JP2008270895A - Ss7 signal processing system and fault recovery method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a SS7 (Signaling System 7) signal processing system which can recover the system more quickly in comparison with the existing system by eliminating the need for reestablishing an SS7 link after restarting a process on a system by allowing system restart while maintaining the establishment of the connection with a communication partner. <P>SOLUTION: A resident resource management resident process 6 which is not supervised by a supervisory process 7 is prepared, and only a file descriptor acquired from an SS7 physical circuit termination device driver 2 is stored in a common memory area 8 by the resource management resident process 6. An SS7 signal link control process 5 accesses the SS7 physical circuit termination device driver 2 by the stored file descriptor when restarted for restoring the SS7 signal processing system. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is an SS7 (Signaling System No. 7) signal transmission / reception / call processing system constructed using a general-purpose OS (operating system), and is a piece of software (process) that realizes various functions on the system. The present invention relates to a technique for quickly recovering from a failure without affecting a signal link performing signal transmission / reception due to a failure of a unit.

  Patent Document 1 (Japanese Patent Laid-Open No. 2000-57095) describes a process that includes a server and a plurality of terminals, establishes a TCP / IP connection between the terminal and the server, and performs communication using a socket. The above communication processing system is configured as follows in order to allow the server and the terminal to continue communication without disconnecting the TCP / IP connection even if the process ends abnormally. Are disclosed.

  That is, a control unit that establishes a control connection with a process to monitor communication and process state monitoring, and a unit that manages a processing state of communication with a terminal using an inter-process shared memory. The TCP / IP connection is established to acquire a socket, and the acquired socket is copied to the control means through the control connection. When the control means detects abnormal termination of the process, the backup socket is passed through the control connection. The process is copied to another process, and this other process continues the communication process with the terminal using the copy of the backup socket.

  However, this is limited to application in a communication system that performs communication using a TCP / IP connection.

  By the way, high-speed and large-capacity signal stations for terminating or transferring SS7 (Signaling System No. 7) signals transmitted / received in the existing telephone network and IP (Internet Protocol) network of the base signal network are being promoted. In particular, system construction using a general-purpose OS (operating system) that can realize high-performance processing at low cost and general-purpose hardware has become mainstream. In these systems, a general-purpose OS such as Linux (registered trademark) can be used to realize various functions and a flexible system configuration. The realization of high system reliability is a challenge.

  In the SS7 signal processing system constructed using a general-purpose OS, each function is realized as a “process” that runs on the OS, and multiple processes such as signal transmission and reception and maintenance functions are executed in parallel. The system is configured and functions are provided. If any one of these software processes operates abnormally, it may affect the processing of the entire system. Therefore, in preparation for the occurrence of a large-scale failure, monitoring that monitors all processes on the OS It is controlled by the process. When an abnormal process occurs, the monitoring process immediately detects it and restarts all processes to restore the system to a normal state.

  However, since all processes operating on the system are restarted due to an abnormality in a process that performs one function, a problem is that a service provided by the system is stopped. For example, an abnormality in the time correction process that has nothing to do with SS7 signal processing leads to service stop of signal link control and signal transmission / reception processing, which are main processing of the system. In particular, the SS7 signal link with the opposite signal station or the process that controls the IP link with the opposite signal station on the IP network is restarted, so that the link with the opposite signal station is disconnected and the network is Will be treated as a major system failure.

  Control resources (file descriptor / socket descriptor) provided by the device driver of the SS7 signal terminator and the OS kernel are used for signal link control, but these resources are automatically released when the process is restarted. The link will be broken. For this reason, the continuation of the link by taking over the link control information is a problem even in the case where the process restart occurs. For these minor system failures, established link links are not affected, and link-less system recovery techniques are desired.

