# Performance of 5G Trials for Industrial Automation
## 4 Evaluation Setup  
### Measurement Setup  
In order to carry out latency and reliability measurements systematically in realistic application scenarios, we have developed an FPGA-based tool that allows the generation of configurable industrial automation protocol traffic. Having the possibility to configure the periodicity and data sizes of the individual messages of the selected protocol for traffic streams using the FPGA-based tool, various application scenarios using Layer-2 (e.g., PROFINET) and Layer-3 (e.g., UDP over IP) have been evaluated. The FPGA-based tool not only allows the emulation of user-configurable application traffic in a highly precise manner but also allows latency measurements to be conducted in the FPGA hardware with sub-microsecond-level accuracy. The measurement setup is illustrated in Figure 3.  
Figure 3: Measurement setup for on-premises 5G network on the shopfloor, where an FPGA-based tool is used for industrial traffic emulation and latency measurements. Source: Ericsson. Figure 2: Selected parts of the URLLC testbed. The middle rack includes the RAN and core network with a phased-array antenna module on top. On the far right, the UE prototype is visible also with an antenna mounted on top. As industrial automation applications do not necessarily have traffic with specific round-trip behavior from the 5G user equipment (UE) to the edge server and back, simple round-trip timing (RTT) measurements (such as ICMP ping measurements) have not been considered. Instead, separate uplink (UL) and downlink (DL) one-way measurements of the user data traffic have been used in our measurement campaign in order to observe the end-to-end (E2E) latency behavior of a 5G network for edge applications. In Figure 3, a bidirectional arrow is used to indicate the traffic flow from the 5G device to the base station radio for UL, while the opposite indicates the DL direction. The setup allows the UL and DL directions to be tested separately. As the support for native Layer-2 communication over 5G is not yet typical in commercial 5G devices and networks, we applied Layer-2 data tunneling over IP-based tunneling on Generic Routing Encapsulation (GRE) for the tests involving PROFINET traffic. The direct transmission of Ethernet frames over 5G has only been carried out in the URLLC testbed. In one set of experiments, we empirically evaluated the benefits of using FRER, which is part of the TSN standard suite. FRER was designed for fixed Ethernet networks to provide, e.g., resilience against equipment failures. In the FRER scheme, the application traffic with specific VLAN tags is replicated over two separate transmission paths followed by potential elimination at the receiving end. While the replication of the application traffic on the redundant paths consumes more resources, FRER provides resilience against transmission failures on one of the paths. FRER can also be applied to wireless networks such as 5G networks. It can be used to establish redundant network paths via different independent network nodes [13] and can provide protection against, e.g., node failures. When the same 5G network nodes are used, FRER can still protect against, e.g., UE failure or performance variations. In addition, FRER can improve the achievable reliability for meeting certain latency bounds whenever wireless links have larger latency variations since the end application can utilize the earliest data received via the separate FRER paths. A simplified setup that can be used for FRER tests over the 5G system is illustrated in Figure 4, where the application data (with specific IEEE 802.1Q VLAN tags to separate from background traffic) are transmitted over two user-plane functions using two UEs. Please note that for simplicity, Figure 4 does not show the Layer-2 tunnel setup or the traffic flow directions.