JP5109857B2 - Apparatus and method for avoiding signal loss in IPover ATM line - Google Patents

Description

  The present invention relates to a technique for avoiding loss of IP packet signals in connection between an IP (Internet Protocol) network and an ATM (Asynchronous Transfer Mode) network.

  In a modern communication network environment, as illustrated in FIG. 7, an ATM line network 704 and an IP line network 705 are mixed, and the connection of these line networks is performed via a router device 701.

  The IP is located in the network layer of the OSI basic reference model, and is used for addressing (addressing) the devices participating in the network and for selecting communication routes (routing) in a plurality of interconnected networks. The method is defined. Data based on IP is communicated using an IP packet composed of an IP header and a variable length data portion. The network layer is located in the third layer of the OSI reference model and defines a method for performing communication between networks connected using a protocol below the data link layer. A unique address is assigned to every computer on the network, and data transmission path selection, packet size conversion, and the like are performed.

  ATM is one of multiplexing schemes in which one line is divided into a plurality of logical lines (channels) and communication is simultaneously performed. Communication in which data of each channel is divided into 53-byte fixed length data and transmitted / received. It is a method. Data transmitted / received by ATM is divided every 48 bytes, and transmitted / received in units of ATM cells to which 5-byte header information is added. In the OSI reference model, it corresponds to the second layer (data link layer), and an optical fiber or copper wire can be used for the physical layer and IP or the like can be used for the network layer.

  In the ATM network 704, a plurality of types of interfaces (hereinafter referred to as “I / F”) such as 155M (megabit / second) optical ATM megalink, 25M, 6.3M, 1.5M,. And an ATM device 706 that performs each communication.

Also in the IP line network 705, there are IP I / Fs with various transmission speeds, and an IP device 707 that performs each communication is configured.
A device for controlling the IP line network 705 or between the IP line network 705 and the ATM line network 704 is called a router device, and relays data flowing on one network to another network. The router device analyzes a part of the protocol of the network layer (third layer) and the transport layer (fourth layer) in the OSI reference model, executes transfer control, looks at the address of the network layer, and passes through which route. Route selection to determine whether to transfer.

  The router device 701 includes an ATM line I / F unit 702 that accommodates the plurality of ATM line I / Fs and an IP line I / F unit 703 that accommodates a plurality of IP lines. And IP side signals are routed.

  As shown in FIG. 8A, communication between the IP line I / F unit 703 in the router device 701 and the IP device 707 is performed by IP packets, and the ATM line I / F unit 702 in the router device 701 is used. Between ATM and the ATM device 706 is performed by ATM cells.

  In order to send IP packets on the IP line network 705 to the ATM line network 704, translation is performed between IP packets having different data formats and ATM cells as shown in FIG. A technique for realizing this is called IPoverATM.

  Under IPover ATM, as shown in FIG. 8B, the router device 701 converts an IP packet received by the IP line I / F unit 703 into a CPCS-PDU (Common Part Convergence Sublayer Protocol Data Unit). It is stored in a protocol data unit called, further divided into a plurality of ATM cell payloads, each of which is appended with an ATM header to generate a plurality of ATM cells, which are sent to the ATM line I / F unit 702.

  Conversely, the router device 701 assembles a CPCS-PDU from the payloads of a plurality of ATM cells received by the ATM line I / F unit 702, converts it into an IP packet, and then converts the IP packet to the IP line I / F unit. To 703.

  Here, the data delimiter in the data assembly from the low-layer ATM cell to the high-layer IP packet described above in the router device 701 is a PTI (Payload) consisting of 3 bits in the ATM cell header shown in FIG. Type Identifier) bit.

When PTI = 0 is set in a certain ATM cell, it is determined that there is a continuing ATM cell in that ATM cell in order to assemble one IP packet, and when PTI = 1 is set, It is determined that no ATM cell continues in the ATM cell. For this reason, when the router device 701 receives an ATM cell with PTI = 0 for each user channel, the router device 701 holds each received ATM cell internally and waits until an ATM cell with PTI = 1 is received. Perform the action.
JP 2004-32123 A

Under the above environment, when the device is restarted and restarted in either the ATM device 706 or the IP device 707 connected to the router device 701, data being transmitted is cut off. Since the router device 701 is in the middle of transmission, the PTI bit of the ATM cell header group performing the standby process in the target user channel remains 0, and as a result, the router device 701 sets PTI = 1. Continue to wait for ATM cells that have been placed. “Resume” is a process that, when an abnormality occurs in the operation of the system, performs processing such as finding an abnormality and removing the cause of the abnormality, returning the system to the state before the abnormality occurred, and restarting the operation That is.

