JP4308287B2 - Redundant gateway system - Google Patents

Description

  The present invention relates to a redundant gateway system including a plurality of gateway devices configured to be multiplexed in a plurality of systems and performing data communication such as voice data communication and video data communication between a packet network and a TDM network such as a telephone network. .

  Generally, a gateway device that interconnects packet networks and telephone networks and relays voice data encodes voice signals received from the telephone network with an encoder and then performs packetization based on RTP (Real-time Transport Protocol). A function to transmit to the packet network. On the contrary, the voice packet received from the packet network is decoded by the decoder and then transmitted to the telephone network. Further, in order to suppress the influence on the user communication due to the occurrence of the failure, the gateway device is often configured to have multiple redundancy more than duplex. For example, in a redundant redundancy configuration where one of the two gateway devices is set as the active system and the other is set as the standby system, if a failure occurs in the active system or device maintenance work is required, System switching between the active system and the standby system is performed. A method has been devised to prevent communication interruption during such system switching.

The method disclosed in Patent Document 1 transfers RTP / RTCP session information and connectivity information other than information related to time stamps and sequence numbers from the active system to the standby system when switching between the active system and the standby system. As a result, the gateway device switched to the active system can start the decoding operation with the parameter value set in the RTP packet transmitted from the IP terminal as the initial value, and without interruption between the active system and the standby system. Can be switched.
JP-A-2005-57461

  However, the conventional technology cannot achieve uninterrupted call interruption. In the disclosed method, since the time stamp value and sequence number of the RTP session information transmitted to the packet network are not taken over, a discontinuity of the time stamp value and sequence number of the RTP packet is detected at the receiving device. It is inevitable that an instantaneous interruption will occur. In addition, the processing of outputting voice data to the telephone network after processing the data received from the packet network cannot be synchronized between the active system and the standby system. Will do. In addition, since the new active device operates from the initial state regardless of the state of the old active device, call quality is not improved until the new active state is restored to the same state as the old active state. A decline is inevitable. For example, until the packet that stayed in the old operational jitter buffer is discarded and the call is interrupted, or the optimization control in the new operational echo canceller is reset and the echo can be correctly removed In addition, a time of about 500 ms to 800 ms is required, and the call during this time is uncomfortable.

  An object of the present invention is to avoid the momentary interruption of data communication caused by system switching in a gateway device configured to be multiplexed in a plurality of systems, and to maintain the communication state before system switching and to reduce communication quality It is to provide a redundant gateway system that can avoid the above-mentioned problem.

The redundant gateway system according to claim 1 includes a plurality of gateway devices that are multiplexed between a packet network and a TDM network, and the gateway device performs TDM conversion on a plurality of packets supplied from the packet network. A redundant gateway system that performs processing and supplies the obtained TDM signal to the TDM network, the same packet supplying means supplying duplicate packets to the plurality of gateway devices by generating a copy of the packet; Generating a common write pointer corresponding to the time stamp TS and / or sequence number SN attached to the packet for each packet, and supplying the common write pointer to the plurality of gateways; Select one of the gateway devices selectively Selection supply means for supplying only the TDM signal obtained from the one gateway device to the TDM network, each of the plurality of gateway devices including at least one jitter buffer and a read pointer of the jitter buffer. And writing the packet to the jitter buffer according to a common write pointer corresponding to the packet for each supplied packet, and sequentially writing the written packet from the jitter buffer according to the jitter buffer read pointer. read look contains a jitter buffer control means to be subjected to the TDM conversion process, the common write pointer generating means and said read pointer generating means is provided in each of the plurality of gateway devices, the one corresponding to the operation command Only the gateway device Commonly it to all gateway devices while generating only pointer and the read pointer and wherein the supplying.

The redundant gateway system according to claim 4 includes a plurality of gateway devices configured to be multiplexed between a plurality of packet networks configured in a multiplexed manner and one TDM network, and a plurality of packets supplied from the packet network are A redundant gateway system that performs TDM conversion processing by the gateway device and supplies the obtained TDM signal to the TDM network, wherein a time stamp TS and / or sequence number attached to the packet for each packet A common write pointer generating means for generating a common write pointer corresponding to the SN and supplying the same to the plurality of gateways, and selectively switching any one of the plurality of gateway devices, the gateway device of the first Selective supplier for supplying only the TDM signal obtained from the network to the TDM network Each of the plurality of gateway devices is supplied from only one of the at least one reception buffer, at least one jitter buffer, means for generating a read pointer of the jitter buffer, and the packet network. The same packet supply means for generating a packet with the same content by copying the copied packet and supplying it to another gateway device other than itself, and the packet captured by the gateway device other than itself The reception buffer control means for sequentially writing and reading both of the supplied packets to the reception buffer, and the same content that is duplicated and read later while making the packet previously read from the reception buffer a valid packet By discarding packets of invalid as invalid packets, only valid packets Effective packet supply means for supplying to the jitter buffer, and for each packet supplied by the effective packet supply means, the packet is written to the jitter buffer according to a common write pointer corresponding to the packet, and the written packet sequentially reads look contains a jitter buffer control means to be subjected to the TDM conversion processing in accordance with the jitter buffer read pointer from the jitter buffer, the common write pointer generating means and said read pointer generating means, said plurality of gateway devices Are provided, and only one gateway device according to an operation command generates the write pointer and the read pointer and supplies them in common to all gateway devices .

