Extensible Markup Language (XML) Formats for Representing Resource Lists
draft-ietf-simple-xcap-list-usage-05
The information below is for an old version of the document that is already published as an RFC.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 4826.
|
|
|---|---|---|---|
| Author | Jonathan Rosenberg | ||
| Last updated | 2020-01-21 (Latest revision 2005-02-09) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | (None) | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 4826 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Ted Hardie | ||
| Send notices to | (None) |
draft-ietf-simple-xcap-list-usage-05
SIMPLE J. Rosenberg
Internet-Draft Cisco Systems
Expires: August 8, 2005 February 7, 2005
Extensible Markup Language (XML) Formats for Representing Resource
Lists
draft-ietf-simple-xcap-list-usage-05
Status of this Memo
This document is an Internet-Draft and is subject to all provisions
of section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of
which he or she is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with
RFC 3668.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 8, 2005.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
In multimedia communications, presence and instant messaging systems,
there is a need to define Uniform Resource Identifiers (URIs) that
represent services which are associated with a group of users. One
example is a resource list service. If a user sends a Session
Initiation Protocol (SIP) SUBSCRIBE message to the URI representing
the resource list service, the server will obtain the state of the
users in the associated group, and provide it to the sender. To
Rosenberg Expires August 8, 2005 [Page 1]
Internet-Draft XML Resource Lists February 2005
facilitate definition of these services, this specification defines
two Extensible Markup Language (XML) documents. One document
contains service URIs, along with their service definition and a
reference to the associated group of users. The second document
contains the user lists which are referenced from the first. This
list of users can be utilized by other applications and services.
Both documents can be created and managed with the XML Configuration
Access Protocol (XCAP).
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Resource Lists Documents . . . . . . . . . . . . . . . . . . . 5
3.1 Structure . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2 Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Example Document . . . . . . . . . . . . . . . . . . . . . 10
3.4 Usage with XCAP . . . . . . . . . . . . . . . . . . . . . 11
3.4.1 Application Unique ID . . . . . . . . . . . . . . . . 11
3.4.2 MIME Type . . . . . . . . . . . . . . . . . . . . . . 11
3.4.3 XML Schema . . . . . . . . . . . . . . . . . . . . . . 11
3.4.4 Default Namespace . . . . . . . . . . . . . . . . . . 12
3.4.5 Additional Constraints . . . . . . . . . . . . . . . . 12
3.4.6 Data Semantics . . . . . . . . . . . . . . . . . . . . 12
3.4.7 Naming Conventions . . . . . . . . . . . . . . . . . . 13
3.4.8 Resource Interdependencies . . . . . . . . . . . . . . 13
3.4.9 Authorization Policies . . . . . . . . . . . . . . . . 14
4. RLS Services Documents . . . . . . . . . . . . . . . . . . . . 14
4.1 Structure . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2 Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3 Example Document . . . . . . . . . . . . . . . . . . . . . 16
4.4 Usage with XCAP . . . . . . . . . . . . . . . . . . . . . 17
4.4.1 Application Unique ID . . . . . . . . . . . . . . . . 17
4.4.2 MIME Type . . . . . . . . . . . . . . . . . . . . . . 17
4.4.3 XML Schema . . . . . . . . . . . . . . . . . . . . . . 17
4.4.4 Default Namespace . . . . . . . . . . . . . . . . . . 17
4.4.5 Additional Constraints . . . . . . . . . . . . . . . . 18
4.4.6 Data Semantics . . . . . . . . . . . . . . . . . . . . 19
4.4.7 Naming Conventions . . . . . . . . . . . . . . . . . . 19
4.4.8 Resource Interdependencies . . . . . . . . . . . . . . 19
4.4.9 Authorization Policies . . . . . . . . . . . . . . . . 21
4.5 Usage of an RLS Services Document by an RLS . . . . . . . 22
5. SIP URI Canonicalization . . . . . . . . . . . . . . . . . . . 23
6. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 24
7. Security Considerations . . . . . . . . . . . . . . . . . . . 25
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
8.1 XCAP Application Unique IDs . . . . . . . . . . . . . . . 25
8.1.1 resource-lists . . . . . . . . . . . . . . . . . . . . 25
Rosenberg Expires August 8, 2005 [Page 2]
Internet-Draft XML Resource Lists February 2005
8.1.2 rls-services . . . . . . . . . . . . . . . . . . . . . 26
8.2 MIME Type Registrations . . . . . . . . . . . . . . . . . 26
8.2.1 application/resource-lists+xml . . . . . . . . . . . . 26
8.2.2 application/rls-services+xml . . . . . . . . . . . . . 27
8.3 URN Sub-Namespace Registrations . . . . . . . . . . . . . 28
8.3.1 urn:ietf:params:xml:ns:resource-lists . . . . . . . . 28
8.3.2 urn:ietf:params:xml:ns:rls-services . . . . . . . . . 29
8.4 Schema Registrations . . . . . . . . . . . . . . . . . . . 29
8.4.1 urn:ietf:params:xml:schema:resource-lists . . . . . . 29
8.4.2 urn:ietf:params:xml:schema:rls-services . . . . . . . 30
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 30
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.1 Normative References . . . . . . . . . . . . . . . . . . . . 30
10.2 Informative References . . . . . . . . . . . . . . . . . . . 31
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 31
Intellectual Property and Copyright Statements . . . . . . . . 32
Rosenberg Expires August 8, 2005 [Page 3]
Internet-Draft XML Resource Lists February 2005
1. Introduction
The Session Initiation Protocol (SIP) [4] defines the SIP Uniform
Resource Identifier (URI) as any resource to which a SIP request can
be generated for the purposes of establishing some form of
communications operation. These URIs can represent users (for
example, sip:joe@example.com). The SIP URI can also represent a
service, such as voicemail, conferencing, or a presence list. A
common pattern across such SIP services is that the service is
defined, and associated with a URI. In order to operate, that
service needs to make use of a list of users (or, more generally, a
list of resources). When a SIP request is sent to the service URI,
the server providing the service reads that list, and then performs
some kind of operation against each resource on the list. This is
shown pictorially in Figure 1.