  However, when the resumed device restarts and starts transmitting valid data, the ATM cell with PTI = 0 in the resume data is abnormally coupled to the above-described fragmented ATM cell group staying in the router device 701. Therefore, in the router device 701, the calculation result of CRC (Cyclic Redundancy Check) at the time when the CPCS-PDU shown in FIG. Had the problem of being destroyed.

  CRC is called “cyclic redundancy check” and is an error detection method capable of detecting consecutively appearing errors (burst errors). When an ATM cell is assembled into a CPCS-PDU, a CRC-32 operation is performed on the CPCS-PDU data, and whether the operation result matches the CRC-32 field value assigned to the CPCS-PDU. By comparing whether or not, error detection is performed.

In the ATM device 706, there are many configurations in which a plurality of subordinate ATM devices 706 are restarted in a chain by resuming the host device. In addition to the above-described problem of reduced data reliability due to loss of valid data, There is also a problem of communication line congestion due to later retransmission processing.

  An object of the present invention is to avoid a situation in which valid data transmitted after restarting in a network environment such as device restart is abnormally combined with unnecessary data staying in the router device, resulting in signal loss. The purpose is to improve reliability and avoid line congestion.

  According to a first aspect of the present invention, an asynchronous transfer mode line network (ATM line network) and an Internet protocol line network (IP line network) are connected to each other by a router device in an asynchronous transfer that constitutes an ATM line network. A signal loss avoidance device or method configured in a mode communication device (ATM device) is assumed.

The restart determination means (restart determination unit 101) determines restart of the ATM device.
The dummy cell sending means (dummy cell sending unit 102) is a dummy asynchronous transfer mode cell (ATM cell) toward the asynchronous transfer mode line (ATM line) at which the ATM apparatus terminates when the restart determining means determines that the ATM apparatus is restarted. ). This dummy cell sending means instructs to send a dummy ATM cell, for example, using a data sending function in a protocol in a higher layer hierarchy than the Internet protocol (IP protocol). More specifically, a ping test transmission function in the Internet control message protocol (ICMP protocol), a telnet login function in the transmission control protocol (TCP protocol), and a file transfer in the TCP protocol Protocol (ftp) login function, simple network management protocol-trap (SNMP-Trap) login function in user datagram protocol (UDP protocol), or trace route test function in UDP protocol Is used.

  Then, when the ATM device is restarted, a dummy ATM cell is combined with the communication data cell with the ATM device staying in the router device in the router device communicating with the ATM device, and the combined data Are discarded by the error detection process.

  According to a second aspect of the present invention, there is provided a signal configured in a router device on a network in which an asynchronous transfer mode circuit network (ATM circuit network) and an Internet protocol circuit network (IP circuit network) are interconnected by the router device. It is assumed that there is a defect avoidance device or method.

The ATM line disconnection detection means (line disconnection detection unit 301) detects disconnection or failure of the asynchronous transfer mode line (ATM line) accommodated in the router device.
The staying data discarding means (the staying data discarding unit 304) corresponds to the ATM line where the staying in the router apparatus is detected based on the ATM line disconnection detecting means by the ATM line disconnection detecting means. The data of the ATM cell to be discarded is discarded.

  In the configuration of the second aspect of the present invention, after the ATM line disconnection detecting means detects the disconnection or failure of the ATM line, the ATM line disconnection determination means (line Further includes a disconnection determination unit 302 and a timer 303), and the staying data discarding means is a part of the staying in the router device when the ATM line disconnection determination means determines disconnection of the ATM line for a predetermined time or the continuation of the failure. The ATM cell data corresponding to the determined ATM line can be discarded.

In the configuration of the second aspect of the present invention, the ATM line disconnection detecting means uses an ATM line alarm selected from a plurality of asynchronous communication mode line alarms (ATM line alarms) notified about the ATM line. It can be configured to detect disconnection or failure of an asynchronous transfer mode line (ATM line) accommodated in the router device.

  According to a third aspect of the present invention, there is provided a signal configured in a router device on a network in which an asynchronous transfer mode circuit network (ATM circuit network) and an Internet protocol circuit network (IP circuit network) are connected to each other by the router device. It is assumed that there is a defect avoidance device or method.

