draft-ietf-regext-rdap-sorting-and-paging-12.txt		draft-ietf-regext-rdap-sorting-and-paging-13.txt
	Registration Protocols Extensions M. Loffredo		Registration Protocols Extensions M. Loffredo
	Internet-Draft M. Martinelli		Internet-Draft M. Martinelli
	Intended status: Standards Track IIT-CNR/Registro.it		Intended status: Standards Track IIT-CNR/Registro.it
	Expires: October 19, 2020 S. Hollenbeck		Expires: November 30, 2020 S. Hollenbeck
	Verisign Labs		Verisign Labs
	April 17, 2020		May 29, 2020
	Registration Data Access Protocol (RDAP) Query Parameters for Result		Registration Data Access Protocol (RDAP) Query Parameters for Result
	Sorting and Paging		Sorting and Paging
	draft-ietf-regext-rdap-sorting-and-paging-12		draft-ietf-regext-rdap-sorting-and-paging-13
	Abstract		Abstract
	The Registration Data Access Protocol (RDAP) does not include core		The Registration Data Access Protocol (RDAP) does not include core
	functionality for clients to provide sorting and paging parameters		functionality for clients to provide sorting and paging parameters
	for control of large result sets. This omission can lead to		for control of large result sets. This omission can lead to
	unpredictable server processing of queries and client processing of		unpredictable server processing of queries and client processing of
	responses. This unpredictability can be greatly reduced if clients		responses. This unpredictability can be greatly reduced if clients
	can provide servers with their preferences for managing large		can provide servers with their preferences for managing large
	responses. This document describes RDAP query extensions that allow		responses. This document describes RDAP query extensions that allow
	skipping to change at page 1, line 41 ¶		skipping to change at page 1, line 41 ¶
	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 October 19, 2020.		This Internet-Draft will expire on November 30, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2020 IETF Trust and the persons identified as the		Copyright (c) 2020 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
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 3, line 24 ¶		skipping to change at page 3, line 24 ¶
	2. Information related to the number of results and the specific		2. Information related to the number of results and the specific
	portion of the result set to be returned, in addition to a set of		portion of the result set to be returned, in addition to a set of
	ready-made links for the result set scrolling, are inserted in		ready-made links for the result set scrolling, are inserted in
	the HTTP header of the request/response.		the HTTP header of the request/response.
	However, there are some drawbacks associated with the use of the HTTP		However, there are some drawbacks associated with the use of the HTTP
	header. First, the header properties cannot be set directly from a		header. First, the header properties cannot be set directly from a
	web browser. Moreover, in an HTTP session, the information on the		web browser. Moreover, in an HTTP session, the information on the
	status (i.e. the session identifier) is usually inserted in the		status (i.e. the session identifier) is usually inserted in the
	header or in the cookies, while the information on the resource		header or in a cookie, while the information on the resource
	identification or the search type is included in the query string.		identification or the search type is included in the query string.
	The second approach is therefore not compliant with the HTTP standard		The second approach is therefore not compliant with the HTTP standard
	[RFC7230]. As a result, this document describes a specification		[RFC7230]. As a result, this document describes a specification
	based on the use of query parameters.		based on the use of query parameters.
	Currently, the RDAP protocol [RFC7482] defines two query types:		Currently, the RDAP protocol [RFC7482] defines two query types:
	o lookup: the server returns only one object;		o lookup: the server returns only one object;
	o search: the server returns a collection of objects.		o search: the server returns a collection of objects.
	While the lookup query does not raise issues in the response		While the lookup query does not raise issues in response size
	management, the search query can potentially generate a large result		management, the search query can potentially generate a large result
	set that could be truncated according to the server limits. In		set that could be truncated according to server limits. In addition,
	addition, it is not possible to obtain the total number of the		it is not possible to obtain the total number of objects found that
	objects found that might be returned in a search query response		might be returned in a search query response [RFC7483]. Lastly,
	[RFC7483]. Lastly, there is no way to specify sort criteria to		there is no way to specify sort criteria to return the most relevant
	return the most relevant objects at the beginning of the result set.		objects at the beginning of the result set. Therefore, the client
	Therefore, the client might traverse the whole result set to find the		might traverse the whole result set to find the relevant objects or,
	relevant objects or, due to truncation, could not find them at all.		due to truncation, might not find them at all.
	The specification described in this document extends RDAP query		The specification described in this document extends RDAP query
	capabilities to enable result sorting and paging, by adding new query		capabilities to enable result sorting and paging, by adding new query
	parameters that can be applied to RDAP search path segments. The		parameters that can be applied to RDAP search path segments. The
	service is implemented using the Hypertext Transfer Protocol (HTTP)		service is implemented using the Hypertext Transfer Protocol (HTTP)
	[RFC7230] and the conventions described in RFC 7480 [RFC7480].		[RFC7230] and the conventions described in RFC 7480 [RFC7480].
	The implementation of the new parameters is technically feasible, as		The implementation of the new parameters is technically feasible, as
	operators for counting, sorting and paging rows are currently		operators for counting, sorting and paging rows are currently
	supported by the major RDBMSs.		supported by the major RDBMSs.
	1.1. Conventions Used in This Document		1.1. Conventions Used in This Document
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"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 BCP 14 [RFC2119]
			[RFC8174] when, and only when, they appear in all capitals, as shown
			here.
	2. RDAP Query Parameter Specification		2. RDAP Query Parameter Specification
	The new query parameters are OPTIONAL extensions of path segments		The new query parameters are OPTIONAL extensions of path segments
	defined in RFC 7482 [RFC7482]. They are as follows:		defined in RFC 7482 [RFC7482]. They are as follows:
	o "count": a boolean value that allows a client to request the total		o "count": a boolean value that allows a client to request return of
	number of objects found (that due to truncation can be different		the total number of objects found;
	from the number of returned objects);
	o "sort": a string value that allows a client to request a specific		o "sort": a string value that allows a client to request a specific
	sort order for the result set;		sort order for the result set;
	o "cursor": a string value representing a pointer to a specific		o "cursor": a string value representing a pointer to a specific
	fixed size portion of the result set.		fixed size portion of the result set.
	Augmented Backus-Naur Form (ABNF) [RFC5234] is used in the following		Augmented Backus-Naur Form (ABNF) [RFC5234] is used in the following
	sections to describe the formal syntax of these new parameters.		sections to describe the formal syntax of these new parameters.
