WO2023184213A1

WO2023184213A1 - Clustered optimized link state routing method based on virtual backbone network

Info

Publication number: WO2023184213A1
Application number: PCT/CN2022/083989
Authority: WO
Inventors: 钟伟峰; 曹晶烨; 丁良辉
Original assignee: 江苏杰泽罗通信科技有限公司
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2023-10-05

Abstract

The present invention relates to the technical field of wireless communications, in particular to a clustered optimized link state routing (OLSR) method based on a virtual backbone network. The method comprises: on a clustered structure which is constructed using a clustered OLSR method based on management message merging, establishing a virtual backbone network and maintaining the virtual backbone network, which involve: a cluster head node first calculating a MCDS capable of dominating all nodes in a cluster, and each cluster head selecting the smallest number of gateway nodes and adding the gateway nodes into the MCDS of a cluster thereof, and then establishing and forming a CDS capable of reaching all adjacent clusters, wherein the CDSs of all the clusters in a network form a backbone network of the network; each cluster also needing to select a relay node from the adjacent clusters, so as to forward a routing message which comes from the present cluster; setting a forwarding rule for flooding the routing message; and a cluster head periodically maintaining the virtual backbone network, and sending a message to notify a member node thereof to update the state of its own backbone network. A virtual backbone network is used to replace an MPR mechanism to flood a routing message, and the number of instances of forwarding during the flooding of the routing message is optimized, such that the routing overhead of an OLSR protocol is reduced.

Description

A clustered optimal link state routing method based on virtual backbone network

Technical field

The present invention relates to the field of wireless communication technology, and in particular to a clustered optimal link state routing method based on a virtual backbone network.

Background technique

In the Chinese invention patent application document with application number 202210303763.8, a clustered OLSR routing method based on management message merging is proposed. This routing method is essentially a new routing protocol. Its main contents include: establishing clustering in the network Structure, nodes elect cluster heads within a two-hop range through the maximum connectivity clustering algorithm, and the cluster heads establish clusters within a two-hop range; design a cluster periodic maintenance mechanism and a cluster merger mechanism, and use the cluster head and member node periodicity to Information interaction and cluster merging mechanism to maintain the stability of the network clustering structure in dynamic networks; design the routing message management mechanism of OLSR, the cluster head node collects the routing messages of member nodes, and the routing messages of the members will be Flooding is performed after merging to reduce routing overhead by reducing the header redundancy of routing messages. The cluster head monitors topology changes based on routing messages of each member and reduces the flooding frequency of routing messages for members with stable topology. to reduce unnecessary routing overhead.

Based on this routing protocol, a new routing mechanism needs to be further developed to optimize the number of forwardings during message flooding and reduce the routing overhead of the OLSR protocol.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned existing technologies, the present invention provides a clustered optimal link state routing method based on a virtual backbone network. The virtual backbone network is used to replace the MPR mechanism for routing message flooding. By optimizing the routing message flooding time, The number of forwardings reduces the routing overhead of the OLSR protocol.

In order to achieve the above objectives, the present invention is implemented through the following technical solutions: a clustered optimal link state routing method based on a virtual backbone network, including: In the Chinese invention patent application document with application number 202210303763.8, it is proposed Establish and maintain a virtual backbone network on a clustered structure constructed by a clustered OLSR routing method based on management message merging;

During the establishment process of the virtual backbone network, the cluster head node first calculates the MCDS that can control all nodes in the cluster. Each cluster head selects a minimum number of gateway nodes to join its clustered MCDS, and then establishes a MCDS that can reach all neighboring clusters. CDS, the CDS of all clusters in the network constitute the backbone of the network; in addition, each cluster also needs to select relay nodes in neighboring clusters, and forward routing messages from this cluster through the relay nodes; based on the virtual backbone network Establish and select relay nodes, and set forwarding rules for routing message flooding;

In the virtual backbone network maintenance phase, the cluster head is used to periodically maintain the virtual backbone network and send messages to notify its member nodes to update their own backbone network status; the gateway node periodically submits the neighboring cluster nodes it discovered to the cluster head, so that the cluster head The latest neighbor cluster information can be obtained.