The IP line disconnection detection means (line disconnection detection unit 301) detects disconnection or failure of the Internet protocol line (IP line) accommodated in the router device.
The staying data discarding unit (the staying data discarding unit 304) is connected to the IP line on which the detection of the staying in the router apparatus is performed based on the detection state of the disconnection or failure of the IP line by the IP line disconnection detecting unit. The data of the ATM cell corresponding to the ATM line for which the routing is set is discarded.

  In the configuration of the third aspect of the present invention, after the IP line disconnection detecting means detects the disconnection or failure of the IP line, the IP line disconnection determination means (line And the staying data discarding means includes a disconnection determination unit 302 and a timer 303), and the staying data discarding means stores the staying in the router device when the IP line disconnection judging means judges disconnection of the IPO line for a predetermined time or the continuation of failure The ATM cell data corresponding to the ATM line for which routing is set with the detected IP line can be discarded.

According to the present invention, it is possible to avoid signal loss of valid data due to abnormal coupling of signals in a router apparatus that can generally occur in a network environment.
According to the present invention, signal loss of valid data is avoided and data reliability is improved.

According to the present invention, it is possible to avoid line congestion due to retransmission processing contention.
According to the present invention, the dummy cell transmission process does not depend on the hardware configuration, and since the degree of freedom of software selection is high, avoidance of signal loss of valid data can be realized without expensive additional equipment investment. Is possible.

  Further, according to the present invention, it is possible to realize the avoidance of signal loss of valid data without changing the hardware configuration by downloading software incorporating the function of the present invention into the existing infrastructure.

Hereinafter, the best mode for carrying out the invention will be described in detail with reference to the drawings.
First, the overall configuration of a network system to which the embodiment described below is applied is the same as that shown in FIG. 7, and the relationship between ATM cells and IP packets is also the same as that shown in FIG. .

FIG. 1 is a configuration diagram of the first embodiment realized in the ATM device 706 of FIG.
In the first embodiment, an ATM device 706 terminates an operating system (OS) execution unit 103 that controls the configuration of the entire device, a hardware device driver unit 104 that includes a VPI / VCI channel management table 105, and an ATM line. In addition to having an ATM line termination unit 106, a restart determination unit 101 that determines device restart, a dummy ATM cell for each user channel determined by each VPI and VCI when the device is restarted (hereinafter referred to as "dummy cell") And a dummy cell sending unit 102 for sending the message.

In the ATM device 706 of FIG. 1, the restart determination unit 101 monitors the restart and restart of the ATM device 706 itself. When the apparatus restarts (S201 in FIG. 2) and then restarts (S202 in FIG. 2), the restart determination unit 101 instructs the dummy cell sending unit 102 to send a dummy cell.

  The dummy cell transmission unit 102 is realized as a dummy cell transmission function in an upper layer by a software application installed in the ATM device 706, and calls a function that is normally equipped in the OS execution unit 103 by a system call.

  As a first specific example of the dummy cell transmission instruction, the dummy cell transmission unit 102 calls the Ping function of the OS execution unit 103, designates necessary arguments (destination IP address, number of transmissions, number of transmission bytes, etc.), and issues a Ping transmission instruction. I do. The Ping function is a program for diagnosing a TCP / IP network. When the IP address of the other party to be checked whether it is connected is specified, data of usually about 32 bytes using ICMP (Internet Control Message Protocol). The network is diagnosed based on data such as whether there is a reply from the other party and how long it takes if there is a reply. Since it is a dummy cell, the minimum value within the settable range is selected for the number of transmissions and the number of transmission bytes. Since the Ping test transmission is performed only by transmitting the dummy cell, the process is forcibly terminated regardless of whether or not a Ping response is received.

  As a second specific example of the dummy cell transmission instruction, the dummy cell transmission unit 102 calls a Telnet login function (protocol: TCP (Transmission Control Protocol)) of the OS execution unit 103. TCP is a standard protocol used on the Internet and corresponds to the transport layer of the OSI reference model. High reliability but low transfer rate. It is assumed that the destination IP address at the time of Telnet login is that during normal communication. Since the Telnet login process is performed only by transmitting the dummy cell, the process is forcibly terminated without proceeding to the subsequent password input process or the like.

  As a third specific example of the dummy cell transmission instruction, the dummy cell transmission unit 102 calls an FTP (file transfer protocol) login function (protocol: TCP) of the OS execution unit 103. It is assumed that the destination IP address at the time of FTP login is that during normal communication. Since the FTP login process is performed only by transmitting the dummy cell, the process is forcibly terminated without shifting to the subsequent password input process or the like.

