4 Overview

24.5243GPPArchitecture, functional description and signallingHosted enterprise servicesRelease 17TS

Hosted Enterprise Services (HES) refers to a solution where an NGN hosts all business communication capabilities to a set of endpoints connected to a plurality of access points to this network. This type of network solution is also known as IP Centrex.

In the simplest configuration all endpoints are connected to a TISPAN NGN IP-CAN. Endpoints may be SIP phones or legacy phones (Analogue or ISDN) connected to a gateway. All services by HES are provided by application servers using standard IMS procedures. User may access services that are specific to the enterprise they belong to as well as services available to any other IMS users.

In more complex configurations some of the endpoints may be connected to a 3GPP IPCAN and/or a circuit-switched network, which is itself connected to the IMS via an MGCF. Endpoints connected to heterogeneous access networks may be served by the same HES.

Endpoints served by a HES shall have the ability to setup a session, identifying the communication target by:

– a SIP URI of the form user @domain;

– an E.164 telephone number;

– a number within a private numbering plan;

– local service numbers.

With regard to supplementary services, HES have strong similarities with the provision of PSTN/ISDN simulation services, although the actual set of services may be different. Examples of services that are enabled by the architecture described in the present document are:

– All commonly used PSTN/ISDN services.

– IMS Multimedia Messaging, Presence and Conferencing services.

– Personal and Corporate Directory.

– Unified Voice mail.

– Operator assisted communications.

– Hot Line Calling.

– Abbreviate dialling.

– Line Hunting.

– Attended Communication Transfer.

– Blind Communication Transfer.

– Communication Pickup.

– Manager/Secretary filtering.

– Click to Dial.

Colour Ring Back Tone.

The sole purpose of the above list of services is to illustrate the type of services that are enabled by the architecture described in the present document. This list is not intended to be exhaustive nor is it expected that all implementations will support all of these services. The list actual of enterprise services hosted in a network is a matter for each operator to decide.

NOTE: The present document provides a number of examples where domain names are used. It should be noted that these are for information only and are not intended to place any constraint on the structure and management of domain names as long as they are globally routable.