It can be seen from the above technical solutions that the present invention has the following beneficial effects:

1. The present invention provides a clustered optimal link state routing method based on a virtual backbone network. It uses the virtual backbone network instead of the MPR mechanism to flood routing messages, and reduces OLSR by optimizing the number of forwardings when routing messages are flooded. The routing overhead of the protocol.

2. The present invention provides a clustered optimal link state routing method based on a virtual backbone network. By maintaining the virtual backbone network, the invention ensures that the clustered optimal link state routing method based on a virtual backbone network is Stability in dynamic networks.

Description of drawings

Figure 1 is a flow chart of the calculation algorithm of the gateway domination point of a clustered optimal link state routing method based on a virtual backbone network according to the present invention;

Figure 2 is an example diagram of isolated nodes that affect global flooding of routing messages in a clustered optimal link state routing method based on a virtual backbone network according to the present invention;

Figure 3 is an example diagram of the backbone network and routing message flooding mechanism of a clustered optimal link state routing method based on a virtual backbone network according to the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and are not to be construed as limiting the present invention.

Example

The content of a clustered optimal link state routing method based on a virtual backbone network described in this embodiment is: a clustered OLSR based on management message merging proposed in the Chinese invention patent application document with application number 202210303763.8 Based on the clustering structure constructed by the routing method, a virtual backbone network is established and maintained. It is mainly divided into two parts: virtual backbone network establishment and virtual backbone network maintenance.

The establishment of a virtual backbone network can be divided into four parts: establishment of intra-cluster MCDS, establishment of intra-cluster CDS, relay node selection, and isolated node processing.

In order to describe the nodes in the backbone network, in this embodiment, we define three different backbone network states, including MPR dominator (MPR dominator, used to identify the node in the minimum connected domination concentration in the cluster), Gateway Dominator (gateway dominator) Point, used to identify the gateway node in the cluster's connectivity domination concentration), Relay Point (relay node, used to identify the relay node selected by the gateway domination point in the neighboring cluster), and unset (not allocated to the backbone network). The initial backbone network status of all nodes is unset. It should be noted that a node can be both an MPR control point and a gateway control point at the same time.

(1) Establishment of intra-cluster MCDS

First, we introduce the establishment process of intra-cluster MCDS. After the clustering is completed, the cluster head node uses its known information to calculate MCDS that can cover all nodes in the cluster. The cluster head can obtain the information of all member nodes through the interaction of HELLO messages. Therefore, the cluster head only needs to peel off the topology view of its own cluster from the neighbor topology information within the two-hop range, and then use the MPR set selection algorithm to calculate the MPR node covering all member nodes in the cluster, which is called MPR. Dominance point. All MPR dominating points and cluster heads constitute MCDS covering all nodes in the cluster. Among them, the selection algorithm of the MPR set is consistent with the OLSR standard protocol document RFC.3626. After completing the calculation of MPR dominating points, the cluster head will send a BACKBONE message to notify all member nodes of the calculated set of MPR dominating points. We give the steps to establish intra-cluster MCDS as follows:

1) Based on the HELLO message interaction content, the cluster head obtains the addresses and topology information of all member nodes, and peels off the topology view of its own cluster.

2) According to the clustering topology, the cluster head uses the MPR set selection algorithm to calculate the MPR nodes covering all member nodes and marks them as MPR dominating points.

3) The cluster head node records its own address and the addresses of these MPR dominator points in the MPR Dominator Set, and notifies all member nodes of the MPR dominator information of this cluster by sending a BACKBONE message.

