WO2007016827A1

WO2007016827A1 - A method for detecting the network topology automatically and realizing the narrow band service and a network structure therefor

Info

Publication number: WO2007016827A1
Application number: PCT/CN2005/002159
Authority: WO
Inventors: Xiaowen Yu; Hui Deng; Xiaoyu Tian
Original assignee: Zte Corporation
Priority date: 2005-08-11
Filing date: 2005-12-13
Publication date: 2007-02-15
Also published as: CN1913485A; CN100463446C

Abstract

A method for detecting the network topology automatically and creating the routing list and realizing the narrow band service, first sets the identifier and the connection relation for each node, then sends the handshaking message packet. Each node judges and fills its identifier according to the message packet received, then forwards the message packet modified. Each node determines the connection relation of the nodes according to the handshaking message packet, and creates the routing list, when a node in the network triggers the service, it searches the service node from the service routing list, if the service destination node and its node are same, the said node processes the service, otherwise, it performs track searching from the node routing list, and sends it to the next hop node to process. The present invention could set up any form network required, and realize smooth network expansion, and create the topological graph nicely and quickly according to the actual network condition, thereby it makes the service management more visible and advantaged.

Description

Method and network structure for automatically detecting network topology and implementing narrowband service

The present invention relates to a wired access technology in the field of communications, and in particular to an open adaptive networking technology involving a narrowband service of a wired access network. Background technique

In the traditional sense, the wired narrowband service access network is generally a star structure in terms of service topology. That is, an OLT (a central office access device of a narrowband access network) is connected to a plurality of ONUs (a remote access device of a narrowband access network) through a coaxial cable. Generally, each ONU takes tens to hundreds of users, communicates with the OLT through a fixed communication channel, and configures a downlink connection on the OLT to communicate with the ONU. The OLT acts as the network element to accept the management of the network management. In the early days, the ONU narrowband service configuration cost was low. Therefore, although the number of users is small, the networking mode is relatively simple and economical, and the network hierarchy is relatively clear.

However, with the development of the broadband and narrowband integrated access network services, the ONU's configuration processing capability is improved, and the network element is separately managed as a network element, so that the status of the ONU is improved and gradually approaches the OLT. In addition, because customers will change their business and reorganize from time to time in order to gain a competitive advantage, a new flexible networking and resource management solution is needed to quickly adapt to this change and provide customers with customized services. . The traditional networking method obviously cannot provide the flexibility of this networking and the agility required by the business. These shortcomings have led to a lack of openness in the network, and each access network is a separate array, and operators cannot integrate them.

Therefore, in today's continuous development of wide and narrowband integrated access network services, how to combine ONU's increasingly enhanced configuration processing capabilities to provide a flexible networking and timely provision of customized services for customers due to continuous business changes and restructuring. The resource management method and the implementation of an open adaptive networking method have become an urgent problem to be solved. Invention disclosure

The technical problem to be solved by the present invention is to provide a method for automatically detecting a network topology, establishing a routing table, and implementing a narrowband service according to the method and a corresponding networking structure to implement flexible networking and users of access nodes of the access network. Smooth network expansion adaptive networking technology, so that users of each node can be based on the current In the networking situation, adaptively select different node routes to complete signaling interaction with the switch.

The present invention provides a method for automatically detecting a network topology, including the following steps: Configuring a node identification number of each access node in the network and a connection relationship between directly connected nodes according to the physical networking situation;

Each node sends a handshake message packet to its directly connected node, where the packet contains the source node identifier and the intermediate node identifier information;

After receiving the handshake message packet, each node reads the source node and the intermediate node identifier information, and compares it with the identifier of the node;

If the node identifier is not included in the source node and the intermediate node in the handshake message packet, each node fills the node identifier number into the intermediate node identifier of the message packet, and forwards the modified node to the node directly connected thereto. Information package

Each node determines the connection relationship between the nodes based on the received node identification in the handshake packet from all other nodes in the network.

