . 7		3.1. Range . . . . . . . . . . . . . . . . . . . . . . . . . . 7
	3.2. If-Range . . . . . . . . . . . . . . . . . . . . . . . . . 9		3.2. If-Range . . . . . . . . . . . . . . . . . . . . . . . . . 9
	4. Responses to a Range Request . . . . . . . . . . . . . . . . . 10		4. Responses to a Range Request . . . . . . . . . . . . . . . . . 9
	4.1. 206 Partial Content . . . . . . . . . . . . . . . . . . . 10		4.1. 206 Partial Content . . . . . . . . . . . . . . . . . . . 10
	4.2. Content-Range . . . . . . . . . . . . . . . . . . . . . . 12		4.2. Content-Range . . . . . . . . . . . . . . . . . . . . . . 12
	4.3. Combining Ranges . . . . . . . . . . . . . . . . . . . . . 14		4.3. Combining Ranges . . . . . . . . . . . . . . . . . . . . . 14
	4.4. 416 Range Not Satisfiable . . . . . . . . . . . . . . . . 15		4.4. 416 Range Not Satisfiable . . . . . . . . . . . . . . . . 15
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
	5.1. Range Unit Registry . . . . . . . . . . . . . . . . . . . 15		5.1. Range Unit Registry . . . . . . . . . . . . . . . . . . . 15
	5.1.1. Procedure . . . . . . . . . . . . . . . . . . . . . . 15		5.1.1. Procedure . . . . . . . . . . . . . . . . . . . . . . 15
	5.1.2. Registrations . . . . . . . . . . . . . . . . . . . . 16		5.1.2. Registrations . . . . . . . . . . . . . . . . . . . . 16
	5.2. Status Code Registration . . . . . . . . . . . . . . . . . 16		5.2. Status Code Registration . . . . . . . . . . . . . . . . . 16
	5.3. Header Field Registration . . . . . . . . . . . . . . . . 16		5.3. Header Field Registration . . . . . . . . . . . . . . . . 16
	skipping to change at page 3, line 44		skipping to change at page 3, line 44
	Appendix A. Internet Media Type multipart/byteranges . . . . . . 18		Appendix A. Internet Media Type multipart/byteranges . . . . . . 18
	Appendix B. Changes from RFC 2616 . . . . . . . . . . . . . . . . 20		Appendix B. Changes from RFC 2616 . . . . . . . . . . . . . . . . 20
	Appendix C. Imported ABNF . . . . . . . . . . . . . . . . . . . . 21		Appendix C. Imported ABNF . . . . . . . . . . . . . . . . . . . . 21
	Appendix D. Collected ABNF . . . . . . . . . . . . . . . . . . . 21		Appendix D. Collected ABNF . . . . . . . . . . . . . . . . . . . 21
	Appendix E. Change Log (to be removed by RFC Editor before		Appendix E. Change Log (to be removed by RFC Editor before
	publication) . . . . . . . . . . . . . . . . . . . . 23		publication) . . . . . . . . . . . . . . . . . . . . 23
	E.1. Since draft-ietf-httpbis-p5-range-19 . . . . . . . . . . . 23		E.1. Since draft-ietf-httpbis-p5-range-19 . . . . . . . . . . . 23
	E.2. Since draft-ietf-httpbis-p5-range-20 . . . . . . . . . . . 23		E.2. Since draft-ietf-httpbis-p5-range-20 . . . . . . . . . . . 23
	E.3. Since draft-ietf-httpbis-p5-range-21 . . . . . . . . . . . 23		E.3. Since draft-ietf-httpbis-p5-range-21 . . . . . . . . . . . 23
	E.4. Since draft-ietf-httpbis-p5-range-22 . . . . . . . . . . . 24		E.4. Since draft-ietf-httpbis-p5-range-22 . . . . . . . . . . . 24
			E.5. Since draft-ietf-httpbis-p5-range-23 . . . . . . . . . . . 24
	Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24		Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
	1. Introduction		1. Introduction
	Hypertext Transfer Protocol (HTTP) clients often encounter		Hypertext Transfer Protocol (HTTP) clients often encounter
	interrupted data transfers as a result of canceled requests or		interrupted data transfers as a result of canceled requests or
	dropped connections. When a client has stored a partial		dropped connections. When a client has stored a partial
	representation, it is desirable to request the remainder of that		representation, it is desirable to request the remainder of that
	representation in a subsequent request rather than transfer the		representation in a subsequent request rather than transfer the
	entire representation. Likewise, devices with limited local storage		entire representation. Likewise, devices with limited local storage
	skipping to change at page 4, line 43		skipping to change at page 4, line 43
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	Conformance criteria and considerations regarding error handling are		Conformance criteria and considerations regarding error handling are
	defined in Section 2.5 of [Part1].		defined in Section 2.5 of [Part1].