	2.1. Sorting and Paging Metadata		2.1. Sorting and Paging Metadata
	According to most advanced principles in REST design, collectively		According to most advanced principles in REST design, collectively
	known as HATEOAS (Hypermedia as the Engine of Application State)		known as HATEOAS (Hypermedia as the Engine of Application State)
	([HATEOAS]), a client entering a REST application through an initial		([HATEOAS]), a client entering a REST application through an initial
	URI should use the server-provided links to dynamically discover		URI should use server-provided links to dynamically discover
	available actions and access the resources it needs. In this way,		available actions and access the resources it needs. In this way,
	the client is not requested to have prior knowledge of the service		the client is not requested to have prior knowledge of the service
	and, consequently, to hard code the URIs of different resources.		and, consequently, to hard code the URIs of different resources.
	This would allow the server to make URI changes as the API evolves		This allows the server to make URI changes as the API evolves without
	without breaking the clients. Definitively, a REST service should be		breaking clients. Definitively, a REST service should be as self-
	as self-descriptive as possible.		descriptive as possible.
	Therefore, servers implementing the query parameters described in		Therefore, servers implementing the query parameters described in
	this specification SHOULD provide additional information in their		this specification SHOULD provide additional information in their
	responses about both the available sorting criteria and the possible		responses about both the available sorting criteria and possible
	pagination. Such information is collected in two OPTIONAL response		pagination. Such information is collected in two OPTIONAL response
	elements named, respectively, "sorting_metadata" and		elements named, respectively, "sorting_metadata" and
	"paging_metadata".		"paging_metadata".
	The "sorting_metadata" element contains the following properties:		The "sorting_metadata" element contains the following properties:
	o "currentSort": "String" (OPTIONAL) either the value of sort		o "currentSort": "String" (OPTIONAL) either the value of sort
	"parameter" as specified in the query string or the sort applied		"parameter" as specified in the query string or the sort applied
	by default, if any;		by default, if any;
	o "availableSorts": "AvailableSort[]" (OPTIONAL) an array of objects		o "availableSorts": "AvailableSort[]" (OPTIONAL) an array of
	each one describing an alternate available sorting criterion.		objects, with each element describing an available sort criterion.
	Members are:		Members are:
	* "property": "String" (REQUIRED) the name that can be used by		* "property": "String" (REQUIRED) the name that can be used by
	the client to request the sorting criterion;		the client to request the sort criterion;
	* "default": "Boolean" (REQUIRED) whether the sorting criterion		* "default": "Boolean" (REQUIRED) whether the sort criterion is
	is applied by default;		applied by default;
	* "jsonPath": "String" (OPTIONAL) the JSONPath of the RDAP field		* "jsonPath": "String" (OPTIONAL) the JSONPath of the RDAP field
	corresponding to the property;		corresponding to the property;
	* "links": "Link[]" (OPTIONAL) an array of links as described in		* "links": "Link[]" (OPTIONAL) an array of links as described in
	RFC 8288 [RFC8288] containing the query string that applies the		RFC 8288 [RFC8288] containing the query string that applies the
	sorting criterion.		sort criterion.
	At least one between "currentSort" and "availableSorts" MUST be		At least one of the "currentSort" and "availableSorts" properties
	present.		MUST be present.
	The "paging_metadata" element contains the following fields:		The "paging_metadata" element contains the following fields:
	o "totalCount": "Numeric" (OPTIONAL) a numeric value representing		o "totalCount": "Numeric" (OPTIONAL) a numeric value representing
	the total number of objects found. It MUST be provided if the		the total number of objects found. It MUST be provided if the
	query string contains the "count" parameter;		query string contains the "count" parameter;
	o "pageSize": "Numeric" (OPTIONAL) a numeric value representing the		o "pageSize": "Numeric" (OPTIONAL) a numeric value representing the
	number of objects returned in the current page. It MUST be		number of objects returned in the current page. It MUST be
	provided when the total number of objects exceeds the page size.		provided when the total number of objects exceeds the page size.
	skipping to change at page 5, line 49 ¶		skipping to change at page 5, line 49 ¶
	be helpful if the end user interacts with the server through a web		be helpful if the end user interacts with the server through a web
	browser;		browser;
	o "pageNumber": "Numeric" (OPTIONAL) a numeric value representing		o "pageNumber": "Numeric" (OPTIONAL) a numeric value representing
	the number of the current page in the result set. It MUST be		the number of the current page in the result set. It MUST be
	provided when the total number of objects found exceeds the page		provided when the total number of objects found exceeds the page
	size;		size;
	o "links": "Link[]" (OPTIONAL) an array of links as described in RFC		o "links": "Link[]" (OPTIONAL) an array of links as described in RFC
	8288 [RFC8288] containing the reference to the next page. In this		8288 [RFC8288] containing the reference to the next page. In this
	specification, only the forward pagination is dealt because it is		specification, only forward pagination is described because it is
	considered satisfactory in order to traverse the result set.		all that is necessary to traverse the result set.
	Examples of additional references are to: the previous page, the
	first page, the last page.
	2.1.1. RDAP Conformance		2.1.1. RDAP Conformance
	Servers returning the "paging_metadata" element in their response		Servers returning the "paging_metadata" element in their response
	MUST include "paging" in the rdapConformance array as well as servers		MUST include the string literal "paging" in the rdapConformance
	returning the "sorting_metadata" element MUST include "sorting".		array. Servers returning the "sorting_metadata" element MUST include
			the string literal "sorting".
	2.2. "count" Parameter		2.2. "count" Parameter
	Currently, the RDAP protocol does not allow a client to determine the		Currently, the RDAP protocol does not allow a client to determine the
	total number of the results in a query response when the result set		total number of the results in a query response when the result set
	is truncated. This is rather inefficient because the user cannot		is truncated. This is inefficient because the user cannot determine
	evaluate the query precision and, at the same time, cannot receive		if the result set is complete.
	information that could be relevant.
	The "count" parameter provides additional functionality (Figure 1)		The "count" parameter provides additional functionality (Figure 1)
	that allows a client to request information from the server that		that allows a client to request information from the server that
	specifies the total number of objects matching the search pattern.		specifies the total number of objects matching the search pattern.
	https://example.com/rdap/domains?name=*nr.com&count=true		https://example.com/rdap/domains?name=*nr.com&count=true
	Figure 1: Example of RDAP query reporting the "count" parameter		Figure 1: Example of RDAP query reporting the "count" parameter
	The ABNF syntax is the following:		The ABNF syntax is the following:
	skipping to change at page 7, line 24 ¶		skipping to change at page 7, line 24 ¶
	"domainSearchResults": [		"domainSearchResults": [
	...		...
