# QoS Management and Flexible Traffic Detection Architecture for 5G Mobile Networks
## 2 General Architecture Considerations and Related Works  
The next generation of mobile networks will bring deep modifications to the mobile architecture, with the requirement of maintaining interoperability with the previous generations of mobile technology. 5G networks are evolving to incorporate NFV, to move the control to the edge of the mobile network, and to be SDN-capable, increasing the separation between the control and data planes [13]. In [14], an interesting overview of the development of software-defined mobile networks was provided, and the contributions were divided into three main issues: radio access network, with the main objective to coordinate and control the radio resource; mobile control, focused on orchestrating the packet processing, mobility, billing, and service provisioning; and Internet or traffic routing, for which the main target is effective and efficient packet forwarding with the appropriate QoS characteristics. The end-to-end mobile network solution must combine all these objectives to achieve the required 5G performance. Due to it being predominantly a survey work, the work in [14] accordingly lacks a specific approach in some important topics, nor does it present tests or possible validations of the presented subjects. In addition, the work in [14] focused on a mobile access network, but it still had a gap in the mobile core network contributions. This paper proposes an architecture that applies SDN to achieve a clear separation between the user and the control planes of the PGW and the SGW mobile elements [15; 16; 17; 18]. The SGW and PGW user plane is implemented by simple OpenFlow [19] switches (called OF-Switch and OF-GW, respectively), and the SGW and PGW control plane is implemented separately in a logical element called PGW-C (PDN Gateway Control). The controller is responsible for managing the data plane of all OF-GW and the physical mobile elements such as the router and switches (implemented as OF-Switches), which are used to transport packets through the mobile core and backhaul (see Figure 1). These separation criteria are applied in 5G [1; 20; 21], where the user plane of PGW is implemented in a new element called UPF (User Plane Function) and the control plane of PGW is implemented in a new element called SMF (Service Management Function). As proposed in [22; 23; 24; 25] and in the recently-presented 5G architecture, the NFV concepts are incorporated into the mobile architecture for scalability reasons and demand variation adaption. The election here consists of implementing the control plane of 4G logical mobile elements: PGW-C, MME (Mobility Management Entity), PCRF (Policy and Charging Rules Function), HSS (Home Subscriber Server), and the controller, or even implementing the control plane of 5G logical mobile elements [1; 21]: SMF, PCF (Policy Control Function), AMF (Access and Mobility Management Function), and UDM (Unified Data Management) as a Virtual Network Function (VNF) over a cloud environment. On the other hand, the OF-Switch, OF-GW, and base station (4G eNB or 5G gNB) are implemented as physical elements distributed over the mobile domain (see Figure 1). In [26], a description of how the SDN and NFV concepts can be combined to build a software-defined wireless network was presented. In this work, the implementation of the control plane of the mobile network entities as NFV in a centralized way was proposed, while the data plane was implemented in a distributed way by simple elements managed by a Controller. The described implementation is general and provides only a high-level interaction between the main mobile architecture elements. In particular, it is noted that the QoS requirements are triggered by UE requests, and the mechanisms can be considered fairly centralized. Our proposal uses the SDN and NFVconcept in a similar way, but exploring more deeply the way it can be implemented. The detection mechanism presented here is distributed and does not require that the UEs trigger QoS requests.