## 5 Simulation Setup  
The proposed schemes are evaluated with MATLAB programs. To verify the generality of the schemes, we employed the network topologies COST239 and ARPA2 [37], which are widely used topologies in evaluations of carrier networks [36]. Figure 3: Frame preemption mechanism for enhanced common public radio interface (eCPRI) streams in the Ethernet-based fronthaul bridged networks (EFBNs). IEEE 1914.3 [20] defines the two encapsulation techniques (namely structure-agnostic and structure-aware) to carry the CPRI/eCPRI streams by mapping in the Ethernet frames. In this work, we employed the structure-agnostic mapping scheme to encapsulate the eCPRI packets in the standard Ethernet frames. In this scheme, eCPRI packets are mapped in the Ethernet frames without the knowledge of framing protocols, while in structure-aware encapsulation, eCPRI packets are broken into antenna-carrier and control-data components to transport through the Ethernet switching nodes. The RRHs connected to the bridging nodes are configured to support the different eCPRI line rates. The RRHs periodically transmit the eCPRI-based bursty traffic toward the BBU pool, which is independent of the end user's data rate and reserves the MFH bandwidth, even when no user is connected with the RRHs. Each RRH is configured to support a single eCPRI line rate randomly from the eCPRI line rate options 1 to 7 such as 0.61 Gbps, 1.22 Gbps, 2.45 Gbps, 3.07 Gbps, 4.91 Gbps, 6.14 Gbps, and 9.83 Gbps, respectively [10]. In contrast, an eCPRI line rate represents the number of IQ samples that an MFH link can transport between the RRH and the BBU pool [11]. Based on the configured line rates, the RRHs could transmit 50 to 100 Gbps of cumulative eCPRI traffic toward the BBU pool. However, for generality, loads are randomly connected to the bridging nodes. This is because the distribution of RRHs is determined by the demand distribution in reality [10; 18]. In the considered EFBNs, each RRH sends a burst of 9000 bytes after every 2 ms toward the BBU pool based on [38] for the backward compatibility with the long term evolution-advanced (LTE-A) standards. The maximum size of the Ethernet payload is considered to be 1500 bytes. The RRHs are connected to bridges through a link of 0.2 km length at the bandwidth of 10 Gbps. It is considered that all the bridges are located within an area of 20 km\({}^{2}\). The link distance between the consecutive bridges is randomly determined from 1 to 5 km similar to realistic networks [18]. The link bandwidth between two bridges is considered to be 10 Gbps. In each topology, the BBU pool is connected to a node where a maximum number of links are connected. In the considered scenarios, the BBU pool is connected to the bridging node-3 and to the bridging node-7 in COST239 and ARPA2 topologies, respectively. The link bandwidth between the BBU-DN is assumed as 100 Gbps and the link length is assumed as 0.2 km. Figure 4 shows the experimental setup to reflect the aforementioned configurations and parameters for simulating the fronthaul scenarios. As shown in Figure 4a,b, the RRHs are configured to support the cumulative eCPRI traffic of approximately 50 Gbps and 60 Gbps for COST239 and ARPA2 topologies, respectively. Analogous to this, the cumulative eCPRI traffic loads of 70 to 100 Gbps are formulated during the simulations for both topologies by randomly connecting the RRHs with different nodes at different line rates. The link length between the RRH bridges and DN-BBU pool is considered as 0.2 km. The link lengths between bridges and bridges would be determined randomly from 1 to 5 km. The bandwidth of all the links is considered to be 10 Gbps except for the link between the DN and the BBU pool, which has 100 Gbps of bandwidth. It is assumed that all the bridges of the fronthaul networks are capable of implementing the frame preemption principles and policies, as discussed in Section 4.2. However, the frame preemption introduces a certain overhead for the preempted frames, which could impact the performance.