CN110417636B

CN110417636B - Decentralized self-organizing instant messaging system and method thereof

Info

Publication number: CN110417636B
Application number: CN201810405220.0A
Authority: CN
Inventors: 黄楚媛; 黄斌
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-04-28
Filing date: 2018-04-28
Publication date: 2022-06-21
Anticipated expiration: 2038-04-28
Also published as: CN110417636A

Abstract

The invention discloses a decentralized self-organizing instant messaging system and a method thereof. The system comprises at least one node management main server and a plurality of subsystem servers, wherein the node management main server and the subsystem servers have a routing function and an instant messaging function; when nodes in the sub-network carry out instant messaging crossing the sub-network, the node management main server only records the ID codes and the real-time IP addresses of the sub-system servers and the nodes where the instant messaging is accessed, and does not store instant messaging content. The invention adopts a unique decentralized architecture and a self-organizing management mode, and can realize instant communication service between people, between people and machines and between machines. In the self-organizing instant messaging system, the node user account book and the access record account book ensure the awareness and credibility in the whole instant messaging service process, and the decentralized architecture ensures that the risk of leakage of instant messaging contents in the transmission process does not exist.

Description

Decentralized self-organizing instant messaging system and method thereof

Technical Field

The invention relates to an instant messaging system, in particular to an instant messaging system which adopts a decentralized architecture and has self-organizing capability, and also relates to a corresponding instant messaging method, belonging to the technical field of instant messaging.

Background

Instant Messaging (IM) refers to a service capable of instantly sending and receiving internet messages and the like, which allows multiple people to use instant messaging software to transfer information streams such as text information, documents, voice, and video in real time. Since 1998, the functions of instant messaging systems have become increasingly abundant, and a comprehensive information platform integrating communication, information, entertainment, search, electronic commerce, office collaboration, enterprise customer service, and the like has been developed.

As shown in fig. 1, the instant messaging system in the related art mainly provides services using a client/server (C/S) manner and/or a peer-to-peer communication (P2P) manner. The C/S mode takes a database as a core, a plurality of computers connected in a network form an organic whole, and a client and an instant messaging server respectively complete different functions. However, in the C/S method, information interaction between clients needs to pass through the instant messaging server, which inevitably generates risks in information security, privacy disclosure, and the like. The P2P method is a decentralized Peer-to-Peer communication method, and each client (Peer) is an equal participant, and takes two roles as a service user and a service provider. The clients are in direct communication, so that the network bandwidth can be fully utilized, the congestion condition of the network is reduced, and the utilization rate of resources is greatly improved. However, due to the characteristics of the P2P mode, such as decentralization, autonomy, and dynamics, the access result of the client is unpredictable in some cases. For example, the client's request may not get any feedback.

For this reason, the currently used instant messaging system generally uses a combination of the C/S scheme and the P2P scheme. For example, the identity authentication phase in login is operated in a C/S mode, and then the P2P mode is used if the clients can directly communicate with each other, otherwise, the communication is realized through the instant messaging server in the C/S mode. However, this combined use method does not eliminate the risks in the aspects of information security and privacy disclosure. Moreover, with the rapid increase of the number of clients, the throughput pressure of the instant messaging server is huge, and communication congestion is easy to occur.

In chinese patent application No. 201410582597.5, a method for ad hoc instant messaging based on Wi-Fi direct is disclosed. The instant communication method comprises the following steps: 1) the user terminal starts the Wi-Fi direct connection network, searches surrounding groups and joins the groups; if the group is not searched or cannot be added, searching surrounding intelligent terminals and establishing the group with the intelligent terminals; the group leader has P2P equipment, saves the equipment information of the group member to the equipment information table and broadcasts in the group; 2) the group member sends a heartbeat packet containing self state information to the group leader periodically, and the group leader updates the state and the time stamp of the corresponding group member according to the received heartbeat packet and feeds back confirmation information; 3) when a group member or group leader needs to communicate with a target member in the group, the IP address of the target member is selected from the locally stored equipment information table to initiate a connection request, and communication is performed after the connection is successful. By using the technical scheme, the short-distance instant messaging between the intelligent terminals can be realized under the condition of not accessing a cellular network base station or a WLAN access point.

Disclosure of Invention

In view of the deficiencies of the prior art, the first technical problem to be solved by the present invention is to provide an instant messaging system (abbreviated as ad hoc instant messaging system) with a decentralized architecture and ad hoc management capability.

