D.6 PS-to-CS preparation XML schema
24.2373GPPIP Multimedia (IM) Core Network (CN) subsystem IP Multimedia Subsystem (IMS) service continuityRelease 17Stage 3TS
D.6.1 General
This subclause defines the XML schema and the MIME type for information exchanged during codec inquiry prior to PS to CS SRVCC access transfer.
D.6.2 XML schema
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<xs:element name="PS-to-CS-preparation-request" type="PS-to-CS-preparation-requestType"/>
<xs:element name="PS-to-CS-preparation-response" type="PS-to-CS-preparation-responseType"/>
<xs:complexType name="PS-to-CS-preparation-requestType">
<xs:sequence>
<xs:element name="MSC-server-supported-codec-list" type="xs:base64Binary"/>
<xs:element name="anyExt" type="anyExtType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>
<xs:complexType name="PS-to-CS-preparation-responseType">
<xs:sequence>
<xs:choice>
<xs:element name="currently-possible" type="currently-possibleType" minOccurs="0"/>
<xs:element name="currently-not-possible" type="currently-not-possibleType" minOccurs="0"/>
</xs:choice>
<xs:element name="anyExt" type="anyExtType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>
<xs:complexType name="currently-possibleType">
<xs:sequence>
<xs:element name="IMS-preferred-codec-list" type="xs:base64Binary"/>
<xs:element name="anyExt" type="anyExtType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>
<xs:complexType name="currently-not-possibleType">
<xs:sequence>
<xs:element name="session" type="sessionType" minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="anyExt" type="anyExtType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>
<xs:complexType name="sessionType">
<xs:sequence>
<xs:element name="state-info" type="xs:string"/>
<xs:element name="direction" type="xs:string"/>
<xs:element name="speech-state" type="xs:string"/>
<xs:element name="supported-features" type="supported-featuresType" minOccurs="0"/>
<xs:element name="anyExt" type="anyExtType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>
<xs:complexType name="supported-featuresType">
<xs:sequence>
<xs:element name="feature-tag" type="feature-tagType" maxOccurs="unbounded"/>
<xs:element name="anyExt" type="anyExtType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:complexType>
<xs:complexType name="feature-tagType">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="name" type="xs:string">
</xs:attribute>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<xs:complexType name="anyExtType">
<xs:sequence>
<xs:any namespace="##any" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:schema>
D.6.3 Additional syntactic rules
The root element of the XML text shall be either the <PS-to-CS-preparation-request> element or the <PS-to-CS-preparation-response> element.
The <PS-to-CS-preparation-request> element:
1) shall include the <MSC-server-supported-codec-list> element;
2) may include the <anyExt> element;
3) may include elements specified in other namespaces; and
4) may include attributes specified in this namespace or other namespaces.
The <PS-to-CS-preparation-response> element:
1) shall include one of the following:
a) the <currently-possible> element; or
b) the <currently-not-possible> element;
2) may include the <anyExt> element;
3) may include elements specified in other namespaces; and
4) may include attributes specified in this namespace or other namespaces.
The <currently-possible> element:
1) shall include the <IMS-preferred-codec-list> element;
2) may include the <anyExt> element;
3) may include XML elements specified in other XML namespaces; and
4) may include attributes specified in this namespace or other namespaces.
The <currently-not-possible> element:
1) may include one or more <session> elements;
2) may include the <anyExt> element;
3) may include XML elements specified in other XML namespaces; and
4) may include attributes specified in this namespace or other namespaces.
The <session> element:
1) shall include the <state-info> element set to one of the values indicated in table D.6.3-1;
Table D.6.3-1: ABNF syntax of values of the <state-info> element
state-info-values = alerting-phase-value / pre-alerting-phase-value / confirmed-dialog-value
alerting-phase-value = %x65.61.72.6c.79 ; "early"
pre-alerting-phase-value = %x70.72.65.2d.61.6c.65.72.74.69.6e.67 ; "pre-alerting"
confirmed-dialog-value = %x63.6f.6e.66.69.72.6d.65.64 ; "confirmed"
2) shall include the <direction> element set to one of the values indicated in table D.6.3-2;
Table D.6.3-2: ABNF syntax of values of the <direction> element
direction-values = initiator-value / receiver-value
initiator-value = %x69.6e.69.74.69.61.74.6f.72 ; "initiator"
receiver-value = %x72.65.63.65.69.76.65.72 ; "receiver"
3) shall include the <speech-state> element set to one of the values indicated in table D.6.3-3; and
Table D.6.3-2: ABNF syntax of values of the <speech-state> element
speech-state-values = active-speech-media-component / inactive-speech-media-component
active-speech-media-component = %x61.63.74.69.76.65 ; "active"
inactive-speech-media-component = %x69.6e.61.63.74.69.76.65 ; "inactive"
4) may include the <supported-features> element.
