QoS differentiation for services offered over IP networks (this includes most of the services). Due to a more complex approach for QoS provisioning and its regulation in IP-based networks, there are different challenges to different parties in the values chain, which include the following: SDOs. These organizations do not define the QoS standards by themselves only, but they are typically industry stakeholders. If stakeholders wish to not invest resources in globally recognized QoS standards, then there is not very much for SDOs to do in that regard. Network equipment manufacturers. They typically rely on QoS requests from network and service providers. However, they also include the standardized QoS protocols and mechanisms in their equipment (e.g. switches, routers, gateways), which can be used optionally by different providers. Terminal device manufacturers. They are directly confronted with the mass end-users' market of today. While in PSTNs the terminal related standards were targeting mini- mum requirements regarding the network interface, in an all-IP network the terminal standards may also target provision of high-level end-to-end QoS toward the cus- tomer. In mobile networks the terminals (e.g. smartphones) have the highest influence on QoS because for many multimedia services QoS performances heavily depend on the terminal capabilities and supported radio interfaces (including supported fre- quency spectrum, access techniques, and hence bitrates in downlink and uplink). Network operators and service providers. The network providers (i.e. national telecom operators) make huge capital investments in both infrastructure and access technolo- gies. The network operators react to QoS issues by investing in new capacity or by optimization of deployed network infrastructure. Additionally, network operators use various traffic management tools to provide the desired QoS level to different services. According to ITU guidelines [2], QoS regulation requires the NRA to perform the following activities (Figure 9.2): 