Another technical problem to be solved by the present invention is to provide an instant messaging method for the ad hoc instant messaging system.

In order to achieve the purpose, the invention adopts the following technical scheme:

according to a first aspect of the embodiments of the present invention, a decentralized self-organizing instant messaging system is provided, which includes at least one node management main server and a plurality of subsystem servers, where the node management main server and the subsystem servers have a routing function and an instant messaging function;

in each subsystem server-centric sub-network, comprising a plurality of nodes;

when the nodes in the sub-network carry out instant messaging spanning the sub-network, the node management main server only records the ID codes and the real-time IP addresses of the sub-system servers and the nodes where the instant messaging is accessed, and does not store instant messaging contents.

Preferably, in the sub-network, instant communication inside the sub-network is realized between the nodes through the subsystem server.

Preferably, the subsystem server is provided with an access record account book which is used for recording the node user account book of the node details and the access records between the nodes respectively; wherein, the access record ledger can only be added and can not be modified.

Preferably, when a node needs to perform distributed computation, the node user account book in the sub-system server of the sub-network where the node is located is accessed, information of other surrounding nodes which can provide computing capability support is obtained, and a distributed computation request is sent to the other nodes.

Preferably, in the distributed computing process, the initiating node packages the computing program and the computing data simultaneously and sends the packaged computing program and the packaged computing data to other nodes participating in the distributed computing, and the other nodes recover all the computing program, the computing data and the computing results after completing the computing.

Preferably, if a certain software plug-in determines to open the service to the outside, the node user ledger in each subsystem server is updated after the software plug-in is installed in the node.

Preferably, the ID code participating in the instant messaging is recorded in the node management main server in advance, otherwise, the node management main server rejects the service; the ID code is bound to the hardware device of the node.

Preferably, in the instant messaging process, the instant messaging content to be temporarily stored is only stored in the subsystem server.

Wherein preferably, in each subsystem server centric sub-network, further comprising a back-end piece; the end piece is plugged in and pulled out of the subsystem server, so that the subsystem server realizes function expansion.

According to a second aspect of the embodiments of the present invention, there is provided an instant messaging method for the above ad hoc instant messaging system, including the steps of:

the source node accesses a first subsystem server Na to which the source node belongs, and obtains an IP address of a second subsystem server Nb where the destination node is located and an IP address of the destination node from a node user account book stored by the first subsystem server Na;

the source node tries to directly access the destination node according to the IP address of the destination node; if the access is successful, the connection is directly established and the message is sent, and if the access is unsuccessful, the second subsystem server Nb is accessed to obtain the IP address or the state of the destination node;

if the destination node is not on-line, the source node establishes connection with a second subsystem server Nb and sends off-line information; the second subsystem server Nb sends the off-line information when the target node is on line; if the destination node is on-line, directly establishing connection and sending a message;

the access record is recorded in the first subsystem server Na and the second subsystem server Nb, and the node user ledger and the access record ledger in the other subsystem servers are updated by the node management main server.

Compared with the prior art, the self-organizing instant messaging system provided by the invention adopts a unique decentralized architecture and a self-organizing management mode, and can realize instant messaging service between people, between people and machines and between machines. In the self-organizing instant messaging system, the node user account book and the access record account book ensure the awareness and credibility in the whole instant messaging service process, and the decentralized architecture ensures that the risk of leakage of instant messaging contents in the transmission process does not exist.

Drawings

FIG. 1 is a block diagram illustrating an overall architecture of a typical instant messaging system in the prior art;

fig. 2 is a schematic diagram of the overall architecture of the ad hoc instant messaging system provided in the present invention;

FIG. 3 is a flow diagram of a distributed computing implementation using a node user ledger;

FIG. 4 is an exemplary diagram of a user ID in an embodiment of the invention;

FIG. 5 is a schematic structural diagram of a patch-plug router as a subsystem server;

FIG. 6 is a schematic diagram of the patch-plug router shown in FIG. 5;

FIG. 7 is a diagram of a female part of the patch router;

FIG. 8 is a schematic diagram of the connected end piece portions of a patch router;

FIG. 9 is a flowchart illustrating an instant messaging between a source node and a destination node according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of an interface for mobile APP, in accordance with an embodiment of the present invention;

fig. 11 is a schematic diagram of an interface configuration of a software plug-in according to an embodiment of the present invention.