/---\
| |
\---/ Resource
+----| | List
| | |
| \---/
|
|
|
|
V
+-------------+
| | -------->
| SIP |
---------------> | Service | -------->
service | |
URI | | -------->
+-------------+
Figure 1
One important example of such a service is a presence [12] list
service. A presence list service allows a client to generate a SIP
SUBSCRIBE request to ask for presence information for a list of
users. The presence list server obtains the presence for the users
on the list, and provides them back to the client. A presence list
server is a specific case of a resource list server (RLS) [15], which
allows a client to generate a SIP SUBSCRIBE request to ask for
notifications of SIP events for a list of resources.
Rosenberg Expires August 8, 2005 [Page 4]
Internet-Draft XML Resource Lists February 2005
Another example of such a service is an instant conference service.
If a client sends a SIP INVITE request to the URI representing the
instance conference service, the conference server will create a
conference call containing the client and the associated group of
users.
It is very useful for a user of these systems to define the groups of
users or resources (generally called a resource list) separately from
the services which access those resource lists. Indeed, there are
usages for resource lists even in the absence of any associated
network-based service. As an example, rather than using a presence
list service, a client might generate individual SUBSCRIBE requests
to obtain the presence of each user in a locally stored presence
list. In such a case, there is a need for a format for storing the
list locally on disk. Furthermore, the user might wish to share the
list with friends, and desire to email it to those friends. This
also requires a standardized format for the resource list.
As such, this document defines two Extensible Markup Language (XML)
document formats. The first is used to represent resource lists,
independent of any particular service. The second is used to define
service URIs for an RLS, and to associate a resource list with the
service URI. This document also defines an XML Configuration Access
Protocol (XCAP) [10] application usage for managing each of these two
documents.
2. Terminology
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and
indicate requirement levels for compliant implementations.
3. Resource Lists Documents
3.1 Structure
A resource lists document is an XML [2] document that MUST be
well-formed and MUST be valid according to schemas, including
extension schemas, available to the validater and applicable to the
XML document. Resource lists documents MUST be based on XML 1.0 and
MUST be encoded using UTF-8. This specification makes use of XML
namespaces for identifying resource lists documents and document
fragments. The namespace URI for elements defined by this
specification is a URN [3], using the namespace identifier 'ietf'
defined by RFC 2648 [6] and extended by RFC 3688 [8]. This URN is:
Rosenberg Expires August 8, 2005 [Page 5]
Internet-Draft XML Resource Lists February 2005
urn:ietf:params:xml:ns:resource-lists
A resource lists document has the <resource-lists> element as the
root element of the document. This element has no attributes. Its
content is a sequence of one or more <list> elements, each of which
defines a single resource list.
Each <list> element can contain an optional "name" attribute. This
attribute is a handle for the list. When present, it MUST be unique
amongst all other <list> elements within the same parent element.
THe <list> element may also contain attributes from other namespaces,
for the purposes of extensibility.
Each <list> element is composed of an optional display name, a
sequence of zero or more elements, each of which may be an <entry>
element, a <list> element, an <entry-ref> element, or an <external>
element, followed by any number of elements from other namespaces,
for the purposes of extensibility. The ability of a <list> element
to contain other <list> elements means that a resource list can be
hierarchically structured. The <display-name> then allows for a
human-friendly name to be associated with each level in the
hierarchy. An <entry> element describes a single resource, defined
by a URI, that is part of the list. An <entry-ref> element allows an
entry in a document within the same XCAP root to be included by
reference, rather than by value. An <external> element contains a
reference to a list stored on this or another server.
The <entry> element describes a single resource. The <entry> element
has a single mandatory attribute, "uri". This attribute is equal to
the URI that is used to access the resource. The resource list
format itself does not constrain the type of URI that can be used.
However, the service making use of the resource list may require
specific URI schemes. For example, RLS services will require URIs
that represent subscribeable resources. This includes the SIP and
pres [16] URIs. The "uri" attribute MUST be unique amongst all other
"uri" attributes in <entry> elements within the same parent.
Uniqueness is determined by case sensitive string comparisons. As
such, it is possible that two "uri" attributes will have the same URI
when compared using the functional equality rules defined for that
URI scheme, but different ones when compared using case sensitive
string comparison. The <entry> element can also contain attributes
from other namespaces for the purposes of extensibility.
The <entry> element contains a sequence of elements that provide
information about the entry. Only one such element is defined at
this time, which is <display-name>. This element provides a UTF-8
encoded string, meant for consumption by a human user, that describes
the resource. Unlike the "name" attribute of the <entry> element,
Rosenberg Expires August 8, 2005 [Page 6]
Internet-Draft XML Resource Lists February 2005
the <display-name> has no uniqueness requirements. The
<display-name> element can contain the "xml:lang" attribute, which
provides the language of the display name. The <entry> element can
contain other elements from other namespaces. This is meant to
support the inclusion of other information about the entry, such as a
phone number or postal address.
The <entry-ref> element allows an entry to be included in the list by
reference, rather than by value. This element is only meaningful
when the document was obtained through XCAP. In such a case, the
referenced entry has to exist within the same XCAP root. The <entry>
element has a single mandatory attribute, "ref". The "ref" attribute
MUST be unique amongst all other "ref" attributes in <entry-ref>
elements within the same parent. Uniqueness is determined by case
sensitive string comparisons. The <entry-ref> element also allows
attributes from other namespaces, for the purposes of extensibility.
The content of an <entry-ref> element is an optional display name,
followed by any number of elements from other namespaces, for the
purposes of extensibility. The display name is useful for providing
a localized nickname as an alternative to the name defined in the
<entry> to which the <entry-ref> refers.
The content of the "ref" attribute is a relative HTTP URI [7].
Specifically, it MUST be a relative path reference, where the base
URI is equal to the XCAP root URI of the document in which the
<entry-ref> appears. This relative URI, if resolved into an absolute
URI according to the procedures in RFC 3986, MUST resolve to an
<entry> element within a resource-lists document. For example, if an
<entry> element within a specific XCAP root was identified by the
following HTTP URI:
http://xcap.example.com/root/resource-lists/users/bill/
mylist/~~/resource-lists/list%5b@name=%22list1%22%5d/
entry%5b@uri=%22sip:petri@example.com%22%5d
If http://xcap.example.com/root is the XCAP root URI, then an
<entry-ref> element pointing to this entry would have the form:
<entry-ref ref="resource-lists/users/bill/
mylist/~~/resource-lists/list%5b@name=%22list1%22%5d/
entry%5b@uri=%22sip:petri@example.com%22%5d"/>
Note that line folding within the HTTP URI and XML attribute above
are for the purposes of readability only. Also note that, as
described in RFC 3986, the relative path URI does not begin with the
Rosenberg Expires August 8, 2005 [Page 7]
Internet-Draft XML Resource Lists February 2005
"/". Since the relative URI used within the "ref" attribute must be
a relative path URI, the "/" will never be present as the first
character within the content of a "ref" attribute. Since the content
of the "ref" attribute is a valid HTTP URI, it must be escape encoded
within the XML document.