	]		]
	}		}
	Figure 2: Example of RDAP response with "paging_metadata" element		Figure 2: Example of RDAP response with "paging_metadata" element
	containing the "totalCount" field		containing the "totalCount" field
	2.3. "sort" Parameter		2.3. "sort" Parameter
	The RDAP protocol does not provide any capability to specify results		The RDAP protocol does not provide any capability to specify result
	sort criteria. A server could implement a default sorting scheme		set sort criteria. A server could implement a default sorting scheme
	according to the object class, but this feature is not mandatory and		according to the object class, but this feature is not mandatory and
	might not meet user requirements. Sorting can be addressed by the		might not meet user requirements. Sorting can be addressed by the
	client, but this solution is rather inefficient. Sorting features		client, but this solution is rather inefficient. Sorting features
	provided by the RDAP server could help avoid truncation of relevant		provided by the RDAP server could help avoid truncation of relevant
	results.		results.
	The "sort" parameter allows the client to ask the server to sort the		The "sort" parameter allows the client to ask the server to sort the
	results according to the values of one or more properties and		results according to the values of one or more properties and
	according to the sort direction of each property. The ABNF syntax is		according to the sort direction of each property. The ABNF syntax is
	the following:		the following:
	sort = "sort=" sortItem *( "," sortItem )		sort = "sort=" sortItem *( "," sortItem )
	sortItem = property-ref [":" ( "a" / "d" ) ]		sortItem = property-ref [":" ( "a" / "d" ) ]
	property-ref = ALPHA *( ALPHA / DIGIT / "_" )		property-ref = ALPHA *( ALPHA / DIGIT / "_" )
	"a" means that the ascending sort MUST be applied, "d" means that the		"a" means that an ascending sort MUST be applied, "d" means that a
	descending sort MUST be applied. If the sort direction is absent, an		descending sort MUST be applied. If the sort direction is absent, an
	ascending sort MUST be applied (Figure 3).		ascending sort MUST be applied (Figure 3).
	https://example.com/rdap/domains?name=*nr.com&sort=name		https://example.com/rdap/domains?name=*nr.com&sort=name
	https://example.com/rdap/domains?name=*nr.com&sort=registrationDate:d		https://example.com/rdap/domains?name=*nr.com&sort=registrationDate:d
	https://example.com/rdap/domains?name=*nr.com&sort=lockedDate,name		https://example.com/rdap/domains?name=*nr.com&sort=lockedDate,name
	Figure 3: Examples of RDAP query reporting the "sort" parameter		Figure 3: Examples of RDAP query reporting the "sort" parameter
	With the only exception of the sort on IP addresses, servers MUST		With the exception of sorting IP addresses, servers MUST implement
	implement sorting according to the JSON value type of the RDAP field		sorting according to the JSON value type of the RDAP field the
	the sorting property refers to: JSON strings MUST be sorted		sorting property refers to. That is, JSON strings MUST be sorted
	lexicographically and JSON numbers MUST be sorted numerically. Even		lexicographically and JSON numbers MUST be sorted numerically. If IP
	if IP addresses are represented as JSON strings, they MUST be sorted		addresses are represented as JSON strings, they MUST be sorted based
	based on their numeric conversion.		on their numeric conversion.
	If the "sort" parameter reports an allowed sorting property, it MUST		If the "sort" parameter reports an allowed sorting property, it MUST
	be provided in the "currentSort" field of the "sorting_metadata"		be provided in the "currentSort" field of the "sorting_metadata"
	element.		element.
	2.3.1. Sorting Properties Declaration		2.3.1. Sorting Properties Declaration
	In the "sort" parameter ABNF syntax, property-ref represents a		In the "sort" parameter ABNF syntax, property-ref represents a
	reference to a property of an RDAP object. Such a reference could be		reference to a property of an RDAP object. Such a reference could be
	expressed by using a JSONPath. The JSONPath in a JSON document		expressed by using a JSONPath. The JSONPath in a JSON document
	[RFC8259] is equivalent to the XPath [W3C.CR-xpath-31-20161213] in a		[RFC8259] is equivalent to the XPath [W3C.CR-xpath-31-20161213] in a
	XML document. For example, the JSONPath to select the value of the		XML document. For example, the JSONPath to select the value of the
	ASCII name inside an RDAP domain object is "$.ldhName", whereby $		ASCII name inside an RDAP domain object is "$.ldhName", where $
	identifies the root of the document (DOM). Another way to select a		identifies the root of the document (DOM). Another way to select a
	value inside a JSON document is the JSON Pointer [RFC6901]. While		value inside a JSON document is the JSON Pointer [RFC6901]. While
	JSONPath or JSON Pointer are both standard ways to select any value		JSONPath or JSON Pointer are both standard ways to select any value
	inside JSON data, neither is particularly easy to use (e.g.		inside JSON data, neither is particularly easy to use (e.g.
	"$.events[?(@.eventAction='registration')].eventDate" is the JSONPath		"$.events[?(@.eventAction='registration')].eventDate" is the JSONPath
	expression of the registration date in an RDAP domain object).		expression of the registration date in an RDAP domain object).
	Therefore, this specification provides a definition of property-ref		Therefore, this specification provides a definition of property-ref
	in terms of RDAP properties. However, not all the RDAP properties		in terms of RDAP properties. However, not all the RDAP properties
	are suitable to be used in sort criteria, such as:		are suitable to be used in sort criteria, such as:
	o properties providing service information (e.g. links, notices,		o properties providing service information (e.g. links, notices,
	remarks, etc.);		remarks, etc.);
	o multivalued properties (e.g. status, roles, variants, etc.);		o multivalued properties (e.g. status, roles, variants, etc.);
	o properties modeling relationships to other objects (e.g.		o properties modeling relationships to other objects (e.g.
	entities).		entities).
