## 4 Experiment
### Experimental Results
This decrease is attributed to the higher queuing delays and increased likelihood of congestion as the number of packets grows, leading to more packets failing to meet the time-sensitive transmission requirements. The SPF (Shortest Path First) algorithm exhibits a relatively higher transmission success rate due to its characteristic of selecting paths with the shortest distance, which helps in routing packets through nodes with shorter propagation paths. While some congestion may occur, most packets are guaranteed timely delivery. On the other hand, the ELB (Equal Load  
Figure 12: (**a**) The total task burden as a function of the number of iterations. (**b**) The maximum completion time of forwarding as a function of the number of iterations. Balancing) algorithm, which utilizes load-balancing mechanisms by perceiving neighboring node states and alternative paths, reduces the overall task burden. However, it may struggle to meet the transmission requirements of time-sensitive tasks, resulting in the lowest success rate. PSFRS proposed in this paper, leveraging reinforcement learning, balances the overall load and avoids nodes with excessively high forwarding delays. This approach satisfies the time-sensitive propagation delay requirements while effectively reducing the overall task burden. The most critical evaluation metric for satellite routing algorithms is the end-to-end delay, which is an important performance indicator for assessing Quality of Service (QoS) in computer networks. In this paper, based on the format of time-sensitive business packets, data packet types were classified into two categories; the first type is packets that are only transmitted within the subnet, where both the source and destination nodes are within the subnet, and the second type is packets that require cross-span transmission, where the source node is within the subnet and the destination node is outside of the subnet. Ten samples were taken from each of these two categories, totaling twenty data packets, with packet numbers marked in ascending order based on the number of hops traversed. For performance evaluation, comparisons were made with the SPF algorithm in terms of end-to-end delay, as shown in the simulation results in Figures 15 and 16. Figure 14: The transmission success rate of different algorithms as the number of data packets increases. Figure 13: The solving time of different algorithms as a function of the number of data packets. Figure 15 indicates that at lower hop counts, there is not a significant difference in performance between the scheduling algorithm in this paper and the SPF algorithm. In some cases, the end-to-end delay of the SPF algorithm is even shorter than that of the algorithm presented in this paper. This is because the SPF algorithm emphasizes current local optimization, while the algorithm in this paper focuses on global optimization, sometimes sacrificing some delay in scheduling certain packets to achieve an overall optimal solution. As the number of hops increases, the end-to-end delay of data packets with the same source and destination nodes transmitted using the SPF algorithm will sharply rise. This is because the SPF algorithm does not consider congestion avoidance and only selects the nearest nodes for transmission based on a greedy strategy. Therefore, in the case of non-cross-span transmission, the PSFRS proposed in this paper performs better than the SPF algorithm. At the same time, this paper also compares the ELB algorithm with the proposed PSFRS algorithm. As shown in Figure 15, it can be observed that the end-to-end delay of the ELB algorithm is similar to that of the PSFRS algorithm during low-hop transmissions. With an increase in the number of hops, the overall transmission delay of the ELB algorithm shows an upward trend, similarly to the SPF algorithm, leading to a significant delay increase. This is because the ELB algorithm optimizes only based on node loads, which in some cases may result in packets taking longer routes for load transmission.