4) After receiving the BACKBONE message sent by its cluster head, the member node records the MPR node address and cluster head address contained in the message in the MPR dominating point set. If the MPR dominator set recorded in the BACKBONE message contains the address of the member node, the member node will mark its backbone network status as MPR dominator.

After the intra-cluster MCDS is established, TC messages and CTC messages can reach all nodes in the cluster through the MPR control point. However, in order for flooding routing messages to reach all nodes in the network, we need to connect MCDS in different clusters.

(2) Establishment of intra-cluster CDS

We add gateway nodes to each clustered MCDS so that it can connect to all neighboring clusters. We call these newly added gateway nodes gateway domination points. The process for a cluster head to select a gateway domination point is as follows: all gateway nodes in this cluster send a GATEWAY message to the cluster head, the content of which includes the gateway node's own address and its discovery. The cluster head addresses of all adjacent clusters; the cluster head selects the minimum number of gateway nodes as gateway dominators based on the neighboring cluster information summarized by all gateway nodes, and adds them to the MCDS within the cluster to form a coverage of all Intra-cluster CDS of neighboring clusters.

The establishment process of intra-cluster CDS is as follows:

1) All gateway nodes send GATEWAY messages to their own cluster heads, whose content includes their own addresses and the cluster head addresses of all neighboring clusters they discover.

2) After receiving the GATEWAY message, the cluster head records the cluster head address and gateway node address of the neighboring cluster contained in it in the Gateway Set. The elements of this set are the cluster head address of the neighboring cluster and all the cluster head addresses related to the neighboring cluster. A vector of adjacent gateway node addresses.

3) The cluster head calculates the gateway control node. First, if the cluster head is adjacent to a neighboring cluster node, it selects itself as the gateway dominating point, and deletes the related entries of all neighboring cluster head addresses found by it in the gateway set; if after the above steps, the gateway set is not If empty, the cluster head selects an MPR dominating point that connects the most neighbor clusters from the MPR dominating point set in each round, selects it as the gateway dominating point, and deletes entries related to all its adjacent neighbor clusters in the gateway set. , until the gateway set is empty; if the gateway set is still not empty after traversing all MPR dominating points, the cluster head selects a gateway node from the gateway nodes in each round that is connected to the most neighbor clusters, marks it as a gateway dominating point, and Entries related to all neighboring clusters adjacent to it are deleted in the gateway set until the gateway set is empty. The algorithm steps are shown in Figure 1.

4) After completing the calculation of gateway domination points, the cluster head records all gateway domination points in the gateway domination point set, adds the gateway domination point set to the BACKBONE message and sends it to all member nodes.

5) After receiving the BACKBONE message sent by the cluster head, all member nodes record the gateway dominating point set. If the gateway dominator set recorded in the BACKBONE message contains the address of the member node, the member node will mark its backbone network status as Gateway dominator.

After completing the selection of gateway control points, we expand the intra-cluster MCDS of each sub-cluster into intra-cluster CDS. The intra-cluster CDS of each cluster has established connections with all neighboring clusters, and the intra-cluster CDS of all clusters constitute the virtual backbone of the network.

(3) Relay node selection

After constructing the virtual backbone network, in order to ensure that each routing message used for flooding can be propagated in the virtual backbone network and reach all nodes in the network, we need to select appropriate relay nodes to make the virtual backbone network in different clusters parts are connected to each other.

When a node learns that it is a gateway dominating point, it needs to select a neighbor node with the highest degree of connectivity in each neighboring cluster it is connected to to forward the TC or CTC message sent or forwarded by the gateway dominating point. The one selected by the gateway dominating point Neighbor nodes of adjacent clusters are called relay nodes (Relay Point) of the gateway control point. Since each member node in a neighboring cluster must be a node in the CDS within the cluster or adjacent to a node in the CDS within the cluster, the routing message generated or forwarded by the gateway dominating point can reach each node through its selected relay node. all nodes in neighboring clusters. The gateway dominating point notifies the neighboring cluster neighbor to become its relay node by sending a RELAY_POINTS message. The relay node will select its gateway dominating point, which is called a relay point selector (Relay Point Selector).

