# Modeling and Performance Analysis of Satellite Network Moving Target Defense System with Petri Nets
## 3 Related Work  
In recent years, the security of satellite networks has been one of the hot topics. With the popularity of new security technologies of active defense, people's attention to satellite network security has started to shift from traditional protection technologies to active defense techniques. The first is the network security situation awareness technology proposed by the academic circle, which aims to actively defend against network intrusion behavior and realize network security protection in advance. In [16], the authors introduced situational awareness technology into safety protection of the satellite, and put forward a situational awareness technology system for broadband satellite networks. This research provided support for satellite network security services and also improved the active defense capability of broadband satellite network infrastructure. In [17], the vulnerabilities of space network and the functions of active defense were analyzed, then a simulation implementation method of active defense modeling based on DTN (delay/disruption tolerant network) was proposed. The proposed method can analyze the performance of space network defense system in real time, effectively avoiding \"zero-day attacks\" and improving the active defense ability of the system. In [18], the authors presented an improved malicious code intrusion detection method for space information network, and the satellite system can achieve fast determination of malicious code attacks. The proposed method has the advantages of high detection rate, low satellite resource consumption, and low latency. In [19], the application design scheme of the endogenous security mechanism of the space-ground integrated information network based on MSD was proposed. This work provided a reference for the construction of a space network active defense security protection system. Although scholars are gradually exploring the application of active defense technology in satellite communication networks, the related theoretical analysis has not been well studied, so the performance evaluation of satellite network based on active defense has become a necessary and urgent problem. Performance analysis is not only an important theoretical basis and supporting technology for system research, but also an important research direction in various fields. As a powerful analytical tool, PN has been used by scholars to conduct a lot of studies on performance analysis. In the rest of this section, we conduct a literature review on research work based on PNs. Research on traditional computer network systems and security skills using PNs are very extensive. In [20], the authors presented an efficient Petri-net-based modeling technique for performance evaluation of application mapping. It could precisely represent the exclusion and pipelining of the communication path. The main advantage of this model is the consideration of parallelism of concurrent tasks and communication, as well as the exclusion of computation and communication with public resources. In [21], the authors developed a configurable CPN model for evaluating the performance and the effectiveness of the IEEE 802.11e protocol. Then, they used a CPN model to provide a comprehensive study of the effectiveness of this protocol. Their CPN model sets the basis for further exploring the performance of the various mechanisms defined by the IEEE 802.11 standard. The paper [22] established a performance analysis model based on SPN to evaluate the influence of honeypot on the performance of system. However, this study only stops at concluding whether it is worth deploying honeypots. The impact of honeypots on network performance deserves further study. In [23], a single server retrial queueing system with preemptive priority for modeling and analyzing spectrum occupancy in CR networks was proposed. They analyzed some performance metrics such as delays, throughput, queue length, number of customers in system, etc., via simulation with the help of STCPN (Stochastic Timed Colored Petri Nets).