In general, a device that terminates a physical line of SS7 is mounted as a single device that is attached to a general-purpose device based on a PC (personal computer) base by a bus connection or the like. In order to control the SS7 line termination device from an application program operating on the OS, a device driver that operates as a kernel module on the OS is provided. The signal processing control process for performing signal link control and signal transmission / reception such as establishment and disconnection of the signal link calls the device driver API (Application Program Interface) to realize the corresponding function.
JP 2000-57095 A

  Therefore, the problem of the present invention is that the system can be recovered while the connection with the communication partner is established, so that the re-establishment process of the SS7 link performed after the process restart on the system becomes unnecessary. It is an object of the present invention to provide an SS7 signal processing system and its failure recovery method that enable quick system recovery as compared with the above.

  The present invention according to claim 1 relates to an SS7 signal processing system, and performs an SS7 physical line termination device driver for controlling an SS7 physical line termination device, a process group for realizing a system maintenance function, and a signal link control / signal transmission / reception. An SS7 signal link control process, a monitoring process that constantly monitors the abnormal state of these processes, and a resident resource management resident process that is not monitored by this monitoring process are provided. This resource management resident process is obtained from the SS7 physical line termination device driver. The SS7 signaling link control process accesses the SS7 physical line termination device driver by the retained file descriptor when the SS7 signaling processing system is restarted to restore the SS7 signaling processing system. When That.

  That is, the process that realized the signal link control in the conventional SS7 signal processing system, the resident process that only holds the file descriptor that is the resource identifier of the SS7 physical line termination device driver, the signal transmission / reception and the link control are realized. The signal link control process is separated, and the link control information is shared between the processes to perform signal processing.

  The invention according to claim 2, which is a preferred form thereof, has a shared memory shared by the SS7 signal link control process and the resource management resident process, writes a file descriptor together with link information to the shared memory, and performs the SS7 signal link control process. Refers to this shared memory at the time of restart for restoring the SS7 signal processing system.

  Similarly, in the invention according to claim 3, when the resource management resident process makes a request to disconnect the signal link from the SS7 signal link control process, the corresponding file descriptor for signal link control is sent to the SS7 physical line termination device driver. Has the function to release.

  Similarly, the invention according to claim 4 has a function that allows the SS7 signal link control process to select whether or not to take over the file descriptor held in the resource management resident process when the SS7 signal processing system is restarted. .

  The invention according to claim 5 relates to a failure recovery method in an SS7 signal processing system, an SS7 physical line termination device driver that controls an SS7 physical line termination device, a process group that implements a system maintenance function, and a signal link control / signal. An SS7 signal link control process that performs transmission and reception, a monitoring process that constantly monitors the abnormal state of these processes, and a resident resource management resident process that is not monitored by this monitoring process are provided. Only the file descriptor obtained from the driver is retained, and upon restart to restore the SS7 signal processing system, the SS7 signal link control process uses the retained file descriptor to access the SS7 physical line termination device driver. Characterized in that it processes.

  The invention according to claim 6, which is a preferred form thereof, writes a file descriptor together with link information to a shared memory shared by the SS7 signal link control process and the resource management resident process, and restarts to restore the SS7 signal processing system Sometimes the SS7 signaling link control process accesses the SS7 physical line termination device driver with reference to the shared memory.

  Similarly, in the invention according to claim 7, when a signal link disconnection request is issued from the SS7 signal link control process, the resource management resident process sends a corresponding signal link control file descriptor to the SS7 physical line termination device driver. Let go.

  Similarly, in the invention according to claim 8, when the SS7 signal processing system is restarted, the SS7 signal link control process selects whether to take over the file descriptor held in the resource management resident process or not.

  As described above, normally, the signal link control resource acquired by the process restart at the time of the failure is released, but in the present invention, the signal processing management process is performed by the SS7 signal link that performs signal transmission and reception and link control. By separating the control process from the resource management resident process that only holds the file descriptor that is the resource identifier for signal link control acquired from the SS7 physical line termination device driver, the possibility of process abnormality occurrence is eliminated. Excluded from process restart when a system failure occurs. Even if the signal transmission / reception / link control process, which is the main function, is restarted due to a software failure on the system that is not related to signal processing, the process is small enough to hold resources for link control. Since the resource management resident process that does not require monitoring stays resident, it is possible to prevent the release of the control resource of the established signal link and to realize a failure recovery method that is transparent to the opposite signal station that does not cause signal link disconnection.