The gateway dominance point may be directly connected to the intra-cluster CDS of the neighboring cluster, but because it lacks the CDS information of the neighboring cluster, it cannot determine whether it is connected to the CDS of the neighboring cluster. In the above situation, the relay node selected by the gateway control point does not need to forward routing messages from the gateway control point. Therefore, if the relay node finds that its relay point selector is connected to the CDS of this cluster, the relay node will not forward the route flooding message from the gateway control point.

(4)Isolated node processing

There may be isolated nodes in the network, and we need to analyze and handle such special situations.

For the processing of isolated points, we explain as follows. Because the isolated node sets its cluster head address field to empty in the HELLO message, it can be detected by neighbor nodes. An isolated node may be surrounded by multiple clusters. If all clusters adjacent to the isolated node add gateway control points to connect to the isolated node, greater redundancy will occur. For each isolated node, it only needs to periodically send TC-REQ messages to ask the neighbor with the maximum connectivity for global topology information, and its adjacent clusters do not need to forward routing messages to it.

However, routing messages from other nodes must be forwarded by isolated nodes in some cases, otherwise the message may not be flooded to the entire network. Figure 2 gives an example of the above situation, in which the white circles are member nodes, the black circles are cluster heads, and the grid circles are isolated nodes; the triangles and squares mark the MPR dominating point and the gateway dominating point respectively, and the diamond marks the center of the gateway dominating point. Relay node; the flooding of TC/CTC messages must pass through the isolated node J.

In order to solve the above problem, after an isolated node receives a TC or CTC message from other nodes, it must forward the message to all its neighbor nodes.

In addition, the routing of data packets may also have to pass through isolated nodes, such as the routing between two clusters in Figure 2. Therefore, TC messages generated by isolated nodes need to be flooded to the entire network. To solve this problem, the isolated node needs to select a relay node in each neighbor cluster adjacent to it to forward the TC message generated by it.

After establishing the virtual backbone network, we give the flooding forwarding rules for routing messages:

1) The gateway dominating point selects a neighbor node with the maximum degree of connectivity in each neighbor cluster adjacent to it as its relay node in the neighbor cluster. After selecting the relay nodes of all neighboring clusters, the gateway node sends a RELAY_POINTS message to notify these nodes to become its relay nodes.

2) When a node receives a RELAY_POINTS message from a neighboring cluster, if the message contains its own address, it records the source node of the message as its own relay point selector.

3) After the relay node receives the TC or CTC message sent or forwarded by its relay point selector, it searches the MPR dominating point set and gateway dominating point set of this cluster to see if there is a node adjacent to the relay point selector. If it is found that there is a node adjacent to the relay point selector, the relay node will not forward the TC or CTC message, otherwise it will be forwarded.

4) If the node is in the virtual backbone network, that is, it is preferred by the cluster as an MPR dominating point or gateway dominating point, then it unconditionally forwards all received TC or CTC messages.

Figure 3 shows an example of a virtual backbone network established by a clustered optimal link state routing method based on a virtual backbone network and routing message flooding rules described in this embodiment. The white circles are member nodes, the black circles are cluster heads, and the grid circles are isolated nodes. The triangles and squares mark the MPR dominating point and the gateway dominating point respectively, and the diamonds mark the relay nodes of the gateway dominating point. The bold arrow represents the flooding process of TC messages generated by node N.

In the virtual backbone network maintenance stage, we provide a maintenance mechanism for the virtual backbone network and routing message flooding rules suitable for dynamic networks.