Preferably, the method further comprises the following steps:

The service node in each node broadcasts a service route setup message to other nodes, and the message includes the service node identification number;

Each node establishes a service node identification number in the message broadcast packet according to the received service route, and determines a service node in each node.

Preferably, the method further comprises the following steps:

When the network management system initiates the network topology data collection operation to any node in the network, the network topology map is displayed on the network management interface according to the connection relationship between the nodes determined by the node.

Preferably, the method further comprises the following steps:

When the network management system initiates the network topology data collection operation to any node in the network, the network topology of the service node is displayed on the network management interface according to the connection relationship between the nodes determined by the node and the determined service node identifier. Figure.

The present invention also provides a method for automatically establishing a network routing table, which generates and updates a routing table for each node in the network, including:

Establishing a node routing table for each node in the network, where the node routing table includes the destination node identification number and the next hop node identification number information, including the following steps:

Configure the node identification numbers of each access node in the network and each directly connected according to the physical networking. The connection relationship between nodes;

If the node identifier is not included in the source node and the intermediate node in the handshake message packet, each node adds a record in the node routing table of the node, and the destination node identification number in the record is the received handshake packet. The source node identification number, the next hop node identification number is the node identification number connected to the channel that received the message, and the local node identification number is filled into the intermediate node identifier of the message packet, and forwarded to the node directly connected thereto The modified package.

Preferably, the method further comprises the following steps:

Establishing a service routing table for each node in the network includes the following steps:

Configuring service data for the service nodes in each network node according to the physical networking situation, where the service data includes the actual circuit identification group corresponding to the service user of the target node and the length of the information content thereof; Broadcasting a service route setup message packet including the service node identification number and its configured service data;

After receiving the service routing setup message packet, each node determines whether the node has information corresponding to the service node. If not, the service information in the message packet is added to the service routing table of the local node. If yes, Then, the service information in the message packet is compared with the service node information stored in the node to update the service routing table of the node.

The present invention also provides a method for implementing a narrowband access network service, including the following steps:

Establishing a node routing table and a service routing table for each node in the network;

When a node in the network triggers a service, the service node is found through the service routing table.

If the service destination node is the same as its own node, the node processes the service. Otherwise, the node is routed through the node routing table and sent to the next hop node for processing.

The present invention further provides a network structure for a narrowband access network that implements narrowband service access by using the method for automatically detecting a network topology according to the present invention, including:

Switch

a plurality of narrowband access network central office access devices connected to the switch, wherein the plurality of central office access devices establish a connection with each other; and A plurality of narrowband access network remote access devices connected to the central office access device, wherein the plurality of remote access devices establish a connection with each other.

Further, the networking structure, wherein one of the remote access devices is connected to one or more of the central office access devices.

Further, in the networking structure, the remote access device is directly connected to the switch through a V5 interface.

The advantages of the present invention over the prior art are:

The invention applies the message propagation mechanism in the field of broadband data communication to the narrowband access network, and can automatically generate the network interconnection topology and the hierarchical structure according to the synchronization data of the network element; thereby greatly reducing the network data configuration and maintenance management. The complexity makes the mesh networking of the narrowband service access network possible. The implementation method of the invention is simple and easy to popularize, as long as the NRT (node routing table) message packet and the SRT (service routing table) message packet are simply standardized. Considering, it can provide open interconnection between different manufacturers' access networks, which facilitates resource optimization and equipment selection of operators; and the network structure is highly reliable. Due to the flexible networking form, it can be redundant from the perspective of network level. After the OLTs establish a connection relationship between the OLTs, the OLTs are not separately allocated, and the service relationship can be established, thereby enhancing the scalability of the application of the access network services in the entire network.

The technical problems, the technical solutions, and the beneficial effects to be solved by the present invention will be further described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a traditional star networking method;

2 is a schematic diagram of the mesh networking capability of the present invention;

Figure 3 NRT establishment process;

Figure 4 SRT establishment process;

Figure 5a—The processing flow of the node that detects the off-hook is detected during the service process of the calling process of the secondary PST call.

