CN100438687C - Method for ensuring general wireless packet business to support node business continuity - Google Patents

Abstract

The present invention relates to a method for guaranteeing service continuity among support nodes of general radio packet service, which comprises procedures that a signaling path among the support nodes of the general radio packet service is detected by a path management message in a tunnel protocol of the general radio packet service; scheduled time is delayed after the disconnection of the signaling path is detected; contexts on the signaling path are processed according to information variation on the signaling path within the scheduled time. The service continuity of a user can be guaranteed in a complicated network environment by the system by utilizing the present invention, and the influence that system performance is lowered and a single plate is reset without heartbeat caused by a large amount of repeated disconnection alarm of the signaling path is avoided.

Description

Method for Ensuring Service Continuity Between GPRS Support Nodes

technical field

The invention relates to the technical field of network communication, in particular to a method for ensuring service continuity between general wireless packet service support nodes.

Background technique

UMTS (Universal Mobile Telecommunications System) is a third-generation mobile communication system that adopts WCDMA (Wideband Code Division Multiple Access) air interface technology, and the UMTS system is usually also called a WCDMA communication system. The UMTS system adopts a structure similar to that of the second generation mobile communication system, including RAN (Radio Access Network) and CN (Core Network), where RAN is used to handle all wireless-related functions, while CN handles all Voice calls and data connections, and realize switching and routing functions with external networks. UTRAN (UMTS Terrestrial Radio Access Network), CN and UE (User Equipment) together constitute the entire UMTS system, and its network structure is shown in Figure 1, where:

The RNC (Radio Network Controller) completes the control and management functions of the base station, the UTRAN is connected to the user equipment through the Uu interface, and is connected to the CN through the Iu interface.

CN is logically divided into CS (Circuit Switched Domain) and PS (Packet Switched Domain). Among them, MSC/VLR (Mobile Switching Center/Visitor Location Register), GMSC (Gateway Mobile Service Switching Center) belong to CS domain, SGSN (Serving GPRS Support Node), GGSN (Gateway GPRS Support Node) belong to PS domain. The HLR (Home Location Register) belongs to a functional node shared by the CS domain and the PS domain. MSC/VLR (Mobile Switching Center/Visitor Location Register) completes the functions of CS domain control, management, authentication and encryption. GMSC is the network management of MSC and is responsible for connection with other fixed or mobile networks.

SGSN and GGSN are functional nodes in the packet switching domain of the WCDMA core network, and are connected through the Gn/Gp interface. Among them, the SGSN is a device connecting the access network and the GGSN, and performs functions such as route forwarding, mobility management, session management, authentication, and encryption in the PS domain. GGSN is the interface with the external IP packet network, and provides routing and encapsulation of data packets between the WCDMA mobile network and the external data network.

The interface between SGSN and GGSN is based on GTP (GPRS Tunneling Protocol) to realize tunnel transmission function, including signaling plane GTP-C (GTP Control Plane Protocol) and user plane GTP-U (GTP User Plane Protocol). GTP-C completes tunnel management and other signaling message transmission functions, and GTP-U transmits user plane data packets. The 3GPP29060 protocol specification defines GTP.

In WCDMA, the data packets of the mobile phone are directly carried by GTP encapsulation between the SGSN and the GGSN, that is, the Gn interface of the GGSN and the SGSN exchange data and signaling through the GTP tunnel, and the GGSN and the SGSN establish legal Based on information such as the user's PDP (Packet Data Protocol) context, the GGSN restores the data message received from the wireless access network side into an IP message, and then performs data interaction with the external packet data network through the Gi interface.

In the GTP protocol, path management functions are included. Described path refers to the path of transmission signaling and data between a pair of GSN, is made up of IP address/UDP (User Datagram Protocol) port number of respective endpoint, can be divided into signaling path and data path; Path protocol is Refers to the UDP/IP protocol used to carry the GTP protocol between GSNs.

At present, the processing of the signaling path in the GSN is in accordance with the provisions of the GTP protocol, and the specific implementation process is as follows:

The signaling path table for maintaining path information is stored in the GSN. The signaling path records the signaling transmission path between the local GSN and other GSN nodes, including: the location of the sending Echo Req path, the maximum number of signaling paths, the number of currently used paths, etc. information. Its function is to maintain the queue of request signaling waiting for response, and record data path information (such as source, destination address, number of contexts on the path, etc.).

