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Question 4/11 – Bearer control and signalling requirements and protocols
(Continuation of Question 4/11)


It is anticipated that new bearer signalling protocols will be required to support efficiently new features of NGN, for example multicast type data transport to support IPTV services1.

In addition, Recommendations related to signalling and control of bearer technologies such as ATM and AAL2 have been created, maintained and enhanced. Specifications related to the signalling requirements and protocols for the support of ATM – MPLS network inter-working were completed as well as Recommendations concerned with the inter-working of AAL2 signalling and IP. Since there is major emphasis on the use of IP in the context of Next Generation Networks (NGN), there is an increasing need for inter-working between the existing transport services and IP or MPLS. This requires preparation of bearer signalling and control Recommendations related to IP, MPLS and other bearer technologies such as ATM, AAL2, FR, TDM and Ethernet.

Note: Bearer signalling requirements are closely related to resource control mechanisms and protocols. The bearer control and resource control operate in a separate functional plane of the NGN control architecture. This implies that the present questions shall be coordinated with the progress and result of the resource control signalling and control protocol question.

Recommendations in force for which the Question is responsible: Q.1970, Q.1990, Q.2630, Q.2761-2764, Q.2920, Q.2931 and Q.2932.1, Q.3150/Y.1416, Q.3151/Y.1417.


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

  • What new Recommendations on bearer signalling and control are required to realize stage 3, protocol development, of Next Generation Networks (NGN) standardization?
  • What new Recommendations on bearer signalling and control protocols are required to support multicast data delivery services in NGN?
  • What new Recommendations on bearer signalling and control protocols are required to support flow state aware transfer capability in NGN? This item should be progressed in close coordination with the resource control protocol question.
  • What enhancements to the existing Recommendations on bearer signalling and control should be made to facilitate the evolution of the current networks to NGN?
  • What new Recommendations on bearer signalling and control are needed to facilitate migration of legacy networks to NGN including those providing signalling for service and network interworking?
  • What associated mechanisms are required to assure security of bearer signalling and control?
  • What functional architecture and entities are required to support services and/or applications of public interest such as emergency call handling, number portability, etc.?
  • 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?


Tasks include, but are not limited to:

  • Enhance the existing bearer control and signalling related Recommendations (e.g. IP, ATM, AAL2...).
  • Develop new bearer control and signalling related Recommendations to support NGN.
  • Develop new Recommendations related to the service inter-working between ATM, AAL2, FR, TDM, Ethernet, MPLS and IP.
  • Develop Recommendations to identify requirements needed for multi-services network and service inter-working with IP.
  • Study and develop Recommendations to identify requirements for service dependent bearer control and signalling related mechanisms.
  • Develop Protocol Implementation Conformance Statements (PICS) for selected protocols.

Consideration should be given to power saving in relation to climate change.



  • I.555, Q.1970, Q.1990, Q.263x and Q. 29XX series, Y.2121.


  • Questions related to RACF architecture, requirements and protocols (3/13, 4/13, 5/11).

Study Groups:

ITU-T Study Group(s) responsible for:

  • user plane interworking aspects.
  • performance aspects.
  • Ethernet aspects.
  • security aspects.
  • mobility aspects.

Standardization bodies:

Organizations such as: IETF, ETSI, Metro Ethernet Forum, and IP/MPLS Forum on topics of mutual interest.

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


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