In the clustered optimal link state routing method based on a virtual backbone network described in this embodiment, the gateway node periodically reports neighbor cluster information to its own cluster head, and the cluster head periodically calculates the MPR dominating point and The gateway dominates the point and broadcasts a BACKBONE message to notify member nodes to confirm their backbone network status. Therefore, member nodes can periodically maintain their own backbone network status and intra-cluster CDS information, thereby maintaining the virtual backbone network and routing message flooding rules in a dynamic network. We record this cycle as the backbone network cycle (Backbone Peirod).

In each backbone network cycle, the gateway node sends a GATEWAY message to the cluster head to submit the latest neighbor cluster information to the cluster head. The cluster head sets an expiration time (a clustering optimal link state routing method based on a virtual backbone network) for each entry in the gateway set to delete expired information. The maintenance algorithm of the gateway set is as follows: each neighboring cluster head address in the gateway set corresponds to multiple gateway nodes. For the entry of a certain neighboring cluster head address, each gateway node has its own expiration time; when the cluster head receives After the gateway node sends a GATEWAY message, for each neighboring cluster head address in the GATEWAY message, the corresponding entry is found in the gateway set, and the expiration time of the gateway node in each neighboring cluster head entry is updated; when the gateway set If the expiration time of a gateway node in an entry expires, the gateway node will be deleted from the entry. If an entry loses all gateway nodes, the entry will be deleted.

Through the above process, the cluster head can obtain the latest neighbor cluster information, so the latest intra-cluster CDS can be calculated in each backbone network cycle: In each backbone network cycle, the cluster head calculates the MPR dominating point set and sum based on the latest neighbor cluster information. The gateway dominates the collection of points and sends a BACKBONE message to notify all member nodes after completing the calculation; the member nodes set the expiration time for their own backbone network status, and check whether their backbone network status has timed out in each backbone network cycle, and receive The BACKBONE message updates the expiration time of its own backbone network status; in addition, each gateway control point needs to recalculate the relay nodes after confirming its backbone network status, and send a RELAY_POINTS message to notify the relay nodes.

It should be noted that the establishment and maintenance of the virtual backbone network depends on the clustering structure of the network. Therefore, when the clustering status of the cluster head or member node expires, it immediately loses the backbone network status and relay point status.

The behavior of the cluster head node during the maintenance phase of the virtual backbone network can be described as follows:

1) After receiving the GATEWAY message, the cluster head updates the information of the relevant entries in the gateway set and updates the expiration time of the entries. At any time, if an entry in the gateway set expires, the cluster head will immediately delete the entry.

2) In each backbone network cycle, the cluster head recalculates the MPR dominating point set and the gateway dominating point set based on the neighboring cluster information in the gateway set, and sends a BACKBONE message to notify all member nodes respectively.

3) If the clustering status of the cluster head changes, it will immediately lose the existing backbone network status and reset the backbone network status to unset.

The behavior of member nodes during the maintenance phase of the virtual backbone network can be described as follows:

1) In each backbone network cycle, members serving as gateway nodes will send GATEWAY messages containing the latest neighbor cluster information to the cluster head.

2) After receiving the BACKBONE message from the cluster head, the member node updates its backbone network status. If the MPR control point and gateway control point find that they have not been selected as the control point in this cycle, they will give up their MPR control point or gateway control point status, otherwise they will update the expiration time of their backbone network status. If a certain backbone network status of a node expires and is not updated, it will immediately lose the corresponding backbone network status.

3) In each backbone network cycle, the gateway control point selects a relay node in each neighboring cluster adjacent to it, and sends a RELAY_POINTS message to notify its own relay node.

4) When a node receives the RELAY_POINTS message from the gateway control point, it becomes the relay node of the message source node and updates the expiration time of its relay node status. If the relay node times out and does not receive the RELAY_POINTS message from the relay point selector, it will give up the relay node as the gateway dominating point.

5) If the clustering status of a member node changes, it will immediately lose the existing backbone network and relay point status, and reset the backbone network status to unset.

