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Home : ITU-T Home : Study Groups : Study Group 11
Question 2/11 – Application control and signalling requirements and protocols
(Continuation of Question 2/11)


The Next Generation Networks (NGN) expression is commonly used to refer to the emerging public network infrastructures based on packet switching and routing technologies, on increasingly distributed control functional architectures, and on the use of evolving and new signalling protocols to control in particular in user sessions, identification, authentication, resource allocations and QoS, the traffic (policing, enforcement), services and applications, between various entities (e.g. media gateways, call/session servers, resource control, service control, services and application platforms) involved in NGN architectures. An objective of the NGN is to support in a secure fashion, fixed and nomadic users with a wide range of services1, from legacy telephony and Intelligent Services to new generation services, encompassing audio, data, video broadcast and conversational services, streaming services, interactive games, including multicast.
With the advances in IP based terminals and web service technologies, possibilities for the provision of new value-added services are broadened. Also, web applications and web service providers are successful and are growing in the market at a considerable rate. For these reasons, the ITU-T should consider how to exploit third-party and in-house web services within NGN applications and how to converge NGN and web based services.

As the ITU-T has led and continues to lead the development of the PSTN/ISDN, packet-based public networks and services signalling requirements, it is believed that ITU-T is the most suitable body to develop the application signalling requirements for emerging NGN architectures.

Recommendations in force for which the Question is responsible: Q.12x8 series.


Study items to be considered include, but are not limited to:

  • What are the application signalling and protocol requirements for the control of services in NGN architectures, at interfaces identified by Q.1/11 as requiring standardization? Specifically:
    • What are, among existing appropriate standards, the candidate service protocol solutions for NGN architectures?
    • What signalling protocols and profiles (if any) need to be defined for the use of such existing service protocols particularly between networks (end-to-end)?
    • What additional service protocol elements or new service protocols (if any) need to be developed?
    • What enhancements to existing Recommendations are required to provide energy savings directly or indirectly in information and communication technologies or in other industries? What enhancements to developing or new Recommendations are required to provide such energy savings?
  • What associated mechanisms are required to assure security of application signalling and control?
  • What signalling architecture and entities are required to support services and/or applications of public interest such as emergency call handling, number portability, etc.?
  • What signalling architecture is required to influence the application layer signalling, and the interworking between the application layer signalling and the network layer signalling in distributed networks?


Tasks include, but are not limited to:

  • Define the requirements for application (service control) protocols between relevant NGN entities for the interfaces identified in the NGN generic control signalling architecture.
  • Model session (or call) processing for the development of application service signalling requirements, as needed to capture the interaction between services and application (including content delivery) platforms or servers.
  • In order to provide new value added converged services in NGN, incorporate web services based functions and interfaces between them such as service registration, discovery, service composition, and service orchestration in application control in NGN.

    NOTE -- Web based application/service support functions are being defined in NGN release 2 architecture (Y.2232, Y.openenv).
  • Provide a specification of the application (services control) protocol for each interface identified in Q1/11. These protocol definitions will be in the form of references when existing specifications are applied.
  • Determine the service signalling requirements to support new value added services intended to emulate or replace existing intelligent services.
  • Determine the service signalling requirements to support new value added services taking into consideration the following:
    • NGN service requirements (Recommendation Y.NGN-SRQ developed by SG13);
    • multimedia service requirements developed by the ITU-T;
    • network control functional architecture developed by the ITU-T;
    • security requirements consistent with the security framework developed by the ITU-T taking into consideration as appropriate, the service creation tools and solutions developed by other expert bodies (e.g. OASIS, W3C, etc.);
    • technology specific requirements resulting from using different service creation tools, e.g. APIs, Web Services, etc.;
    • the concept of nomadic users.
  • Determine signalling requirements and protocol elements to resolve interactions between services.
  • Develop specifications of interfaces to adjacent layers (session) jointly with relevant Questions/groups.
  • Determine signalling requirements and protocols for application layer signalling and to support interworking between the application layer signalling and the network layer signalling in distributed networks.



  • As required.


Questions responsible for:

  • signalling and control architecture (1/11).
  • session control and signalling (3/11).
  • bearer control and signalling (4/11).
  • resource control and signalling (5/11).
  • network attachment control and signalling (7/11).

Study Groups:

ITU-T Study Group(s) responsible for:

  • voice and video IP application over cable television networks.
  • TMN aspects.
  • principles, requirements, frameworks and architectures for an overall heterogeneous network environment.
  • multimedia architecture aspects.
  • IMT2000 and beyond.

Standardization bodies:

Organizations such as: 3GPP (via ETSI), 3GPP2 (via TIA), ASTAP (Asia-Pacific Telecommunity Standardization Program), ATIS (Alliance for Telecommunications Industry Solutions), ATM Forum, DSL Forum, ETSI, IETF, MSF, W3C.

1The word “service” in this context is not meant necessarily to represent an ITU-T-defined Service.


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Updated : 2008-12-10