  According to the redundant gateway system according to the present invention, the gateway device configured to be multiplexed in a plurality of systems avoids data communication interruptions caused by system switching as much as possible, and maintains the communication state before the system switching. Thus, it is possible to avoid a decrease in communication quality.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the term “pointer” is used to mean an address that defines the information holding position.
<First embodiment>
FIG. 1 shows an embodiment of the present invention, and shows an overall configuration including a redundant gateway system. The redundant gateway system according to the present invention is provided between a packet network 70, which is a packet network, and a telephone network 60, which is a TDM network, and includes at least two gateway devices 10 and gateway devices 20 that are multiplexed to form a plurality of systems. A control unit 50, a TDM switching unit 30, and two packet interface units 40 and 41.

  The gateway device 10 and the gateway device 20 have the same internal configuration. The gateway device 10 includes a packet selection unit 100, an IP processing unit 101, an RTP / RTCP processing unit 102, a jitter buffer control unit 103, a jitter buffer 104, an audio processing unit 105, and a TDM processing unit 106. Has been. Similarly, the gateway device 20 includes a packet selection unit 200, an IP processing unit 201, an RTP / RTCP processing unit 202, a jitter buffer control unit 203, a jitter buffer 204, a voice processing unit 205, and a TDM processing unit. It consists of 206.

  Each of the packet selectors 100 and 200 is mutually connected to both of the packet network interface units 40 and 41 via the received packet confounding line PL. The packet network interface units 40 and 41 are previously connected by the control unit 50 to the packet network 70. A physical address and an IP address necessary for connection are set and connected to the packet network 70 respectively. Because of the redundant configuration, only the active packet network interface unit among the packet network interface units 40 and 41 is selectively switched to transmit / receive packets to / from the packet network 70.

  The packet network interface units 40 and 41 have a function of copying received packets, and output packets having the same content to both the packet selection unit 100 and the packet selection unit 200 connected thereto. The packet selection units 100 and 200 select a packet from the active packet network interface unit, and output the packet to the IP processing unit 101 and the IP processing unit 201.

  Hereinafter, the connection relationship between both systems of the gateway devices 10 and 20 will be described simultaneously. Accordingly, a description will be given below on the assumption that a certain component in one gateway device is connected to other components in the gateway device in principle unless otherwise noted, such as “between systems”. .

  The IP processing unit 101 and the IP processing unit 201 are connected to the RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202, respectively, and the data from the packet network 70 in the RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 are connected. Are supplied to the jitter buffer 104 and the jitter buffer 204, respectively, and data from the telephone network 60 is supplied via the voice processing unit 105 and the voice processing unit 205, respectively. The RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 are connected to the jitter buffer control unit 103 and the jitter buffer control unit 203.

  In order to synchronize the jitter buffer operation, the jitter buffer control unit 103 and the jitter buffer control unit 203 are connected to each other across the systems, and the write pointer WP and the common used in the redundant gateway system according to the present invention A read pointer RP can be supplied from either one to the other. Also, for synchronization of RTP / RTCP processing, the RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 are connected to each other across the systems, and the time stamp TS and the sequence number SN are determined from either one. The other can be supplied. In the operation in this embodiment, the write pointer WP, the read pointer RP, the time stamp TS, and the sequence number SN are supplied from the active gateway device to the standby gateway device.

  The audio processing unit 105 and the audio processing unit 205 are connected to the TDM processing unit 106 and the TDM processing unit 206, respectively. The TDM processing unit 106 and the TDM processing unit 206 are respectively connected to the TDM exchange unit 30, the control unit 50 is connected to the gateway device 10, the gateway device 20 and the TDM exchange unit 30, respectively, and the TDM exchange unit 30 is Connected to the telephone network 60. In addition, for audio processing timing synchronization, the timing signal generation unit 301 includes a TDM processing unit 106 and a TDM processing unit 206, an audio processing unit 105 and an audio processing unit 205, a jitter buffer control unit 103 and a jitter buffer control unit 203, / RTCP processing unit 102 and RTP / RTCP processing unit 202 are connected to each other.

  The gateway device 10 and the gateway device 20 have a redundant configuration, and each is alternatively set to an active system or a standby system by a switching operation according to a switching signal from the control unit 50. Only the gateway device (for example, the gateway device 10) set to the active system is connected to the packet network 70 provided with the IP telephone service by the VoIP technology via the packet network interface unit. The two gateway devices 10 and 20 are always connected to the TDM switching unit 30 regardless of the settings of the active system and the standby system. The TDM switching unit 30 is connected to a normal telephone network 60 that transmits voice using a TDM signal, such as a public subscriber telephone network.

