ct QoS provisioning and those that have higher flexibility regarding QoS). The NGN helps the traditional telecom operators (which also have become the main ISPs) to deliver new services to their customers with less capital investment and reduced operational costs, References better regulation, and higher QoS. In conclusion, there are many types of business and regulation challenges facing NGNs, but business opportunities are varied, unlimited, reliable, and promising in the long term, especially with the continuous development of NGN toward future networks based on network virtualization and slicing, with QoS provided per network slice, service need, or connection request. References 1 Janevski, T. (2014). NGN Architectures, Protocols and Services. Chichester: Wiley. 2 ITU-T Recommendation Y.3001, Future Networks: Objectives and Design Goals, May 2011. 3 J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler, SIP: Session Initiation Protocol, RFC 3261, June 2002. 4 ITU-T Recommendation Y.2021, IMS for Next Generation Networks, September 2006. 5 ITU-T Recommendation Y.2808, Fixed Mobile Convergence with a Common IMS Session Control Domain, June 2009. 6 3GPP TS 23.228, IP Multimedia Subsystem (IMS); Stage 2 (Release 12), June 2013. 7 IETF RFC 7826, Real-Time Streaming Protocol Version 2.0, December 2016. 8 IETF RFC 4566, SDP: Session Description Protocol, July 2006. 9 IETF RFC 3550, RTP: A Transport Protocol for Real-Time Applications, July 2003, 10 IETF RFC 6733, Diameter Base Protocol, October 2012. 11 IETF RFC 5624, Quality of Service Parameters for Usage with Diameter, August 2009. 12 IETF RFC 5866, Diameter Quality-of-Service Application, May 2010. 13 ITU-T Recommendation Y.2111, Resource and Admission Control Functions in Next Generation Networks, November 2011. 14 ITU-T Recommendation Y.2171, Admission Control Priority Levels in Next Generation Networks, September 2006. 15 ITU-T Recommendation Y.2113, Ethernet QoS Control for Next Generation Networks, January