  Therefore, in a system that realizes connection control by SS7 signaling link or SCTP (Stream Control Transmission Protocol) association, in the event of a minor system failure, without disconnecting the connection with the communication partner facing this system, System recovery that is transparent to the opposite system can be realized. It is possible to recover from a failure without causing a temporary service interruption due to a system abnormality, thereby providing high fault tolerance as a system. In addition, since the system can be restored while the connection with the communication partner is established, the SS7 link re-establishment process that is performed after the process restart on the system is not required. Recovery is possible.

  According to the second and sixth aspects of the invention, the shared memory shared by the SS7 signaling link control process and the resource management resident process can efficiently perform operations between these processes.

  According to the third and seventh aspects of the present invention, when there is a signal link disconnection request from the SS7 signal link control process, the resource management resident process applies the corresponding signal link control to the SS7 physical line termination device driver. Therefore, even if the signal processing management process is separated into the SS7 signal link control process and the resource management resident process, the signal link can be disconnected and reconnected without any trouble.

  According to the inventions according to claims 4 and 8, when the SS7 signal processing system is restarted, the SS7 signal link control process determines whether the file descriptor held in the resource management resident process is taken over or not. Therefore, it is possible to arbitrarily select whether to take over the previous information, discard the previous information (link disconnection), and establish a new link according to the situation.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  The SS7 signal processing system according to the present invention terminates a TDM (Time Division Multiplexing) or ATM (Asynchronous Transfer Mode) physical line that constitutes a base network of an existing telephone network, and transfers an SS7 signal or executes a call processing. It is applied to signal station servers such as End Point) and STP (Signaling Transfer Point). The signal station server is constructed by mounting a dedicated SS7 line termination device on a general-purpose hardware base based on a PC or the like.

FIG. 1 shows a configuration example of an SS7 signal processing system according to the present invention.
This SS7 signal processing system, as hardware, terminates a TDM (Time Division Multipexing) or ATM (Asynchronous Transfer Mode) physical line with an SS7 physical line termination device 1 and operates it on a general-purpose OS such as Linux. Operate with SS7 physical line termination device driver 2. As software for controlling the device driver 2, there are a maintenance operation process group 3 and a call control process 4. In the present invention, the conventional signal processing management process is replaced with an SS7 signal link control process 5 for performing signal transmission and reception and link control. SS7 is separated from the resource management resident process 6 that holds only the file descriptor that is the resource identifier for signal link control acquired from the physical line termination device driver 2 and is arranged on the system.

  The SS7 signaling link control process 5 is subject to monitoring by the monitoring process 7 on the system in the same manner as the maintenance operation process group 3 and the call control process 4, but the resource management resident process is a small program that limits the processing to be realized. Therefore, the monitoring process 7 does not need to be monitored, and the process is started simultaneously with the OS startup and stays resident until the system ends.

  The SS7 signal link control process 5 and the resource management resident process 6 share information using the shared memory area 8, and exchange control information by inter-process communication.

  When the resource management resident process 6 receives a request for link establishment from the SS7 signal link control process 5, the resource management resident process 6 calls the API of the device driver 2 and acquires a file descriptor for signal link control. The corresponding signal link information is written in the shared memory area 8 and delivered to the SS7 signal link control process 5 together with the acquired file descriptor information. In the SS7 signal link control process 5, using the file descriptor delivered by the resource management resident process 6, the API of the device driver 2 is called to perform subsequent signal link control and signal transmission / reception processing.

  If an abnormality occurs in a process in the system while establishing a signal link with the opposite signal station, the monitoring process 7 restarts all processes to be monitored in order to restore the system to a normal state. At this time, the resource management resident process 6 is not subject to monitoring, so that it is not necessary to restart, and the link control file descriptor held by the resource management resident process 6 remains held by the resource management resident process 6.