The <external> element is similar to the <entry-ref> element. Like
<entry-ref>, it is only meaningful in documents obtained from an XCAP
server. It too is a reference to content stored elsewhere. However,
it refers to an entire list, and furthermore, allows that list to be
present on another server. The <external> element has a single
mandatory attribute, "anchor", which specifies the external list by
means of an absolute HTTP URI. The "anchor" attribute MUST be unique
amongst all other "anchor" attributes in <external> elements within
the same parent. Uniqueness is determined by case sensitive string
comparisons. The <external> element can also contain attributes from
other namespaces, for the purposes of extensibility. The content of
an <external> element is an optional <display-name> followed by any
number of elements from another namespace, for the purposes of
extensibility. The value of the "anchor" attribute MUST be an
absolute HTTP URI. This URI MUST identify an XCAP resource, and in
particular, it MUST represent a <list> element within a resource
lists document. The URI MUST be escape coded.
For both the <entry-ref> and <external> elements, the responsibility
of resolving their references falls upon the entity that is making
use of the document. When used in conjunction with XCAP, this means
that the burden falls on the XCAP client. If the XCAP client is a PC
based application using the resource-lists document as a presence
list, the references would likely be resolved upon explicit request
by the user. They can, of course, be resolved at any time. If the
XCAP client is an RLS itself, the references would be resolved when
the RLS receives a SUBSCRIBE request for an RLS service associated
with a resource list that contains one of these references (see
below). An XCAP server defined by this specification will not
attempt to resolve the references before returning the document to
the client. Similarly, if, due to network errors or some other
problem, the references cannot be resolved, the handling is specific
to the usage of the document. For resource lists being used by RLS
services, the handling is discussed below.
3.2 Schema
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="urn:ietf:params:xml:ns:resource-lists"
xmlns="urn:ietf:params:xml:ns:resource-lists"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
Rosenberg Expires August 8, 2005 [Page 8]
Internet-Draft XML Resource Lists February 2005
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:import namespace="http://www.w3.org/XML/1998/namespace"
schemaLocation="http://www.w3.org/2001/xml.xsd"/>
<xs:complexType name="listType">
<xs:sequence>
<xs:element name="display-name" type="display-nameType" minOccurs="0"/>
<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:choice>
<xs:element name="list">
<xs:complexType>
<xs:complexContent>
<xs:extension base="listType"/>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="external" type="externalType"/>
<xs:element name="entry" type="entryType"/>
<xs:element name="entry-ref" type="entry-refType"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:choice>
</xs:sequence>
<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="name" type="xs:string" use="optional"/>
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
<xs:complexType name="entryType">
<xs:sequence>
<xs:element name="display-name" minOccurs="0">
<xs:complexType>
<xs:simpleContent>
<xs:extension base="display-nameType"/>
</xs:simpleContent>
</xs:complexType>
</xs:element>
<xs:any namespace="##other" processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="uri" type="xs:anyURI" use="required"/>
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
<xs:complexType name="entry-refType">
<xs:sequence>
<xs:element name="display-name" type="display-nameType" minOccurs="0"/>
<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="ref" type="xs:anyURI" use="required"/>
Rosenberg Expires August 8, 2005 [Page 9]
Internet-Draft XML Resource Lists February 2005
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
<xs:complexType name="externalType">
<xs:sequence>
<xs:element name="display-name" type="display-nameType" minOccurs="0"/>
<xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="anchor" type="xs:anyURI"/>
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
<xs:element name="resource-lists">
<xs:complexType>
<xs:sequence maxOccurs="unbounded">
<xs:element name="list" type="listType"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:complexType name="display-nameType">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute ref="xml:lang"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:schema>
3.3 Example Document
The following is an example of a document compliant to the schema.
All line feeds within element content are for display purposes only.
Rosenberg Expires August 8, 2005 [Page 10]
Internet-Draft XML Resource Lists February 2005
<?xml version="1.0" encoding="UTF-8"?>
<resource-lists xmlns="urn:ietf:params:xml:ns:resource-lists"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<list name="friends">
<entry uri="sip:bill@example.com">
<display-name>Bill Doe</display-name>
</entry>
<entry-ref ref="resource-lists/users/bill/mylist/~~/resource-lists/l
ist%5b@name=%22list1%22%5d/entry%5b@uri=%22sip:petri@example.com%22%5d"/>
<list name="close-friends">
<display-name>Close Friends</display-name>
<entry uri="sip:joe@example.com">
<display-name>Joe Smith</display-name>
</entry>
<entry uri="sip:nancy@example.com">
<display-name>Nancy Gross</display-name>
</entry>
<external anchor="http://www.example.org/xcap/resource-lists/users/a
/foo/~~/resource-lists/list%5b@name=%22mkting%22%5d">
<display-name>Marketing</display-name>
</external>
</list>
</list>
</resource-lists>
3.4 Usage with XCAP
Resource lists documents can be manipulated with XCAP. This section
provides the details necessary for such a usage.
3.4.1 Application Unique ID
XCAP requires application usages to define a unique application usage
ID (AUID) in either the IETF tree or a vendor tree. This
specification defines the "resource-lists" AUID within the IETF tree,
via the IANA registration in Section 8.
3.4.2 MIME Type
The MIME type for this document is "application/resource-lists+xml".
3.4.3 XML Schema
The XML Schema for this document is defined as the sole content of
Section 3.2.
Rosenberg Expires August 8, 2005 [Page 11]
Internet-Draft XML Resource Lists February 2005
3.4.4 Default Namespace
The default namespace used in expanding URIs is
urn:ietf:params:xml:ns:resource-lists.