Detailed Description

The technical contents of the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

Fig. 2 is a schematic diagram of an overall architecture of the ad hoc instant messaging system provided by the present invention. In one embodiment of the self-organizing instant communication system, the system comprises at least one node management main server (S node for short) and a plurality of subsystem servers (N node for short), wherein each subsystem server and the node management main server are communicated in a wired and/or wireless mode; the subsystem servers can also communicate directly with each other in a wired and/or wireless manner. In the invention, the node management main server and the subsystem server have basic routing function and instant communication function, and a known and credible peer-to-peer network is formed by the combination of the node management main server (S node), the subsystem server (N node) and the subsystem server (N node) … ….

In each sub-system server-centric sub-network, a plurality of personally owned end-pieces (simply referred to as D-nodes) are included. The subsystem server is used as a master part in a sub-network, and a plurality of end part ports are arranged on the subsystem server and can be used for direct plugging and unplugging of various end parts, so that the function expansion of the subsystem server is realized. In addition, the subsystem server may be provided with a wireless routing module (or plug-in end-piece with a wireless routing function), so as to form a wireless local area network in a specific area, and provide access to each end-piece and a user terminal (e.g., a network terminal for a user such as a smart phone or a tablet computer). A mobile APP (a user terminal with the mobile APP is referred to as an a node for short) for a user to realize a management control function can be set on the user terminal. Through the combination of subsystem server (N node) + end piece (D node) + mobile APP (a node) ", it is possible to form sub-networks that are independent of each other.

In the ad-hoc instant messaging system provided by the invention, in order to ensure information security and avoid privacy disclosure, it is explicitly specified that the S node can only record ID codes (such as MAC addresses of network cards or user IDs mentioned later) and real-time IP addresses of various nodes participating in instant messaging, so as to facilitate mutual access among sub-networks centering on the N node. It should be noted that the ID code is bound to hardware devices (such as a network card, a hard disk, and a CPU) of each node (N node, D node, a node, etc.) participating in instant messaging, and single hardware device information is avoided when binding. Moreover, the ID code is recorded in the S node, and the ID code that is not recorded cannot participate in any instant messaging service. Through the technical measures, the occurrence of cheating behaviors such as network agents and the like is effectively avoided. In addition, instant messaging content transferred between different subnetworks may be cryptographically processed and may not be stored in the S node. Thus, the risk of leakage of the instant communication content in the transmission process is avoided. In the above process, the S node cannot access and store the instant messaging content transmitted via it, and cannot intervene in the instant messaging service provided by it. The technical characteristics of the ad-hoc instant messaging system provided by the invention adopting the decentralized peer-to-peer network architecture are reflected.

On the other hand, in the existing instant messaging system, if the called client is not online, the corresponding communication content can be temporarily stored in the instant messaging server, and the client is forwarded after being online. This approach brings convenience to the instant messaging user, and also inevitably poses a risk of information leakage. Therefore, in the self-organizing instant communication system provided by the invention, instant communication contents needing to be temporarily stored are stored in the subsystem server, and any instant communication contents are forbidden to be stored in the node management main server. Moreover, the subsystem server is directly controlled by the user, and any information cannot be transmitted outwards without permission. Therefore, the self-organizing instant communication system can meet the actual demand of the instant communication client for receiving and sending information offline, and the defect that the existing instant communication system is easy to cause information leakage is overcome.

Since a subsystem server having a routing function and an instant messaging function exists in each sub-network, an instant messaging service can be provided inside the sub-network. But the internal instant messaging service does not transmit communication content outwards, so that the risk of information leakage does not exist.

Besides the routing function and the instant messaging function, the subsystem server is also provided with two distributed accounts for recording node details (node user account book, abbreviated as Z1) and access records (access record account book, abbreviated as Z2) between nodes. The node user account book records the names and addresses (including but not limited to subnet addresses, IP addresses or GPS positioning information) of all nodes participating in instant messaging in the sub-network in which the node user account book is located in an encrypted manner. The access record book records access record logs among all nodes (including nodes in a sub-network and nodes in other sub-networks) in an encryption mode, wherein the access record logs comprise access time, user IDs, real IP addresses and the like. It is emphasized that the access record ledger can only be appended and cannot be modified in order to maintain network security.

By the node user account book and the access record account book, the self-organizing instant messaging system can be known and credible. The term "to know" means that each node participating in instant messaging can learn the name and address of other nodes through the two distributed ledgers when necessary. The credibility means that some bad accesses can be processed by the two distributed accounts in combination with a corresponding transaction backtracking mechanism, an election rule and the like, so that the safety credibility of the whole self-organizing instant communication system is realized.

