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Question 11/12

Question 11/12 – Performance interworking and traffic management for Next-Generation Networks
(Continuation of Question 11/12)


There is a continued need for guidance on general transmission planning and keeping it up with technological evolution. Especially in light of the migration of modern telecommunication networks towards packet-based technologies (NGN), replacing traditional circuit-switched systems, guidance is needed on transmission planning with respect to heterogeneous and interconnected networks.
With the increasing industry focus on Next-Generation Networks (NGN), there is a need for guidance on the associated end-to-end QoS, performance and resource management issues for multimedia services (e.g. voice, video, and data) carried by NGN's, in order to ensure customer satisfaction. This includes interworking aspects between different networks (e.g. cellular, wireless, wireline) and packet-based technologies (including IP, ATM, Ethernet and MPLS), as well as apportionment of performance objectives between different network segments.
In TDM networks, management of transmission impairments has been based on a simple but effective concept: networks have been divided into a chain of network sections and impairment budgets allocated accordingly. Responsibility for management of end to end QoS in Packet networks is less defined and there are a wider range of provider techniques available to achieve end to end service quality. In some cases multiple networks may be available to the end devices simultaneously. Services must therefore be considered as applications executed in the terminal devices, which today have an increased contribution to the quality of experience. Consequently the transport networks are less likely to solely achieve end-to-end QoS, but can provide sets of transport behaviours or classes, selectable by the application, which enable QoS differentiation.
Performance interworking issues requiring consideration include but are not limited to:
End to end multimedia performance interworking and interoperability issues, including
  • definition of interworking functions
  • impacts of interworking functions
  • performance objectives across multiple networks and technologies.
With NGN the differences between voice (voiceband) services and data services are becoming blurred. For transmission planning with respect to the network performance of services the point of interest is whether the connection will be transparent and what delay will occur. This makes it more important to study the effect of delay on data services/application. For the time being there is no detailed information on this topic or even a planning tool available.
Furthermore due to the migration towards packet-switched networks the functionality and intelligence of the networks is shifting towards the terminal. The impacts of this development on transmission planning need to be studied and specified. Guidance is needed on how voiceband data and multimedia services can be planned reliably in NGN infrastructures.
As IP technology is introduced into the PSTN, attention is being given to the TCP/IP protocol suite for carrying voiceband services (VoIP). This technology will affect the way that operators think about transport and switching (routing) in their networks, and will have a major impact on the range of services that are available to end users. Issues and guidelines for transmission performance necessary to ensure high end-user satisfaction must be reconsidered in light of this shift in the basic technology of speech and voiceband services.
The following Recommendations, in force at the time of approval of this Question, fall under its responsibility:
G.101, G.102, G.103, G.105, G.108, G.108.1, G.108.2, G.109, G.111, G.113, G.114, G.115, G.116, G.117, G.120, G.121, G,122, G.126, G.131, G.136, G.142, G.172, G.173, G.174, G.175, G.176, G.177, P.11, I.352, I.354, I.358, I.359, I.371, I.378, Y.1221, Y.1222, Y.1223, Y.1530, Y.1531, Y.1542.


Study items to be considered include, but are not limited to:
  • Transmission planning for voice, data and multimedia services taking into account that end-to-end connections are established via heterogeneous and interconnected networks with different transmission technologies.
  • Studying the effects of the transmission delay on services including multimedia.
  • What guidance can be provided in transmission planning for the interconnection of evolving Networks?
  • What are the main performance parameters in end-to-end communication paths and how can the values of performance parameters be managed across multiple network segments?
  • How can the cases of multiple concatenated networks be considered, based on a flexible apportionment of transmission impairments?
  • What are the interworking requirements necessary to support interfacing between the many combinations of wireless and wireline networks sufficient to enable service providers to comply with end to end performance objectives for the QoS classes and to take into consideration the network performance parameters across network sections?
  • How does application based differentiated traffic management affect network QoS planning?
  • What new or revised transfer capabilities and traffic descriptors should be defined for packet-based networks?
  • What traffic engineering methods and tools should be specified for packet-based traffic?
  • What traffic engineering methods and tools can be recommended for resource management and congestion control in hybrid network configurations?
  • What reference models and parameters should be used as a basis for specifying and measuring the call processing performance of IP-based networks?
  • Studying the effects in cases of service handover in order to elaborate transmission planning guidelines and performance considerations (like e.g. allowable packet loss and handover latency during handover).
  • Determination of the impairment effect of each new coding algorithm, so that it can be considered in the context of Recommendation G.113.
  • Considerations on how to help measure and mitigate climate change.


Tasks include, but are not limited to:

  • Analysis of end to end QoS aspects of interworking between different network sections (e.g. cellular, wireless, wireline networks).
  • Analysis of application based differentiated traffic management aspects in order to identify potential impact on end-to-end QoS planning for a wide range of services.
  • Revisions of ITU-T G-Series Recommendations as may be needed to accommodate end to end QoS interworking between different network sections (e.g. cellular, wireless, wireline networks).
  • Development of new Recommendations specifying the performance of interworking between different network sections (e.g. cellular, wireless, wireline networks).
  • Development of new Recommendations specifying performance parameter apportionment functions and methods between different network sections (e.g. cellular, wireless, wireline networks).
  • Update of Recommendations Y.1221 and Y.1222 to include traffic engineering methods and traffic engineering tools for IP and Ethernet traffic.
  • Creation of a new Recommendation on resource management and traffic control in hybrid network configurations.
  • Frequent update of Appendix I to G.113.
  • Creation of a new Recommendation, providing guidance on transmission planning and performance for service handover.
  • Creation of new Recommendations on transmission planning aspects as needed.

An up-to-date status of work under this Question is contained in the SG 12 work programme



  • G.100 – G.149, G.170-series, G.1000-series, I.350 series, I.360 series, I.370 series; Y.1541. I.350, I.351, I.353, I.356, I.358, Q-series Recommendations defining layer 3 call processing protocols


  • 3/12, 8/12, 12/12, 13/12, 14/12, 17/12

Study Groups

  • ITU-T SG 9, SG 11 SG 13, SG 15, SG 16

Standardization bodies

  • ETSI STQ, ATIS PRQC, IETF, Broadband Forum, MEF