Integrated IMS Core

In fully distributed IP Multimedia Subsystem networks, MetaSphere acts as a pure IMS Application Server, supporting the IMS Service Control (ISC) interface to separate session control function (CSCF).

Alternatively, MetaSphere can be deployed with integrated session and gateway control functions. This simpler configuration, which also includes an embedded Home Subscriber Server (HSS) component, enables rapid deployment and reduces complexity while retaining an upgrade path to full IMS.

Session Control

The optional integrated Session Control function (CSCF) is concerned primarily with call control and routing but it also performs a number of other critical functions.

• Routing calls to Application Servers - detection of trigger points and routing of SIP messages to Application Servers as required.
• Routing calls to trunks - number analysis, translation of numbers via off-board data sources to support Local Number Portability and Non-Geographic Number mappings, and selection of an outbound TDM or SIP trunk based on a wide range of call attributes.
• Billing - generation of call detail records in standard formats, and transmission of billing files to off-board storage.
• Lawful intercept - delivery of call content and call data to law enforcement agencies in accordance with legal requirements on service providers.
• SIP registration - processing of inbound registration requests from SIP endpoints and storage of contact address details.
• SIP call forking - routing of calls to multiple SIP endpoints that share the same Address of Record.

Gateway Control

The optional integrated Gateway Control function (AGCF/MGCF) enables MetaSphere applications to be deployed in networks that require TDM connectivity. It performs the following functions:

• Protocol interworking - translation of TDM signaling protocols including SS7 / C7, ISDN, MF and GR-303 into SIP.
• Access gateway control - supporting all kinds of TDM access including POTS, ISDN and CAS via access gateways, including the Universal Media Gateway as well as a wide range of third-party access gateways, using H.248, MGCP or NCS.
• Trunk gateway control - supporting all kinds of TDM trunks including SS7, ISDN and MF via trunking gateways such as the Universal Media Gateway or a variety of third party trunking gateways, using H.248, MGCP or TGCP.

Gateway Control is not needed in distributed IMS networks with a separate gateway control function, or in pure VoIP networks that rely exclusively on SIP-based connectivity to the PSTN.