CN101552992B - A Dynamic Routing Method for Satellite Networks Based on Mobile Agent Security - Google Patents

Abstract

The satellite network dynamic routing method based on mobile agent security is a dynamic routing method suitable for satellite networks, adding mobile agent technology to it, and traversing the network to collect information and transmit information through the migration of mobile agents in the network. In the present invention, the satellite network is divided into several regional sub-networks, the sub-networks are managed through the central satellite, and the satellites in the sub-networks can directly communicate with each other. The method of sending TestDataAgent between subnets and running detection in the virtual area ensures the security of agent migration in the network. At the same time, the central satellites in the subnet can alternately take turns to avoid network congestion caused by excessive information volume at the central satellites, resulting in a decrease in network performance.

Description

A Dynamic Routing Method for Satellite Networks Based on Mobile Agent Security

technical field

The invention is a dynamic routing method based on the mobile agent technology, which is mainly used to solve the problem of realizing the dynamic routing algorithm of the safe transmission of data by using the mobile agent technology in the satellite network, and belongs to the field of network protocol design.

Background technique

The satellite network is composed of spacecraft. According to the principle of maximum effective comprehensive utilization of space information resources, it is an organic space wireless communication system that is interconnected through inter-satellite wireless communication links. Compared with terrestrial communication facilities, satellite network communication has a wide coverage, especially can cover vast areas (such as oceans, deserts, and polar regions) where ground networks are difficult to lay, is not affected by natural disasters on the ground, and communication costs have nothing to do with distance. , which can meet the increasing demand of users for services such as high-definition television, conference television, high-speed data transmission, videophone, image-on-demand and distance education. The research on satellite network technology has gradually become a hot spot in the research field.

Mobile agent technology is a new technology that can effectively simplify the design, implementation and maintenance of distributed systems in large networks. It is widely used in e-commerce, information collection and release, real-time network monitoring and other fields at this stage. Agent is a software entity that can operate continuously and autonomously in a specific environment. A mobile agent can automatically move from one node to another to perform different tasks on behalf of the user. Agents generally have the following characteristics:

1) Reactivity: an ability to perceive and act selectively.

2) Autonomy: the ability to autonomously control one's own behavior and internal state.

3) Cooperative: coordinate and cooperate with other Agents to achieve common goals.

4) Self-learning ability: It has certain knowledge itself, and can learn new knowledge in the interaction with users and other Agents.

Because the mobile agent transmits information in the open network, when the Agent program roams in the network, its program code and data are not safe, and there may be great security threats in data transmission and communication links. Generally speaking, the security problems of mobile agents are mainly divided into two types: one is to protect the host from other mobile agents' attacks; the other is to protect mobile agents from other hosts' attacks. In this regard, people have come up with various mechanisms to improve the security performance of mobile agents, such as encrypting mobile agents, restricting hosts in the network, and so on.

Routing algorithm is the key technology supporting network transmission. There are many routing algorithms at present, which are generally divided into two categories: static routing algorithms and dynamic routing algorithms, each with its own advantages and disadvantages for different types of needs. Static routing is a special routing, it is manually set by the administrator, the algorithm complexity is relatively simple, but has limitations, after the network topology changes, it will not change automatically; dynamic algorithm is automatically calculated by the router Routing can better adapt to the network whose topology is easy to change. With the development of network scale and the development of new services, the traditional dynamic routing algorithm has gradually become the bottleneck of the centralized processing mechanism. An important aspect to solve this problem is to redesign the routing algorithm.

Because mobile agents have various advantages such as mobility, multiple routing mobile agents sent by routing nodes can traverse the network to collect information and improve routing algorithms. At the same time, although the existing methods of improving the security performance of mobile agents can protect the Agent to a certain extent, they all have defects. Therefore, it is necessary to propose a dynamic routing algorithm for satellite networks based on mobile agent security, and to further in-depth research on satellite networks.