Figure 5b - The process of processing the off-hook message of the intermediate node in the process of the service process of the PSTN call as an example;

Figure 5c - The processing flow of the BCC allocation message received by the service node in the service processing process of the secondary PSTN call as an example; Figure 5d - The processing flow of the non-service node in the service process of the example of the calling process of the secondary PSTN call;

Figure 6a shows a network connection topology relationship generated by node 7 in a topology generated by a node using a certain network as an example;

Figure 6b takes a network as an example. In the topology generated by a node, the network connection topology relationship diagram of the network layer is adjusted for the service node. The best way to implement the invention

The present invention performs global numbering on each access node (including the ONU and the OLT), and performs topology and resource configuration management on each access node, so that each access node can perform any form of networking on the service relationship according to the needs of the client. And it is easy to achieve smooth expansion of the network. The present invention provides a simple, practical, and open networking method for the networking flexibility and service agility of the access network, which will have a significant impact on the networking of the narrowband service of the access network, and through the present invention. Interconnection of various types of access networks is made possible.

As shown in Figure 1, it is a schematic diagram of the traditional access network networking capability. As can be seen from the figure, each optical network unit ONU (ONU 100, ONU 101...ONU 10η) forms a star network centered on the optical line terminal OLT100, and each OLT 100 is independent and has no connection; each ONU Only one OLT is connected, and the OLT 100 is connected to the switch LE 10 through the V5 interface.

As shown in FIG. 2, it is a schematic diagram of the access network networking capability after adopting the technology of the present invention. It can be seen from the figure that it differs from FIG. 1 in that: First, a connection can be established between optical line terminals OLT, and services can be opened between OLTs (such as between OLT 21 and OLT 22), so that the entire range can be The service is extended within the access network. Secondly, the ONU can connect not only multiple OLTs through the internal interface, but also can connect with other ONUs (such as ONU 201 and ONU 20n). It can even be configured to connect the V5 interface directly to the switch LE 20.

First, let's introduce the basic configuration process.

The first step is to uniformly number all the access nodes in the network and configure the node identification numbers of the access nodes. The second step is to configure the connection relationship between the nodes, including the connection configuration of the communication channel between the nodes and the configuration of the voice channel resources. This step is mainly to establish a logical topology relationship between nodes and a basic NRT that is consistent with the physical network (but not related to the physical location).

Step 3 If the node is a service node, configure the service data of the node. Business festival A point is a node configured with a narrowband service, such as a V5 interface PSTN service, an ISDN service, a DDN service, and a Z interface service. If the node needs to provide a V5 interface, configure the V5 interface on the node and allocate the user circuit to the V5 interface, that is, assign the V5 L3 address to the user circuit. It should be noted that the user circuit may be located at this node or it may be located at another node.

Below, we introduce the process of establishing NRT as the basis for business process and SRT adaptive establishment.

NRT is the basis of the routing logic independent of the service. The principle is similar to the traditional Ethernet routing method. However, due to the point-to-point nature of the access network networking structure and the relative stability of the physical topology, we decided to adopt a kind of A more simplified basic path finding strategy. Mainly have the following characteristics:

Timing, for example: Sending a Hello packet (handshake packet) in a 10-second period to establish and update the NRT of the entire network.

A relatively simple but still effective method for loop routing that may occur during pathfinding is described later.

First, the format of the Hello packet used to create and update the NRT is as follows:

The message structure content and processing flow are described as follows:

E- HELLO is the event number, used to notify the directly connected node, this message is a Hello message for maintaining NRT; the source node indicates that the message is from this node; the number of intermediate nodes n indicates from the source node to receive this message The number of nodes in the path between nodes; node 1... all the way to node n represents the node of the path.

As shown in FIG. 3, when a node receives the message (step 301), the message is parsed, and a judgment is made to determine whether the message is a loop message (step 302):

If the node is a source node in the message content, or is included in the intermediate node, it indicates that the message has been routed to the node, and the message is discarded and is not processed to avoid an infinite loop of message transmission, step 303.