It should be noted that the node user ledger Z1 may also be used to implement distributed computation, so as to reduce the amount of local computation. Referring to fig. 3, the nodes that are filed all around are stored in the node user ledger Z1. Thus, by accessing the subsystem server, the information of surrounding nodes which can provide the support of computing power can be obtained through the node user book Z1, so that distributed computing requests are sent to the nodes, and computed data is obtained from the nodes and then is locally integrated and presented. In the distributed computing process, the self-organizing instant communication system separates the computing program from the computing data. The node initiating the distributed computation (referred to as initiating node for short) packages the computation program and the computation data at the same time and sends the packaged computation program and the packaged computation data to other nodes participating in the distributed computation, and the computation program, the packaged computation data and the packaged computation result are all recycled after the computation is completed by other nodes. In this way, each node participating in distributed computation does not retain any computation program, computation data and computation result at all, and the security and the confidentiality of distributed computation are ensured.

On the other hand, in the ad hoc instant messaging system provided by the invention, through the names and addresses of the nodes participating in instant messaging in the sub-network where the account book records of the node users are located, the ad hoc management of the nodes is realized without a central server (the S node cannot access and store the instant messaging content transmitted by the S node, cannot intervene in the instant messaging service provided by the S node, and therefore does not have the function of the central server). The access record ledger records the access conditions among all nodes so as to track, feed back and even intervene when necessary, thereby effectively avoiding network attack behaviors initiated among all nodes. In addition, each node can selectively open own information and service to the outside, and the information and service are prevented from being provided blindly and repeatedly by managing through an intelligent contract based on the block chain technology after the node is opened to the outside.

In the self-organizing instant communication system provided by the invention, the information access process and the content thereof in each sub-network are not usually published outwards, and can be selectively opened outwards under special conditions. The endpieces (D-nodes) inside each subnetwork can be marked as open and not open to the outside: 1) for the end-piece that is open outside, nodes outside the sub-network can apply for access and record in the access record ledger; 2) the access is not open to the outside end-pieces, but only to the end-pieces and the mobile APP inside the home network.

In order to facilitate mutual access among all nodes in The ad hoc instant Messaging system, all communication processes among The nodes are realized by adopting an XMPP (The Extensible Messaging and Presence Protocol) Protocol. In addition, each node participating in instant messaging is given a uniform user ID. As shown in fig. 4, in one embodiment of the invention, the user ID comprises a four-digit system identification code, such as CXY 1; a 16-bit random number as a UUID for each hardware device; the four-digit type identification code is specifically shown in table 1, where 01 denotes that the user is an XMPP software client, 02 denotes that the user is Web client software, 03 denotes that the user is a hardware device, and 04 denotes that the user is a software endpoint.

01	XMPP software client
		02	Web client software
03	Hardware device
		04	Software endpoint

TABLE 1 type identification code

In one embodiment of the invention, the subsystem server (N-node) used may be a patch-type router that is modified from the structure of an existing switch, socket, or socket board. As shown in fig. 5 and fig. 6, in an embodiment of the patch-plug type router, the patch-plug type router includes a housing 1, an external connection area 2 and an expansion area 3 are disposed on the housing 1, a routing module 4, a power carrier module 5, a wireless transmission module 6, a storage module 8 and a power module 9 are disposed inside the housing 1, the routing module 4 is connected to the power carrier module 5, the wireless transmission module 6 and the storage module 8, respectively, and the power module 9 is connected to the routing module 4, the power carrier module 5, the external connection area 2 and the expansion area 3, respectively; wherein, the external connection area 2 and the expansion area 3 are respectively provided with a plurality of interfaces; the interface of the outer connection area 2 is used to connect the patch router with the wide area network, so as to realize the instant communication function. The interface that extension zone 3 set up is used for connecting the end part, realizes the function extension of piece together formula of inserting router. In addition, the interface arranged in the expansion area can realize the splicing between at least two adjacent routers, and the requirement that a user uses more gateway devices for data exchange is met.

In the above-mentioned patch router, the fixed part is called a female part, and the pluggable end part is also called a male part. As shown in fig. 7, each master 13 includes a power module 9, a power carrier module 5, and a routing module 4, and the power module 9 and the power carrier module 5 are respectively connected to the routing module 4.