	On the contrary, some properties expressed as values of other		On the contrary, properties expressed as values of other properties
	properties (e.g. registration date) could be used in such a context.		(e.g. registration date) could be used in such a context. The list
			of properties an RDAP server MAY implement are divided into two
	In the following, a list of properties an RDAP server MAY implement		groups: object common properties and object specific properties.
	is presented. The properties are divided into two groups: object
	common properties and object specific properties.
	o Object common properties. Object common properties are derived		o Object common properties. Object common properties are derived
	from the merge of the "eventAction" and the "eventDate"		from the merge of the "eventAction" and the "eventDate"
	properties. The following values of the "sort" parameter are		properties. The following values of the "sort" parameter are
	defined:		defined:
	* registrationDate		* registrationDate
	* reregistrationDate		* reregistrationDate
	* lastChangedDate		* lastChangedDate
	* expirationDate		* expirationDate
	* deletionDate		* deletionDate
	* reinstantiationDate		* reinstantiationDate
	* transferDate		* transferDate
	* lockedDate		* lockedDate
	* unlockedDate		* unlockedDate
	o Object specific properties. With regard to the specific		o Note that some of the object specific properties are also defined
	properties, some of them are already defined among the query		as query paths. The object specific properties include:
	paths. In the following a list of possible sorting properties,
	grouped by objects, is shown:
	* Domain: name		* Domain: name
	* Nameserver: name, ipV4, ipV6.		* Nameserver: name, ipV4, ipV6.
	* Entity: fn, handle, org, email, voice, country, cc, city.		* Entity: fn, handle, org, email, voice, country, cc, city.
	The correspondence between the sorting properties and the RDAP fields		The correspondence between these sorting properties and the RDAP
	is shown in Table 1:		object classes is shown in Table 1:
	+-----------+-----------+---------------------+------+-------+------+		+-----------+-----------+---------------------+------+-------+------+
	| Object | Sorting | RDAP property | RFC | RFC | RFC |		| Object | Sorting | RDAP property | RFC | RFC | RFC |
	| class | property | | 7483 | 6350 | 8605 |		| class | property | | 7483 | 6350 | 8605 |
	+-----------+-----------+---------------------+------+-------+------+		+-----------+-----------+---------------------+------+-------+------+
	| Searchabl | Common pr | eventAction values | 4.5. | | |		| Searchabl | Common pr | eventAction values | 4.5. | | |
	| e objects | operties | suffixed by "Date" | | | |		| e objects | operties | suffixed by "Date" | | | |
	| | | | | | |		| | | | | | |
	| Domain | name | unicodeName/ldhName | 5.3. | | |		| Domain | name | unicodeName/ldhName | 5.3. | | |
	| | | | | | |		| | | | | | |
	skipping to change at page 10, line 36 ¶		skipping to change at page 10, line 36 ¶
	| | | vcard adr | | | |		| | | vcard adr | | | |
	| | cc | country code in | 5.1. | | 3.1 |		| | cc | country code in | 5.1. | | 3.1 |
	| | | vcard adr | | | |		| | | vcard adr | | | |
	| | city | locality in vcard | 5.1. | 6.3.1 | |		| | city | locality in vcard | 5.1. | 6.3.1 | |
	| | | adr | | | |		| | | adr | | | |
	+-----------+-----------+---------------------+------+-------+------+		+-----------+-----------+---------------------+------+-------+------+
	Table 1: Sorting properties definition		Table 1: Sorting properties definition
	With regard to the definitions in Table 1, some further		With regard to the definitions in Table 1, some further
	considerations must be made to disambiguate some cases:		considerations are needed to disambiguate some cases:
	o since the response to a search on either domains or nameservers		o Since the response to a search on either domains or nameservers
	might include both A-labels and U-labels ([RFC5890]) in general, a		might include both A-labels and U-labels ([RFC5890]) in general, a
	consistent sorting policy shall take unicodeName and ldhName as		consistent sorting policy MUST treat the unicodeName and ldhName
	two formats of the same value rather than separately. Therefore,		as two representations of the same value. By default, the
	the unicodeName value MUST be taken while sorting, when		unicodeName value MUST be used while sorting. When unicodeName is
	unicodeName is missing, the value of ldhName MUST be considered		unavailable, the value of ldhName MUST be used instead;
	instead;
	o the jCard "sort-as" parameter MUST be ignored for the purpose of		o The jCard "sort-as" parameter MUST be ignored for the purpose of
	the sorting capability as described in this document;		the sorting capability described in this document;
	o even if a nameserver can have multiple IPv4 and IPv6 addresses,		o Even if a nameserver can have multiple IPv4 and IPv6 addresses,
	the most common configuration includes one address for each IP		the most common configuration includes one address for each IP
	version. Therefore, the assumption of having a single IPv4 and/or		version. Therefore, the assumption of having a single IPv4 and/or
	IPv6 value for a nameserver cannot be considered too stringent.		IPv6 value for a nameserver cannot be considered too stringent.
	When more than one address per IP version is reported, sorting		When more than one address per IP version is reported, sorting
	MUST be applied to the first value;		MUST be applied to the first value;
	o multiple events with a given action on an object might be		o Multiple events with a given action on an object might be
	returned. When it occurs, sorting MUST be applied to the most		returned. If this occurs, sorting MUST be applied to the most
	recent event;		recent event;
	o with the exception of handle values, all the sorting properties		o With the exception of handle values, all the sorting properties
	defined for entity objects can be multivalued according to the		defined for entity objects can be multivalued according to the
	definition of vCard as given in RFC 6350 [RFC6350]. When more		definition of vCard as given in RFC 6350 [RFC6350]. When more
	than one value is reported, sorting MUST be applied to the		than one value is reported, sorting MUST be applied to the
	preferred value identified by the parameter pref="1". If the pref		preferred value identified by the parameter pref="1". If the pref
	parameter is missing, sorting MUST be applied to the first value.		parameter is missing, sorting MUST be applied to the first value.
	Each RDAP provider MAY define other sorting properties than those
	shown in this document as well as it MAY map those sorting properties
	onto different locations.
	The "jsonPath" field in the "sorting_metadata" element is used to		The "jsonPath" field in the "sorting_metadata" element is used to
	clarify the RDAP field the sorting property refers to. The mapping		clarify the RDAP field the sorting property refers to. The mapping
	between the sorting properties and the JSONPaths of the RDAP fields		between the sorting properties and the JSONPaths of the RDAP fields
	is shown in Table 2. The JSONPaths are provided according to the		is shown in Table 2. The JSONPaths are provided according to the
	Goessner v.0.8.0 specification ([GOESSNER-JSON-PATH]). Further		Goessner v.0.8.0 specification ([GOESSNER-JSON-PATH]). Further
	documentation about JSONPath operators used in Table 2 is included in		documentation about JSONPath operators used in Table 2 is included in
	Appendix A.		Appendix A.
