### Related Works  
Researchers have a long history of studying packet loss recovery and network reliability, which involves Forward Error Correction (FEC), automatic repeat request (ARQ), frame replication and elimination for reliability (FRER), and so on. The choice of mitigation measures for each system depends mainly on the transmission medium. The first approach is FEC [10; 11; 12]. In particular, there is a study titled _Wharf that Uses Field-Programmable Gate Arrays (FPGAs) to Implement FEC in Faulty Links_[12]. However, FEC typically employs fixed redundancy parameters, which may not be suitable for dynamic packet loss rates. This rigidity can lead to inefficiencies, as the predetermined level of redundancy may not align with the actual network conditions. Furthermore, increased redundancy requires higher bandwidth, which can increase costs for certain network application scenarios like RDMA [2]. Consequently, while FEC provides a valuable mechanism for error correction,its limitations in terms of adaptability and bandwidth consumption must be carefully considered when designing solutions for varying network environments. FRER reduces the impact of packet loss through redundant transmissions [13; 14], but it also has a similar problem to FEC in that it requires more bandwidth. Another existing method for fast packet recovery involves retransmitting lost packets directly at intermediate nodes. Link-local retransmission has been extensively studied and widely deployed in wireless networks [15]. With the development of network technology, both switches and relay nodes now have larger packet cache spaces and network processing capabilities integrated with turn-save-compute. Numerous previous efforts have implemented buffers at intermediate nodes to facilitate such link-local retransmissions (LL-ReTx). Therefore, in addition to its deployment and application in wireless networks, link-local retransmission has increasingly been recognized by researchers in recent years for its potential value in other types of networks, such as data centers [16; 17] and satellite networks [18], which can significantly reduce recovery delays and conserve bandwidth. A comparison of link-layer packet loss recovery schemes in recent years is shown in Table 1. Some of these schemes are optimized for Flow Completion Time (FCT), while others are optimized for throughput and bandwidth. Shared Queue Ring (SQR) is an on-switch mechanism that recovers packets that could be lost during the period from the detection of a link failure to the completion of the subsequent network configuration [17]. However, while SQR can cache lost packets during link corruption and facilitate their recovery, it opts to switch routes instead of utilizing the potentially damaged link. This approach may lead to suboptimal resource utilization, as the original link could still be viable for certain types of traffic or under specific conditions. By not leveraging the existing link, SQR may miss opportunities to maintain network capacity and efficiency, particularly in scenarios where the damage is intermittent or localized. Link Guardian, which leverages faulty links, primarily focuses on managing short flows, incorporating specific designs, and optimizing for them. Furthermore, it does not offer detailed optimizations for handling out-of-order packets and timeouts, and the recovery mechanism has some potential bandwidth utilization problems like fake retransmissions. These issues are especially important in bandwidth-hungry WANs. Despite P4's ability to achieve extremely high forwarding line rates, it has certain limitations in terms of buffer space and protocol flexibility. In contrast, SatGuard is specifically optimized for the dynamic node characteristics of satellite networks, whereas our work remains concentrated on static networks in wide-area networks (WANs) and network communication across data centers. In summary, for certain scenarios, link-layer recovery strategies and LL-ReTx still present opportunities for further exploration and optimization.