As shown in fig. 8, each of the subcomponents 14 includes at least an extended function module 17 and an XMPP module 18. The extended function module 17 is connected to the XMPP module 18, the power module 9, the power carrier module 5, and the routing module 4, respectively. The extended function module 17 may be determined according to different functional requirements of each sub-component, and may be, for example, various sensors, a collector, a light controller, a temperature controller, and the like. The XMPP module, as a functional module executing an XMPP protocol, may be implemented in software or firmware, and is used to perform interfacing with a server and data processing. The mother piece 13 and the child piece 14 are connected through a clamping spring clamp 19 to form a subsystem server capable of meeting different function expansion requirements. For example, the extended function module 17 with wireless network transmission function is plugged into the sub-component 13 of the subsystem server which is distributed at different locations (for example, different rooms) and is composed of a switch, a socket or a socket board, so that wireless network services can be provided for different locations, and the problem of instability existing after the existing wireless network penetrates through the wall is solved. Therefore, different extended function modules 17 are replaced according to actual requirements, and the extended function of the patch-plug type router can be realized based on a carrier communication mode.

In an embodiment of the patch-plug type router, a side surface (except a side surface serving as an external connection area) of the housing 1 may be used as the extension area 3, the extension area 3 is provided with a plurality of interfaces 301 and heat dissipation holes 302, and each interface 301 is connected to the routing module 4 and the power module 9 respectively. Each of the headers 301 may be a female slot to facilitate connection with the end pieces and to avoid interference between the end pieces that are plugged into the female slots. The shape and size of the interface 301 may be determined according to the shape and size of the connection end of the end piece plugged into the patch-type router, and the interface 301 may be connected to different types of end pieces through a conversion connector. These end pieces may be various sensors, collectors, light controllers, etc. When the interface 301 of the add-and-drop router is inserted into the end piece, the add-and-drop router has a corresponding expansion function, for example, if the end piece is a temperature sensor, the add-and-drop router inserted with the temperature sensor can have a temperature sensing function; the end piece is a light controller, and the split-plug type router inserted into the light controller can have a light control function. Of course, the tip may be readily removed from the hub 301 when it is no longer in use, to allow the hub 301 to be inserted into another tip as required. This feature is particularly useful for implementing smart homes using patchwork routers.

It should be noted that some common general interfaces, such as a USB interface, may be provided on the extension area 3. In an embodiment of the present invention, an interface for connecting an SSD memory (solid state memory) may be provided on the expansion area 3, and the interface is connected with the routing module 4 and the power module 9, respectively, for further expanding the storage capacity of the patch router.

Fig. 9 is a flowchart illustrating an operation of a node a (source node) performing instant messaging with another node b (destination node) through a mobile APP according to an embodiment of the present invention. In the instant communication process, the node a firstly accesses the subsystem server Na to which the node a belongs, and the node user account book Z stored in the subsystem server Na₁The subsystem server N in which the node b is located_bIP address and Z₁The IP address of the intermediate node b. Node a then attempts to base directly on Z₁The IP address of the middle node b accesses the node b; if access is toIf successful, directly establishing connection and sending message, if access is unsuccessful, accessing subsystem server N_bThe IP address or status of node b is obtained. If node b is not online, node a directly contacts subsystem server N_bAnd establishing connection and sending off-line information. Subsystem server N_bWhen the node b is on line, the message is sent; if node b is online, the connection is established directly and the message is sent. Then, the subsystem server Na and the subsystem server N_bThe access record is recorded, and the records in the node user account book Z1 and the access record account book Z2 in other subsystem servers in the instant messaging system are updated through the node management main server.

FIG. 10 is a diagram illustrating an interface for mobile APP, in accordance with an embodiment of the present invention. The mobile APP includes a plurality of native software plug-ins and object software plug-ins. In use, the local software plug-in and the object software plug-in for providing external services can be obtained through a local automatic search function, and the algorithm is similar to the algorithm adopted by the 'nearby people' provided by the existing instant messaging software (such as WeChat), and thus the detailed description is omitted. Through the functions, the mobile phone can directly use local software plug-ins which are open to the outside on other mobile phones; or, corresponding object software plug-ins are directly downloaded from other mobile phones and installed and operated on the mobile phone, so that the service capability of the mobile phone is greatly enriched and expanded.

As shown in fig. 11, when the software plug-in is installed, it must pass through authority authentication given by the node management main server (S node) and the subsystem server (N node), and be given a specific software plug-in ID. After obtaining the software plug-in ID, the software plug-in itself can independently set whether it is open to the outside world for service. If it is determined that the service is open to the outside, after the software plug-in is installed, the records in the node user account Z1 of each subsystem server in the whole instant messaging system need to be updated correspondingly, so that other nodes can remotely access the software plug-in to obtain the corresponding service when needed.

