1. IMS Service Discovery over PADP
September 2014
doc.: IEEE /1293r0
September 2014
IMS Service Discovery over PADP
Date:
Authors:
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility

2. September 2014
doc.: IEEE /1293r0
September 2014
Abstract
Overview of IMS service identifier formats suitable for pre-association discovery, including voice, video, and messaging
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility

3. IMS IP Multimedia Subsystem
September 2014
doc.: IEEE /1293r0
September 2014
IMS
IP Multimedia Subsystem
Specification for delivery of telephony and other services over IP for mobile and other network types
Currently curated by 3GPP, with additional services specified by GSMA
Services
Voice, video telephony, SMS, IM, Presence
Protocols
IPv4/v6, SIP, SDP, XCAP, OMA SIMPLE
Security
IPsec, AKA, sec-agree, secure media
Codecs
AMR, AMR-WB, H.263, H.264, telephony-event
Networks
UTRAN, E-UTRAN, EV-DO,
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility

4. Cellular Network Service Discovery
September 2014
doc.: IEEE /1293r0
September 2014
Cellular Network Service Discovery
3GPP defines similar signalling for UTRAN and E-UTRAN
Network/UE radio capabilities [1] [2]
System Information Block IMS Emergency Support
UE radio access capabilities
Mobility Management settings [3] [4]
Network support in Voice over PS and Emergency over PS bits in (EPS) Network Feature Support IE
UE support in Voice domain preference and UE’s setting IE
ASN.1 encoded in cellular-specific messages
Indications of IMS support, not specific services
Not good candidates for ULP encapsulation
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility

5. SIP-based service registration and discovery
September 2014
doc.: IEEE /1293r0
September 2014
SIP-based service registration and discovery
3GPP specifies the use [5] of Contact header feature tags [6] to communicate UE capabilities in REGISTER and OPTIONS messages
URN encoded [7] IMS Communication Service Identifier (ICSI) [5] for defined services
SMS: +g.3gpp.smsip (24.341)
Voice: +g.3gpp.icsi-ref=“urn:urn-7:3gpp- service.ims.icsi.mmtel” (24.173)
Video Call: video (IR.94)
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility

6. SIP Contact header tags (cont’d)
September 2014
doc.: IEEE /1293r0
September 2014
SIP Contact header tags (cont’d)
GSMA specifies similar tags [8] [9] [10] for their Rich Communication Services based on IMS
SMS: +g.3gpp.smsip
IP Telephony: +g.gsma.rcs.ipcall
Voice Call: +g.3gpp.icsi-ref="urn%3Aurn-7%3A3gppservice.
ims.icsi.mmtel"
Video Call: video
Video Call non-downgradeable: +g.gsma.rcs.ipvideocallonly
IM: +g.oma.sip-im
Also tags for Standalone IP Messaging, Chat, File Transfer, Image Share, Video Share, Social Presence, Geolocation, and various service features/variants
Tags are useful for identifying services, but lack attribute detail
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility

7. OMA SIMPLE Presence service information
September 2014
OMA SIMPLE Presence service information
GSMA specifies [10] OMA’s SIMPLE extensions [11] for service identifiers as part of providing service capabilities through a presence service [12] [13]
<xs:element name="service-description">
<xs:complexType>
<xs:sequence>
<xs:element name="service-id" type="xs:token"/>
<xs:element name="version" type="xs:token"/>
<xs:element name="description" type="xs:token" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:anyAttribute processContents="lax"/>
</xs:complexType>
</xs:element>
Robert Slater, Motorola Mobility

8. OMA SIMPLE Presence service information
September 2014
OMA SIMPLE Presence service information
Example <service-id>s
IP Voice Call: org.3gpp.urn:urn-7:3gpp-service.ims.icsi.mmtel
Standalone Messaging: org.openmobilealliance:StandaloneMsg
Full Store and Forward Group Chat: org.3gpp.urn:urn-7:3gpp- application.ims.iari.rcs.fullsfgroupchat
PIDF and OMA extensions include service attribute information, but also presentity and contact information that is not appropriate for pre- association network service discovery
Robert Slater, Motorola Mobility

9. IMS service advertisement using PADP
September 2014
IMS service advertisement using PADP
OMA SIMPLE as a ULP for encapsulation
Service type mask bitfields as per enabled services
VoIP/video call -> Interactive Multimedia
Geolocation Push/Pull -> Location Based Services
OMA specified service-id strings used for Service Identifier Hash generation
SIP SUBSCRIBE/NOTIFY with dummy/anonymous identities and addresses to request service information
PIDF document with dummy/anonymous identities, services and attributes as per network support
Next step: AQ Annex example text
Robert Slater, Motorola Mobility

10. References September 2014 doc.: IEEE 802.11-14/1293r0 September 2014
[1] 3GPP TS Radio Resource Control (RRC); Protocol specification v
[2] 3GPP TS Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification v
[3] 3GPP TS Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 v
[4] 3GPP TS Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 v
[5] 3GPP TS IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3 v
[6] RFC 3840 Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)
[7] RFC 2141 URN Syntax
[8] GSMA IR.92 IMS Profile for Voice and SMS Version 8.0
[9] GSMA IR.94 IMS Profile for Conversational Video Service Version 6.0
[10] GSMA Rich Communication Suite 5.1 Advanced Communications Services and Client Specification Version 4.0
[11] OMA Instant Messaging using SIMPLE Approved Version 1.0
[12] RFC 3856 A Presence Event Package for the Session Initiation Protocol (SIP)
[13] RFC 3863 Presence Information Data Format (PIDF)
Robert Slater, Motorola Mobility
Robert Slater, Motorola Mobility