If the node is neither the source node nor the intermediate node in the message content, it indicates that the node information message is received by the node for the first time, according to the source node in the Hello message and the channel that receives the message. Updating the local NRT table (step 304), and adding the node information to the Hello message, and forwarding to all directly connected nodes (step 305), the specific steps are as follows:

Add a route record to the NRT of the node. The destination node in the record is the source node in the Hello message, and the Next Hop is the node connected to the channel that received the message.

To all other nodes directly connected to this node (received the section connected to the Hello message channel) Except for the point), this Hello information message is forwarded, but the content of the message needs to be modified. First, the number of intermediate nodes is increased by one, and the identification number of this node is filled to the end of the message.

After each node receives this message, repeat the first two steps.

In this way, each node can establish a basic NRT through this simple protocol. This NRT lays the foundation for the establishment of the next SRT and the processing of the business call flow logic.

The format of an NRT entry is as follows:

In addition to the basic routing entries, the NRT table can be accompanied by a record of the Next Hop state for each entry. The status mainly identifies whether the Next Hop is available. For example, an abnormal communication between nodes causes the Next Hop to be unavailable. This state is refreshed by the channel detection logic timing detection.

If you add a Next Hop count record in the NRT (this can be obtained from the Hello packet), you can select the route with the least number of intermediate nodes when routing, thus achieving a smaller call delay.

Next, introduce the process of establishing the SRT, which is related to service routing. The establishment of the SRT requires a Service Route Add message, which is broadcasted by the service node to the other nodes as the source.

The structure of the Service Route Add message is as follows:

The message content and corresponding processing flow are as follows:

E-SvcRouteAdd is the event number, indicating that it is a message to establish an SRT. The service node is a service node number configured to be a V5 port. The SLNs are the actual circuit identifier groups corresponding to the service users of the target node on the V5 port. The length of the information content of the corresponding SLNs. If there is no service user corresponding to the service node in the target node, the ϋlen is empty. The processing flow after the target node receives the message is as follows:

First, the receiving node determines whether the information corresponding to the service node already exists: if not, the service information is added to the local node and added to the SRT table; if yes, the information about the message structure and the service node information stored by the node Compare to update the SRT table. The service node is recorded into a list containing service nodes. This list stores the identification numbers of all service nodes in the network, so that the network management system generates a topology map with the service nodes as the vertices. As shown in Figure 4, in order to ensure that the SRT can keep updating when the service configuration changes (for example, changing the configuration of the V5 port), we adopt a simple strategy: For the sending node, the service change transmission and the timing transmission phase are adopted. The combined method sends a Service Route Add message to ensure that the SRT table of each node is updated in time when the service changes; the timing sending mechanism ensures the correctness of the SRT table of each node. For the receiving node, it is always based on the recently received Service Route Add message. If the newly received one is consistent with the SRT, it will not be processed. Otherwise, the SRT will be updated based on the newly received one. At the same time, a simple aging algorithm is considered. If the ServiceRouteAdd message sent by the service node is not received within a certain period of time, the original SRT information of the service node is cleared to ensure that the service user can be updated. As shown in FIG. 4, the following steps can be summarized as follows: Step 401: The SRT update timer expires;

Step 402: Send a ServiceRouteAdd message to the service user node.

Step 403, receiving a ServiceRouteAdd message;

Step 404, updating the SRT table according to the content of the message.

The format of an SRT entry is as follows:

SLN service node

In addition, in the Hello packet, as long as the "way number of idle channels" is filled in the session information, the number of idle channels of the new message is modified according to the occupancy of the session slot of the node and the adjacent node. If the number of idle channels of the node and the uplink node is greater than the number of idle channels in the original message, the number of idle channels in the new message remains unchanged in the original message, otherwise the number of idle channels is modified to The number of idle sessions between this node and this upstream node. As long as there is a record of the number of idle channels in the NRT, when the node receives the Hello packet, it fills in the field, and when the Next Hop is selected according to the node number of the SLN, it can be allocated in the service time slot. The route with the largest "number of idle channels" is selected to achieve a high connection rate.