	1.2. Syntax Notation		1.2. Syntax Notation
	This specification uses the Augmented Backus-Naur Form (ABNF)		This specification uses the Augmented Backus-Naur Form (ABNF)
	notation of [RFC5234] with the list rule extension defined in Section		notation of [RFC5234] with the list rule extension defined in Section
	1.2 of [Part1]. Appendix C describes rules imported from other		7 of [Part1]. Appendix C describes rules imported from other
	documents. Appendix D shows the collected ABNF with the list rule		documents. Appendix D shows the collected ABNF with the list rule
	expanded.		expanded.
	2. Range Units		2. Range Units
	A representation can be partitioned into subranges according to		A representation can be partitioned into subranges according to
	various structural units, depending on the structure inherent in the		various structural units, depending on the structure inherent in the
	representation's media type. This "range unit" is used in the		representation's media type. This "range unit" is used in the
	Accept-Ranges (Section 2.3) response header field to advertise		Accept-Ranges (Section 2.3) response header field to advertise
	support for range requests, the Range (Section 3.1) request header		support for range requests, the Range (Section 3.1) request header
	skipping to change at page 7, line 20		skipping to change at page 7, line 20
	other-range-unit = token		other-range-unit = token
	2.3. Accept-Ranges		2.3. Accept-Ranges
	The "Accept-Ranges" header field allows a server to indicate that it		The "Accept-Ranges" header field allows a server to indicate that it
	supports range requests for the target resource.		supports range requests for the target resource.
	Accept-Ranges = acceptable-ranges		Accept-Ranges = acceptable-ranges
	acceptable-ranges = 1#range-unit / "none"		acceptable-ranges = 1#range-unit / "none"
	Origin servers that support byte-range requests MAY send		An origin server that supports byte-range requests for a given target
			resource MAY send
	Accept-Ranges: bytes		Accept-Ranges: bytes
	but are not required to do so. Clients MAY generate range requests		to indicate what range units are supported. A client MAY generate
	without having received this header field for the resource involved.		range requests without having received this header field for the
	Range units are defined in Section 2.		resource involved. Range units are defined in Section 2.
	Servers that do not support any kind of range request for the target		A server that does not support any kind of range request for the
	resource resource MAY send		target resource resource MAY send
	Accept-Ranges: none		Accept-Ranges: none
	to advise the client not to attempt a range request.		to advise the client not to attempt a range request.
	3. Range Requests		3. Range Requests
	3.1. Range		3.1. Range
	The "Range" header field on a GET request modifies the method		The "Range" header field on a GET request modifies the method
	skipping to change at page 8, line 7		skipping to change at page 8, line 8
	other-range-set = 1*CHAR		other-range-set = 1*CHAR
	A server MAY ignore the Range header field. However, origin servers		A server MAY ignore the Range header field. However, origin servers
	and intermediate caches ought to support byte ranges when possible,		and intermediate caches ought to support byte ranges when possible,
	since Range supports efficient recovery from partially failed		since Range supports efficient recovery from partially failed
	transfers and partial retrieval of large representations. A server		transfers and partial retrieval of large representations. A server
	MUST ignore a Range header field received with a request method other		MUST ignore a Range header field received with a request method other
	than GET.		than GET.
	An origin server MUST ignore a Range header field that contains a		An origin server MUST ignore a Range header field that contains a
	range unit it does not understand. A proxy MAY either discard a		range unit it does not understand. A proxy MAY discard a Range
	Range header field that contains a range unit it does not understand		header field that contains a range unit it does not understand.
	or pass it to the next inbound server when forwarding the request.