Contents of the invention

Technical problem: the purpose of this invention is to propose a dynamic routing method applicable to satellite networks, adding mobile mobile agent technology to it, and traversing the network to collect information and transmit information through the migration of mobile mobile agents in the network. At the same time, aiming at the security threats that mobile agents will encounter in the network, a new method is proposed to ensure the security of mobile agents.

Technical scheme: the method of the present invention is that the node collection S of whole satellite network is divided into several regional subnetworks N1, N2, ... Nm( $S\⋐N1\∪N2\∪N3...\∪\mathrm{N\; m}$ ), each subnet has a central satellite, other satellites in the subnet are called ordinary satellites, and the central satellite is responsible for managing all satellite nodes in the subnet. Each satellite node has a sub attribute and a neighbor table Nlist (Net List). The sub attribute records the subnet number where the satellite is located, and the Nlist neighbor table records the route selection for the satellite to reach other satellites in the subnet. The Nlist of the central satellite node not only records the route selection to the satellite nodes of this subnet, but also records the paths to the central satellites of other subnets. The central satellite has a trust table Tlist (TrustList), which records which subnets are trusted and can directly carry out data communication.

The central satellite manages all satellite nodes in the subnet, is responsible for the behavior of ordinary satellites, regularly detects each ordinary satellite, and ensures that the satellite nodes in the subnet are safe and will not engage in malicious behavior. Ordinary satellites in the same subnet trust each other, and absolutely trust the central satellite, so satellites in the same subnet can directly transmit information without worrying about the data agent transmitting data being attacked by malicious nodes or malicious access node. At the same time, the central satellite is also responsible for communicating with satellites in other subnets and judging communication security. The central satellite of each subnet will regularly send the test data agent to the central satellites in other subnet regions. After the central satellite of the receiving subnet receives it, it will divide a virtual area for TestDataAgent to run, and record the action of the test data agent. If the test If no malicious behavior is recorded after the data agent runs, the test data agent is given an authorization to allow access, indicating that the central satellite of the receiving subnet trusts the central satellite of the sending subnet. After the test data agent migrates back to the central satellite of the sending subnet, check whether some of its important resources and attributes have been modified. If it has not been tampered with and has obtained access authorization, the central satellite of the sending subnet trusts the center of the receiving subnet satellite. When the central satellite of subnetwork P trusts the central satellite of subnetwork Q, it means that all satellite nodes of subnetwork P trust the satellites of subnetwork Q, and the satellites between the two subnetworks can safely exchange data without Worry about safety issues.

When transmitting data between satellites, if the source satellite and the destination satellite are in the same subnet, the data exchange between the two can be performed directly; if the source satellite and the destination satellite are in different subnets, the source satellite will first send the data to the The central satellite of the subnet, and then the central satellite sends the data to the central satellite of the subnet where the destination satellite is located, and then forwards the data to the destination satellite.

The central satellite has many tasks. It is not only responsible for managing the subnet area, communicating with the satellites in the subnet, updating the routing table in the subnet, detecting the behavior of ordinary satellites, and dealing with communication problems between ordinary satellites. Communicate with other subnets, update the routing table between subnets, and be responsible for the security of communication with other subnets. If one satellite is always used as the central satellite, it is likely that congestion will occur at the central satellite due to the excessive amount of information at the central satellite, which will become the bottleneck of the entire network and cause network performance degradation. For this reason, a threshold Ef can be set. When the information amount of the center satellite is greater than Ef, a new center satellite is selected in this area, and the original center satellite becomes an ordinary satellite.

The routing algorithm of the present invention is a dynamic routing algorithm, which can automatically update the routing selection of the satellite nodes according to the change of the topology structure of the satellite network. Satellite nodes send path agents regularly to detect paths and update routing tables. Ordinary satellites only send path agents to the satellites in this subnet to update their own Nlist; in addition to updating the routing selection of this subnet, the central satellite also regularly sends path agents to the center satellites of other subnets to update the Nlist of other subnet satellites. Routing.