3.4.5 Additional Constraints
In addition to the schema, there are constraints on the values
present in the the "name" attribute of the <list> element, the "uri"
attribute of the <external> element, the "ref" attribute of the
<entry-ref> element and the "anchor" attribute of the <external>
element. These constraints are defined in Section 3.1. Some of
these constraints are enforced by the XCAP server. Those constraints
are:
o The "name" attribute in a <list> element MUST be unique amongst
all other "name" attributes of <list> elements within the same
parent element. Uniqueness is determined by case sensitive string
comparison.
o The "uri" attribute in a <entry> element MUST be unique amongst
all other "uri" attributes of <entry> elements within the same
parent element. Uniqueness is determined by case sensitive string
comparison.
o The URI in the "ref" attribute of the <entry-ref> element MUST be
unique amongst all other "ref" attributes of <entry-ref> elements
within the same parent element. Uniqueness is determined by case
sensitive string comparison. The value of the attribute MUST be a
relative path reference. Note that the server is not responsible
for verifying that the reference resolves to an <entry> element in
a document within the same XCAP root.
o The URI in the "anchor" attribute of the <external> element MUST
be unique amongst all other "anchor" attributes of <external>
elements within the same parent element. Uniqueness is determined
by case sensitive string comparison. The value of the attribute
MUST be an absolute HTTP URI. Note that the server is not
responsible for verifying that the URI resolves to a <list>
element in a document. Indeed, since the URI may reference a
server in another domain, referential integrity cannot be
guaranteed without adding substantial complexity to the system.
3.4.6 Data Semantics
Semantics for the document content are provided in Section 3.1.
Rosenberg Expires August 8, 2005 [Page 12]
Internet-Draft XML Resource Lists February 2005
3.4.7 Naming Conventions
Resource lists documents are usually identified as references from
other application usages. For example, an RLS services document
contains a reference to the resource list it uses.
Frequently, an XCAP client will wish to insert or remove an <entry>,
<entry-ref> or <external> element from a document without having a
cached copy of that document. In such a case, the "uri" attribute of
the <entry> element, the "ref" attribute of the <entry-ref> element
or the "anchor" attribute of the <external> element is used as an
index to select the element to operate upon. The XCAP server will
determine uniqueness by case sensitive string comparison. However,
each of these attributes contain URIs, and the URI equality rules for
their schemes may allow for two URI to be the same, even if they are
different by case sensitive string comparison. As such, it is
possible that a client will attempt a PUT or DELETE in an attempt to
modify or remove an existing element, but instead, the PUT ends up
inserting a new element, or the DELETE ends up returning an error
response.
To mitigate against this case, if the client knows that the user
intent is to explicitly modify an existing element, as opposed to
creating a new one, the client SHOULD make the request conditional,
using an If-Match header field with a value of *. This will cause
the request to fail if it is not a replacement.
If the XCAP client cannot determine whether the user intent is to
create or replace, the client SHOULD canonicalize the URI before
performing the operation. For a SIP URI (often present in the "uri"
attribute of the <entry> element), this canonicalization procedure is
defined in Section 5. We expect that the SIP URIs that will be
placed into resource lists documents will usually be of the form
sip:user@domain, and possibly include a user parameter. The
canonicalization rules work perfectly for these URIs.
For HTTP URIs, a basic canonicalization algorithm is as follows. If
the the port in the URI is equal to the default port (80 for http
URIs), the port is removed. The hostname is converted to all
lowercase. Any characters that are escape encoded are un-escaped,
and only re-escaped if they cannot be represented within their
component of the URI. In other words, if the grammar for a part of
the URI disallows a certain character, but that character needs to be
present, it is escape coded.
3.4.8 Resource Interdependencies
There are no resource interdependencies identified by this
Rosenberg Expires August 8, 2005 [Page 13]
Internet-Draft XML Resource Lists February 2005
application usage.
3.4.9 Authorization Policies
This application usage does not modify the default XCAP authorization
policy, which is that only a user can read, write or modify their own
documents. A server can allow privileged users to modify documents
that they don't own, but the establishment and indication of such
policies is outside the scope of this document. It is anticipated
that a future application usage will define which users are allowed
to modify a list resource.
4. RLS Services Documents
4.1 Structure
An RLS services document is used to define URIs that represent
services provided by a Resource List Server (RLS) as defined in [15].
An RLS services document is an XML [2] document that MUST be
well-formed and MUST be valid according to schemas, including
extension schemas, available to the validater and applicable to the
XML document. RLS services documents MUST be based on XML 1.0 and
MUST be encoded using UTF-8. This specification makes use of XML
namespaces for identifying RLS services documents and document
fragments. The namespace URI for elements defined by this
specification is a URN [3], using the namespace identifier 'ietf'
defined by RFC 2648 [6] and extended by RFC 3688 [8]. This URN is:
urn:ietf:params:xml:ns:rls-services
The root element of an rls-services document is <rls-services>. It
contains a sequence of <service> elements, each of which defines a
service available at an RLS.
Each <service> element has a single mandatory attribute, "uri". This
URI defines the resource associated with the service. That is, if a
client subscribes to that URI, they will obtain the service defined
by the corresponding <service> element. The <service> element can
also contain attributes from other namespaces, for the purposes of
extensibility. The <service> element contains child elements that
define the service. For an RLS service, very little service
definition is needed - just the resource list to which the server
will perform virtual subscriptions [15] and the set of event packages
that the service supports. The former can be conveyed in one of two
ways. There can be a <resource-list> element, which points to a
<list> element in a resource-lists document, or there can be a <list>
element, which includes the resource list directly. The supported
packages are contained in the <packages> element. The <service>
Rosenberg Expires August 8, 2005 [Page 14]
Internet-Draft XML Resource Lists February 2005
element can also contain elements from other namespaces, for the
purposes of extensibility.
By including the contents of the resource list directly, a user can
create lists and add members to them with a single XCAP operation.
However, the resulting list becomes "hidden" within the RLS service
definition, and is not usable by other application usages. For this
reason, the <resource-list> element exists as an alternative. It can
reference a <list> element in a resource-lists document. Since the
list is separated from the service definition, it can be easily
reused by other application usages.
The <list> element is of the list type defined by the schema for
resource lists. It is discussed in Section 3.1.
The <resource-list> element contains a URI. This element is only
meaningful when the document was obtained through XCAP. The URI MUST
be an absolute HTTP URI representing an XCAP element resource. Its
XCAP root MUST be the same as the XCAP root of the RLS services
document. When the RLS services document is present in a user's home
directory, the HTTP URI MUST exist underneath that user's home
directory in the resource-lists application usage. When the RLS
services document is in the global directory, the HTTP URI MUST exist
underneath any user's home directory in the resource-lists
application usage. In either case, the element referenced by the URI
MUST be a <list> element within a resource-lists document. All of
these constraints except for the latter one (which is a referential
integrity constraint) will be enforced by the XCAP server.