The <supported-features> element:
1) shall include zero or more <feature-tag> elements;
2) may include the <anyExt> element; and
3) may include elements specified in other namespaces; and
4) may include attributes specified in this namespace or other namespaces.
The <feature-tag> element shall include the "name" attribute.
D.6.4 Semantic
A entity receiving an XML text compliant to the XML schema specified in subclause D.6.2 shall ignore any unknown element and any unknown attribute.
Presence of the <PS-to-CS-preparation-request> element shall indicate that the XML text carries the PS-to-CS-preparation-request.
Presence of the <PS-to-CS-preparation-response> element shall indicate that the XML text carries the PS-to-CS-preparation-response.
The <MSC-server-supported-codec-list> element shall contain an SDP body with one audio m= line with one or more RTP payload types that are supported commonly by the served SC UE, the target RAN and the target CS-MGW selected by the MSC server.
Presence of the <currently-possible> element shall indicate that the PS to CS SRVCC access transfer is currently possible.
The <IMS-preferred-codec-list> element shall contain an SDP body with one audio m= line with one or more RTP payload types that are preferred by the ATCF to be used by the MSC server.
Presence of the <currently-not-possible> element shall indicate that the PS to CS SRVCC access transfer is currently not possible.
The <session> element describe a session of the served SC UE in PS.
The <state-info> element indicates the state of the session, i.e. whether the session is in the pre-alerting phase, is in the alerting phase or is a confirmed dialog.
The <direction> element indicates the direction of the session, i.e. whether the served SC UE is an initiator of the session or a receiver of the session.
The <speech-state> element indicates the state of the speech media component of the session, i.e. whether the speech media component is an active speech media component or an inactive speech media component.
The "name" attribute of the <feature-tag> element indicates a media feature tag supported by the entity sending the XML text. The value, if included, of the <feature-tag> element indicates a value of the media feature tag supported by the sender of the XML text.
The <anyExt> element shall convey extensions.
D.6.5 IANA registration template
Editors’ note (CR#1258, WID: TEI14): MCC is request to register the MIME type when the Rel-14 is completed.
Your Name:
<MCC name>
Your Email Address:
<MCC email address>
Media Type Name:
Application
Subtype name:
vnd.3gpp.PS-to-CS-preparation+xml
Required parameters:
None
Optional parameters:
"charset" the parameter has identical semantics to the charset parameter of the "application/xml" media type as specified in section 9.1 of IETF RFC 7303.
Encoding considerations:
binary.
Security considerations:
Same as general security considerations for application/xml media type as specified in section 9.1 of IETF RFC 7303. In addition, this media type provides a format for exchanging information in SIP, so the security considerations from IETF RFC 3261apply.
The information transported in this media type does not include active or executable content.
Mechanisms for privacy and integrity protection of protocol parameters exist. Those mechanisms as well as authentication and further security mechanisms are described in 3GPP TS 24.229.
This media type does not include provisions for directives that institute actions on a recipient’s files or other resources.
This media type does not include provisions for directives that institute actions that, while not directly harmful to the recipient, may result in disclosure of information that either facilitates a subsequent attack or else violates a recipient’s privacy in any way.
This media type does not employ compression.
Interoperability considerations:
Same as general interoperability considerations for application/xml media type as specified in section 9.1 of IETF RFC 7303.
Published specification:
3GPP TS 24.237 "IP Multimedia Subsystem (IMS) Service Continuity", version 14.2.0, available via http://www.3gpp.org/specs/numbering.htm.
Applications which use this media type:
Applications supporting the service continuity as described in the published specification.
Fragment identifier considerations:
The handling in section 5 of IETF RFC 7303 applies.
Restrictions on usage:
None
Provisional registration? (standards tree only):
N/A
Additional information:
1. Deprecated alias names for this type: none
2. Magic number(s): none
3. File extension(s): none
4. Macintosh File Type Code(s): none
5. Object Identifier(s) or OID(s): none
Intended usage:
Common
Person to contact for further information:
– Name: <MCC name>
– Email: <MCC email address>
– Author/Change controller:
i) Author: 3GPP CT1 Working Group/3GPP_TSG_CT_WG1@LIST.ETSI.ORG
ii) Change controller: <MCC name>/<MCC email address>
Annex E (informative):
INFO packages defined in the current document