The present invention divides the entire network into several small subnets based on the satellite network dynamic routing method of mobile agent security, traverses the network for data transmission through the mobility characteristics of the mobile agent, and adopts a virtual space method to ensure that the mobile agent is in the network security in which,

The subnet division steps are as follows:

1.1. Satellite i has three attributes: center _i , cover _i , and sub _i . Set center _i and cover _i as false, and sub _i = 100 means that satellite i is neither a center satellite nor joined any subnet.

1.2. Broadcast message msg(D _i ) to neighbor satellites of satellite i with probability p=2 ^-α , where α is the number of neighbors of satellite i,

1.3. If the information msg(D _i ) is sent successfully, set center _i as true, sub _i =i, indicating that satellite i becomes the center satellite of subnet i, and turn to step 1.5,

1.4. After V time slices, detect center _i and cover _i attributes, if both are false, double the probability p, broadcast message msg(D _i ) to neighboring satellites, go to step 1.3,

1.5. When satellite j receives the message msg(D _i ), it first judges whether it has become a center satellite or has joined a certain subnet; if center _j and cover _j are both false, it indicates that satellite j is neither a center satellite nor a center satellite. Become a common satellite without joining a certain subnet; return a message msg(BD _j ) to satellite i, indicating that satellite j joins subnet i and becomes a common satellite of subnet i, set cover _j as true, sub _j = i, otherwise discard msg(D _i ),

1.6. After satellite i receives msg(BD _j ), it lists satellite j as an ordinary satellite of this subnet;

After the subnet division is completed, each subnet includes a central satellite and several ordinary satellites. The central satellite is responsible for notifying each ordinary satellite of the satellite members of this subnet, and then performing routing update and information transmission:

2.1. The satellite regularly sends the routing mobile agent t to the surrounding satellites to update its own routing selection,

2.1.1. Ordinary satellites use the satellites of this subnet as the destination satellites to send routing mobile agents in sequence,

2.1.2. The central satellite lists the satellites of this subnet and the central satellites of other subnets as the destination satellites and sends routing mobile agents in turn,

2.1.3. When the routing mobile agent migrates back from the destination satellite, the sending satellite updates its own routing table according to its passing path;

2.2. The central satellite regularly sends detection information to ordinary satellites, supervises the actions of ordinary satellites, prevents malicious behavior, checks the network status and resource usage of ordinary satellites, and handles improper behavior of ordinary satellites.

2.2.1. The central satellite regularly sends detection information to ordinary satellites in the subnet,

2.2.2. After the detection information reaches the ordinary satellite, record the behavior of the satellite node, network status and resource usage, and return to the central satellite.

2.2.3. If the detection information records the operation that is not allowed by the detected satellite or the network resource status is abnormal, the central satellite will process it to ensure normal operation,

2.2.4. If there is a problem between ordinary satellites, the problem will be submitted to the central satellite for processing;

2.3. The central satellites of different subnets regularly send TestDataAgent to detect the security of the mobile Agent transmitting information between subnets. The mutual detection process is as follows:

2.3.1 Satellite k regularly sends test data mobile agent to satellite r,

2.3.2. After satellite r receives the test data mobile agent, it divides a virtual area for TestDataAgent to run, and records the actions of the test data mobile agent.

2.3.3. After the test data mobile agent runs, if all actions are legal, the satellite r will add the area K to its trust list, and set the allowed access attribute of the test data mobile agent to true; if there are Malicious behavior, remove area K from the trust list, set the allowed access attribute of the test data mobile agent to false,

2.3.4. Test data The mobile agent t migrates back to the satellite k, and the satellite k checks its important resources and attributes. If it has not been tampered with and the access permission attribute is true, then the region R is added to the trust list, otherwise the region K is removed from the trust list,

2.4. Data is transmitted between satellites through a mobile agent. If the sending satellite and the destination satellite are in the same subnet, they will be sent directly according to the route selection; if they are in two different subnets, the migration path of the data mobile agent is: sending satellite -> The central satellite of the subnet where the sending satellite is located -> the central satellite of the subnet where the destination satellite is located -> the destination satellite,

2.5. The central satellite regularly detects its own information flow. When the amount of information exceeds the threshold Ef, the central satellite is replaced. The replacement steps are as follows:

2.5.1. Evaluate the ordinary satellites in the subnet, and select a new central satellite from the aspects of information volume, resource utilization, network conditions, etc.,

2.5.2. The original center satellite sends relevant information to the new center satellite. The center attribute of the original center satellite is set to false, and the cover attribute is set to true.