The <packages> element contains a sequence of <package> elements.
The content of each <package> element is the name of a SIP event
package [14]. The <packages> element may also contain elements from
additional namespaces, for the purposes of extensibility. The
<packages> element is optional. When not present, it means that the
RLS service will accept subscriptions for any event package.
4.2 Schema
Rosenberg Expires August 8, 2005 [Page 15]
Internet-Draft XML Resource Lists February 2005
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="urn:ietf:params:xml:ns:rls-services"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="urn:ietf:params:xml:ns:rls-services"
xmlns:rl="urn:ietf:params:xml:ns:resource-lists"
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:element name="rls-services">
<xs:complexType>
<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:element name="service" type="serviceType"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:complexType name="serviceType">
<xs:sequence>
<xs:choice>
<xs:element name="resource-list" type="xs:anyURI"/>
<xs:element name="list" type="rl:listType"/>
</xs:choice>
<xs:element name="packages" type="packagesType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="uri" type="xs:anyURI" use="required"/>
<xs:anyAttribute namespace="##other"/>
</xs:complexType>
<xs:complexType name="packagesType">
<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:element name="package" type="packageType"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:simpleType name="packageType">
<xs:restriction base="xs:string"/>
</xs:simpleType>
</xs:schema>
4.3 Example Document
This document shows two services. One is sip:mybuddies@example.com,
and the other is sip:marketing@example.com. The former service
references a resource list in a resource-lists document, and the
latter one includes a list locally. Both services are for the
presence event package only.
Rosenberg Expires August 8, 2005 [Page 16]
Internet-Draft XML Resource Lists February 2005
<?xml version="1.0" encoding="UTF-8"?>
<rls-services xmlns="urn:ietf:params:xml:ns:rls-services"
xmlns:rl="urn:ietf:params:xml:ns:resource-lists"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<service uri="sip:mybuddies@example.com">
<resource-list>http://xcap.example.com/resource-lists/users/joe/index/~~/
resource-lists/list%5b@name=%22l1%22%5d</resource-list>
<packages>
<package>presence</package>
</packages>
</service>
<service uri="sip:marketing@example.com">
<list name="marketing">
<rl:entry uri="sip:joe@example.com"/>
<rl:entry uri="sip:sudhir@example.com"/>
</list>
<packages>
<package>presence</package>
</packages>
</service>
</rls-services>
4.4 Usage with XCAP
RLS services documents can be manipulated with XCAP. This section
provides the details necessary for such a usage.
4.4.1 Application Unique ID
XCAP requires application usages to define a unique application usage
ID (AUID) in either the IETF tree or a vendor tree. This
specification defines the "rls-services" AUID within the IETF tree,
via the IANA registration in Section 8.
4.4.2 MIME Type
The MIME type for this document is "application/rls-services+xml".
4.4.3 XML Schema
The XML Schema for this document is defined as the sole content of
Section 4.2.
4.4.4 Default Namespace
The default namespace used in expanding URIs is
urn:ietf:params:xml:ns:rls-services.
Rosenberg Expires August 8, 2005 [Page 17]
Internet-Draft XML Resource Lists February 2005
4.4.5 Additional Constraints
In addition to the schema, there are constraints on the URIs present
in the <service> and <resource-list> elements. These constraints are
defined in Section 3.1. Some of these constraints are enforced by
the XCAP server. Those constraints are:
o The URI in the "uri" attribute of the <service> element MUST be
unique amongst all other URIs in "uri" elements in any <service>
element in any document on a particular server. This uniqueness
constraint spans across XCAP roots. Furthermore, the URI MUST NOT
correspond to an existing resource within the domain of the URI.
If a server is asked to set the URI to something that already
exists, the server MUST reject the request with a 409, and use the
mechanisms defined in [10] to suggest alternate URIs that have not
yet been allocated.
o The URI in a <resource-list> element MUST be an absolute URI. The
server MUST verify that the URI path contains "resource-lists" in
the path segment corresponding to the AUID. If the RLS services
document is within the XCAP user tree (as opposed to the global
tree), the server MUST verify that the XUI in the path is the same
as the XUI in the URI of to the RLS services document. These
checks are made by examining the URI value, as opposed to
de-referencing the URI. The server is not responsible for
verifying that the URI actually points to a <list> element within
a valid resource lists document.
o In addition, an RLS services document can contain a <list>
element, which in turn can contain <entry>, <entry-ref> and
<external> elements. The constraints defined for these elements
in Section 3.4.7 MUST be enforced.
o In some cases, an XCAP client will wish to create a new RLS
service, and wish to assign it a "vanity URI", such as
sip:friends@example.com. However, the client does not know
whether this URI meets the uniqueness constraints defined above.
In that case, it can simply attempt the creation operation, and if
the result is a 409 that contains a detailed conflict report with
the <uniqueness-failure> element, the client knows that the URI
could not be assigned. It can then retry with a different vanity
URI, or use one of the suggestions in the detailed conflict
report.
o If the client wishes to create a new RLS service, and it doesnt
care what the URI is, the client creates a random one, and
attempts the creation operation. As discussed in [10], if this
should fail with a uniqueness conflict, the client can retry with
Rosenberg Expires August 8, 2005 [Page 18]
Internet-Draft XML Resource Lists February 2005
different URIs with increasing randomness.
4.4.6 Data Semantics
Semantics for the document content are provided in Section 4.1.
4.4.7 Naming Conventions
Typically, there are two distinct XCAP clients that access RLS
services documents. The first is a client acting on behalf of the
end user in the system. This client edits and writes both resource
lists and RLS services documents as they are created or modified by
the end user. The other XCAP client is the RLS itself, which reads
the RLS services documents in order to process SUBSCRIBE requests.
To make it easier for an RLS to find the <service> element for a
particular URI, the XCAP server maintains, within the global tree, a
single RLS services document representing the union of all of the
<service> elements across all documents created by all users within
the same XCAP root. There is a single instance of this document, and
its name is "index". Thus, if the root services URI is
http://xcap.example.com/root, the following is the URI that an RLS
would use to fetch this index:
http://xcap.example.com/root/rls-services/global/index
As discussed below, this index is created from all of the documents
in the user tree that have the name "index" as well. An implication
of this is that a client operating on behalf of a user SHOULD define
its RLS services within the document named "index". If the root
services URI is http://xcap.example.com/root, for user "joe" the URI
for this document would be:
http://xcap.example.com/root/rls-services/users/joe/index
If a client elects to define RLS services in a different document,
this document will not be "picked up" in the global index, and
therefore, not used as an RLS service.