	A server that supports range requests ought to ignore or reject a		A server that supports range requests MAY ignore or reject a Range
	Range header field that consists of more than two overlapping ranges,		header field that consists of more than two overlapping ranges, or a
	or a set of many small ranges that are not listed in ascending order,		set of many small ranges that are not listed in ascending order,
	since both are indications of either a broken client or a deliberate		since both are indications of either a broken client or a deliberate
	denial of service attack (Section 6.1). A client SHOULD NOT request		denial of service attack (Section 6.1). A client SHOULD NOT request
	multiple ranges that are inherently less efficient to process and		multiple ranges that are inherently less efficient to process and
	transfer than a single range that encompasses the same data.		transfer than a single range that encompasses the same data.
	A client that is requesting multiple ranges SHOULD list those ranges		A client that is requesting multiple ranges SHOULD list those ranges
	in ascending order (the order in which they would typically be		in ascending order (the order in which they would typically be
	received in a complete representation) unless there is a specific		received in a complete representation) unless there is a specific
	need to request a later part earlier. For example, a user agent		need to request a later part earlier. For example, a user agent
	processing a large representation with an internal catalog of parts		processing a large representation with an internal catalog of parts
	skipping to change at page 9, line 10		skipping to change at page 9, line 10
	If all of the preconditions are true, the server supports the Range		If all of the preconditions are true, the server supports the Range
	header field for the target resource, and the specified range(s) are		header field for the target resource, and the specified range(s) are
	invalid or unsatisfiable, the server SHOULD send a 416 (Range Not		invalid or unsatisfiable, the server SHOULD send a 416 (Range Not
	Satisfiable) response.		Satisfiable) response.
	3.2. If-Range		3.2. If-Range
	If a client has a partial copy of a representation and wishes to have		If a client has a partial copy of a representation and wishes to have
	an up-to-date copy of the entire representation, it could use the		an up-to-date copy of the entire representation, it could use the
	Range header field with a conditional GET (using either or both of		Range header field with a conditional GET (using either or both of
	If-Unmodified-Since and If-Match.) However, if the condition fails		If-Unmodified-Since and If-Match.) However, if the precondition
	because the representation has been modified, the client would then		fails because the representation has been modified, the client would
	have to make a second request to obtain the entire current		then have to make a second request to obtain the entire current
	representation.		representation.
	The "If-Range" header field allows a client to "short-circuit" the		The "If-Range" header field allows a client to "short-circuit" the
	second request. Informally, its meaning is: if the representation is		second request. Informally, its meaning is: if the representation is
	unchanged, send me the part(s) that I am requesting in Range;		unchanged, send me the part(s) that I am requesting in Range;
	otherwise, send me the entire representation.		otherwise, send me the entire representation.
	If-Range = entity-tag / HTTP-date		If-Range = entity-tag / HTTP-date
	A client MUST NOT generate an If-Range header field containing an
	entity-tag that is marked as weak. A client MUST NOT generate an If-
	Range header field containing a Last-Modified date unless the client
	has no entity-tag for the corresponding representation and the Last-
	Modified date is strong in the sense defined by Section 2.2.2 of
	[Part4].
	A server that evaluates a conditional range request that is
	applicable to one of its representations MUST evaluate the condition
	as false if the entity-tag used as a validator is marked as weak or,
	when an HTTP-date is used as the validator, if the date value is not
	strong in the sense defined by Section 2.2.2 of [Part4]. (A server
	can distinguish between a valid HTTP-date and any form of entity-tag
	by examining the first two characters.)
	A client MUST NOT generate an If-Range header field in a request that		A client MUST NOT generate an If-Range header field in a request that
	does not contain a Range header field. A server MUST ignore an If-		does not contain a Range header field. A server MUST ignore an If-
	Range header field received in a request that does not contain a		Range header field received in a request that does not contain a
	Range header field. An origin server MUST ignore an If-Range header		Range header field. An origin server MUST ignore an If-Range header
	field received in a request for a target resource that does not		field received in a request for a target resource that does not
	support Range requests.		support Range requests.