2.5.3. The new center satellite sets its own center attribute to true,

2.5.4. Send information to inform the satellites in the subnet and other subnets about the replacement of the central satellite.

Beneficial effects: the purpose of the present invention is to propose a dynamic routing algorithm applicable to satellite networks, adding mobile agent technology in the routing algorithm, traversing the network to collect information through the migration of mobile agents in the network, and performing routing in the satellite network information transmission.

Compared with the previous routing algorithm, the present invention utilizes various advantages such as the mobility of the mobile agent, and multiple routing agents sent by the routing node traverse the network to collect information, cooperate through a special communication mode, and update the route adaptively tables and network conditions.

Divide the entire satellite network into several local subnets. When a certain part of the network topology changes, only the changed local subnet area needs to be changed without affecting other parts of the network. Each subnet is managed by a central satellite, which can maximize the guarantee that the satellite nodes in the subnet are credible and will not perform malicious acts. Only the central satellites between the subnets need to trust each other to ensure the entire area All satellites can trust each other, which greatly reduces the system overhead and network resources needed to ensure the trust between satellites. Different subnets use virtual space to run the mobile agent, record the behavior of the mobile agent, and improve the security of the mobile agent in the network.

Ordinary satellites in the subnet can alternately become central satellites, which avoids network congestion and network performance degradation caused by the excessive information volume of central satellites. At the same time, with the dynamic routing algorithm used in the present invention, each satellite only needs to regularly update the routing selection of the subnet satellite, without recording the routing of the entire network, which greatly reduces the system overhead and network resources caused by path detection. It reduces the load of the network and helps to keep the network smooth.

Description of drawings

Figure 1 is a flow chart of dividing subnet areas.

FIG. 2 is a schematic diagram of a network subnet divided.

Figure 3 is a diagram of the operation of the mobile agent t in the satellite network.

Fig. 4 is a schematic diagram of secure communication between subnets.

Fig. 5 is a schematic diagram of data communication between satellites.

Detailed ways

1. Architecture

The satellite network dynamic routing algorithm based on mobile agent security realizes the update of routing algorithm and data transmission through mobile agent technology. The entire satellite network is divided into several regional subnets, which become satellite node communication in the subnet and data communication between each subnet, which simplifies the network structure. The communication security of the mobile agent is ensured by using the virtual area. Wherein, the division module of the regional subnet, the internal management module of the subnet, the safety communication module between the subnets, the routing update module, and the central satellite replacement module are the main functional parts for realizing the method of the present invention, and several specific parts are explained below :

Division of regional subnets

Each satellite node has sub attribute, center attribute, cover attribute and Nlist neighbor list. Initialize the satellite network, set sub to 100, the attributes of center and cover to false, and record the neighboring satellites that can communicate directly in Nlist. Satellite nodes broadcast messages to neighbor satellites with probability p. If the message is sent successfully, set the attribute of center to true, and sub is the node number of the satellite to form a subnetwork area. The satellite is the center satellite of this subnetwork. When the neighbor satellite receives the message, if both the center attribute and the cover attribute are false, a message will be sent back, indicating that it will join the subnet and become an ordinary satellite. Set sub equal to the node number of the center satellite joining the subnet, and set the cover attribute to real. After all subnets are divided, the central satellite sends the subnet number and member node number of this subnet to all member satellites.