  When restarting due to the occurrence of a process failure, it is not necessary to release the file descriptor, which is a kernel resource, and the already established signal link is continued without being disconnected. When the SS7 signal link control process 5 is started by process restart, the SS7 signal link control process 5 refers to the shared memory area 8 with the resource management resident process 6 and continuously uses the already established signal link information. In this way, signal transmission / reception and control are started immediately after recovery.

The operation of the configuration of the SS7 signal processing system in FIG. 1 is shown as a flowchart in FIG.
The resource management resident process 6 is started individually when the OS is started up when the system is started. Thereafter, the monitoring process 7 is activated, and the processes 3 to 5 to be monitored are sequentially activated by the monitoring process 7. The processes 3 to 5 started by the monitoring process 7 are always monitored for abnormalities.

  When a link establishment instruction is requested by a user of this system, the SS7 signal link control process 5 receives the link establishment request and transfers the link establishment request to the resource management resident process 6 through inter-process communication. When the resource management resident process 6 receives the request, it calls the API of the device driver 2 of the SS7 physical line termination device 1, acquires a file descriptor for link establishment / control, and writes it in the shared memory area 8 together with the link information. When the acquisition of the file descriptor is completed, the resource management resident process 6 transmits the result to the SS7 signal link control process 5 by inter-process communication. At this time, the copy information of the acquired file descriptor is also transmitted. Then, the resource management resident process 6 idles without waiting for the next request and waits.

  In the SS7 signal link control process 5, the API of the device driver 2 is called using the file descriptor acquired via the resource management resident process 6 to perform signal processing such as signal link control and signal transmission / reception. If an abnormal condition occurs in one of the maintenance function processes monitored in the system while establishing a signal link with the opposite signal station, the monitored process 7 detects the abnormality and restores the system to the normal condition. Restart all processes in. At this time, since the resource management resident process 6 is not monitored, it is not restarted and the file descriptor for link control remains held in the resource management resident process 6. Since the release (record deletion) of the file descriptor that is a kernel resource does not occur, the already established signal link is continued without being disconnected even at the time of system recovery. During this time, the signal transmitted from the opposite signal station is accumulated in the reception buffer held by the device driver 2, and the SS7 signal link control process 5 is received and processed without omission after activation.

  The SS7 signal link control process 5 confirms the shared memory area 8 with the resource management resident process 6 after restart, confirms the already established signal link information, and copies the file descriptor of the corresponding link from the resource management resident process 6. Signal acquisition and link control are continued by reacquiring information.

  Normally, link information is inherited in this way. However, according to the option specification at the time of activation request (by a request from the maintenance person), the existing resource can be discarded and the new resource can be established as follows.

  When the process is restarted by the intervention of the maintenance person, when the SS7 signaling link control process 5 determines that the establishment of a new link is necessary, it requests the resource management resident process 6 to establish it. In response to this, the resource management resident process 6 calls the API of the device driver 2 to release (record delete) the file descriptor for the corresponding signal link control, and to delete the corresponding entry from the information written in the shared memory area 8. delete.

  Thereafter, the resource management resident process 6 calls the API of the device driver 2 again, acquires a file descriptor for new link establishment / control, and writes it in the shared memory area 8 together with the link information. When the acquisition of the new file descriptor is completed, the resource management resident process 6 transmits the result to the SS7 signal link control process 5 by inter-process communication. At this time, copy information of the newly acquired file descriptor is also transmitted.

  In the SS7 signal link control process 5, the API of the device driver 2 is called using the file descriptor newly obtained via the resource management resident process 6, and signal processing such as signal link control and signal transmission / reception is performed. .

  In the above embodiment, the signal link non-disconnection failure recovery method in the SS7 signal processing system such as SEP or STP in the existing telephone signal network has been described. However, the IP-SEP (transmission / reception / transfer of the SS7 signal on the IP network) The present invention can also be applied to IP signal links such as an IP-Signaling End Point) station and SGW (Signaling Gate Way). The IP signal link for transmitting and receiving SS7 signals on the IP network uses SCTP (Stream Control Transmission Protocol), which is a connection-oriented transport protocol. In the process of controlling the IP signal link on the system, SCTP It manages socket descriptors for connection control and data transmission / reception. This socket descriptor is also a resource provided by the kernel of the general-purpose OS, and the resource is released by restarting the process.

