Content for TR 22.809 Word version: 11.2.0
1 Scope
2 References
3 Definitions and abbreviations
3.1 Definitions
3.2 Abbreviations
4 Background
4.1 Analysis of related standardization
4.2 Enterprise-based service control
5 Reference Model
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1 Scope p. 7
This study aims to provide use cases and requirements for the following aspects of interworking between 3GPP networks and Enterprise voice services:
- Support for CS and IMS voice services interworking with IP-PBX services while at the same time maintaining full operator visibility and control of the related voice service signalling in the mobile operator's core network,
- Mobile operator control of security, manageability and operation of IP-PBX interworking function,
- Mobile operator control of availability of IP-PBX services to 3GPP mobile devices,
- Mobility between cellular and Enterprise environments, and
- Continuity when an IMS session is moved between cellular and Enterprise environments and when the IMS session is moved between mobile and fixed devices in the Enterprise environment.
- CS and IMS services,
- Enterprise specific value-added services (e.g. "short code dialling", conferencing, transfer of sessions to a soft-phone on a PC), and
- Interaction between services provided by the mobile operator and services provided by the Enterprise.
2 References p. 7
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1]
TR 21.905: "Vocabulary for 3GPP Specifications".
[2]
ETSI TS 181 019 version 2.0.0 (November 2007): "Business Communication Requirements".
[3]
ETSI TS 182 023 version 2.1.1 (January 2009): "Core and enterprise NGN interaction scenarios; Architecture and functional description".
[4]
ETSI TS 182 024 version 2.1.1 (August 2008): "Hosted Enterprise Services; Architecture, functional description and signalling".
[5]
ETSI TS 182 025 version 2.1.1 (September 2008): "Business trunking; Architecture and functional description".
[6]
TS 23.228: "IP Multimedia Subsystem (IMS); Stage 2".
[7]
TS 22.101: "Service aspects; Service principles".
3 Definitions and abbreviations p. 8
3.1 Definitions p. 8
For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.
3GPP mobile device:
An end-user device that can attach to the 3GPP core network via 3GPP access or non-3GPP access (e.g. WLAN connected via the EPS).
IP-PBX device:
An end-user device connected to the IP-PBX. In the context of this study it is assumed that an IMS subscription exists in the Mobile Operator Network for the user of the device.
Service delivery point:
Selects a particular application to be provided on an IM session.
3.2 Abbreviations p. 8
For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.
IP-PBX
Internet Protocol-based Private Branch eXchange
MNO
Mobile Network Operator
NGCN
Next Generation Corporate Network
TISPAN
Telecommunications and Internet converged Services and Protocols for Advanced Networking
4 Background p. 8
4.1 Analysis of related standardization p. 8
Work has been done in other standards bodies pertaining to mobility in Enterprise networks, notably in ETSI TISPAN ([2], [3], [4] and [5]). Although mobility aspects are present in both TISPAN Stage 1 [2] and Stage 2 [3], [4] and [5], they are very limited. Session continuity and inter-device session transfer are not addressed in TISPAN.
As already described in the previous paragraph, there is no support for 3GPP mobile devices. Support in the Enterprise network for 3GPP mobile devices (i.e., a radio access network and how it interconnects to an NGN) is not present.
The Hosted Enterprise Service, as documented in ETSI TS 181 019 [2] and ETSI TS 182 024 [4] for wireline networks, is considered completely documented. TISPAN specifications do not make any assumption as to whether the IMS is owned by a fixed operator, a mobile operator or a converged operator. Comparison of the Hosted Enterprise Service with the use cases and requirements in this technical report shows that it is very similar, but the requirement to allow the Enterprise to host the applications is not supported.
The wireline business trunking application is well understood between 3GPP and TISPAN at the Stage 1 level, and is addressed in Common IMS. TISPAN specifications do not make any assumption as to whether the IMS is owned by a fixed operator, a mobile operator or a converged operator. Analysis of the business trunking requirements that exist in Release 8 show that they do not meet the needs of the current study. The registration of the end-user device and the service delivery point are assumed, in the business trunking specifications, to be in the Enterprise network. The business trunking applications are assumed to be in the mobile operator network, and apply to the Enterprise as a whole, rather than to individual subscribers. This means that functionality such as call transfer from IP-PBX device to/from 3GPP mobile device is not supported. It is concluded that business trunking is not impacted by this study.
4.2 Enterprise-based service control p. 9
4.2.1 Introduction p. 9
In a Hosted Enterprise Services scenario, the IMS core and all services reside in the operator network and are hosted on an AS owned by the network operator. In an Enterprise-based service scenario it is possible to control at least some subscriber services from within the Enterprise via an Enterprise AS, while retaining all mobility options associated with the IMS.
Subclause 4.2.4 of TS 23.228 defines the IMS service control interface to an AS in both an internal and an external network AS.
Thus an Enterprise can behave as an external network to provide an IMS AS to host and execute services on behalf of a user in the operator network. 3GPP has not defined the authentication and security functions for this configuration.
4.2.2 Existing standards implementation p. 9
The provisions to realize Hosted-Enterprise Service (HES) are described in TS 182 024 [4].
To realize Enterprise-based service control, the 3GPP mobile device must be registered in the operator network with placement of the SIP AS within the Enterprise. This AS is called an Enterprise AS (E-AS). Subscriber profile data (e.g., initial filter criteria) can ensure that IMS acts as a service delivery point and properly invokes the E-AS for service execution.
4.2.3 Standards gap analysis p. 9
Neither ETSI TISPAN nor 3GPP currently describe the realization of Enterprise-based service control, where the AS is in the Enterprise domain.
3GPP specifications do not address the following aspects of IMS interconnection to a Third Party AS:
- Special consideration must be given to authentication and security for the service control interface between the operator network and the Enterprise. The potential role of a security gateway is TBD.
- The interface should allow only authorized service requests on behalf of valid users.
- The E-AS may need to have direct access to subscriber data in the operator network.
- The realization of service data management between the UE and E-AS is TBD.
- The nature of the security associated with the data management interface is TBD.
- It is TBD whether the E-AS will always access media resources within the Enterprise or whether the E-AS must be able to access media resources in the operator network.
5 Reference Model p. 9
The Reference Model is provided in Figure 1 below in order to help in development of the use cases and the potential requirements. The Reference Model is provided for the retail model in which the mobile operator manages and authenticates the 3GPP mobile device and authenticates the IP-PBX access to IMS services. The wholesale model, in which an Enterprise purchases 3GPP mobile devices and services in bulk, is not in the scope of this study item.
Figure 1 shows the relationship between the mobile operator and the Enterprise. The mobile operator network comprises the IMS network that connects to the PSTN and the SS7 network as well as Presence and Location information, for example. One or more 3GPP access networks are also provided by the mobile operator macro network.
The Enterprise network comprises fixed and/or wireless access networks (e.g. WLAN) and the IP-PBX. The wireless access networks can be either 3GPP access networks or non-3GPP access networks (e.g., WLAN) and the fixed access network can be any wired IP access in the Enterprise. The Enterprise network is connected to the mobile operator core network via a managed IP network using two kinds of connections:
- The Enterprise access network is connected to the mobile operator core network via managed IP network.
- The Enterprise IP-PBX is connected to the mobile operator IMS network via managed IP network.