The signaling path is allocated once when the system is initialized, so the signaling path table is determined when the system is initialized. The resource management module in the GSN is responsible for maintaining the signaling path table. The resource management module maintains an idle path chain, records the chain head and the chain tail, when the path entry needs to be allocated, it starts from the head of the linked list, and when the path entry is released, it is added to the end of the linked list, and the linked list uses the path table A domain to achieve.

GSN regularly sends ECHO request messages and waits for the response from the peer GSN. When the ECHO request message sent on the signaling path times out, the number of timeouts on the path is increased; if the number of timeouts is greater than the set threshold, the signaling path is disconnected. , release the request message waiting queue on the path, trigger the signaling path disconnection alarm, and perform the operation of deleting the context on the signaling path.

Although the existing schemes fully follow the description of the protocol, they do not fully consider the operation of the actual network equipment. Because the connection situation of the network may be very complicated, the performance of the network may not maintain a good level, and performance problems such as QOS (Quality of Service) on the GPRS backbone network have not been completely resolved, and the congestion of the network is inevitable. In this case, it is unavoidable that the temporary communication between the GGSN and a certain SGSN is interrupted due to reasons such as network congestion, or the request message sent by the GGSN to the SGSN is lost. In this way, it is possible to temporarily interrupt the connection between the GGSN and the SGSN and cause deletion of all users on the corresponding path. Since the temporary interruption of the connection between two devices is inevitable in the current network environment, such an approach is actually unreasonable.

In addition, before deleting the context on the signaling path, the signaling path detection timer will detect that the signaling path is broken according to the context, and report the warning line of the path breaking. According to the existing technical solution, if there are multiple contexts on the signaling path, the It is possible to trigger multiple identical alarm logs. When there are a large number of contexts on this signaling path, the printed and reported alarm logs may completely occupy the CPU (Central Processing Unit) resources of the system, thus making the system unable to work. Serious will cause the system to reboot.

Contents of the invention

The purpose of the present invention is to provide a method for ensuring the continuity of services between GPRS support nodes, so as to overcome the shortcomings in the prior art that all users are disconnected due to a temporary failure of the network and the repeated alarms caused by the disconnection of the signaling path , so that the system can fully guarantee the continuity of business processing under the condition of network congestion.

For this reason, the present invention provides following technical scheme:

A method for ensuring service continuity between GPRS support nodes, the method comprising:

A. Initialize the pre-established signaling path table between GPRS support nodes, and detect the signaling path in the signaling path table through the path management message in the GPRS tunneling protocol;

B. When it is detected that the signaling path is disconnected, a path disconnection alarm is triggered, and the corresponding path state in the signaling path table is set as the path disconnection state, and the predetermined time is delayed;

C. Process the context on the signaling path according to the change of the information on the signaling path within the predetermined time.

Before said step A, also include:

A1. Establish a signaling path table, the signaling path table includes: the location of the path sending the response request, the maximum number of signaling paths, the number of currently used paths, data path information, path break counter, path status, and the path status Including: idle state, normal state, path disconnected state.

The pre-established signaling path table between the initialized GPRS support nodes includes:

A21. Setting the path state corresponding to each entry in the signaling path table to an idle state;

A22. Set the path break counter corresponding to each entry in the signaling path table to 0;

A23. Set the threshold of the path break counter.

The detecting the signaling path in the signaling path table includes:

A31. Establish a path detection mechanism;

A32. Detect the signaling path in the signaling path table according to the path detection mechanism.

The step A31 is specifically: setting the T3 timer and the N3 counter in the path management message, the T3 timer is used for the response time of the preset message, and the N3 counter is used for resetting the preset message. number of passes.

Described step A32 comprises:

selecting a detected signaling path from the signaling path table;

sending a path management message on the detected signaling path;

If a response message from the opposite end is received within the time specified by the T3 timer, then the signaling path is protected as a normal state;

Otherwise, at the frequency set by the T3 timer, repeatedly send the path management message;

If the response message from the opposite end is received within the timeout range of the N3 counter, then protect the signaling path as a normal state;

Otherwise, set the signaling path to the path disconnected state.