  As a fourth specific example of the dummy cell transmission instruction, the dummy cell transmission unit 102 calls an SNMP-Trap login function (protocol: UDP (user datagram protocol)) of the OS execution unit 103. This function is a protocol for monitoring and controlling communication devices connected to the network such as router devices, computers, and terminal devices in the IP network. The device to be controlled has a management information database called MIB, and the managing device performs appropriate settings based on the MIB information of the target device. UDP is a standard protocol used on the Internet and corresponds to the transport layer of the OSI reference model. It bridges the network layer IP and the protocol above the session layer. High transfer speed but low reliability. It is assumed that the destination IP address during SNMP-Trap transmission is that during normal communication. Since the SNMP-Trap process is performed only by transmitting the dummy cell, the process transmits an SNMP-Trap signal in a single transmission.

  As a fifth specific example of the dummy cell transmission instruction, the dummy cell transmission unit 102 calls the Trace-Route test function (protocol: UDP) of the OS execution unit 103. The Trace-Route test function confirms the route of the network and is mapped on the UDP. The other party's IP address and the number of hops are designated and transmitted as a message mapped on UDP. The network path is confirmed by receiving a response from the relay path including the other party. It is assumed that the destination IP address at the time of Trace-Route test transmission is that during normal communication. Since the Trace-Route test is performed only for transmitting the dummy cell, the process is forcibly terminated regardless of whether or not a response is received.

  As described above, when a dummy cell transmission instruction is issued from the application of the dummy cell transmission unit 102 to the OS execution unit 103, the OS execution unit 103 sends the ATM cell transmission instruction specified by the function and the argument to the hardware. Notify the device driver unit 104.

  The hardware device driver unit 104 uses the VPI / VCI channel management table 105 to manage user channels linked based on two identifiers of VPI (Virtual Pass Identifier) and VCI (Virtual Channel Identifier). .

  The VPI is an 8-bit identifier assigned to the ATM header to identify which path is used as a virtual path among the paths multiplexed in the virtual path (VP) in ATM. This is a 16-bit identifier assigned to the ATM cell header to identify a virtual channel (VC) on the virtual path (see FIG. 7B).

  The hardware device driver unit 104 uses the VPI / VCI channel management table 105 to select a VPI / VCI corresponding to information such as a destination IP address instructed from the OS execution unit 103, and to the ATM line termination unit 106 The VPI / VCI issues an ATM cell transmission instruction set in the ATM header.

  The ATM line termination unit 106 stores the data instructed by the hardware device driver unit 104 in the ATM cell and sends it to the ATM line as a dummy cell. The dummy cell usually has one cell in which PTI = 1 is set.

FIG. 2 is a sequence diagram showing an operation between the ATM device 706 having the first embodiment shown in FIG. 1 and the router device 701 connected thereto.
In the ATM device 706 of FIG. 1, the restart determination unit 101 monitors the restart and restart of the ATM device 706 itself. When the apparatus restarts (S201 in FIG. 2) and then restarts (S202 in FIG. 2), the restart determination unit 101 instructs the dummy cell sending unit 102 to send a dummy cell.

As a result, the dummy cell is transmitted from the ATM device 706 for each activated VPI / VCI by the above-described operation, and reaches the router device 701 (S203 in FIG. 2).
Since PTI = 1 is set in the dummy cell, in the ATM line I / F unit 702 that accommodates the ATM line of the ATM device 706 in the router device 701 that has restarted, the dummy cell is the ATM device 706. The ATM cell (garbage ATM cell) that has been sent from the apparatus 706 and stayed in the ATM line I / F unit 702 before the restart is started. These combined ATM cell groups are collectively discarded when the CRC calculation result becomes NG (abnormal) when the CRCS-PDU is assembled (S204 in FIG. 2).

  Thereafter, the communication between the ATM device 706 and the router device 701 is restored to a normal state, and effective data cells are sequentially transmitted from the ATM cell 706 to the ATM line I / F unit 702 in the router device 701 from the first cell. In the router device 701, routing from the ATM line network 704 to the IP line network 705 is performed.

  The stay data discarding process does not affect the internal data of the ATM line I / F unit 702 other than the ATM line I / F unit 702 to which the ATM device 706 that has resumed is connected.

