# Programmable Data Plane Applications in 5G and Beyond Architectures: A Systematic Review
## 4 Findings and Discussion
### Characteristics of the Reviewed work
Additionally, active monitoring and security capabilities are included in the data plane pipeline. [PERSON] et al. [68] present an implementation of a UPF offloaded to a P4 switch. The demonstration includes GTP-U encapsulation/decapsulation functions, automatic forwarding and steering functions, and configurable monitoring of selected GTP flows' performance, such as the online latency experienced at a node. Additionally, in [89], the same authors introduce use cases that showcase the potential of programmable data planes in 5G SDN networks. P4 switches are utilized to provide advanced functionalities such as traffic engineering, cybersecurity, multi-tenancy, 5G offloading, and telemetry. [PERSON] et al. [69] evaluate various UPF implementations in an end-to-end 5G standalone test network, including a P4 switch based UPF. The Kaloom 5G UPF [70] employs an Intel Tofino ASIC and offloads QoS processing (i.e., bit rate policing) and GTP processing to the programmable hardware. Additionally, it supports network slicing and SRv6. Metaswitch Fusion Core [71] is a private 5G Core designed for MEC. It features a UPF that carries out packet classification, routing, and forwarding tasks. The platform includes a cross-compiler that facilitates the use of the P4 programming language for defining UPF pipelines. [PERSON] et al. [75] and [PERSON] et al. [76; 77] present a solution that aims to ensure performance isolation for network slicing, specifically with regards to bandwidth and delay guarantees, in order to support three Industry 4.0 case scenarios, such as digital twin, telemetry, and remote support. The proposed implementation integrates P4- and OpenFlow-based switches at the transport network data plane. The former deploy packet marking and meter coloring actions to provide the necessary network slicing functionality. [PERSON] et al. [78] propose a comprehensive framework for achieving end-to-end network slicing in 5G networks. In their approach, P4 switches are utilized to enable transport network slicing, allowing for the enforcement of slice identification and bandwidth control in accordance with the QoS requirements of each slice. [PERSON] et al. [79] propose a network slicing framework for an eHealth use case in the 5G context. The framework employs P4 FPGA boards to perform traffic parsing and classification, as well as QoS control, for video transmission. To enable QoS control, an API is utilized to specify the priority of the network traffic processed by the board. FestNet [80] is a sliced transport network, which utilizes P4 switches to implement a virtualized programmable data plane (vPDP) and a two-layer design. This enables the provision of network slicing and live slice mobility functionalities. FSA [81, 82] provides dynamic network slicing by utilizing the wireless schedule to identify the slice for each fronthaul packet. This architecture uses P4 switches and enables packet prioritization. [PERSON] et al. [83] propose an optical 5G inter-data center architecture that utilizes a P4 FPGA board as server-edge processor. The architecture facilitates network slicing and inter-data center communication. P4-TINS [84] is a solution that provides bandwidth guarantee and management for network slices. The solution adopts a two-level priority queue framework in which a meter serving each slice receives all traffic belonging to that slice and dispatches packets to high- and low-priority queues. This ensures that there is no interference between slices. AHAB [85] is a hierarchical per-user bandwidth allocator designed for network slicing. This solution operates directly in the data plane using a P4 switch which dynamically adjusts the user bandwidth limit for each slice in real-time. It adopts a maximum-minimum fairness approach that considers the bandwidth demand of all users across all slices, thereby avoiding the need to store per-user state in switch memory. [PERSON] et al.