Described step C comprises:

C1. Start the idle path detection mechanism. The idle path detection mechanism includes: T3 timer, which is used to preset the response time of the message;

C2. When the T3 timer expires, accumulating the path break counter;

C3. When the accumulated value of the path disconnection counter exceeds the threshold, delete the context on the corresponding signaling path.

Said step C also includes:

If there is a context activation or update on the signaling path within the predetermined time, or a response request message sent by the peer GPRS support node, then clear the path disconnection counter of the corresponding entry in the signaling path table 0.

The GPRS support node includes: a gateway GPRS support node and/or a serving GPRS support node.

As can be seen from the technical solution provided by the present invention above, the present invention detects the path through the path management message during the GSN device connection process, and does not immediately delete the user context information on the path after detecting that the path is broken, but keeps a predetermined During the predetermined time, due to the elimination of temporary network failure or congestion, the path may have context activation or update or ECHO request again, so that it is possible to make the signaling path return to the normal state, avoiding the present In the existing technology, the user context is deactivated due to the temporary failure of the network, and at the same time, unnecessary signaling path disconnection alarms are reduced, thereby improving the fault tolerance of the system and enhancing the stability of the system; by increasing the signaling path table The status and detection times counter enable the system to ensure the continuity of user services in a complex network environment, and avoid the impact of a large number of repeated signaling path disconnection alarms that degrade system performance and even cause board restarts; It can effectively clear the users and avoid problems such as redundant billing for users.

Description of drawings

Fig. 1 is a schematic diagram of the network unit structure of the universal mobile communication system;

Fig. 2 is a flow chart of the inventive method;

Fig. 3 is a flow chart of detecting a signaling path through an idle path detection mechanism;

Fig. 4 is a flow chart of performing idle path detection within a predetermined time in the method of the present invention.

Detailed ways

The core of the present invention is to use the activation mechanism when detecting the path through the path management message, and add a "path broken" status indication in the signaling path entry, that is, when the path is detected to be broken, the path is set to the "path broken" state. , the user context information on the path will not be deleted immediately, but will be kept for a predetermined time. If there is a context activation or update or ECHO request on the path within the predetermined time, the path will be reset to "normal" ” state, that is, activate the path, and take the path state as a necessary condition for the alarm. After the path is broken, no matter the ECHO detection or the delete signaling operation will no longer trigger the path broken alarm. In this way, the processing method of deleting the user context information on the path immediately after detecting that the path is broken in the prior art can avoid the impact on the system in the case of a temporary network failure, and maintain the continuity of services between GSNs (General Packet Radio Service Support Nodes) .

Those skilled in the art know that 3GPP protocol 29060 stipulates that there are three kinds of path management messages: Echo Request (Echo request) message, Echo Response (Echo response) message, VersionNot Supported (GTP version does not support) message, respectively as follows:

1. Echo Request message: sent on the path to detect whether the GSN or RNC at the opposite end is normal. Echo Request messages are sent on the "active path". A path "in use" means that at least one PDP context uses this path to connect to the peer GSN. The sending interval of the Echo Request message should not be less than 60 seconds. A GSN or RNC device should be able to receive Echo Request messages at any time and respond to Echo Response messages. It is optional for GSN or RNC to send Echo Request messages.

2. Echo Response message: This message is the response to the Echo Request message.

3. Version Not Supported message: This message only contains the GTP header, indicating the GTP protocol version supported by the GTP entity on the UDP/IP address.

Use the Echo Request message and Echo Response message of the GTP protocol path management message to detect the connectivity of the signaling path and the data path. The Echo Request message is sent to the peer GSN, and the peer device returns an Echo Response message after receiving it. If the local GSN device does not receive a response message within a certain period of time, the path is considered broken.

To ensure reliable delivery of signaling messages, each path maintains a queue of signaling messages sent to peer entities. If the message at the front of the queue is a request message with a defined response, it will be sent with a serial number and kept until the corresponding response is received. Each path has its own path table. In a routing table, the sequence number of each pending request message is unique. A GSN or RNC may have multiple pending requests while waiting for a response. When sending a signaling request message, the T3 timer (preset response time) should be started, and the number of requests N3 (preset retransmission times) should be set.

