## 1 Introduction  
With the continuous advancement of communication technology, global internet users and traffic have grown significantly in recent decades. A report from Statista [1] indicates that by July 2024, about 5.45 billion individuals, representing 67.1% of the global population, were active internet users. The rapid development of internet technology has led to numerous new network applications and services, including streaming media, blockchain, virtual reality, and big data. These emerging applications place higher demands on network transmission performance, driving the continuous evolution and advancement of network technologies. The original design of the TCP/IP architecture was intended to prioritize accurate end-to-end data transmission. However, in today's complex internet environment, the traditional single-path best-effort transmission approach shows limitations in bandwidth utilization and transmission stability [2]. In response, various multipath transmission protocols have been proposed, such as Equal-Cost Multipath (ECMP) [3], Weighted-Cost Multipath (WCMP) [4], as well as transport-layer protocols like Multipath TCP (MPTCP) [5], Stream Control Transmission Protocol (SCTP) [6], and Multipath QUIC (MPQUIC) [7]. These technologies improve network transmission quality by aggregating bandwidth. However, the tight coupling of identifiers and locators in TCP/IP confines it to host-centric communication, making it difficult to meet the demands of future network applications for widespread content distribution and retrieval. In this context, the concept of Information-Centric Networking (ICN) [8] has been proposed. ICN supports name-based routing and extensive in-network caching, and the content distribution process of ICN, which is inherently characterized by multi-source and multi-path capabilities [9], makes it more effective in meeting future network application demands for transmission efficiency and reliability. However, ICN addresses the inherent limitations of the TCP/IP architecture by fundamentally altering the underlying network protocols, which makes deploying a pure ICN architecture impractical due to the high costs associated with replacing the globally pervasive IP infrastructure. As a result, ICN is currently implemented through compatible deployments [10]. Incremental ICN deployment within existing network infrastructure often adopts an overlay approach, while external IP devices require gateways to interconnect with ICN. Gateways not only facilitate protocol conversion but also play a critical role in data management at the convergence point of the two networks, serving as key nodes in the integrated system with potential for further optimization and functional enhancement. Packet disorder caused by multipath transmission has attracted widespread attention [11]. Research on ICN multipath transmission [12; 13; 14; 15] primarily focuses on optimizing strategies such as path selection and packet scheduling to reduce the occurrence of disorder. However, these optimizations during data transmission do not typically address the disorder of packets that have already happened, making it difficult to avoid reordering at multipath convergence points. This issue is particularly pronounced in IP-ICN hybrid systems. Since IP devices remain unmodified when accessing ICN through gateways, their built-in receiver-side ordering and buffering mechanisms struggle to handle the complex out-of-order patterns introduced by ICN multipath transmission. This not only limits the utilization of ICN's performance benefits but also imposes additional system burdens. Integrating a packet reordering module into the gateway, which serves as the final hop before delivering ICN content to IP terminals, is a feasible solution to this problem. ICN multipath transmission exhibits significant variability in flow size, path parameters, and flexible path switching, resulting in complex out-of-order patterns [16].