	+-------+-------------+---------------------------------------------+		+-------+-------------+---------------------------------------------+
	| Objec | Sorting | JSONPath |		| Objec | Sorting | JSONPath |
	skipping to change at page 12, line 38 ¶		skipping to change at page 12, line 34 ¶
	| | country | $.entitySearchResults[*].vcardArray[1][?(@[ |		| | country | $.entitySearchResults[*].vcardArray[1][?(@[ |
	| | | 0]=="adr")][3][6] |		| | | 0]=="adr")][3][6] |
	| | cc | $.entitySearchResults[*].vcardArray[1][?(@[ |		| | cc | $.entitySearchResults[*].vcardArray[1][?(@[ |
	| | | 0]=="adr")][1].cc |		| | | 0]=="adr")][1].cc |
	| | city | $.entitySearchResults[*].vcardArray[1][?(@[ |		| | city | $.entitySearchResults[*].vcardArray[1][?(@[ |
	| | | 0]=="adr")][3][3] |		| | | 0]=="adr")][3][3] |
	+-------+-------------+---------------------------------------------+		+-------+-------------+---------------------------------------------+
	Table 2: Sorting properties - JSONPath Mapping		Table 2: Sorting properties - JSONPath Mapping
	Note about the JSONPaths of Table 2 that:		Table 2 JSONPath notes:
	o those related to the event dates are defined only for the "domain"		o Those related to the event dates are defined only for the "domain"
	object. To obtain the equivalent JSONPaths for "entity" and		object. To obtain the equivalent JSONPaths for "entity" and
	"nameserver", the path segment "domainSearchResults" must be		"nameserver", the path segment "domainSearchResults" must be
	replaced with "entitySearchResults" and "nameserverSearchResults"		replaced with "entitySearchResults" and "nameserverSearchResults"
	respectively;		respectively;
	o those related to vCard elements are specified without taking into		o Those related to vCard elements are specified without taking into
	account the "pref" parameter. Servers always applying sorting to		account the "pref" parameter. Servers that sort those values
	those values identified by the pref parameter SHOULD update a		identified by the pref parameter SHOULD update a JSONPath by
	JSONPath by adding an appropriate filter. For example, if the		adding an appropriate filter. For example, if the email values
	email values identified by pref="1" are considered for sorting,		identified by pref="1" are considered for sorting, the JSONPath of
	the JSONPath of the "email" sorting property should be:		the "email" sorting property should be:
	$.entitySearchResults[*].vcardArray[1][?(@[0]=="email" &&		$.entitySearchResults[*].vcardArray[1][?(@[0]=="email" &&
	@[1].pref=="1")][3]		@[1].pref=="1")][3]
	2.3.2. Representing Sorting Links		2.3.2. Representing Sorting Links
	An RDAP server MAY use the "links" array of the "sorting_metadata"		An RDAP server MAY use the "links" array of the "sorting_metadata"
	element to provide ready-made references [RFC8288] to the available		element to provide ready-made references [RFC8288] to the available
	sort criteria (Figure 4). Each link represents a reference to an		sort criteria (Figure 4). Each link represents a reference to an
	alternate view of the results.		alternate view of the results.
	skipping to change at page 15, line 11 ¶		skipping to change at page 15, line 11 ¶
	Figure 4: Example of a "sorting_metadata" instance to implement		Figure 4: Example of a "sorting_metadata" instance to implement
	result sorting		result sorting
	2.4. "cursor" Parameter		2.4. "cursor" Parameter
	The cursor parameter defined in this specification can be used to		The cursor parameter defined in this specification can be used to
	encode information about any pagination method. For example, in the		encode information about any pagination method. For example, in the
	case of a simple implementation of the cursor parameter to represent		case of a simple implementation of the cursor parameter to represent
	offset pagination information, the cursor value		offset pagination information, the cursor value
	"b2Zmc2V0PTEwMCxsaW1pdD01MAo=" is the mere Base64 encoding of		"b2Zmc2V0PTEwMCxsaW1pdD01MAo=" is the Base64 encoding of
	"offset=100,limit=50". Likewise, in a simple implementation to		"offset=100,limit=50". Likewise, in a simple implementation to
	represent keyset pagination information, the cursor value		represent keyset pagination information, the cursor value
	"a2V5PXRoZWxhc3Rkb21haW5vZnRoZXBhZ2UuY29t=" represents the mere		"a2V5PXRoZWxhc3Rkb21haW5vZnRoZXBhZ2UuY29t=" represents the Base64
	Base64 encoding of "key=thelastdomainofthepage.com" whereby the key		encoding of "key=thelastdomainofthepage.com" whereby the key value
	value identifies the last row of the current page.		identifies the last row of the current page.
	This solution lets RDAP providers to implement a pagination method		This solution lets RDAP providers implement a pagination method
	according to their needs, the user access levels, the submitted		according to their needs, a user's access level, and the submitted
	queries. In addition, servers can change the method over time		query. In addition, servers can change the method over time without
	without announcing anything to the clients. The considerations that		announcing anything to clients. The considerations that has led to
	has led to this solution are reported in more detail in Appendix B.		this solution are reported in more detail in Appendix B.
	The ABNF syntax of the cursor paramter is the following:		The ABNF syntax of the cursor paramter is the following:
	cursor = "cursor=" 1*( ALPHA / DIGIT / "/" / "=" / "-" / "_" )		cursor = "cursor=" 1*( ALPHA / DIGIT / "/" / "=" / "-" / "_" )
	https://example.com/rdap/domains?name=*nr.com		https://example.com/rdap/domains?name=*nr.com
	&cursor=wJlCDLIl6KTWypN7T6vc6nWEmEYe99Hjf1XY1xmqV-M=		&cursor=wJlCDLIl6KTWypN7T6vc6nWEmEYe99Hjf1XY1xmqV-M=
	Figure 5: An example of RDAP query reporting the "cursor" parameter		Figure 5: An example of RDAP query reporting the "cursor" parameter
	2.4.1. Representing Paging Links		2.4.1. Representing Paging Links
	An RDAP server SHOULD use the "links" array of the "paging_metadata"		An RDAP server SHOULD use the "links" array of the "paging_metadata"
	element to provide a ready-made reference [RFC8288] to the next page		element to provide a ready-made reference [RFC8288] to the next page
	of the result set (Figure 6). Examples of additional "rel" values a		of the result set (Figure 6). Examples of additional "rel" values a
	server MAY implements are "first", "last", "prev".		server MAY implement are "first", "last", and "prev".
