## 5 Performance Evaluation
### Basic Performance Evaluation  
As shown in Figure 5, we first implement a multipath transmission system with random scheduling in a simple topology. The ICN routers (E1, E2, R1-R5) operate an identifier-based ICN protocol stack, while the edge gateway nodes (E1, E2) are equipped with reordering buffers. The data source (S) and receiver (C) are standard IP network nodes. To simulate different disorder patterns caused by variations in path parameters during transmission, we design four experimental scenarios, as listed in Table 2. Each scenario features a combination of bandwidth and latency with varying degrees of difference. Figure 5: Simulation topology 1. Table 3 outlines the parameter settings of our simulation experiments. To better represent the heavy-tailed characteristics of real-world internet traffic, we model the size of data flows using a Pareto distribution, following the empirical findings in [47]. According to its recommendation, the \(\alpha\) parameter of the Pareto distribution is dynamically adjusted within the range of [0.606, 0.726], while the \(\beta\) value is set to 92. Each data flow contains between 128 and 2048 packets, with packet sizes varying from 64 to 1024 bytes, resulting in total flow sizes ranging from 8 KB to 2 MB. To meet the reordering service demands of large flows and maintain transmission efficiency, the reordering buffer size is configured as the sum of the bandwidth-delay products (BDP) across all transmission paths and the size of the largest flow. The update interval for the reserved buffer threshold, \(\Delta t\), is set to 10 ms, with the EWMA parameter \(\gamma\) set to 0.8 [48]. A flow exceeding the size threshold of \(\alpha\cdot\theta\), which remains in the buffer for longer than twice the average link delay, is marked as a PHRD flow. To ensure that bandwidth constraints only occur within the network, the default bandwidth and delay for the access links between the data source and the receiving node are set to 100 Mbps and 1 ms, respectively. Except for the reordering buffer at the receiver-side gateway node, which organizes packets using a Red-Black Tree structure, all other routers in the network use the default FIFO queuing model. Additionally, the reserved buffer size is fixed at 10% of the total buffer capacity when there is 0 or 1 flow in the buffer to prevent abrupt fluctuations during the startup and termination phases. During transmission, each flow has a 20% probability of selecting 2 paths, a 35% probability of selecting 3 paths, a 30% probability of selecting 4 paths, and a 15% probability of selecting 5 paths. In the subsequent experiments, we first investigate the sensitivity of the dynamic threshold control parameter through its impact on network throughput. After determining the optimal parameter, we proceed with performance evaluations focusing on packet queuing delay and flow completion time. Based on our research into buffer partitioning and replacement strategies, we design the following comparative experiments:  
* Simple Complete Sharing (CS): No buffer management is applied, allowing flows to use the buffer until overflow. Packets exceeding the buffer capacity are directly forwarded to the terminal. This experiment serves as a baseline to illustrate the worst-case scenario without management. * Static Threshold (ST) + Random Flow Smallest Sequence Number Forwarding: A static threshold of 10% of the buffer capacity is set. When the threshold is reached, a random flow is selected, and the packet with the smallest sequence number in its Red-Black Tree is forwarded. This experiment is compared with the dynamic threshold (DT) mechanism to emphasize the importance of dynamic buffer size adjustment. * DT + Random Flow Smallest Sequence Number Forwarding: The classical DT calculates the reserved buffer size. Once the threshold is reached, a random flow is selected, and the packet with the smallest sequence number in its Red-Black Tree is forwarded. This experiment illustrates the performance of the original DT in this study.