In the present invention, on the basis of using the protocol to manage the path, when the path is detected, after detecting that the path is broken, the user context information on the path is kept for a predetermined time, and then deleted after confirming that the path is indeed broken contextual information.

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

With reference to Fig. 2, Fig. 2 is the flowchart of the inventive method, comprises the following steps:

Step 201: Establish a signaling path table, the signaling path table includes: the location of the path sending the response request, the maximum number of signaling paths, the number of currently used paths, data path information, path break counter, path status, the path The states include: idle state, normal state, and path disconnected state.

Step 202: Initialize the signaling path table, the signaling path table needs to initialize the following content:

(1) The path state corresponding to each entry in the signaling path table is set to an idle state;

(2) Set the path break counter corresponding to each entry in the signaling path table to 0;

(3) Set the threshold of the path break counter.

It can be seen that, compared with the prior art solution, the present invention modifies the structure of the signaling path:

In order to save the signaling path information when the signaling path is temporarily interrupted, so as to keep the signaling context unchanged, the signaling path state is added to the two states of "idle" and "normal" in the prior art. In addition, through this state, only one alarm can be triggered after the same signaling path is disconnected, and the context is not deleted immediately when the signaling path is detected to be disconnected, but the context is temporarily maintained for a predetermined time, According to the change of information on the signaling path within the predetermined time, specific processing is performed, or the context is deleted, or the path is restored to a normal state. At the same time, in order to maintain the disconnection state of the signaling path for a certain period of time, but not permanently, a path disconnection counter is added to the signaling path structure. Even after the path is disconnected, the signaling path still passes the EchoRequest of the GTP protocol. The message is detected, the counter is accumulated according to the number of detections, and the context information on the path is deleted when the counter reaches the set threshold.

Step 203: Establish a path detection mechanism.

Step 204: Detect the signaling paths in the signaling path table according to the established path detection mechanism.

That is, the Echo Request message and the Echo Response message of the GTP protocol path management message are used to detect the connectivity of the signaling path and the data path. To this end, it is necessary to set the T3 timer and N3 counter in the path management message. Then, the signaling paths in the signaling path table are detected in turn, and the specific detection method is the same as in the prior art, that is, the resource management module on the GSN maintains an idle path chain, records the chain head and the chain tail, and when it is necessary to allocate When the path entry is allocated, it is allocated from the head of the linked list; when the path entry is released, it is added to the end of the linked list, and the linked list is implemented using a field in the path table. For each signaling path, send the Echo Request message regularly and wait for the response. When the Echo Request message sent on the signaling path times out, that is, exceeds the set T3 timer time, increase the number of timeouts on the path; if it times out If the number of times is greater than the value of the set N3 counter, it is considered that the signaling path is disconnected.

Figure 3 is a process for detecting each signaling path, including the following steps:

Step 301: Set T3 timer and N3 counter.

Step 302: Select the signaling path to be detected from the signaling path table.

Step 303: Start the T3 timer.

Step 304: Send an Echo Request (Echo request) message through the signaling path.

The message includes the version number of the GTP protocol supported by the local device, which may be V0 and V1 of the GTP protocol specified by 3GPP (Third Generation Mobile Communications Standardization Partnership Project).

The source address of the Echo Request message is the network address of the local device, and the destination address is the network address of the peer device. These network addresses have been pre-configured in the routing table of each endpoint device when the network is built.

Then, go to step 305: judge whether the T3 timer expires.

If the T3 timer has not expired, go to step 306: receive the Echo response message from the peer device.

For the Echo Request message, there may be two types of response messages from the peer: Echo Response (Echo response) message; Version Not Supported (GTP version does not support) message. The EchoResponse message includes the version number of the GTP protocol supported by the peer device.

If an Echo Response message is received, it is considered that the interface with the peer device is connected, indicating that the peer device is active and the GTP protocol is running normally;

If a Version Not Supported message is received, it is considered that the interface with the peer device is connected, indicating that the peer device is active, but does not support the GTP protocol version of the local end.

In this way, it indicates that the signaling path is normal, so go to step 307: keep the path as normal.

