Evolution of QoS Control in Next Generation Mobile Networks

ITU-T QoS Specifications

In order to support end-to-end QoS solutions in the converging world of Internet and Telecommunications, Next Generation Networks (NGN) have to offer a common set of IP packet transfer performance parameters and QoS objectives (Song, 2007). With this objective in mind the Telecommunication Standardization Sector (ITU-T) that coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU), started in 2002 to prepare international standards (recommendations) to help with 3G definition.

ITU-T has produced recommendations for defining standard performance parameters for packet transfer in IP-based networks, network-interface-to-network-interface (NI–NI) objectives, different QoS classes and many other standards for performance objectives and QoS parameters.

ITU-T specified the Resource and Admission Control Function (RACF) in order to provide the required NGN independence between service and transport stratum. The RACF is the element that determines resources availability in the transport layer and appropriately controls the network element. It defines different QoS control scenarios for the User Equipment (UE) with different QoS signaling capabilities, which are:

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  The UE cannot signal QoS (No signaling capability);

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  The UE has QoS SIP signaling capability;

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  The UE can reserve resources directly in the transport layer (e.g., RSVP)

QoS control in the RACF is done in pull or in push mode, which are described in the Policy and Charging Control (PCC) architecture section. Finally, the RACF is also responsible for defining Network Address and Port Translation (NAPT) control function.