## 5 Performance Evaluation
### Comprehensive Evaluation  
As shown in Figure 10, we perform experiments on the European Academic Network (GEANT2 [51]) topology, with two additional data source nodes (S1 and S2) and two receiver nodes (C1 and C2) positioned at the network edge. E1 to E4 serve as gateway nodes connecting to IP terminals, and our RBMM-based reordering module is deployed on E3 and E4. Based on the study in [14], we select 10 relay nodes to establish 10 transmission paths. By adjusting the bandwidth distribution between nodes, we simulate various network conditions to generate various experimental scenarios. The default bandwidth between nodes follows a uniform distribution, varying from 25-35 Mbps to 25-115 Mbps in 10 Mbps increments. Delays are randomly set to either 1 ms or 2 ms. The data flow composition and threshold update interval are configured similarly to the experiments in Section 5.1. The access link bandwidth and delay between the data source and destination nodes are set to 200 Mbps and 1 ms, respectively. Due to changes in the topology and path parameters, the buffer capacity and the marking time for PHRD flow need to be adjusted. We use a simple Python program to randomly generate path parameters for 50 different topologies and calculate the values for \(B=\text{FlowSize}_{\text{max}}+\sum_{i=1}^{\ell}\text{BDP}_{i}\) and \(T=\frac{2}{\ell}\sum_{i=1}^{k}\text{Delay}_{i}\). The average values are used as parameters for the experiment. Specifically, \(T\) is set to 22.46 ms and 25.58 ms in E3 and E4, respectively, and the buffer size configurations are detailed in Table 5.  
Figure 9: Flow completion time for different flow sizes: (a) Scenario 1; (b) Scenario 2; (c) Scenario 3; (d) Scenario 4. Throughput and data transmission completion time are key metrics for assessing user experience. To evaluate the overall effectiveness of the proposed reordering and buffer management method, we measure the average throughput and transmission completion time of IP terminals across various experimental scenarios, both with and without the reordering mechanism enabled. For consistency, we measure transmission completion time by transmitting 500 identical data flows (approximately 64.80 MB) in each scenario. Additionally, we test single-path transmission performance to determine whether IP terminals experience improvements when accessing the ICN multipath system. The transmission performance under the RCBRB method is also evaluated. The experimental results are shown in Figure 11. With higher bandwidth, throughput increases and transmission completion time decreases when the reordering function is enabled at the gateway node, consistently exceeding the performance of single-path transmission. This demonstrates that with the proposed method, IP terminals experience performance improvements when accessing the ICN multipath transmission system through the gateway. In contrast, when the reordering function is disabled, the sliding window mechanism for out-of-order correction at the IP terminal is ineffective in handling the complex out-of-order issues caused by ICN multipath transmission. As a result, throughput remains low, and transmission completion time is prolonged, often performing worse than single-path transmission. In high-bandwidth scenarios, performance further deteriorates due to severe out-of-order packet delivery and frequent retransmissions. Therefore, enabling the reordering function at the gateway node is essential for IP terminals to fully leverage the advantages of the ICN multipath transmission system. Without it, not only is there no improvement in performance, but the IP terminals may also experience a significant burden. When using the RCBRB method, throughput and transmission completion time are comparable to those of RBMM in bandwidth distributions ranging from 25-35 Mbps to 25-75 Mbps. However, in scenarios with larger bandwidth distributions, the performance of the RCBRB method begins to lag behind that of RBMM. This is primarily attributed to the increased data scale within the  
Figure 10: Simulation Topology 2.