4.4.8 Resource Interdependencies
As with other application usages, the XML schema along with the XCAP
resource naming conventions describes most of the resource
interdependencies applicable to this application usage.
Rosenberg Expires August 8, 2005 [Page 19]
Internet-Draft XML Resource Lists February 2005
This application usage defines an additional resource interdependence
between a single document in the global tree and all documents in the
user tree with the name "index". This global document is formed as
the union of all of the index documents for all users within the same
XCAP root. In this case, the union operation implies that each
<service> element in a user document will also be present as a
<service> element in the global document. The inverse is true as
well. Every <service> element in the global document exists within a
user document within the same XCAP root.
As an example, consider the RLS services document for user joe:
<?xml version="1.0" encoding="UTF-8"?>
<rls-services>
<service uri="sip:mybuddies@example.com">
<resource-list>http://xcap.example.com/resource-lists/users/joe/index/~~/
resource-lists/list%5b@name=%22l1%22%5d</resource-list>
<packages>
<package>presence</package>
</packages>
</service>
</rls-services>
And consider the RLS services document for user bob:
<?xml version="1.0" encoding="UTF-8"?>
<rls-services>
<service uri="sip:marketing@example.com">
<list name="marketing">
<rl:entry uri="sip:joe@example.com"/>
<rl:entry uri="sip:sudhir@example.com"/>
</list>
<packages>
<package>presence</package>
</packages>
</service>
</rls-services>
The global document at
http://xcap.example.com/root/rls-services/global/index would look
like:
Rosenberg Expires August 8, 2005 [Page 20]
Internet-Draft XML Resource Lists February 2005
<?xml version="1.0" encoding="UTF-8"?>
<rls-services xmlns="urn:ietf:params:xml:ns:rls-services"
xmlns:rl="urn:ietf:params:xml:ns:resource-lists"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<service uri="sip:mybuddies@example.com">
<resource-list>http://xcap.example.com/resource-lists/users/joe/index/~~/
resource-lists/list%5b@name=%22l1%22%5d</resource-list>
<packages>
<package>presence</package>
</packages>
</service>
<service uri="sip:marketing@example.com">
<list name="marketing">
<rl:entry uri="sip:joe@example.com"/>
<rl:entry uri="sip:sudhir@example.com"/>
</list>
<packages>
<package>presence</package>
</packages>
</service>
</rls-services>
Requests made against the global document MUST generate responses
that reflect the most recent state of all the relevant user
documents. This requirement does not imply that the server must
actually store this global document. It is anticipated that most
systems will dynamically construct the responses to any particular
request against the document resource.
The uniqueness constraint on the "uri" attribute of <service> will
ensure that no two <service> elements in the global document have the
same value of that attribute.
4.4.9 Authorization Policies
This application usage does not modify the default XCAP authorization
policy, which is that only a user can read, write or modify their own
documents. A server can allow privileged users to modify documents
that they don't own, but the establishment and indication of such
policies is outside the scope of this document. It is anticipated
that a future application usage will define which users are allowed
to modify an RLS services document.
The index document maintained in the global tree represents sensitive
information, as it contains the union of all of the information for
all users on the server. As such, its access MUST be restricted to
trusted elements within domain of the server. Typically, this would
be limited to the RLSs that need access to this document.
Rosenberg Expires August 8, 2005 [Page 21]
Internet-Draft XML Resource Lists February 2005
4.5 Usage of an RLS Services Document by an RLS
This section discusses how an RLS, on receipt of a SUBSCRIBE request,
uses XCAP and the RLS services document to guide its operation.
When an RLS receives a SUBSCRIBE request for a URI (present in the
Request URI), it obtains the <service> element whose uri attribute
matches (based on URI equality) the URI in the SUBSCRIBE request.
This document makes no normative statements on how this might be
accomplished. The following paragraph provides one possible
approach.
The RLS canonicalizes the Request URI as described in Section 5. It
then performs an XCAP GET operation against the URI formed by
combining the XCAP root with the document selector of the global
index with a node selector of the form
"rls-services/service[@uri=<canonical-uri>]", where <canonical-uri>
is the canonicalized version of the Request URI. If the response is
a 200 OK, it will contain the service definition for that URI.
Once the <service> element has been obtained, it is examined. If the
<packages> element is present, and the event package in the SUBSCRIBE
request is not amongst those listed in the <package> elements within
<packages>, the request MUST be rejected with a 489 (Bad Event)
response code, as described in [14]. Otherwise, it SHOULD be
processed. The next step is to authorize that the client is allowed
to subscribe to the resource. This can be done using the data
defined in [13], for example. Assuming the subscriber is authorized
to subscribe to that resource, the subscription is processed
according to the procedures defined in [15]. This processing
requires the RLS to compute a flat list of URIs that are to be
subscribed to. If the <service> element had a <list> element, it is
extracted. If the <service> element had a <resource-list> element,
its URI content is dereferenced. The result should be a <list>
element. If it is not, the request SHOULD be rejected with a 502
(Bad Gateway). Otherwise, that <list> element is extracted.
At this point the RLS has a <list> element in its possession. The
next step is to obtain a flat list of URIs from this element. To do
that, it traverses the tree of elements rooted in the <list> element.
Before traversal begins, the RLS initializes two lists - the "flat
list", which will contain the flat list of URI after traversal, and
the "traversed list", which contains a list of HTTP URIs in
<external> elements that have already been visited. Once these lists
are initialized, tree traversal begins. A server can use any
tree-traversal ordering it likes, such as depth first search or
breadth first search. The processing at each element in the tree
depends on the name of the element:
Rosenberg Expires August 8, 2005 [Page 22]
Internet-Draft XML Resource Lists February 2005
o If the element is <entry> the URI in the "uri" attribute of the
element is added to the flat list if it is not already present
(based on case sensitive string equality) in that list, and the
URI scheme represents one that can be used to service
subscriptions, such as SIP [4] and pres [16].
o If the element is an <entry-ref>, the relative path reference
making up the value of the "ref" attribute is resolved into an
absolute URI. This is done using the procedures defined in
Section 5.2 of RFC 3986 [7], using the XCAP root of the RLS
services document as the base URI. This absolute URI is resolved.
