## 2 Methodology  
### System Model  
This paper proposes a dual-network architecture for secure and reliable transmission in heterogeneous networks. The system model comprises heterogeneous transmission network resources, including satellite networks, the Internet, mobile networks, and self-organized networks, as illustrated in Figure 1. The network architecture employs a layered decoupling design to separate the transmission control layer from the network resource layer. This separation forms a flexible dual-network structure, corresponding to the transmission control network and the network resource network. The network resource layer is designed to ensure stability and reliability while allowing for network flexibility, scalability, and programability of the forwarding plane. It provides redundant physical transmission channels, enhancing the robustness of the network. The transmission control layer is responsible for the reliable transmission of information. It utilizes innovative lightweight sharing algorithms, Delay Tolerant Networking (DTN), and other technological means to flexibly address diverse information transmission needs. The transmission control layer constructs a logically independent overlay network, with virtual nodes abstracted from the transmission control system. These virtual links correspond to the heterogeneous network access points in the network resource layer. Neighboring nodes are connected by multiple virtual links, forming redundant and reliable transmission paths. By covering the network, the overall information of the network is shared with each other through lightweight consensus algorithms, and the transmission path is pre-calculated in the stacked network for information transmission in the physical network. The business system issues tasks and instructions at the upper level, while the transmission control layer encapsulates transmission-related functions into service-oriented entities, forming corresponding transmission control service entities. With the help of transmission control interfaces, resource collection and synchronization, path strategy control, and information transmission control are completed. We establish an identification system in the resource network layer to achieve automatic conversion of heterogeneous access protocol systems and consensus broadcasting between nodes, forming a unified resource status table for the entire network and providing support for transmission control services. For the resource network layer, to address the characteristics of physical transmission network resources, such as heterogeneity and mobility, an overlay network based on overlay technology is constructed. This overlay network leverages various heterogeneous network resources to build a transmission control system, thus enabling the unified management and utilization of these diverse resources. By employing heterogeneous multi-means connections between disparate resource networks, the system ensures that at least two or  
Figure 1: System architecture diagram. more independent transmission channels are linked, thereby enhancing communication reliability and robustness. The transmission control layer is the fundamental component of the system, responsible for establishing and managing physical information transmission channels across heterogeneous networks to support the operation of the secure transmission control overlay network. By interconnecting multiple heterogeneous network resources and utilizing dynamic networking functions, the transmission control system can effectively establish physical information transmission channels across heterogeneous networks. A consensus algorithm is used between transmission control systems to achieve information synchronization among distributed transmission control systems, thereby establishing a unified node resource and link state information table across the network.