The technical principles of the present invention have been described above in conjunction with specific embodiments. These descriptions are only for explaining the principles of the present invention and cannot be construed as limiting the scope of the present invention in any way. Based on the explanations here, those skilled in the art can think of other specific embodiments of the present invention without any creative effort, and these methods will all fall within the protection scope of the present invention.

Claims

A clustered optimal link state routing method based on a virtual backbone network, which is characterized by: including establishing a virtual backbone network and maintaining the virtual backbone network on a clustered structure constructed by a clustered OLSR routing method based on management message merging;

During the establishment process of the virtual backbone network, the cluster head node first calculates the MCDS that can control all nodes in the cluster. Each cluster head selects a minimum number of gateway nodes to join its clustered MCDS, and then establishes a MCDS that can reach all neighboring clusters. CDS, the CDS of all clusters in the network constitute the backbone of the network; in addition, each cluster also needs to select relay nodes in neighboring clusters, and forward routing messages from this cluster through the relay nodes; based on the virtual backbone network Establish and select relay nodes, and set forwarding rules for routing message flooding;

In the virtual backbone network maintenance phase, the cluster head is used to periodically maintain the virtual backbone network and send messages to notify its member nodes to update their own backbone network status; the gateway node periodically submits the neighboring cluster nodes it discovered to the cluster head, so that the cluster head The latest neighbor cluster information can be obtained.
A clustered optimal link state routing method based on a virtual backbone network according to claim 1, characterized in that: the establishment of intra-cluster MCDS includes the following steps:

S1. Based on the HELLO message interaction content, the cluster head obtains the addresses and topology information of all member nodes, and peels off the topology view of its own cluster;

S2. According to the clustering topology, the cluster head uses the MPR set selection algorithm to calculate the MPR nodes covering all member nodes and marks them as MPR dominating points;

S3. The cluster head node records its own address and the addresses of these MPR dominating points in the MPR dominating point set, and notifies all member nodes of the MPR dominating point information of this cluster by sending a BACKBONE message;

After receiving the BACKBONE message sent by its cluster head, the member node records the MPR node address and cluster head address contained in the message in the MPR dominating point set; if the MPR dominating point set recorded in the BACKBONE message contains the address of the member node, Then the member node marks its own backbone network status as an MPR dominant point.
A cluster-based optimal link state routing method based on a virtual backbone network according to claim 2, characterized in that: the establishment of intra-cluster CDS includes the following steps:

S1. All gateway nodes send GATEWAY messages to their own cluster heads, the content of which includes their own address and the cluster head addresses of all neighboring clusters they discover;

S2. After receiving the GATEWAY message, the cluster head records the cluster head address and gateway node address of the neighboring cluster contained in it in the gateway set. The elements of this set are the cluster head address of the neighboring cluster and all gateways adjacent to the neighboring cluster. A vector composed of node addresses;

S3. The cluster head calculates the gateway control node;

S4. After completing the calculation of gateway domination points, the cluster head records all gateway domination points in the gateway domination point set, adds the gateway domination point set to the BACKBONE message and sends it to all member nodes;