  Thus, in the first embodiment, by providing the dummy cell sending unit 102 in the ATM device 706, the ATM device 706 stays in the corresponding ATM line I / F unit 702 in the router device 701 when the ATM device 706 is restarted. By intentionally combining dummy cells with unnecessary data and discarding them by CRC check, it is possible to avoid loss of valid data after resumption.

  In addition, the dummy cell transmission unit 102 performs dummy cell transmission in an upper layer by a software application installed in the ATM device 706, thereby enabling effective data without newly installing a special hardware mechanism for dummy cell transmission. Deficiency avoidance can be realized.

FIG. 3 is a configuration diagram of the second embodiment of the present invention realized in each ATM line I / F unit 702 of the router device 701 of FIG.
In the second embodiment, the router device 701 includes a line disconnection detecting unit 301 that detects disconnection or failure of an ATM line accommodated in each ATM line I / F unit 702 (see FIG. 7), and a line disconnection is detected. The line disconnection determination unit 302 that activates the timer 303 and determines whether the line disconnection continues for a certain period of time or more. It has a staying data discarding unit 304 that discards ATM cells staying in the F unit 702.

As described above, in the second embodiment, when the ATM line is disconnected, the router apparatus 701 itself discards the accumulated data in the router, so that the ATM apparatus 706 connected to the router apparatus 701 restarts from the same apparatus 706. Avoiding loss of valid data sent.
The staying data discarding process does not affect the internal data of the ATM line I / F unit 702 other than the ATM line I / F unit 702 where the line disconnection has occurred.

FIG. 4 is a sequence diagram showing an operation between the router device 701 having the second embodiment shown in FIG. 3 and the ATM device 706 connected thereto.
The line disconnection detection unit 301 in FIG. 3 detects disconnection or failure of the ATM line accommodated by the ATM line I / F unit 702 to which it belongs (S401 in FIG. 4).
The determination of the line disconnection can be made based on the ATM line alarm displayed in the ATM signal in addition to the determination of the physical line disconnection. There can be a plurality of types of ATM lines accommodated by each ATM line I / F unit 702 in the router device 701 (FIG. 7). Since the line alarm also differs depending on the type of the line, it is desirable to change for each ATM line I / F unit 702 which line alarm is determined as line disconnection.

FIG. 5 is a table showing whether or not the ATM line I / F unit 702 accommodating the 155M optical ATM megalink determines that the line is disconnected for each ATM line alarm. Each alarm has the following meaning:
LOS (Loss Of Signal): Physical signal line synchronization loss state LOF (Loss Of Frame): Transmission frame synchronization loss state LOP (Loss Of Pointer): Transmission frame pointer is off VP-AIS: VP-AIS of F4 OAM cell When a cell is received VP-RDI: When a VP-RDI cell of an F4 OAM cell is received P-AIS: Pointer (H1, H2) of LOP transmission frame is shifted P-RDI: Pointer (G1) of LOP transmission frame is shifted LCD (Loss of Cell Delineation): ATM cell HEC out of sync. These alarm display / release functions are 10 bytes in the case of a frame configuration called STM1 in the case of a 155M optical ATM megalink as shown in FIG. Assigned to each bit of the overhead portion.

As shown in FIG. 6B, the ATM cell header consisting of 5 bytes of the ATM cell itself also plays a part of the alarm monitoring.
The example of FIG. 5 indicates that the line disconnection detection unit 301 of FIG. 3 should operate so as to detect a line disconnection when the LOS, LOF, LOP, and LCD alarms are turned on. The ATM line I / F unit 702 internally has a determination table as shown in FIG. 5, and the line disconnection detection unit 301 detects the line disconnection based on the setting contents.

  When the line disconnection detection unit 301 in FIG. 3 detects the line disconnection of the ATM line, the line disconnection determination unit 302 in FIG. 3 starts the timer 303 (S402 in FIG. 4) and waits for the expiration of the timer. (The determination in S403 in FIG. 4 is NO).

  When the timer expires (the determination in S403 in FIG. 4 is YES), the line disconnection determination unit 302 determines that the line disconnection detection unit 301 still detects a line disconnection (the determination in S404 in FIG. 4 is YES), the ATM cell which is the garbage data staying in the ATM line I / F unit 702 (see FIG. 7) to which the line disconnection determination unit 302 belongs is discarded (S405 in FIG. 4).

  Thereafter, when the line break in the ATM line is recovered, the communication state between the ATM line I / F unit 702 of the ATM apparatus 706 and the router apparatus 701 is restored to the normal state, and the ATM line I / F unit is transferred from the ATM apparatus 706 to the normal state. Transmission of valid data to 702 is resumed sequentially from the top data.