Subnet internal management

The central satellite is responsible for managing all common satellites in the subnet. Regularly send some detection information to ordinary satellites to detect the operation status of each ordinary satellite and whether there is any malicious behavior. If there is malicious behavior, the central satellite will supervise the ordinary satellite and order it to modify its own behavior. Problems and disputes arising from communication between ordinary satellites will also be submitted to the central satellite for judgment. The central satellite has absolute supervision and judgment rights in the subnet, manages the normal operation of the subnet, and ensures that all ordinary satellites in the subnet are safe and reliable.

Secure communication between subnets

The satellite transfers the data directly through the migration of the mobile agent of the data. Each central satellite represents the satellite subnet it is in. To judge whether a subnet can be trusted, you only need to judge whether its central satellite can be trusted. In the present invention, the method of virtual space is adopted to realize the safe communication between the subnets, so as to ensure the safety of the mobile agent transmitting data. Communication between any two subnetworks K (center satellite is k) and subnetwork R (center satellite is r), satellite k regularly sends the mobile agent of the test data to satellite r, after satellite r receives it, it divides a virtual area for The mobile agent of the test data runs and records the actions of the mobile agent of the test data. When the mobile agent of the test data runs, if all the actions are legal, the satellite r adds the area K to its trust list, indicating the area K DataAgents migrated from area K are safe and trustworthy. At the same time, set the allowed access attribute of the mobile agent of the test data to true; if there is malicious behavior, remove the area K from the trust list, set the allowed access attribute of the TestDataAgent to false, and then for the data migrated from area K The mobile agent of is not accepted. TestDataAgent migrates back to satellite k after the execution of satellite r, and satellite k checks whether some of its important resources and attributes have been modified. If they have not been tampered with and the allowed access attribute is true, then add region R to the trust list, which can be It is safe for mobile agents to send data to region K, otherwise, region R is insecure.

routing update

As time changes, the topology of the satellite network and the position of the satellites will also change, and the routing table of the satellite needs to be updated in real time. Routing updates include routing updates within a subnet and routing updates between subnets. For ordinary satellites, their routing table only records the routing to the satellites in the subnet, and only needs to regularly send routing mobile agents to other satellites in the subnet to update the routing. For the central node, in addition to recording the route selection to the satellites in the subnet, it is also necessary to regularly update the routes to other central satellites.

Center Satellite Replacement

The standard for whether the center satellite is changed is the threshold value Ef of the amount of information. When the amount of information at the center satellite is greater than Ef, the ordinary satellites in the subnet will be evaluated, and a new center satellite will be selected. The original center satellite will transfer the relevant information After being sent to the new center satellite, it becomes an ordinary satellite, and at the same time, the new center satellite sends information to inform the satellites in the subnet and other subnets about the replacement of the center satellite.

2. Method flow

Initialize the entire satellite network, record the neighboring satellites that can communicate directly in the Nlist neighbor table of each satellite, set the information volume threshold Ef of the central satellite, and divide the subnetwork.

The subnet division process is as follows:

1) Satellite i has three attributes: center _i , cover _i , and sub _i . Set center _i and cover _i as false, and sub _i = 100, indicating that satellite i is neither a center satellite nor joined any subnet

2) Broadcast message msg(D _i ) to neighbor satellites of satellite i with probability p=2 ^- α, where α is the number of neighbors of satellite i

3) If the message msg(D _i ) is sent successfully, set center _i as true, sub _i = i, which means satellite i becomes the center satellite of subnet i, go to step 5

4) After V time slices, check the center _i and cover _i attributes, if both are false, double the probability p, broadcast the message msg(D _i ) to the neighbor satellite, go to step 3

5) When satellite j receives the message msg(D _i ), it first judges whether it has become a central satellite or has joined a certain subnet. If both center _j and cover _j are false, it means that satellite j is neither a center satellite nor a common satellite that joins a certain subnet. Send back a message msg(BD _j ) to satellite i, indicating that satellite j joins subnet i and becomes an ordinary satellite of subnet i, set cover _j as true, sub _j = i, otherwise discard msg(D _i )