For network systems that can be flexibly networked, topology management of the network is an important content. The invention enables the network management system to accurately and quickly generate a topology map of the network device according to the actual networking situation, and reflect the communication state and resource usage information between the network nodes in real time in the topology map. The method is: through the relay node information recorded in the Hello packet and the channel status recorded in the NRT table, the topology relationship of the network can be accurately generated, and a node can be established from any node according to the SRT service configuration. Business nodes are top-level maps of vertices, making business management more intuitive and convenient.

The following describes the calling process of a PSTN call as an example. The PSTN service is narrow. With the most typical business in the access network.

Figure 5a shows the processing flow after a node detects the off-hook action of the user circuit:

Step 5a01: An access node detects that a user circuit is off-hook, obtains a logical number SLN of the corresponding circuit, and triggers an off-hook message.

Step 5a02, find the SRT table and find the service node.

Step 5a03, determining whether the service node number and the own node number are the same;

Step 5a04: If the destination node is the same as the own node, hand the message to the corresponding V5 interface, send a call setup message Establish, and start interacting with the switch, otherwise go to the next step.

In step 5a05, the path is searched according to the NRT and sent to the Next Hop node.

Figure 5b shows the processing flow of the off-hook message sent by the intermediate node (that is, the Next Hop node above) to the source node (the node where the user circuit is located).

The processing flow is basically the same as that in Figure 5a. The steps are as follows:

Step 5b01, receiving an off-hook message of the neighboring node;

Step 5b02, determining whether the service node number and the own node number are the same;

Step 5b03, if the same, then the message is handed over to the corresponding V5 interface, the call setup message Establish is initiated, and the switch is started to interact, otherwise proceeds to step 5c04;

In step 5b04, the path is searched according to the NRT and sent to the Next Hop node.

Figure 5c shows the processing flow of the service node receiving the BCC allocation message of the switch. The processing steps are as follows: Step 5c01, the service node receives the BCC assignment session message that the switch responds.

Step 5c02, parsing the BCC allocation message, obtaining the V5 interface identifier, the link number LinkNo, the time slot V5Ts, and the V5 address allocated by the switching side. After receiving the message, the access node finds the V5 user according to the V5 interface number and the V5 L3 address. The corresponding user logical number SLN.

Step 5c03, the access node compares the node identification number in the SLN with its own node, and determines whether the user is the user of the node:

In step 5c04, if it is the user of the node, the time slot is connected to the user port, and the PSTN call process of the access network user to the switch is completed.

If it is not a user of this node, go to the next step.

Step 5c05: Find the corresponding Next Hop node according to the node identification number in the user logical number SLN in the NRT table; 'Assign the downlink time slot 11111⁄2 18 of the ^^ to the user. Connect the switching network, and set the downlink time slot InnerTs. Connected to the uplink time slot. (The uplink time slot here means the switch. Matching time slot). The connection message is sent to Next Hop, and the message structure carries the user's logic circuit number SLN and the downlink time slot InnerTs allocated for Next Hop.

Figure 5d shows the processing flow of the non-service node receiving the connection message sent by the previous node, which is processed as follows:

In step 5d01, the connected node receives the connection message sent by the connected node.

Step 5d02, parsing InnerTs and SLN.

Step 5d03, comparing the node identification number in the SLN with its own node, and determining whether the user is a local node user:

In step 5d04, if it is the user of the node, the time slot is connected to the user port, and the PSTN call process of the access network user to the switch is completed.

If it is not a user of this node, go to the next step.

Step 5d05: Find a corresponding Next Hop node according to the node identification number in the user logical number SLN in the NRT table; assign the user the downlink time slot InnerTs to Next Hop. The switching network is connected, and the downlink time slot InnerTs and the uplink time slot are connected. (The upstream time slot here means: the time slot InnerTs field in the continuation message). The connection message is sent to Next Hop, and the message structure carries the user's logical circuit number SLN and the downlink time slot InnerTs allocated for Next Hop.

According to the above steps, we can see that the Pstn call service can be successfully completed regardless of the complexity of the networking mode of the access network.