If the result is not a 200 OK containing a <entry> element, the
SUBSCRIBE request SHOULD be rejected with a 502 (Bad Gateway).
Otherwise, the <entry> element returned is processed as described
in the previous step.
o If the element is an <external> element, the absolute URI making
up the value of the "anchor" attribute of the element is examined.
If the URI is on the traversed list, the server MUST cease
traversing the tree, and SHOULD reject the SUBSCRIBE request with
a 502 (Bad Gateway). If the URI is not on the traversed list, the
server adds the URI to the traversed list, and de-references the
URI. If the result is not a 200 OK containing an <list> element,
the SUBSCRIBE request SHOULD be rejected with a 502 (Bad Gateway).
Otherwise, the RLS replaces the <external> element in its local
copy of the tree with the <list> element that was returned, and
tree traversal continues.
Because the <external> element is used to dynamically construct the
tree, there is a posibility of recursive evaluation of references.
The traversed list is used to prevent this from happening.
Once the tree has been traversed, the RLS can create virtual
subscriptions to each URI in the flat list, as defined in [15].
In the processing steps outlined above, when an <entry-ref> or
<external> element contains a reference that cannot be resolved,
failing the request is at SHOULD strength. In some cases, an RLS may
provide better service by creating virtual subscriptions to the URIs
in the flat list that could be obtained, omitting those that could
not. Only in those cases should the SHOULD recommendation be
ignored.
5. SIP URI Canonicalization
This section provides a technique for URI canonicalization. This
canonicalization produces a URI that, in most cases, is equal to the
original URI (where equality is based on the URI comparison rules in
Rosenberg Expires August 8, 2005 [Page 23]
Internet-Draft XML Resource Lists February 2005
RFC 3261). Furthermore, the canonicalized URI will usually be
lexically equivalent to the canonicalized version of any other URI
equal to the original.
To canonicalize the URI, the following steps are followed:
1. First, the domain part of the URI is converted into all
lowercase, and any tokens (such as "user" or "transport" or
"udp") are converted to all lowercase.
2. Secondly, the URI is un-escape coded. Then, it is re-coded.
However, when it is recoded, the only characters that are coded
are those which are not permitted to appear based on the grammar
of that portion of the URI. For example, if a SIP URI is
sip:%6aoe%20smith@example.com, it is decoded to sip:joe
smith@example.com and the re-coded to
sip:joe%20smith@example.com. In the original URI, the character
'j' was escape coded. This is allowed, but not required, since
the grammar allows a 'j' to appear in the user part. As a
result, it appears as 'j' after this step of canonicalization.
3. Thirdly, any URI parameters are reordered so that they appear in
lexical order based on parameter name. The ordering of a
character is determined by the US-ASCII numerical value of that
character, with smaller numbers coming first. Parameters are
ordered with the leftmost character as most significant. For
parameters that contain only letters, this is equivalent to an
alphabetical ordering.
4. Finally, any header parameters are discarded. This canonicalized
URI is used instead of the original URI.
If two URIs A and B are functionally equal (meaning that they are
equal according to the URI comparison rules in RFC 3261), their
canonicalized URIs are equal under case sensitive string comparison
if the following are true:
o Neither URI contains header parameters
o If one of the URI contains a URI parameter not defined in RFC
3261, the other does as well.
6. Extensibility
Resource-lists and RLS services documents are meant to be extended.
An extension takes place by defining a new set of elements in a new
namespace, governed by a new schema. Every extension MUST have an
Rosenberg Expires August 8, 2005 [Page 24]
Internet-Draft XML Resource Lists February 2005
appropriate XML namespace assigned to it. The XML namespace of the
extension MUST be different from the namespaces defined in this
specification. The extension MUST NOT change the syntax or semantics
of the schemas defined in this document. All XML tags and attributes
that are part of the extension MUST be appropriately qualified so as
to place them within that namespace.
This specification defines explict places where new elements or
attributes from an extension can be placed. These are explicitly
indicated in the schemas by the <any> and <anyAttribute> elements.
Extensions to this specification MUST specify where their elements
can be placed within the document.
As a result, a document that contains extensions will require
multiple schemas in order to determine its validity - a schema
defined in this document, along with those defined by extensions
present in the document. Because extensions occur by adding new
elements and attributes governed by new schemas, the schemas defined
in this document are fixed and would only be changed by a revision to
this specification. Such a revision, should it take place, would
endeavor to allow documents compliant to the previous schema to
remain compliant to the new one. As a result, the schemas defined
here don't provide explicit schema versions, as this is not expected
to be needed.
7. Security Considerations
The information contained in rls-services and resource-lists
documents are particularly sensitive. It represents the principle
set of people with whom a user would like to communicate. As a
result, clients SHOULD use TLS when contacting servers in order to
fetch this information. Note that this does not represent a change
in requirement strength from XCAP.
8. IANA Considerations
There are several IANA considerations associated with this
specification.
8.1 XCAP Application Unique IDs
This section registers two new XCAP Application Unique ID (AUID)
according to the IANA procedures defined in [10].
8.1.1 resource-lists
Rosenberg Expires August 8, 2005 [Page 25]
Internet-Draft XML Resource Lists February 2005
Name of the AUID: resource-lists
Description: A resource lists application is any application that
needs access to a list of resources, identified by a URI, to which
operations, such as subscriptions, can be applied.
8.1.2 rls-services
Name of the AUID: rls-services
Description: An Resource List Server (RLS) services application is
Session Initiation Protocol (SIP) application whereby a server
receives SIP SUBSCRIBE requests for resource, and generates
subscriptions towards the a resource list.
8.2 MIME Type Registrations
This specification requests the registration of two new MIME types
according to the procedures of RFC 2048 [9] and guidelines in RFC
3023 [5].
8.2.1 application/resource-lists+xml
MIME media type name: application
MIME subtype name: resource-lists+xml
Mandatory parameters: none
Optional parameters: Same as charset parameter application/xml as
specified in RFC 3023 [5].
Encoding considerations: Same as encoding considerations of
application/xml as specified in RFC 3023 [5].
Security considerations: See Section 10 of RFC 3023 [5] and
Section 7 of RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please replace
XXXX with the RFC number of this specification]].
Interoperability considerations: none.
