# Research on SWIM Services Dynamic Migration Method +
## 2 Related Work  
The SWIM shares service data through a global interoperability network architecture, which looks like a virtual service pool that combines multiple civil aviation services. It adopts loosely coupled architecture and unified standards to facilitate the transmission and sharing of heterogeneous data. The global interoperability network architecture is shown in Figure 1[8; 9].  
SWIM service providers (SP) and SWIM service consumers (SC) provide or consume SWIM services through SWIM-Enabled Applications, and they use a unified exchange models for data sharing, such as Aeronautical Information Exchange Model (AIXM), ATM Information Reference Model (AIRM), Weather Information Exchange Model (WXXM) and Flight Information Exchange Model (FIXM). SWIM Infrastructure provides the infrastructure for sharing information. It provides the core services such as interface management, request-reply and publish-subscribe messaging, service security, and enterprise service management [10].  
SWIM is a distributed large-scale network. The SWIM service registration information list is distributed and has global consistency. In the SWIM service registration information list, there are multiple SPs with the same service topic, and the key service data is distributed in different places. The SWIM service information interaction process is shown in Figure 2.  
Publish-subscribe is the main way of SWIM information interaction. First, SWIM service providers publish SWIM services in three steps through A-B-C, and register content in the registration information database including service topics, WSDL and other information. Then SWIM service consumers search SWIM service in three steps through 1-2-3, SWIM sends SC subscription information to SP, Finally SP push service information to subscribers. This multi-source architecture provides innate conditions for survivability enhancement and disaster recovery backup. Our main research focus is on the SWIM infrastructure layer, which uses SWIM core services to seamlessly migrate service permissions to enhance network survivability.  
Figure 1: The global interoperability network architecture.  
At present, the research on the service migration mechanism has achieved a lot of results. [PERSON] [11] uses a variety of random competition mechanism to implement process migration in a service cluster. Server drift is highly random, but an attacker may initiate a time interval attack. The migration mechanism lacks controllability and may cause network oscillations. [PERSON] et al. [12] improves the triggering mechanism and competition mechanism of service migration in [11]. It can effectively resist time interval attacks, but the single service migration mode reduces the randomness of service migration. [PERSON] et al. [13] proposes a service migration model abstracting the service model into a partially observable Markov decision process, and it can maximize customer benefits by computing service drift strategies. But the model trigger mechanism is unreasonable and can easily cause time conflicts. In [14], an active service migration model based on network survivability situational awareness is proposed by using the alarm information of various detection platforms. This model cannot jointly analyze alarm data, which is prone to false alarm drift and increase system workload. [PERSON] et al. [15] proposes an optimal Web service migration architecture in a cloud computing environment. The architecture uses the load as the migration service triggering metric, and the triggering conditions are single, the security of the service cannot be guaranteed.