When the timer expires (the determination in S403 in FIG. 4 is YES), the line disconnection determination unit 302 determines that the line disconnection detection unit 301 has not detected a line disconnection (the determination in S404 in FIG. 4). NO), it is determined that the line disconnection was an instantaneous disconnection, and the normal operation state is restored.
In the operation of the above-described second embodiment, it is desirable that the timer 303 can be freely set by the user who operates the router device 701 and is variable according to the environment.

Next, a third embodiment of the present invention will be described.
In the third embodiment, the configuration shown in FIG. 3 similar to that of the second embodiment is not limited to each ATM line I / F unit 702 of the router device 701 in FIG. Also installed. The basic operation is the same as the sequence of FIG. 4 in the second embodiment.

  In the third embodiment, the line break detection unit 301 in a certain IP line I / F unit 703 communicates with the IP line I / F unit 703 to which the line break detection unit 301 belongs as shown in S406 of FIG. When a certain IP device 707 is restarted, the disconnection or failure of the IP line is detected (S401 in FIG. 4).

  Subsequently, when the line disconnection determination unit 302 in FIG. 3 belonging to the same IP line I / F unit 703 as the line disconnection detection unit 301 activates the timer 303 and determines the continuation of the line disconnection (S402-> in FIG. 4). S403-> S404), the staying data discarding unit 304 in FIG. 3 in the same IP line I / F unit 703 refers to the routing table (not shown) in the router device 701, so that the IP line I / F unit One or more ATM line I / F units 702 (FIG. 7) for which routing is set up with respect to 703 are recognized, and the above IPs staying inside each recognized ATM line I / F unit 702 The ATM cell for the line I / F unit 703 is discarded (S405 in FIG. 4). Whether or not each staying cell is for the IP line I / F unit 703 is determined by looking at the VPI / VCI stored in the header part of each staying cell.

  The staying data discarding process affects the internal data of the ATM line I / F unit 702 in which routing is not set with the IP line I / F unit 703 in which continuous line disconnection is detected. Absent.

  Thereafter, when the line disconnection in the IP line is restored, between the ATM line I / F unit 702 corresponding to the ATM device 706 and the router device 701 and between the corresponding IP line I / F unit 703 inside the IP device 707 and the router device 701. Each communication state is restored to a normal state, and transmission of valid data from the ATM device 706 to the ATM line I / F unit 702 is sequentially resumed from the top data.

  The first to third embodiments described above can also be realized by software on the ATM device 706 or the router device 701, and these devices have a function as a computer. Therefore, in the first to third embodiments, a program having these functions may be distributed via a network or recorded in an external storage device or a portable recording medium, and these are also included in the scope of the present invention. It is.