Compared with the prior art, the self-organizing instant messaging system provided by the invention provides a competitive network architecture for instant messaging service in the era of the Internet of things. The system adopts a unique decentralized architecture and a self-organizing management mode, and can realize instant messaging service between people, between people and machines and between machines. In the self-organizing instant messaging system, the node user account book and the access record account book ensure the awareness and credibility in the whole instant messaging service process, and the decentralized architecture ensures that the risk of leakage of instant messaging contents in the transmission process does not exist.

The decentralized self-organizing instant messaging system and the method thereof provided by the invention are explained in detail above. It will be apparent to those skilled in the art that any obvious modifications thereto can be made without departing from the true spirit of the invention, which is to be accorded the full scope of the claims herein.

Claims

1. A decentralized self-organizing instant messaging system is characterized by comprising at least one node management main server and a plurality of subsystem servers, wherein the node management main server and the subsystem servers have a routing function and an instant messaging function; in each subsystem server-centric sub-network, a plurality of nodes are included; when the nodes in the sub-network carry out instant communication crossing the sub-network, the node management main server only records the ID codes and the real-time IP addresses of the sub-system servers and the nodes where the instant communication is accessed, does not store the instant communication content,

an access record account book for recording node user account books of node details and access records among nodes is arranged in the subsystem server; the access record account book can only be added and can not be modified, and the node user account book records the name and the address of each node participating in instant messaging in a sub-network in which the node user account book is located in an encryption mode; the access record account book records access record logs among all nodes in an encryption mode;

the node manages the instant messaging content that the global server cannot access, save, and intervene with the instant messaging services provided by the global server,

in the sub-network, instant communication inside the sub-network is realized among the nodes through the subsystem server;

when a certain node needs to perform distributed computation, the node user account book in the subsystem server of the sub-network where the node is located is accessed, information of other nodes which can provide computing capability support around the node is obtained, and a distributed computation request is sent to the other nodes.

2. The ad hoc instant messaging system of claim 1, wherein: in the distributed computing process, the initiating node packs the computing program and the computing data at the same time and sends the computing program and the computing data to other nodes participating in the distributed computing, and the other nodes recover all the computing program, the computing data and the computing result after completing the computing.

3. The ad hoc instant messaging system of claim 2, wherein: and if the certain software plug-in determines that the service is open to the outside, updating the node user account book in each subsystem server after the software plug-in is installed in the node.

4. The ad hoc instant messaging system of claim 1, wherein: ID codes participating in instant messaging are recorded in the node management main server in advance, otherwise, the node management main server refuses service; the ID code is bound to the hardware device of the node.

5. The ad hoc instant messaging system of claim 1, wherein: in the instant communication process, the instant communication content needing to be temporarily stored is only stored in the subsystem server.

6. The ad hoc instant messaging system of claim 1, wherein: in each subsystem server centric sub-network, further comprising an end-piece; the end piece is plugged in and pulled out of the subsystem server, so that the subsystem server realizes function expansion.

7. An instant messaging method for the ad hoc instant messaging system of claim 1, comprising the steps of: the source node accesses a first subsystem server (Na) to which the source node belongs, and obtains the IP address of a second subsystem server (Nb) where the destination node is located and the IP address of the destination node from a node user account book stored by the first subsystem server (Na); the source node tries to directly access the destination node according to the IP address of the destination node; if the access is successful, directly establishing a connection and sending a message, and if the access is unsuccessful, accessing a second subsystem server (Nb) to obtain the IP address or the state of the destination node; if the destination node is not on-line, the source node establishes connection with a second subsystem server (Nb) and sends off-line information; a second subsystem server (Nb) sends the off-line information when a target node is on line; if the destination node is on-line, directly establishing connection and sending a message; recording the access record in the first subsystem server (Na) and the second subsystem server (Nb), updating the account book of the node user and the account book of the access record in the other subsystem servers through the node management main server,

an access record account book for recording node user account books of node details and access records among nodes is arranged in the subsystem server; the access record account book can only be added and can not be modified, and the node user account book records the name and the address of each node participating in instant messaging in a sub-network in which the node user account book is located in an encryption mode; the access record book records access record logs among all nodes in an encryption mode;

the node management main server can not access and store the instant communication content transmitted by the node management main server, and does not intervene in the instant communication service provided by the node management main server.