If the T3 timer expires, then go to step 308: the N3 counter is decremented by 1, indicating that a detection has been completed.

Then, go to step 309: judge whether the number of detections is 0, that is to say whether N3 detections have been completed;

If N3 detections have been completed, it indicates that the response from the peer device has not been received after the duration of N3*T3. At this time, it can be considered that the path between the peer device and the peer device has been interrupted. Go to step 310: set the path It is the broken state of the path.

If the N3 detections have not been completed, return to step 303: restart the T3 timer.

When a path disconnection is detected, a path disconnection alarm needs to be reported, and then the path status corresponding to the signaling path needs to be set to the path disconnection state.

That is, go to step 205: when it is detected that the signaling path is disconnected, delay for a predetermined time, and within the predetermined time, first trigger a path disconnection alarm, and then set the corresponding signaling path in the signaling path table as the path off state.

After the signaling path is set to be in the path disconnection state, after that, as long as the path is in the path disconnection state, neither the ECHO detection nor the signaling deletion operation can trigger the path disconnection alarm. In this way, because the signaling path has a path broken state, even when the context is deleted, no alarm message is sent and the alarm log is no longer printed. It ensures that the path disconnection alarm is not sent repeatedly on the same path, and avoids a large number of path disconnection alarms and logs that cause the CPU to be monopolized, and even cause serious impacts on board restarts.

Then, go to step 206: process the context on the signaling path according to the change of the information on the signaling path within a predetermined time.

When the context is activated or updated on the signaling path, it is necessary to allocate a path entry from the idle path chain or accumulate the context count on the existing path. At the same time, the signaling path state is reset to a normal state, and the path disconnection counter of the corresponding entry in the signaling path table is set to 0.

In this way, it is ensured that when the signaling path is disconnected, the signaling path may still be restored to normal. That is, if there is a context activation or update or a response request message sent by the peer GSN node on the signaling path within a predetermined time, the counter of this signaling path disconnection is immediately set to 0, so that the path disconnection counter does not exceed the set threshold, This ensures that the context is not deleted immediately.

In addition to the above processing, after the path state is disconnected, the above-mentioned idle path detection mechanism needs to be started. Keep the path disconnected for a certain period of time and then delete the path after confirming that the path cannot be restored.

Idle path detection is performed within a predetermined time, and whenever the T3 timer expires, the path disconnection counter corresponding to the path is accumulated; when the accumulated value of the path disconnection counter exceeds the set threshold, all traffic on the corresponding signaling path is deleted context, and finally delete this signaling path.

The process of performing idle path detection within a predetermined time is shown in Figure 4, including the following steps:

Step 401: Set a path break counter threshold.

Step 402: Start an idle path detection mechanism.

Step 403: Start the T3 timer.

Step 404: Determine whether the timer T3 expires.

If the T3 timer has not expired, go to step 405: receive the Echo request message from the opposite end. That is to say, within a predetermined time, the Echo request message from the opposite end is received again on the signaling path, indicating that the path is "resurrected" again.

Go to step 406: clear the path break counter.

Then, go to step 411: set the path as a normal state.

If the T3 timer expires, go to step 407: add 1 to the path disconnection counter.

Then, go to step 408: determine whether the path break counter exceeds the set threshold.

If the path break counter has exceeded the threshold, go to step 409: delete the context information on the path.

Then, go to step 410: delete the path.

If the path break counter has not exceeded the threshold, return to step 403: restart the T3 timer.

For example, to detect a signaling path between GGSN and SGSN:

For the GGSN node, it is necessary to send an Echo request message from the GGSN to the SGSN, and the SGSN sends an Echo response message to the GGSN.

Under normal circumstances, after receiving the Echo request message sent by the GGSN, the SGSN will respond to the Echo response message to the GGSN. If the GGSN receives the Echo response message within the T3 time limit, the path is considered to be in a normal state; wait for the T3 timer again After the timeout, continue sending Echo request messages.