The above is an implementation process of the Pstn service as an example to illustrate the implementation process of the present invention. The implementation method for the ISDN service is similar to that of the PSTN. For a simpler narrowband service such as DDN, it is also easy to implement. No longer repeated.

As shown in FIG. 6a and FIG. 6b, the generation process of the network topology map is illustrated by an example. At the same time, the node 7 of the example is taken as an example to give an NRT table of the network.

First, the process of generating the network topology map is described. The network management configuration data process is as follows:

First configure the node identification number for the 7 nodes, and the connection relationship between them: establish the connection between the following nodes: 4 and 3, 3 and 6, 6, and 7, 5 and 2, 2 No. 6 and No. 6, and No. 1. Secondly, the services are configured on nodes 4 and 5, and the V5 interface is connected to the switch.

The configuration process ends.

For Node 7, the process of generating the network topology is as follows: Receive a Hello packet from each node, which contains the active node identification number and the intermediate node identification number experienced by the packet, for this example. For example, the node information of all the Hello packets received by node 7 is as follows: The Hello packet from node 1 is:

The Hello packet from node 4 is:

The Hello packet from node 6 is:

Thus, the network node topology information obtained by Node 7 from the above Hello packet is: From Node 1 - 1, 6, 7

From node 2: 2, 6, 7

From node 3: 3, 6, 7

From node 4: 4, 3, 6, 7

From node 5: 5, 2, 6, 7

From node 6: 6, 7 Thus, the node connection relationship shown in Fig. 6a can be obtained.

At the same time, since nodes 4 and 5 are configured with traffic, the E-SvcRouteAdd message packet is broadcasted to all other nodes including node 7, so that node 7 knows that the service node is node 4 and node 5. By increasing the network level of nodes 4 and 5, the network topology shown in Figure 6b is obtained. Finally, when the network management system initiates a network topology data collection operation to node 7, the network topology map can be displayed on the network management interface.

The following table shows the NRT table generated by Node 7 based on the Hello packets sent by the other 6 nodes:

As can be seen from the table, Node 7 must send a message to other nodes, which must be sent through Node 6.

Finally, when the node 7 receives the Service Route Add service route sent from nodes 4 and 5, it updates the SRT table. This completes the process of establishing NRT and SRT tables.

For network systems that can be flexibly networked, topology management of the network is an important content. The invention enables the network management system to accurately and quickly generate a topology map of the network device according to the actual networking situation, and reflect the communication state and resource usage information between the network nodes in real time in the topology map. Through the relay node information recorded in the Hello packet and the channel status recorded in the NRT table, the topology relationship of the network can be accurately generated, and a service node can be established from any node according to the SRT service configuration. The topology of the vertices makes business management more intuitive and convenient.

The networking technology of the present invention is not limited to the applications listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present invention, and can be easily realized by those skilled in the art. The invention is not limited to the specific details, the representative device, and the illustrated examples shown and described herein, without departing from the spirit and scope of the general concept and the scope of the invention. . Industrial applicability

Compared with the prior art, the present invention applies the message propagation mechanism in the field of broadband data communication to a narrowband access network, and can automatically generate a network interconnection topology and a hierarchical structure according to the synchronization data of the network element; thereby greatly reducing the The complexity of network data configuration and maintenance management makes the mesh networking of the narrowband service access network possible. The implementation method of the present invention is simple and easy to promote and use. As long as the NRT message packet and the SRT message packet are simply standardized, It can provide open interconnection between different manufacturers to access the network, which is convenient for operators to optimize resources and equipment selection; and the network structure is highly reliable. Due to the flexible networking mode, redundant backup can be performed from the perspective of the network level; By establishing a connection relationship between the OLTs, the OLTs are not separately allocated independently, and a service relationship can be established, thereby enhancing the scalability of the application of the access network service in the entire network.

Claims

Claim

A method for automatically detecting a network topology, which is used for a wired narrowband service access network, and includes the following steps:

Configure the node identification number of each access node in the network and the connection relationship between each directly connected node according to the physical networking situation.