			A client MUST NOT generate an If-Range header field containing an
			entity-tag that is marked as weak. A client MUST NOT generate an If-
			Range header field containing an HTTP-date unless the client has no
			entity-tag for the corresponding representation and the date is a
			strong validator in the sense defined by Section 2.2.2 of [Part4].
			A server that evaluates an If-Range precondition MUST use the strong
			comparison function when comparing entity-tags (Section 2.3.2 of
			[Part4]) and MUST evaluate the condition as false if an HTTP-date
			validator is provided that is not a strong validator in the sense
			defined by Section 2.2.2 of [Part4]. (A server can distinguish
			between a valid HTTP-date and any form of entity-tag by examining the
			first two characters.)
	If the validator given in the If-Range header field matches the		If the validator given in the If-Range header field matches the
	current validator for the selected representation of the target		current validator for the selected representation of the target
	resource, then the server SHOULD process the Range header field as		resource, then the server SHOULD process the Range header field as
	requested. If the validator does not match, then the server MUST		requested. If the validator does not match, the server MUST ignore
	ignore the Range header field.		the Range header field.
	4. Responses to a Range Request		4. Responses to a Range Request
	4.1. 206 Partial Content		4.1. 206 Partial Content
	The 206 (Partial Content) status code indicates that the server is		The 206 (Partial Content) status code indicates that the server is
	successfully fulfilling a range request for the target resource by		successfully fulfilling a range request for the target resource by
	transferring one or more parts of the selected representation that		transferring one or more parts of the selected representation that
	correspond to the satisfiable ranges found in the request's Range		correspond to the satisfiable ranges found in the request's Range
	header field (Section 3.1).		header field (Section 3.1).
	If a single part is being transferred, the server generating the 206		If a single part is being transferred, the server generating the 206
	response MUST generate a Content-Range header field, describing what		response MUST generate a Content-Range header field, describing what
	skipping to change at page 10, line 34		skipping to change at page 10, line 31
	Content-Length: 26012		Content-Length: 26012
	Content-Type: image/gif		Content-Type: image/gif
	... 26012 bytes of partial image data ...		... 26012 bytes of partial image data ...
	If multiple parts are being transferred, the server generating the		If multiple parts are being transferred, the server generating the
	206 response MUST generate a "multipart/byteranges" payload, as		206 response MUST generate a "multipart/byteranges" payload, as
	defined in Appendix A, and a Content-Type header field containing the		defined in Appendix A, and a Content-Type header field containing the
	multipart/byteranges media type and its required boundary parameter.		multipart/byteranges media type and its required boundary parameter.
	To avoid confusion with single part responses, a server MUST NOT		To avoid confusion with single part responses, a server MUST NOT
	generate a Content-Range header field in the HTTP header block of a		generate a Content-Range header field in the HTTP header section of a
	multiple part response (this field will be sent in each part		multiple part response (this field will be sent in each part
	instead).		instead).
	Within the header area of each body part in the multipart payload,		Within the header area of each body part in the multipart payload,
	the server MUST generate a Content-Range header field corresponding		the server MUST generate a Content-Range header field corresponding
	to the range being enclosed in that body part. If the selected		to the range being enclosed in that body part. If the selected
	representation would have had a Content-Type header field in a 200		representation would have had a Content-Type header field in a 200
	(OK) response, the server SHOULD generate that same Content-Type		(OK) response, the server SHOULD generate that same Content-Type
	field in the header area of each body part. For example:		field in the header area of each body part. For example:
	skipping to change at page 12, line 20		skipping to change at page 12, line 20
	If a 206 is generated in response to a request with an If-Range		If a 206 is generated in response to a request with an If-Range
	header field, the sender SHOULD NOT generate other representation		header field, the sender SHOULD NOT generate other representation
	header fields beyond those required above, because the client is		header fields beyond those required above, because the client is
	understood to already have a prior response containing those header		understood to already have a prior response containing those header
	fields. Otherwise, the sender MUST generate all of the		fields. Otherwise, the sender MUST generate all of the
	representation header fields that would have been sent in a 200 (OK)		representation header fields that would have been sent in a 200 (OK)
	response to the same request.		response to the same request.