6) After satellite i receives msg(BD _j ), it lists satellite j as an ordinary satellite of this subnet

After the subnet is divided, each subnet includes a central satellite and several common satellites. The central satellite is responsible for notifying each ordinary satellite of the satellite members of the subnet. Then perform routing update and information transmission:

1. The satellite regularly sends the routing mobile agent to the surrounding satellites to update its own routing selection

a) Ordinary satellites use the satellites of this subnet as the destination satellites to send routing mobile agents in sequence

b) The center satellite lists the satellites of this subnet and the center satellites of other subnets as the destination satellites and sends routing mobile agents in turn

c) When the routing mobile agent migrates back from the destination satellite, the sending satellite updates its own routing table according to the route it passes through.

2. The central satellite regularly sends detection information to ordinary satellites to monitor the actions of ordinary satellites and prevent malicious behaviors.

Check the network status and resource usage of ordinary satellites, and deal with improper behavior of ordinary satellites

a) The central satellite regularly sends detection information to ordinary satellites in the subnet

b) After the detection information reaches the ordinary satellite, record the behavior of the satellite node, network status and resource usage, and return to the central satellite

c) If the detection information records the operation that is not allowed by the detected satellite or the network resource status is abnormal, the central satellite will process it to ensure normal operation

d) If there is a problem between ordinary satellites, submit the problem to the central satellite for processing

3. The test data mobile agent is regularly sent between the central satellites of different subnets to detect the security of the mobile Agent transmitting information between subnets, such as subnet K (the central satellite is satellite k) and subnet R (the central satellite is satellite r ) between the mutual detection process is as follows:

a) Satellite k sends test data mobile agent to satellite r at regular intervals. After satellite r receives TestDataAgent, it divides a virtual area for test data mobile agent to run and records the actions of test data mobile agent.

b) After the test data mobile agent runs, if all actions are legal, the satellite r adds area K to its trust list, and sets the allowed access attribute of the test data mobile agent to true; if there is any malicious behavior , remove area K from the trust list, and set the allowed access attribute of TestDataAgent to false

c) The test data mobile agent migrates back to satellite k, and satellite k checks its important resources and attributes. If it has not been tampered with and the access permission attribute is true, then region R is added to the trust list, otherwise region K is removed from the trust list delist

4. Data transfer between satellites through data mobile agents. If the sending satellite and the destination satellite are in the same subnet, they will be sent directly according to the routing selection; if they are in two different subnets, the migration path of the test data mobile agent is: sending satellite -> central satellite of the subnet where the sending satellite is located -> The center satellite of the subnet where the destination satellite is located -> the destination satellite

5. The central satellite regularly detects its own information flow. When the amount of information exceeds the threshold Ef, the central satellite is replaced. The replacement steps are as follows

a) Evaluate the ordinary satellites in the subnet, and select a new central satellite from the aspects of information volume, resource utilization, network status, etc.

b) The original center satellite sends relevant information to the new center satellite, the center attribute of the original center satellite is set to false, and the cover attribute is set to true

c) The new center satellite sets its own center attribute to true

d) Send information to inform the satellites in the subnet and other subnets about the replacement of the central satellite

Claims (1)