Published specification: RFC XXXX [[NOTE TO IANA/RFC-EDITOR:
Please replace XXXX with the RFC number of this specification]]
Rosenberg Expires August 8, 2005 [Page 26]
Internet-Draft XML Resource Lists February 2005
Applications which use this media type: This document type has
been used to support subscriptions to lists of users [15] for
SIP-based presence [12].
Additional Information:
Magic Number: None
File Extension: .rl
Macintosh file type code: "TEXT"
Personal and email address for further information: Jonathan
Rosenberg, jdrosen@jdrosen.net
Intended usage: COMMON
Author/Change controller: The IETF.
8.2.2 application/rls-services+xml
MIME media type name: application
MIME subtype name: rls-services+xml
Mandatory parameters: none
Optional parameters: Same as charset parameter application/xml as
specified in RFC 3023 [5].
Encoding considerations: Same as encoding considerations of
application/xml as specified in RFC 3023 [5].
Security considerations: See Section 10 of RFC 3023 [5] and
Section 7 of RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please replace
XXXX with the RFC number of this specification]].
Interoperability considerations: none.
Published specification: RFC XXXX [[NOTE TO IANA/RFC-EDITOR:
Please replace XXXX with the RFC number of this specification]]
Applications which use this media type: This document type has
been used to support subscriptions to lists of users [15] for
SIP-based presence [12].
Rosenberg Expires August 8, 2005 [Page 27]
Internet-Draft XML Resource Lists February 2005
Additional Information:
Magic Number: None
File Extension: .rs
Macintosh file type code: "TEXT"
Personal and email address for further information: Jonathan
Rosenberg, jdrosen@jdrosen.net
Intended usage: COMMON
Author/Change controller: The IETF.
8.3 URN Sub-Namespace Registrations
This section registers two new XML namespace, as per the guidelines
in RFC 3688 [8].
8.3.1 urn:ietf:params:xml:ns:resource-lists
URI: The URI for this namespace is
urn:ietf:params:xml:ns:resource-lists.
Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
Jonathan Rosenberg (jdrosen@jdrosen.net).
XML:
BEGIN
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type"
content="text/html;charset=iso-8859-1"/>
<title>Resource Lists Namespace</title>
</head>
<body>
<h1>Namespace for Resource Lists</h1>
<h2>urn:ietf:params:xml:ns:resource-lists</h2>
<p>See <a href="[URL of published RFC]">RFCXXXX [NOTE
TO IANA/RFC-EDITOR: Please replace XXXX with the RFC number of this
specification.]</a>.</p>
Rosenberg Expires August 8, 2005 [Page 28]
Internet-Draft XML Resource Lists February 2005
</body>
</html>
END
8.3.2 urn:ietf:params:xml:ns:rls-services
URI: The URI for this namespace is
urn:ietf:params:xml:ns:rls-services.
Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
Jonathan Rosenberg (jdrosen@jdrosen.net).
XML:
BEGIN
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type"
content="text/html;charset=iso-8859-1"/>
<title>Resource List Server (RLS) Services Namespace</title>
</head>
<body>
<h1>Namespace for Resource List Server (RLS) Services</h1>
<h2>urn:ietf:params:xml:ns:rls-services</h2>
<p>See <a href="[URL of published RFC]">RFCXXXX [NOTE
TO IANA/RFC-EDITOR: Please replace XXXX with the RFC number of this
specification.]</a>.</p>
</body>
</html>
END
8.4 Schema Registrations
This section registers two XML schemas per the procedures in [8].
8.4.1 urn:ietf:params:xml:schema:resource-lists
URI: urn:ietf:params:xml:schema:resource-lists
Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
Jonathan Rosenberg (jdrosen@jdrosen.net).
Rosenberg Expires August 8, 2005 [Page 29]
Internet-Draft XML Resource Lists February 2005
The XML for this schema can be found as the sole content of
Section 3.2.
8.4.2 urn:ietf:params:xml:schema:rls-services
URI: urn:ietf:params:xml:schema:rls-services
Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
Jonathan Rosenberg (jdrosen@jdrosen.net).
The XML for this schema can be found as the sole content of
Section 4.2.
9. Acknowledgements
The authors would like to thank Hisham Khartabil, Jari Urpalainen and
Spencer Dawkins for their comments and input. Thanks to Ted Hardie
for his encouragement and support of this work.
10. References
10.1 Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
"Extensible Markup Language (XML) 1.0 (Second Edition)", W3C
FirstEdition REC-xml-20001006, October 2000.
[3] Moats, R., "URN Syntax", RFC 2141, May 1997.
[4] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002.
[5] Murata, M., St. Laurent, S. and D. Kohn, "XML Media Types", RFC
3023, January 2001.
[6] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
August 1999.
[7] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
January 2005.
Rosenberg Expires August 8, 2005 [Page 30]
Internet-Draft XML Resource Lists February 2005
[8] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[9] Freed, N., Klensin, J. and J. Postel, "Multipurpose Internet
Mail Extensions (MIME) Part Four: Registration Procedures", BCP
13, RFC 2048, November 1996.
[10] Rosenberg, J., "The Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)",
draft-ietf-simple-xcap-05 (work in progress), November 2004.
10.2 Informative References
[11] Day, M., Rosenberg, J. and H. Sugano, "A Model for Presence and
Instant Messaging", RFC 2778, February 2000.
[12] Rosenberg, J., "A Presence Event Package for the Session
Initiation Protocol (SIP)", RFC 3856, August 2004.
[13] Rosenberg, J., "Presence Authorization Rules",
draft-ietf-simple-presence-rules-01 (work in progress), October
2004.
[14] Roach, A., "Session Initiation Protocol (SIP)-Specific Event
Notification", RFC 3265, June 2002.
[15] Roach, A., Rosenberg, J. and B. Campbell, "A Session Initiation
Protocol (SIP) Event Notification Extension for Resource
Lists", draft-ietf-simple-event-list-07 (work in progress),
January 2005.
[16] Peterson, J., "Common Profile for Presence (CPP)", RFC 3859,
August 2004.
Author's Address
Jonathan Rosenberg
Cisco Systems
600 Lanidex Plaza
Parsippany, NJ 07054
US
Phone: +1 973 952-5000
EMail: jdrosen@cisco.com
URI: http://www.jdrosen.net
Rosenberg Expires August 8, 2005 [Page 31]
Internet-Draft XML Resource Lists February 2005
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Rosenberg Expires August 8, 2005 [Page 32]