	A 206 response is cacheable unless otherwise indicated by explicit		A 206 response is cacheable unless otherwise indicated by explicit
	cache controls (see Section 4.1.2 of [Part6]).		cache controls (see Section 4.2.2 of [Part6]).
	4.2. Content-Range		4.2. Content-Range
	The "Content-Range" header field is sent in a single part 206		The "Content-Range" header field is sent in a single part 206
	(Partial Content) response to indicate the partial range of the		(Partial Content) response to indicate the partial range of the
	selected representation enclosed as the message payload, sent in each		selected representation enclosed as the message payload, sent in each
	part of a multipart 206 response to indicate the range enclosed		part of a multipart 206 response to indicate the range enclosed
	within each body part, and sent in 416 (Range Not Satisfiable)		within each body part, and sent in 416 (Range Not Satisfiable)
	responses to provide information about the selected representation.		responses to provide information about the selected representation.
	skipping to change at page 14, line 20		skipping to change at page 14, line 20
	Content-Range: bytes 734-1233/1234		Content-Range: bytes 734-1233/1234
	4.3. Combining Ranges		4.3. Combining Ranges
	A response might transfer only a subrange of a representation if the		A response might transfer only a subrange of a representation if the
	connection closed prematurely or if the request used one or more		connection closed prematurely or if the request used one or more
	Range specifications. After several such transfers, a client might		Range specifications. After several such transfers, a client might
	have received several ranges of the same representation. These		have received several ranges of the same representation. These
	ranges can only be safely combined if they all have in common the		ranges can only be safely combined if they all have in common the
	same strong validator, where "strong validator" is defined to be		same strong validator (Section 2.1 of [Part4]).
	either an entity-tag that is not marked as weak (Section 2.3 of
	[Part4]) or, if no entity-tag is provided, a Last-Modified value that
	is strong in the sense defined by Section 2.2.2 of [Part4].
	A client that has received multiple partial responses to GET requests		A client that has received multiple partial responses to GET requests
	on a target resource MAY combine those responses into a larger		on a target resource MAY combine those responses into a larger
	continuous range if they share the same strong validator.		continuous range if they share the same strong validator.
	If the most recent response is an incomplete 200 (OK) response, then		If the most recent response is an incomplete 200 (OK) response, then
	the header fields of that response are used for any combined response		the header fields of that response are used for any combined response
	and replace those of the matching stored responses.		and replace those of the matching stored responses.
	If the most recent response is a 206 (Partial Content) response and		If the most recent response is a 206 (Partial Content) response and
	skipping to change at page 17, line 39		skipping to change at page 17, line 39
	memory, and bandwidth consumed by attempting to serve the requested		memory, and bandwidth consumed by attempting to serve the requested
	data in many parts. Servers ought to ignore, coalesce, or reject		data in many parts. Servers ought to ignore, coalesce, or reject
	egregious range requests, such as requests for more than two		egregious range requests, such as requests for more than two
	overlapping ranges or for many small ranges in a single set,		overlapping ranges or for many small ranges in a single set,
	particularly when the ranges are requested out of order for no		particularly when the ranges are requested out of order for no
	apparent reason. Multipart range requests are not designed to		apparent reason. Multipart range requests are not designed to
	support random access.		support random access.
	7. Acknowledgments		7. Acknowledgments
	See Section 9 of [Part1].		See Section 10 of [Part1].
	8. References		8. References
	8.1. Normative References		8.1. Normative References
	[Part1] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[Part1] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Message Syntax and Routing",		Protocol (HTTP/1.1): Message Syntax and Routing",
	draft-ietf-httpbis-p1-messaging-23 (work in progress),		draft-ietf-httpbis-p1-messaging-24 (work in progress),
	July 2013.		September 2013.
	[Part2] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[Part2] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Semantics and Content",		Protocol (HTTP/1.1): Semantics and Content",
	draft-ietf-httpbis-p2-semantics-23 (work in progress),		draft-ietf-httpbis-p2-semantics-24 (work in progress),
	July 2013.		September 2013.
