# Programmable Data Plane Applications in 5G and Beyond Architectures: A Systematic Review
## 4 Findings and Discussion
### Characteristics of the Reviewed work
[86] propose a P4 switch-based network slicing framework that can handle time-sensitive tasks such as overload and underload detection, rerouting, and state transfer. A custom slice management protocol is implemented using a SM header to enable efficient slice management. [PERSON] et al. [87] propose a content permutation algorithm for handling IoT traffic in 5G networks. Their approach involves implementing the algorithm in P4 switches, where packet payloads are split into code words and shuffled according to a secret cipher generated at an SDN controller. [PERSON] et al. [91] propose a virtual testbed for 5G security experimentation, including a P4 switch for prototyping defense mechanisms and developing traffic rules. The defense mechanism uses a modified countmin sketch data structure to detect UEs exceeding a threshold, limiting the maximum bit rate with a TrTCM meter. FrameRTP4 [92] is a framework that aims to deliver real-time attack detection and mitigation mechanisms in network slicing. For this, it provides a customizable P4 program that includes a service function chain to enable the lifecycle management of slices. Additionally, the P4 program deploys a monitoring system, namely SFCMon, that uses bloom filters and sketches to support a mechanism to track network flows. [PERSON] et al. [93] describe a 4G/5G testbed where P4 switches are used to perform in-band network telemetry. The telemetry data is sent to a collector that gathers information about traffic flows and switch queue status. This approach enables end-to-end performance testing to enhance quality of experience (QoE) for end-users. [PERSON] et al. [94] propose a P4-based INT mechanism for 5G and beyond networks. The proposed mechanism allows for end-to-end monitoring using headers that incorporate information on latency and geolocation, thereby enabling steering policies without the need for SDN controller intervention. SDNPS [95] is an SDN framework that utilizes P4 switches and implements an INT data packet format to support mMTC and URLLC slices. The INT data, which include queue occupancy, link throughput, and processing delay, are recorded in data packets forwarded by P4 switches and collected by an INT data collector module in the application plane. TurboEPC [96] presents control plane offloading of a small amount of user state to MAts in P4 switches. These devices process a subset of signaling messages e.g., S1 release and service request. SMARTHO [97] implements a smart handover procedure using programmable switches between 5G CU and DU. For this purpose, switches spoof the behavior of UEs and perform resource allocation in advance. INCA [98; 99] utilizes the SRv6 protocol for traffic identification and chaining. This solution is deployed using P4 software switches and Smart NICs, and it is capable of parsing SRH, TEID, and QoS ID. GRED [100] presents a data placement and retrieval service for MEC to enhance routing path lengths and forwarding table sizes. This mechanism is implemented on a P4 device, which is not specified by the authors. HDS [101] is a hybrid data sharing framework for hierarchical MEC. The data location service is divided into two parts: intra-region--based on a cuckoo summary--and inter-region, using a geographic MDT-based routing scheme. The authors did not provide any information on the specific programmable device utilized in their implementation. [PERSON] et al. [102] propose a coding scheme implemented in P4 switches for SDN-based 5G networks. This coding scheme performs arithmetic aggregation based on the residue number system (RNS) for multiple data packets generated by mMTC-IIoT devices. [PERSON] et al. [103] present an in-network approach for adaptative beamforming towards the UE. In this approach, the UE periodically reports its location to a P4 hardware switch, which uses this information along with the base station information to compute the angle required to reconfigure the beam between the base station and the UE. The angle computations are approximated with MATs to improve computational efficiency.