Regarding the above first to third embodiments, the following additional notes are further disclosed.
(Appendix 1)
In an asynchronous transfer mode communication device (ATM device) constituting the ATM line network on a network in which an asynchronous transfer mode line network (ATM line network) and an Internet protocol line network (IP line network) are interconnected by a router device. A device configured to:
Resumption determining means for determining resumption of the ATM device;
Dummy cell transmission for instructing transmission of a dummy asynchronous transfer mode cell (ATM cell) toward an asynchronous transfer mode line (ATM line) terminated by the ATM apparatus when the restart determination means determines the restart of the ATM apparatus. Means,
Including
When the ATM device is restarted, the router device communicating with the ATM device combines the dummy ATM cell with the communication data cell with the ATM device staying in the router device, and the combined data is Discard by error detection processing,
An apparatus for avoiding signal loss in an IPoverATM line.
(Appendix 2)
The dummy cell transmission means instructs transmission of the dummy ATM cell using a data transmission function in a protocol of a higher layer than the Internet protocol (IP protocol).
The apparatus for avoiding signal loss in an IPoverATM line according to Supplementary Note 1, wherein
(Appendix 3)
As a data transmission function in the upper layer layer protocol, a ping test transmission function in the Internet control message protocol (ICMP protocol), a telnet login function in the transmission control protocol (TCP protocol), File transfer protocol (ftp) login function in the TCP protocol, Simple network management protocol-trap (SNMP-Trap) login function in the user datagram protocol (UDP protocol), Trace route in the UDP protocol Use one of the (traceroute) test functions,
The apparatus for avoiding signal loss in an IPover ATM line according to Supplementary Note 2, wherein
(Appendix 4)
An apparatus configured in the router device on a network in which an asynchronous transfer mode circuit network (ATM circuit network) and an Internet protocol circuit network (IP circuit network) are connected to each other by a router device;
ATM line disconnection detecting means for detecting disconnection or failure of an asynchronous transfer mode line (ATM line) accommodated in the router device;
Based on the detection status of disconnection or failure of the ATM line by the ATM line disconnection detecting means, the retention of discarding the data of the ATM cell corresponding to the ATM line in which the detection has been performed staying in the router device Data discarding means;
An apparatus for avoiding signal loss in an IPoverATM line characterized by comprising:
(Appendix 5)
Further comprising ATM line disconnection determining means for determining whether or not the ATM line is disconnected for a predetermined time or continuing after the ATM line disconnection detecting means detects disconnection or failure of the ATM line;
When the ATM line disconnection determining unit determines that the ATM line is disconnected for a predetermined time or the continuation of the failure, the staying data discarding unit is connected to the ATM line that has been determined to be staying in the router device. Discard the corresponding ATM cell data;
The apparatus for avoiding signal loss in an IPoverATM line according to appendix 4, characterized in that:
(Appendix 6)
The ATM line disconnection detecting means disconnects an ATM line accommodated by the router device using an ATM line alarm selected from a plurality of asynchronous communication mode line alarms (ATM line alarms) notified about the ATM line. Or detect faults,
6. An apparatus for avoiding signal loss in an IPover ATM line according to any one of appendix 4 or 5, characterized in that:
(Appendix 7)
An apparatus configured in the router device on a network in which an asynchronous transfer mode circuit network (ATM circuit network) and an Internet protocol circuit network (IP circuit network) are connected to each other by a router device;
IP line disconnection detecting means for detecting disconnection or failure of the Internet protocol line (IP line) accommodated in the router device;
The ATM in which routing is set with the detected IP line staying in the router device based on the detection state of the disconnection or failure of the IP line by the IP line disconnection detecting means A staying data discarding means for discarding the ATM cell data corresponding to the line;
An apparatus for avoiding signal loss in an IPoverATM line characterized by comprising:
(Appendix 8)
Further comprising: an IP line disconnection determining means for determining whether the IP line is disconnected for a predetermined time or continuing the failure after the IP line disconnection detecting means detects the disconnection or failure of the IP line;
The staying data discarding unit is configured such that when the IP line disconnection determination unit determines disconnection of the IP line for a predetermined time or continuation of a failure, the detected IP line staying in the router device is detected. The data of the ATM cell corresponding to the ATM line for which routing is set between
The apparatus for avoiding signal loss in an IPoverATM line according to appendix 7, wherein
(Appendix 9)
A method for avoiding signal loss on a network in which an asynchronous transfer mode network (ATM network) and an Internet protocol network (IP network) are interconnected by a router device,
A restart determination step for determining restart of an asynchronous transfer mode communication device (ATM device) constituting the ATM line network;
A dummy cell for instructing transmission of a dummy asynchronous transfer mode cell (ATM cell) toward an asynchronous transfer mode line (ATM line) terminated by the ATM apparatus when the restart of the ATM apparatus is determined by the restart determining step. A sending step;
When the ATM device is restarted, the router device communicating with the ATM device combines the dummy ATM cell with the communication data cell with the ATM device staying in the router device, and the combined data is A stagnant data discarding step to be discarded by error detection processing;
A method for avoiding signal loss in an IPoverATM line.
(Appendix 10)
In the dummy cell transmission step, transmission of the dummy ATM cell is instructed using a data transmission function in a protocol of a higher layer layer than the Internet protocol (IP protocol).
The method for avoiding a signal loss in an IPoverATM line according to appendix 9, wherein
(Appendix 11)
A method for avoiding signal loss on a network in which an asynchronous transfer mode network (ATM network) and an Internet protocol network (IP network) are interconnected by a router device,
An ATM line disconnection detecting step for detecting disconnection or failure of the asynchronous transfer mode circuit (ATM line) accommodated in the router device;
Based on the detection state of disconnection or failure of the ATM line in the ATM line disconnection detecting step, the retention of discarding the data of the ATM cell corresponding to the detected ATM line staying in the router device A data discarding step;
A method for avoiding signal loss in an IPoverATM line.
(Appendix 12)
An ATM line disconnection determining step for determining whether the ATM line is disconnected or continuing for a predetermined time after the ATM line disconnection or failure is detected in the ATM line disconnection detecting step;
In the staying data discarding step, if it is determined in the ATM line disconnection determining step that the ATM line is disconnected for a predetermined time or the continuation of the failure, the ATM in which the determination of staying in the router device is made is made. The ATM cell data corresponding to the line is discarded;
14. A method for avoiding signal loss in an IPover ATM line according to appendix 12.
(Appendix 13)
A method for avoiding signal loss on a network in which an asynchronous transfer mode network (ATM network) and an Internet protocol network (IP network) are interconnected by a router device,
An IP line disconnection detecting step of detecting disconnection or failure of an Internet protocol line (IP line) accommodated in the router device;
An ATM line in which routing is set with the detected IP line staying in the router device based on the detection state of disconnection or failure of the IP line in the IP line disconnection detecting step A retention data discarding step for discarding ATM cell data corresponding to
A method for avoiding signal loss in an IPoverATM line.