	[Part4] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[Part4] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Conditional Requests",		Protocol (HTTP/1.1): Conditional Requests",
	draft-ietf-httpbis-p4-conditional-23 (work in progress),		draft-ietf-httpbis-p4-conditional-24 (work in progress),
	July 2013.		September 2013.
	[Part6] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,		[Part6] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
	Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",		Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
	draft-ietf-httpbis-p6-cache-23 (work in progress),		draft-ietf-httpbis-p6-cache-24 (work in progress),
	July 2013.		September 2013.
	[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail		[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
	Extensions (MIME) Part Two: Media Types", RFC 2046,		Extensions (MIME) Part Two: Media Types", RFC 2046,
	November 1996.		November 1996.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234, January 2008.		Specifications: ABNF", STD 68, RFC 5234, January 2008.
	skipping to change at page 20, line 38		skipping to change at page 20, line 38
	...the first range...		...the first range...
	--THIS_STRING_SEPARATES		--THIS_STRING_SEPARATES
	Content-Type: video/example		Content-Type: video/example
	Content-Range: exampleunit 11.2-14.3/25		Content-Range: exampleunit 11.2-14.3/25
	...the second range		...the second range
	--THIS_STRING_SEPARATES--		--THIS_STRING_SEPARATES--
	Appendix B. Changes from RFC 2616		Appendix B. Changes from RFC 2616
			Servers are given more leeway in how they respond to a range request,
			in order to mitigate abuse by malicious (or just greedy) clients.
			(Section 3.1)
	A weak validator cannot be used in a 206 response. (Section 4.1)		A weak validator cannot be used in a 206 response. (Section 4.1)
	The Content-Range header field only has meaning when the status code		The Content-Range header field only has meaning when the status code
	explicitly defines its use. (Section 4.2)		explicitly defines its use. (Section 4.2)
	Servers are given more leeway in how they respond to a range request,		This specification introduces a Range Unit Registry. (Section 5.1)
	in order to mitigate abuse by malicious (or just greedy) clients.
	multipart/byteranges can consist of a single part. (Appendix A)		multipart/byteranges can consist of a single part. (Appendix A)
	This specification introduces a Range Unit Registry. (Section 5.1)
	Appendix C. Imported ABNF		Appendix C. Imported ABNF
	The following core rules are included by reference, as defined in		The following core rules are included by reference, as defined in
	Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return),		Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return),
	CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double		CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double
	quote), HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any		quote), HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any
	8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII		8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII
	character).		character).
	Note that all rules derived from token are to be compared case-		Note that all rules derived from token are to be compared case-
	skipping to change at page 24, line 24		skipping to change at page 24, line 24
	o <http://tools.ietf.org/wg/httpbis/trac/ticket/438>: "media type		o <http://tools.ietf.org/wg/httpbis/trac/ticket/438>: "media type
	registration template issues"		registration template issues"
	o <http://tools.ietf.org/wg/httpbis/trac/ticket/462>: "Editorial		o <http://tools.ietf.org/wg/httpbis/trac/ticket/462>: "Editorial
	suggestions"		suggestions"
	o <http://tools.ietf.org/wg/httpbis/trac/ticket/485>: "MUSTs and		o <http://tools.ietf.org/wg/httpbis/trac/ticket/485>: "MUSTs and
	other feedback"		other feedback"
			E.5. Since draft-ietf-httpbis-p5-range-23
			Closed issues:
			o <http://tools.ietf.org/wg/httpbis/trac/ticket/489>: "is P5's
			definition of strong validator consistent with P4?"
			o <http://tools.ietf.org/wg/httpbis/trac/ticket/490>: "p5 editorial
			comments"
	Index		Index
	2		2
	206 Partial Content (status code) 10		206 Partial Content (status code) 10
	4		4
	416 Range Not Satisfiable (status code) 15		416 Range Not Satisfiable (status code) 15
	A		A
	Accept-Ranges header field 7		Accept-Ranges header field 7
End of changes. 30 change blocks.
	59 lines changed or deleted		66 lines changed or added
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