	{		{
	"rdapConformance": [		"rdapConformance": [
	"rdap_level_0",		"rdap_level_0",
	"paging"		"paging"
	],		],
	...		...
	"notices": [		"notices": [
	{		{
	"title": "Search query limits",		"title": "Search query limits",
	skipping to change at page 16, line 46 ¶		skipping to change at page 16, line 46 ¶
	...		...
	]		]
	}		}
	Figure 6: Example of a "paging_metadata" instance to implement cursor		Figure 6: Example of a "paging_metadata" instance to implement cursor
	pagination		pagination
	3. Negative Answers		3. Negative Answers
	The value constraints for the parameters are defined by their ABNF		The value constraints for the parameters are defined by their ABNF
	syntax. Therefore, each request including an invalid value for a		syntax. Therefore, each request that includes an invalid value for a
	parameter SHOULD obtain an HTTP 400 (Bad Request) response code. The		parameter SHOULD produce an HTTP 400 (Bad Request) response code.
	same response SHOULD be returned in the following cases:		The same response SHOULD be returned in the following cases:
	o if in both single and multi sort the client provides an		o If in both single and multi sort the client provides an
	unsupported value for the "sort" parameter as well as a value		unsupported value for the "sort" parameter, as well as a value
	related to an object property not included in the response;		related to an object property not included in the response;
	o if the client submits an invalid value for the "cursor" parameter.		o If the client submits an invalid value for the "cursor" parameter.
	Optionally, the response MAY include additional information regarding		Optionally, the response MAY include additional information regarding
	the negative answer in the HTTP entity body.		the negative answer in the HTTP entity body.
	4. Implementation Considerations		4. Implementation Considerations
	The implementation of the new parameters is technically feasible, as		Implementation of the new parameters is technically feasible, as
	operators for counting, sorting and paging are currently supported by		operators for counting, sorting and paging are currently supported by
	the major RDBMSs.		the major RDBMSs. Similar operators are completely or partially
			supported by the most known NoSQL databases (MongoDB, CouchDB, HBase,
	Similar operators are completely or partially supported by the most		Cassandra, Hadoop).
	known NoSQL databases (MongoDB, CouchDB, HBase, Cassandra, Hadoop) so
	the implementation of the new parameters seems to be practicable by
	servers working without the use of an RDBMS.
	5. Implementation Status		5. Implementation Status
	NOTE: Please remove this section and the reference to RFC 7942 prior		NOTE: Please remove this section and the reference to RFC 7942 prior
	to publication as an RFC.		to publication as an RFC.
	This section records the status of known implementations of the		This section records the status of known implementations of the
	protocol defined by this specification at the time of posting of this		protocol defined by this specification at the time of posting of this
	Internet-Draft, and is based on a proposal described in RFC 7942		Internet-Draft, and is based on a proposal described in RFC 7942
	[RFC7942]. The description of implementations in this section is		[RFC7942]. The description of implementations in this section is
	skipping to change at page 18, line 46 ¶		skipping to change at page 18, line 43 ¶
	Published specification: This document.		Published specification: This document.
	Contact: IESG <iesg@ietf.org>		Contact: IESG <iesg@ietf.org>
	Intended usage: This extension describes a best practice for		Intended usage: This extension describes a best practice for
	result set sorting.		result set sorting.
	7. Security Considerations		7. Security Considerations
	Security services for the operations specified in this document are		Security services for the operations specified in this document are
	described in RFC 7481 [RFC7481].		described in RFC 7481 [RFC7481].
	The search query typically requires more server resources (such as		A search query typically requires more server resources (such as
	memory, CPU cycles, and network bandwidth) when compared to the		memory, CPU cycles, and network bandwidth) when compared to a lookup
	lookup query. This increases the risk of server resource exhaustion		query. This increases the risk of server resource exhaustion and
	and subsequent denial of service due to abuse. This risk can be		subsequent denial of service due to abuse. This risk can be
	mitigated by either restricting search functionality or limiting the		mitigated by either restricting search functionality or limiting the
	rate of search requests. Servers can also reduce their load by		rate of search requests. Servers can also reduce their load by
	truncating the results in the response. However, this last security		truncating the results in a response. However, this last security
	policy can result in a higher inefficiency if the RDAP server does		policy can result in a higher inefficiency if the RDAP server does
	not provide any functionality to return the truncated results.		not provide any functionality to return the truncated results.
	The new parameters presented in this document provide the RDAP		The new parameters presented in this document provide RDAP operators
	operators with a way to implement a secure server without penalizing		with a way to implement a server that reduces inefficiency risks.
	its efficiency. The "count" parameter gives the user a measure to		The "count" parameter gives the client te ability to evaluate the
	evaluate the query precision and, at the same time, returns a		completeness of a response. The "sort" parameter allows the client
	significant information. The "sort" parameter allows the user to		to obtain the most relevant information at the beginning of the
	obtain the most relevant information at the beginning of the result		result set. This can reduce the amount of unnecessary search
	set. In both cases, the user doesn't need to submit further		requests. Finally, the "cursor" parameter enables the user to scroll
	unnecessary search requests. Finally, the "cursor" parameter enables		the result set by submitting a sequence of sustainable queries within
	the user to scroll the result set by submitting a sequence of		server-acceptable limits.
	sustainable queries according to the server limits.
	8. Acknowledgements		8. Acknowledgements
	The authors would like to acknowledge Brian Mountford, Tom Harrison,		The authors would like to acknowledge Brian Mountford, Tom Harrison,
	Karl Heinz Wolf and Jasdip Singh for their contribution to the		Karl Heinz Wolf and Jasdip Singh for their contribution to the
	development of this document.		development of this document.