It is a block diagram of 1st Embodiment. It is a sequence diagram of a 1st embodiment. It is a block diagram of 2nd and 3rd embodiment. It is a sequence diagram of 2nd and 3rd embodiment. It is a table | surface explaining the relationship between an ATM line alarm and line disconnection determination. It is a figure explaining the relationship between an ATM line alarm and an ATM signal structure. It is a figure which shows the network structural example of an IPoverATM line. It is a principle explanatory view of an IPoverATM line.

Explanation of symbols

101 Restart determination unit 102 Dummy cell sending unit 103 Operation system execution unit (OS execution unit)
DESCRIPTION OF SYMBOLS 104 Hardware device driver part 105 VPI / VCI channel management table 106 ATM line termination | terminus part 301 Line | wire disconnection detection part 302 Line | wire disconnection determination part 303 Timer 304 Staying data discard part 701 Router apparatus 702 ATM line interface part (ATM line I / F part) )
703 IP line interface part (IP line I / F part)
704 ATM line network 705 IP line network 706 ATM apparatus 707 IP apparatus

Claims (4)

In an asynchronous transfer mode communication device (ATM device) constituting the ATM line network on a network in which an asynchronous transfer mode line network (ATM line network) and an Internet protocol line network (IP line network) are interconnected by a router device. A device configured to:
Resumption determination means for determining execution of resumption processing for abnormal operation of the ATM device;
When the restart determination means determines the execution of the restart process for the abnormal operation of the ATM device, the dummy asynchronous transfer mode cell (ATM cell) of the dummy transfer mode cell (ATM cell) is terminated toward the asynchronous transfer mode line (ATM line) where the ATM device terminates. Dummy cell sending means for instructing sending;
Including
At the time of executing the restart process for the abnormal operation of the ATM device, in the router device communicating with the ATM device, the dummy ATM cell is combined with the communication data cell with the ATM device staying in the router device, Causing the combined data to be discarded by error detection processing;
An apparatus for avoiding signal loss in an IPoverATM line. The dummy cell transmission means instructs transmission of the dummy ATM cell using a data transmission function in a protocol of a higher layer than the Internet protocol (IP protocol).
The apparatus for avoiding signal loss in an IPover ATM line according to claim 1. As a data transmission function in the upper layer layer protocol, a ping test transmission function in the Internet control message protocol (ICMP protocol), a telnet login function in the transmission control protocol (TCP protocol), File transfer protocol (ftp) login function in the TCP protocol, Simple network management protocol-trap (SNMP-Trap) login function in the user datagram protocol (UDP protocol), Trace route in the UDP protocol Use one of the (traceroute) test functions,
The apparatus for avoiding signal loss in an IPover ATM line according to claim 2. A method for avoiding signal loss on a network in which an asynchronous transfer mode network (ATM network) and an Internet protocol network (IP network) are interconnected by a router device,
A restart determination step for determining execution of restart processing for an abnormal operation of an asynchronous transfer mode communication device (ATM device) constituting the ATM line network;
A dummy asynchronous transfer mode cell (ATM cell) toward the asynchronous transfer mode line (ATM line) at which the ATM device terminates when the restart determination step determines execution of a restart process for an abnormal operation of the ATM device. A dummy cell sending step for instructing sending
At the time of executing the restart process for the abnormal operation of the ATM device, in the router device communicating with the ATM device, the dummy ATM cell is combined with the communication data cell with the ATM device staying in the router device, A staying data discarding step for discarding the combined data by error detection processing;
A method for avoiding signal loss in an IPoverATM line.