1. A satellite network dynamic routing method based on mobile agent security, characterized in that the method divides the entire network into several small subnets, and traverses the network for data transmission through the mobility characteristics of mobile agents, while using virtual space A method to ensure the security of the mobile agent in the network, wherein, The subnet division steps are as follows: 1.1. Satellite i has three attributes: center _i , cover _i , and sub _i . Set center _i and cover _i as false, and sub _i = 100 means that satellite i is neither a center satellite nor joined any subnet. 1.2. Broadcast message msg(D _i ) to neighbor satellites of satellite i with probability p=2 ^-α , where α is the number of neighbors of satellite i, 1.3. If the message msg(D _i ) is sent successfully, then set center _i as true, sub _i =i, which means satellite i becomes the center satellite of subnet i, and go to step 1.5; if the message msg(D _i ) fails to send, then Go to step 1.4; 1.4. After V time slices, detect center _i and cover _i attributes, if both are false, double the probability p, broadcast message msg(D _i ) to neighboring satellites, go to step 1.3, 1.5. When satellite j receives the message msg(D _i ), it first judges whether it has become a center satellite or has joined a certain subnet; if center _j and cover _j are all false, it means that satellite j is neither a center satellite, Also did not join a certain subnet to become an ordinary satellite; return a message msg(BD _j ) to satellite i, indicating that satellite j joins subnet i and becomes an ordinary satellite of subnet i, set cover _j as true, sub _j = i, Otherwise discard msg(D _i ), 1.6. After satellite i receives msg(BD _j ), it lists satellite j as an ordinary satellite of this subnet; After the subnet division is completed, each subnet includes a central satellite and several ordinary satellites. The central satellite is responsible for notifying each ordinary satellite of the satellite members of this subnet, and then performing routing update and information transmission: 2.1. The satellite regularly sends the routing mobile agent t to the surrounding satellites to update its own routing selection, 2.1.1. Ordinary satellites use the satellites of this subnet as the destination satellites to send routing mobile agents in sequence, 2.1.2. The central satellite lists the satellites of this subnet and the central satellites of other subnets as the destination satellites and sends routing mobile agents in turn, 2.1.3. When the routing mobile agent migrates back from the destination satellite, the sending satellite updates its own routing table according to its passing path; 2.2. The central satellite regularly sends detection information to ordinary satellites, supervises the actions of ordinary satellites, prevents malicious behavior, checks the network status and resource usage of ordinary satellites, and handles improper behavior of ordinary satellites. 2.2.1. The central satellite regularly sends detection information to ordinary satellites in the subnet, 2.2.2. After the detection information reaches the ordinary satellite, record the behavior of the satellite node, network status and resource usage, and return to the central satellite, 2.2.3. If the detection information records the operation that is not allowed by the detected satellite or the network resource status is abnormal, the central satellite will process it to ensure normal operation, 2.2.4. If there is a problem between ordinary satellites, the problem will be submitted to the central satellite for processing; 2.3. The central satellites of different subnets regularly send TestDataAgent to detect the security of the mobile Agent transmitting information between subnets. The mutual detection process is as follows: 2.3.1 Satellite k regularly sends test data mobile agent to satellite r, 2.3.2. After satellite r receives the test data mobile agent, it divides a virtual area for TestDataAgent to run, and records the actions of the test data mobile agent. 2.3.3. After the test data mobile agent runs, if all actions are legal, the satellite r will add the area K to its trust list, and set the allowed access attribute of the test data mobile agent to true; if there are Malicious behavior, remove area K from the trust list, set the allowed access attribute of the test data mobile agent to false, 2.3.4. Test data The mobile agent t migrates back to the satellite k, and the satellite k checks its important resources and attributes. If it has not been tampered with and the access permission attribute is true, then the region R is added to the trust list, otherwise the region R is removed from the trust list, 2.4. Data is transmitted between satellites through a mobile agent. If the sending satellite and the destination satellite are in the same subnet, they will be sent directly according to the route selection; if they are in two different subnets, the migration path of the data mobile agent is: sending satellite -> The central satellite of the subnet where the sending satellite is located -> the central satellite of the subnet where the destination satellite is located -> the destination satellite, 2.5. The central satellite regularly detects its own information flow. When the amount of information exceeds the threshold Ef, the central satellite is replaced. The replacement steps are as follows: 2.5.1. Evaluate the ordinary satellites in the subnet, and select a new central satellite from the three aspects of information volume, resource utilization, and network conditions. 2.5.2. The original center satellite sends relevant information to the new center satellite. The center attribute of the original center satellite is set to false, and the cover attribute is set to true. 2.5.3. The new center satellite sets its own center attribute to true, 2.5.4. Send information to inform the satellites in the subnet and other subnets about the replacement of the central satellite.

Images