	9. References		9. References
	9.1. Normative References		9.1. Normative References
	skipping to change at page 20, line 30 ¶		skipping to change at page 20, line 25 ¶
	[RFC7483] Newton, A. and S. Hollenbeck, "JSON Responses for the		[RFC7483] Newton, A. and S. Hollenbeck, "JSON Responses for the
	Registration Data Access Protocol (RDAP)", RFC 7483,		Registration Data Access Protocol (RDAP)", RFC 7483,
	DOI 10.17487/RFC7483, March 2015,		DOI 10.17487/RFC7483, March 2015,
	<https://www.rfc-editor.org/info/rfc7483>.		<https://www.rfc-editor.org/info/rfc7483>.
	[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running		[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
	Code: The Implementation Status Section", BCP 205,		Code: The Implementation Status Section", BCP 205,
	RFC 7942, DOI 10.17487/RFC7942, July 2016,		RFC 7942, DOI 10.17487/RFC7942, July 2016,
	<https://www.rfc-editor.org/info/rfc7942>.		<https://www.rfc-editor.org/info/rfc7942>.
			[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
			2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
			May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data		[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
	Interchange Format", STD 90, RFC 8259,		Interchange Format", STD 90, RFC 8259,
	DOI 10.17487/RFC8259, December 2017,		DOI 10.17487/RFC8259, December 2017,
	<https://www.rfc-editor.org/info/rfc8259>.		<https://www.rfc-editor.org/info/rfc8259>.
	[RFC8288] Nottingham, M., "Web Linking", RFC 8288,		[RFC8288] Nottingham, M., "Web Linking", RFC 8288,
	DOI 10.17487/RFC8288, October 2017,		DOI 10.17487/RFC8288, October 2017,
	<https://www.rfc-editor.org/info/rfc8288>.		<https://www.rfc-editor.org/info/rfc8288>.
	[RFC8605] Hollenbeck, S. and R. Carney, "vCard Format Extensions:		[RFC8605] Hollenbeck, S. and R. Carney, "vCard Format Extensions:
	skipping to change at page 22, line 16 ¶		skipping to change at page 22, line 16 ¶
	A JSONPath expression represents a path to find an element (or a set		A JSONPath expression represents a path to find an element (or a set
	of elements) in a JSON content.		of elements) in a JSON content.
	The base JSONPath specification requires that implementations support		The base JSONPath specification requires that implementations support
	a set of "basic operators". These operators are used to access the		a set of "basic operators". These operators are used to access the
	elements of a JSON structure like objects and arrays, and their		elements of a JSON structure like objects and arrays, and their
	subelements, respectively, object members and array items. No		subelements, respectively, object members and array items. No
	operations are defined for retrieving parent or sibling elements of a		operations are defined for retrieving parent or sibling elements of a
	given element. The root element is always referred to as $		given element. The root element is always referred to as $
	regardless if it is an object or array.		regardless of it being an object or array.
	Additionally, the specification permits implementations to support		Additionally, the specification permits implementations to support
	arbitrary script expressions: these can be used to index into an		arbitrary script expressions. These can be used to index into an
	object or an array, or to filter elements from an array. While		object or an array, or to filter elements from an array. While
	script expression behaviour is implementation-defined, most		script expression behaviour is implementation-defined, most
	implementations support the basic relational and logical operators,		implementations support the basic relational and logical operators,
	as well as both object member and array item access, sufficiently		as well as both object member and array item access, sufficiently
	similarly for the purposes of this document. Commonly-supported		similarly for the purposes of this document. Commonly-supported
	operators/functions divided into "top-level operators" and "filter		operators/functions divided into "top-level operators" and "filter
	operators" are documented in Table 3 and Table 4 respectively.		operators" are documented in Table 3 and Table 4 respectively.
	+-------------------+-----------------------------------------+		+-------------------+-----------------------------------------+
	| Operator | Descritpion |		| Operator | Descritpion |
	skipping to change at page 23, line 30 ¶		skipping to change at page 23, line 30 ¶
	Table 4: JSONPath Filter Operators		Table 4: JSONPath Filter Operators
	Appendix B. Approaches to Result Pagination		Appendix B. Approaches to Result Pagination
	An RDAP query could return a response with hundreds, even thousands,		An RDAP query could return a response with hundreds, even thousands,
	of objects, especially when partial matching is used. For that		of objects, especially when partial matching is used. For that
	reason, the cursor parameter addressing result pagination is defined		reason, the cursor parameter addressing result pagination is defined
	to make responses easier to handle.		to make responses easier to handle.
	Presently, the most popular methods to implement pagination in REST		Presently, the most popular methods to implement pagination in a REST
	API are: offset pagination and keyset pagination. Both two		API include offset pagination and keyset pagination. Neither
	pagination methods don't require the server to handle the result set		pagination method requires the server to handle the result set in a
	in a storage area across the requests since a new result set is		storage area across multiple requests since a new result set is
	generated each time a request is submitted. Therefore, they are		generated each time a request is submitted. Therefore, they are
	preferred in comparison to any other method requiring the management		preferred in comparison to any other method requiring the management
	of a REST session.		of a REST session.
	Using limit and offset operators represents the traditionally used		Using limit and offset operators represents the traditionally used
	method to implement results pagination. Both of them can be used		method to implement results pagination. Both of them can be used
	individually:		individually:
	o "limit": means that the server must return the first N objects of		o "limit": means that the server MUST return the first N objects of
	the result set;		the result set;
	o "offset": means that the server must skip the first N objects and		o "offset": means that the server MUST skip the first N objects and
	must return objects starting from position N+1.		MUST return objects starting from position N+1.
	When limit and offset are used together, they allow to identify a		When limit and offset are used together, they provide the ability to
	specific portion of the result set. For example, the pair		identify a specific portion of the result set. For example, the pair
	"offset=100,limit=50" returns first 50 objects starting from position		"offset=100,limit=50" returns the first 50 objects starting from
	101 of the result set.		position 101 of the result set.
	Despite its easiness of implementation, offset pagination raises some		Though easy to implement, offset pagination also includes drawbacks:
	well known drawbacks:
	o when offset has a very high value, scrolling the result set could		o When offset has a very high value, scrolling the result set could
	take some time;		take some time;
	o it always requires to fetch all the rows before dropping as many		o It always requires fetching all rows before dropping as many rows
	rows as specified by offset;		as specified by offset;
	o it may return inconsistent pages when data are frequently updated		o It may return inconsistent pages when data are frequently updated
	(i.e. real-time data) but this doesn't seem the case of		(i.e. real-time data).
	registration data.