  Therefore, by applying the present invention, the resource management resident process that realizes only the acquisition and release of file descriptors and the signal link control process that realizes signal transmission / reception and connection control are separated, and even when a failure occurs on the system By using a mechanism in which the management resident process is not restarted, it is possible to realize a recovery mechanism that is transparent to the opposite apparatus without disconnecting the SCTP connection.

As can be seen from the above description, the present invention can be applied to the following cases.
Signaling station that terminates and relays signals from existing telephone networks (SEP: Signaling End Point, STP: Signaling Transfer Point)
A signaling relay station (SGW) that relays between a fixed telephone network and a mobile telephone network and an IP network.
A signal termination station (IPSEP: IP Signalilng End Point) that terminates and processes signals of the fixed telephone network and mobile telephone network on the IP network.
Communication between IP servers that require high reliability using SCTP as the transport protocol.

It is a block diagram which shows the structural example of SS7 signal processing system by this invention. It is a flowchart of the operation example of the SS7 signal processing system.

Explanation of symbols

1 SS7 Physical Line Termination Device 2 SS7 Physical Line Termination Device Driver 3 Maintenance Operation Process Group 4 Call Control Process 5 SS7 Signal Link Control Process 6 Resource Management Resident Process 7 Monitoring Process 8 Shared Memory Area

Claims (8)

  SS7 physical line termination device driver that controls the SS7 physical line termination device, process group that implements system maintenance functions, SS7 signal link control process that performs signal link control and signal transmission, and constantly monitors the abnormal state of these processes A monitoring process, a resident resource management resident process that is not monitored by this monitoring process, is provided. This resource management resident process holds only the file descriptor obtained from the SS7 physical line termination device driver, and the SS7 signal link control process The SS7 signal processing system is configured to access the SS7 physical line termination device driver by the held file descriptor at the time of restart for restoring the SS7 signal processing system.   A shared memory shared by the SS7 signal link control process and the resource management resident process is written, and a file descriptor is written in the shared memory together with link information. The SS7 signal link control process is re-established to restore the SS7 signal processing system. 2. The SS7 signal processing system according to claim 1, wherein the shared memory is referred to at the time of startup.   The resource management resident process causes the SS7 physical line termination device driver to release the corresponding signal link control file descriptor when a signal link disconnection request is issued from the SS7 signal link control process. The SS7 signal processing system according to 1 or 2.   The SS7 signal link control process can select whether or not to take over the file descriptor held in the resource management resident process when the SS7 signal processing system is restarted. The SS7 signal processing system described.   SS7 physical line termination device driver that controls the SS7 physical line termination device, process group that implements system maintenance functions, SS7 signal link control process that performs signal link control and signal transmission, and constantly monitors the abnormal state of these processes A monitoring process and a resident resource management resident process that is not monitored by this monitoring process are provided, and by this resource management resident process, only the file descriptor acquired from the SS7 physical line termination device driver is held, and the SS7 signal processing system is restored. In the SS7 signal processing system, the SS7 signal link control process accesses the SS7 physical line termination device driver by the held file descriptor at the restart. Recovery method.   The file descriptor is written together with link information in the shared memory shared by the SS7 signal link control process and the resource management resident process, and the SS7 signal link control process refers to the shared memory when restarting to restore the SS7 signal processing system. The failure recovery method in the SS7 signal processing system according to claim 5, wherein the SS7 physical line termination device driver is accessed.   The resource management resident process causes the SS7 physical line termination device driver to release a corresponding signal link control file descriptor when a signal link disconnection request is issued from the SS7 signal link control process. The failure recovery method in the SS7 signal processing system according to 5 or 6.   The SS7 signal link control process selects whether to take over the file descriptor held in the resource management resident process or not when the SS7 signal processing system is restarted. The failure recovery method in the SS7 signal processing system according to claim 7.

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