2. The method according to claim 1, further comprising the steps of: the service node in each node broadcasting a service route setup message to the other node, the message including the service node identification number;

The method according to claim 1, wherein the handshake message packet further includes intermediate node quantity information; after the comparing step, if the local node identifier is not included in the handshake message packet In the source node and the intermediate node, each node fills the node identification number into the intermediate node identifier of the message packet, and after adding the number of the intermediate node to 1, transfers the modified information packet to the node directly connected thereto.

The method according to claim 1, further comprising the following steps: when the network management system initiates a network topology data collection operation to any node in the network, according to the connection relationship between the nodes determined by the node, The network topology diagram is displayed on the network management interface.

The method according to claim 2, further comprising the following steps: when the network management system initiates a network topology data collection operation to any node in the network, according to the node The connection relationship between the nodes and the determined service node identifiers are displayed on the network management interface, and the network topology diagram with the service nodes as the vertices is displayed.

The method according to claim 1, wherein, after the comparing step, if the node identifier is included in the source node and the intermediate node in the handshake message packet, each node receives the received The handshake message packet is discarded.

7. The method according to claim 1, wherein the step of forwarding the modified information packet to a node directly connected thereto is directly to a node connected to the channel that receives the handshake message packet. Connected nodes are forwarded.

8. A method for automatically establishing a network routing table, which generates and updates a routing table for each node in the network, and is used for a wired narrowband service access network, and is characterized by:

The method according to claim 8, wherein in the step of establishing a node routing table, after the comparing step, if the local node identifier is included in the source node and the intermediate node in the handshake message packet, Each node discards the received handshake message packet.

The method according to claim 8, wherein in the step of establishing a node routing table, the step of forwarding the modified information packet to a node directly connected thereto is to receive a channel of the handshake message packet Directly connected nodes other than connected nodes are forwarded.

The method according to claim 8, wherein in the step of establishing a node routing table, Further includes the following steps:

Each node periodically sends a handshake message packet to update the node routing table of each node.

The method according to claim 8, further comprising the steps of: establishing a service routing table for each node in the network, comprising the following steps:

The method according to claim 12, wherein in the step of establishing a service routing table, the step of the broadcast service route establishment message packet is broadcast transmission when the service changes, or/and a scheduled broadcast transmission.

The method according to claim 12, wherein the step of establishing a service routing table further comprises the following steps:

If the node does not receive the service route setup message packet sent by a service node within a predetermined time, the node clears the service routing table information of the service node.

The method according to claim 8, wherein the node routing table further includes a next hop node status record, indicating whether the next hop is available, and the channel detection logic timing

The method of claim 8, wherein the handshake message packet further includes intermediate node quantity information; after the comparing step, if the local node identifier is not included in the handshake message packet In the source node and the intermediate node, each node fills the node identification number into the intermediate node identifier of the message packet, and after adding 1 to the number of intermediate nodes, forwards the modified information packet to the node directly connected thereto; '

The node routing table further includes a record of the number of next hops, which is obtained from the information of the number of intermediate nodes in the received handshake message packet.

17. The method of claim 8 wherein said handshake message packet further The voice channel information is filled with the number of idle voice channels, and the node routing table further includes a record of the number of idle voice channels. After the nodes receive the handshake message packet, if the node and the uplink node are empty, If the number of idle channels is greater than the number of idle channels in the original message, the number of voice channels is kept and filled in the routing table of the node; otherwise, the number of idle channels is modified to the number of idle channels of the node and the uplink node, and is filled in. In the node routing table.

18. A method for implementing a narrowband access network service using the method for establishing a network routing table according to claim 12, comprising the steps of:

A narrowband access network networking structure that utilizes the method of claim 1 to implement narrowband service access, and includes:

Switch

a plurality of narrowband access network central office access devices connected to the switch, wherein the plurality of central office access devices establish a connection with each other; and

A plurality of narrowband access network remote access devices connected to the central office access device, the plurality of remote access devices establishing a connection with each other.

The networking structure of claim 19, wherein one of the remote access devices is connected to one or more of the central office access devices.

The networking structure of claim 19 or 20, wherein the remote access device is directly connected to the switch through a V5 interface.