	The keyset pagination [SEEK] consists in adding a query condition		Keyset pagination [SEEK] adds a query condition that enables the
	that enables the selection of the only data not yet returned. This		selection of the only data not yet returned. This method has been
	method has been taken as the basis for the implementation of a		taken as the basis for the implementation of a "cursor" parameter
	"cursor" parameter [CURSOR] by some REST API providers (e.g.		[CURSOR] by some REST API providers (e.g.
	[CURSOR-API1],[CURSOR-API2]). The cursor is an opaque URL-safe		[CURSOR-API1],[CURSOR-API2]). The cursor is an opaque URL-safe
	string representing a logical pointer to the first result of the next		string representing a logical pointer to the first result of the next
	page (Figure 5).		page (Figure 5).
	Nevertheless, even keyset pagination can be troublesome:		Nevertheless, even keyset pagination can be troublesome:
	o it needs at least one key field;		o It needs at least one key field;
	o it does not allow to sort just by any field because the sorting		o It does not allow to sort just by any field because the sorting
	criterion must contain a key;		criterion must contain a key;
	o it works best with full composite values support by DBMS (i.e.		o It works best with full composite values support by DBMS (i.e.
	[x,y]>[a,b]), emulation is possible but ugly and less performant;		[x,y]>[a,b]), emulation is possible but ugly and less performant;
	o it does not allow to directly navigate to arbitrary pages because		o It does not allow direct navigation to arbitrary pages because the
	the result set must be scrolled in sequential order starting from		result set must be scrolled in sequential order starting from the
	the initial page;		initial page;
	o implementing the bi-directional navigation is tedious because all		o Implementing bi-directional navigation is tedious because all
	comparison and sort operations have to be reversed.		comparison and sort operations have to be reversed.
	B.1. Specific Issues Raised by RDAP		B.1. Specific Issues Raised by RDAP
	Furthermore, in the RDAP context, some additional considerations can		Furthermore, in the RDAP context, some additional considerations can
	be made:		be made:
	o an RDAP object is a conceptual aggregation of information		o An RDAP object is a conceptual aggregation of information
	generally collected from more than one data structure (e.g. table)		generally collected from more than one data structure (e.g. table)
	and this makes even harder for the developers the implementation		and this makes it even harder to implement keyset pagination, a
	of the keyset pagination that is already quite difficult. For		task that is already quite difficult. For example, the entity
	example, the entity object can gather information from different		object can include information from different data structures
	data structures (registrars, registrants, contacts, resellers, and		(registrars, registrants, contacts, resellers, and so on), each
	so on), each one with its own key field mapping the RDAP entity		one with its own key field mapping the RDAP entity handle;
	handle;
	o depending on the number of the page results as well as the number		o Depending on the number of page results as well as the number and
	and the complexity of the properties of each RDAP object in the		the complexity of the properties of each RDAP object in the
	response, the time required by offset pagination to skip the		response, the time required by offset pagination to skip the
	previous pages could be much faster than the processing time		previous pages could be much faster than the processing time
	needed to build the current page. In fact, RDAP objects are		needed to build the current page. In fact, RDAP objects are
	usually formed by information belonging to multiple data		usually formed by information belonging to multiple data
	structures and containing multivalued properties (i.e. arrays)		structures and containing multivalued properties (i.e. arrays)
	and, therefore, data selection might be a time consuming process.		and, therefore, data selection might be a time consuming process.
	This situation occurs even though the selection is supported by		This situation occurs even though the selection is supported by
	indexes;		indexes;
	o depending on the access levels defined by each RDAP operator, the		o Depending on the access levels defined by each RDAP operator, the
	increase of complexity and the decrease of flexibility of keyset		increase of complexity and the decrease of flexibility of keyset
	pagination with respect to the offset pagination could be		pagination with respect to offset pagination could be considered
	considered impractical.		impractical.
	Ultimately, both pagination methods have benefits and drawbacks.		Ultimately, both pagination methods have benefits and drawbacks.
	Appendix C. Change Log		Appendix C. Change Log
	00: Initial working group version ported from draft-loffredo-regext-		00: Initial working group version ported from draft-loffredo-regext-
	rdap-sorting-and-paging-05		rdap-sorting-and-paging-05
	01: Removed both "offset" and "nextOffset" to keep "paging_metadata"		01: Removed both "offset" and "nextOffset" to keep "paging_metadata"
	consistent between the pagination methods. Renamed		consistent between the pagination methods. Renamed
	"Considerations about Paging Implementation" section in ""cursor"		"Considerations about Paging Implementation" section in ""cursor"
	skipping to change at page 26, line 27 ¶		skipping to change at page 26, line 23 ¶
	* corrected the JSONPath of the "lastChanged" sorting property;		* corrected the JSONPath of the "lastChanged" sorting property;
	* provided a JSONPath example taking into account the vCard		* provided a JSONPath example taking into account the vCard
	"pref" parameter.		"pref" parameter.
	10: Corrected the JSONPaths of both "fn" and "org" sorting		10: Corrected the JSONPaths of both "fn" and "org" sorting
	properties in Table 2. Corrected JSON content in Figure 4. Moved		properties in Table 2. Corrected JSON content in Figure 4. Moved
	[W3C.CR-xpath-31-20161213] and [RFC7942] to the "Normative		[W3C.CR-xpath-31-20161213] and [RFC7942] to the "Normative
	References". Changed the rdapConformance tags "sorting_level_0"		References". Changed the rdapConformance tags "sorting_level_0"
	and "paging_level_0" to "sorting" and "paging" respectively.		and "paging_level_0" to "sorting" and "paging" respectively.
	11: Added the "JSONPath operators" section to appendix.		11: Added the "JSONPath operators" section to appendix.
	12: Changed the content of "JSONPath operators" section.		12: Changed the content of "JSONPath operators" section.
			13: Minor pre-AD review edits.
	Authors' Addresses		Authors' Addresses
	Mario Loffredo		Mario Loffredo
	IIT-CNR/Registro.it		IIT-CNR/Registro.it
	Via Moruzzi,1		Via Moruzzi,1
	Pisa 56124		Pisa 56124
	IT		IT
	Email: mario.loffredo@iit.cnr.it		Email: mario.loffredo@iit.cnr.it
End of changes. 72 change blocks.
	169 lines changed or deleted		156 lines changed or added
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