If the GGSN does not receive the Echo response message within the T3 timing time, at this time, the N3 counter is started to count, and each time an Echo request message is sent, if the GGSN does not receive the Echo response message within the T3 timing time, the N3 counter is incremented by 1 ,So on and so forth. If the GGSN receives the Echo response message from the SGSN before N3 exceeds the set threshold, it resets the N3 counter to 0; otherwise, it considers that the signaling path is disconnected. At this time, the context is not deleted immediately, but the state of the signaling path is set as the path broken state, and the path broken counter corresponding to the signaling path is started at the same time, and the ECHO cycle timer T3 is used as the clock source. Accumulate the signaling path disconnection counter. If the counter does not exceed the threshold (the parameters such as the specific field value can be configured by the network management system), and an Echo response message is received, the context will be restored, and the signaling path disconnection counter will be cleared; otherwise, when the count exceeds the set When the threshold is , it is considered that the signaling path is completely disconnected, so the context information on the path is deleted, and finally the signaling path is deleted.

For the SGSN node, it is necessary to send an Echo request message from the SGSN to the GGSN, and the GGSN sends an Echo response message to the SGSN.

The detection process is the same as that described above, and will not be repeated here.

While the invention has been described by way of example, those skilled in the art will appreciate that there are many variations and changes to the invention without departing from the spirit of the invention, and it is intended that the appended claims cover such variations and changes without departing from the spirit of the invention.

Claims (9)

1, a kind of method that guarantees business continuance between the GPRS support node is characterized in that, described method comprises:

The signaling paths table of setting up in advance between A, initializing universal grouping service wireless support node, and by the path management information in the GPRS tunnel protocol signaling paths in the described signaling paths table is detected;

B, after detecting described signaling paths and breaking, trigger the disconnected alarm in path, and corresponding path status is set to the disconnected state in path, delay scheduled time in the signaling paths table;

C, handle context on the described signaling paths according to change in information on the described signaling paths in the described scheduled time.

2, method according to claim 1 is characterized in that, before the described steps A, also comprises:

A1, set up the signaling paths table, described signaling paths table comprises: send the path position of response request, maximum signaling paths number, the number of path of current use, data path information, the path counter that breaks, path status, described path status comprises: idle condition, and normal condition, state breaks in the path.

3, method according to claim 2 is characterized in that, the signaling paths table of setting up in advance between described initializing universal grouping service wireless support node comprises:

The path status of each list item correspondence is set to idle condition in A21, the described signaling paths table;

A22, the disconnected counter in the path of each list item correspondence in the described signaling paths table is put 0;

The threshold value of A23, the disconnected counter in the described path of setting.

4, method according to claim 3 is characterized in that, described signaling paths in the described signaling paths table is detected comprises:

A31, set up path detection mechanism;

A32, the signaling paths in the described signaling paths table is detected according to described path detection mechanism.

5, method according to claim 4 is characterized in that, described steps A 31 is specially: set T3 timer and N3 counter in the described path management information, described T3 timer, the response time that is used for presetting message, described N3 counter is used for the number of retransmissions of presetting message.

6, method according to claim 5 is characterized in that, described steps A 32 comprises:

From described signaling paths table, select detected signaling paths;

Transmit path administrative messag on described detected signaling paths;

If receive receiveing the response of opposite end in described T3 timer timing, then protecting this signaling paths is normal condition;

Otherwise the frequency so that described T3 timer is set repeats the transmit path administrative messag;

If receive receiveing the response of opposite end in the expired times scope of described N3 counter, then protecting this signaling paths is normal condition;

Otherwise it is the disconnected state in path that this signaling paths is set.

7, method according to claim 3 is characterized in that, described step C comprises:

C1, start the idle route testing mechanism, described idle route testing mechanism comprises: the T3 timer is used for response time of presetting message;

C2, behind described T3 timer expiry, the disconnected counter in the described path of adding up;

C3, after the accumulated value of the disconnected counter in described path surpasses described threshold value, delete the context on the corresponding signaling paths.

8, method according to claim 2 is characterized in that, described step C comprises:

If the response request message that has context activation or renewal or opposite end GPRS support node to send in the described scheduled time on the described signaling paths is then with the disconnected counter clear 0 in the path of corresponding list item in the described signaling paths table.

9, method according to claim 1 is characterized in that, described GPRS support node comprises: gateway general grouping service wireless support node and/or service general grouping service wireless support node.

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