After receiving the BACKBONE message sent by the cluster head, all member nodes record the set of gateway dominating points; if the set of gateway dominating points recorded in the BACKBONE message contains the address of the member node, the member node marks its own backbone network status as Gateway control point.
A clustering optimal link state routing method based on a virtual backbone network according to claim 3, characterized in that: the method for calculating gateway dominated nodes includes the following steps: first, if the cluster head is adjacent to the neighboring cluster node, Then it selects itself as the gateway dominating point, and deletes the related entries of all adjacent cluster head addresses found by it in the gateway set; if the gateway set is not empty after the above steps, the cluster heads gather from the MPR dominating point in each round. in After the point, the gateway set is still not empty, then the cluster head selects a gateway node from the gateway nodes in each round that is connected to the most neighbor clusters, marks it as a gateway dominating point, and deletes all neighbor clusters adjacent to it from the gateway set. Related entries until the gateway collection is empty.
A clustering optimal link state routing method based on a virtual backbone network according to claim 4, characterized in that: the relay node selection method includes: the gateway control point notifies neighboring cluster neighbors to become its relay by sending a RELAY_POINTS message Node, the relay node will select its gateway dominating point, which is called the relay point selector; if the relay node finds that its relay point selector is connected to the CDS of this cluster, the relay node will not forward the route from the gateway dominating point. Flood news.
A clustered optimal link state routing method based on a virtual backbone network according to claim 5, characterized in that it also includes a processing method for isolated nodes: each isolated node periodically sends a TC request message to the The neighbor with the maximum connectivity asks for global topology information, and its adjacent clusters do not need to forward routing messages to it; after an isolated node receives a TC or CTC message from other nodes, it must forward the message to all its neighbors. Node; an isolated node needs to select a relay node in each neighboring cluster to forward the TC message it generates.
A clustered optimal link state routing method based on a virtual backbone network according to claim 6, characterized in that: the flooding forwarding rules of routing messages include the following steps:

S1. The gateway dominating point selects a neighbor node with the maximum connectivity in each neighboring cluster as its relay node in the neighboring cluster; after selecting the relay nodes of all neighboring clusters, the gateway Nodes send RELAY_POINTS messages to notify these nodes to become their relay nodes;

S2. When a node receives the RELAY_POINTS message from a neighboring cluster, if the message contains its own address, it records the source node of the message as its own relay point selector;

S3. After the relay node receives the TC or CTC message sent or forwarded by its relay point selector, it searches the MPR dominating point set and gateway dominating point set of the cluster to see if there is a node adjacent to the relay point selector; If it is found that there is a node adjacent to the relay point selector, the relay node will not forward the TC or CTC message, otherwise it will forward it;

S4. If the node is in the virtual backbone network, that is, it is preferred by the cluster as an MPR dominating point or gateway dominating point, then it unconditionally forwards all received TC or CTC messages.
A clustering optimal link state routing method based on a virtual backbone network according to claim 7, characterized in that: during the maintenance phase of the virtual backbone network, the gateway node periodically reports neighbor cluster information to its own cluster head, and the cluster head First, the MPR dominance point and gateway dominance point are periodically calculated, and a BACKBONE message is broadcast to notify member nodes to confirm their backbone network status.
A cluster-based optimal link state routing method based on a virtual backbone network according to claim 8, characterized in that: during the maintenance phase of the virtual backbone network, the gateway node periodically sends GATEWAY messages to the cluster head, and the cluster head is Each entry in the gateway set sets an expiration time to delete expired information; the maintenance algorithm of the gateway set is as follows: each neighboring cluster head address in the gateway set corresponds to multiple gateway nodes. For an entry with a neighboring cluster head address , each gateway node has its own expiration time; when the cluster head receives the GATEWAY message from the gateway node, for each neighboring cluster head address in the GATEWAY message, the corresponding entry is found in the gateway set and the gateway node is updated The expiration time in each neighboring cluster head entry; when the expiration time of a gateway node in an entry in the gateway set times out, the gateway node is deleted from the entry. If an entry loses all gateway nodes, then Delete this entry.
A clustering optimal link state routing method based on a virtual backbone network according to claim 9, characterized in that in each cycle, the cluster head calculates the MPR domination point set and the gateway domination based on the latest neighbor cluster information. Point collection, and after completing the calculation, send a BACKBONE message to notify all member nodes; the member nodes set the expiration time for their own backbone network status, and check whether their backbone network status has timed out in each backbone network cycle, and receive the BACKBONE message Update the expiration time of its own backbone network status; in addition, each gateway control point needs to recalculate the relay nodes after confirming its backbone network status, and send a RELAY_POINTS message to notify the relay nodes; when the cluster head or member node's clustering status expires , it immediately loses the backbone network status and relay point status.