  The control unit 50 is connected to the TDM switching unit 30, the gateway device 10 and the gateway device 20, and the packet network interface units 40 and 41, respectively, and has a function of controlling the operations of these units. When a system switching request is generated due to a system failure or maintenance work, the control unit 50 transmits a system switching signal by automatic processing based on an external command operation or failure detection. In addition, the control unit 50 sends and holds RTP session information such as packetization information such as the RTP packet size of the voice data to the gateway device 10 and the gateway device 20 in advance. Further, at the time of system switching, the control unit 50 sends a system switching signal to the gateway device 10 and the gateway device 20, and changes its operation to an active system or a standby system. Further, the control unit 50 sets the physical address and IP address necessary for determining the normality of the received packet and for assembling the transmitted packet to the active system or standby system gateway device and the packet network 70. The communication possible state is formed.

  The TDM exchange unit 30 is connected to the telephone network 60 and terminates the network transmission system, and has a function of supplying voice data extracted from the TDM signal from the telephone network 60 to both the gateway device 10 and the gateway device 20. . The TDM exchange unit 30 includes a timing signal generation unit 301. The timing signal generation unit 301 generates a processing timing signal S1 that has an integral multiple of the frame clock period of the TDM signal supplied from the telephone network 60 and is common in the redundant system. Always supply to both parts of the 20.

  The TDM processing unit 106 and the TDM processing unit 206 accumulate audio data for each channel from the TDM signal supplied from the TDM exchange unit 30, and the audio data is transmitted to the audio processing unit 105 and the audio at a timing based on the processing timing signal S1. A function of outputting to the processing unit 205 is provided. As shown in FIG. 2, the TDM signal is voice data transmitted in a plurality of call sessions. In this embodiment, the integration timing at which voice data is integrated and packetized for each channel from the TDM signal is synchronized with the timing of the frame clock (integer multiple) of the TDM signal.

  The voice processing unit 105 and the voice processing unit 205 perform voice processing such as echo cancellation processing and compression coding processing on the voice data from the TDM processing unit 106 and the TDM processing unit 206, and RTP / RTCP processing unit 102 and RTP / A function for supplying to the RTCP processing unit 202 is provided. The audio data is audio data accumulated for each channel (for example, 10 ms) of the processing timing signal S1. The audio data is subjected to audio processing for each cycle of the processing timing signal S1, an integer multiple of the cycle, or a cycle divided based on the cycle. The audio data obtained by the audio processing is supplied to the RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 with a predetermined RTP packet size at predetermined intervals according to the size.

  The RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 packetize the audio data supplied from the audio processing unit 105 and the audio processing unit 205 into RTP packets, and supply the RTP packet to the IP processing unit 101 and the IP processing unit 201. It has a function. The voice data is captured in units of RTP packet size for each channel. The RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 are also set in the operational system and the function for determining the time stamp value TS and the sequence number SN for each channel to be set in the header part of the RTP packet. The RTP / RTCP processing unit of the gateway device and the RTP / RTCP processing unit of the gateway device set as the standby system have a function of mutually transmitting / receiving them. In the RTP packet obtained by packetization, voice data for each channel is stored in its payload portion, and the above-mentioned time stamp value TS and sequence number SN are stored in its header portion.

  The IP processing unit 101 and the IP processing unit 201 receive the RTP packet supplied from the RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202, generate an IP packet according to the packetization information from the control unit 50, A function of outputting this to the packet network interface unit 40 and the packet network interface unit 41 is provided.

  The two gateway devices 10 and 20 commonly receive supply of the same TDM signal from the TDM exchange unit, and execute processing synchronized with the processing timing signal S1 based on the TDM signal in each unit. As a result, IP packets from both the gateway device 10 and the gateway device 20 are sent out toward the packet network 70 at exactly the same and substantially the same interval. Actually, as described above, since only the gateway device set to the active system is in a communicable state with the packet network 70 via the packet network interface unit, the IP packet from the gateway device set to the active system is received. An IP packet transmitted to the packet network 70 and set from the gateway device set as the standby system is discarded by the connected packet network interface unit.

  FIG. 3 shows the input / output timing of voice data and packets in the active system and the standby system. In this figure, for ease of explanation, one RTP packet and one IP packet are generated for every period of the processing timing signal S1 in all channels. Here, the processing timing signal S1 is supplied to both the active and standby gateway devices. For each clock of the processing timing signal S1, audio data for a plurality of channels is input to the active and standby audio processing units. Similarly, audio data for a plurality of channels is input to the active and standby RTP / RTCP processing units for each clock of the processing timing signal S1.

In the operation system, a time stamp value TS and a sequence number SN are determined for each piece of audio data for one channel. As shown in the figure, a time stamp value TS = 100 and a sequence number SN = 10 are determined for the channel ch0. The time stamp value TS and sequence number SN for each channel are transmitted from the active RTP / RTCP processing unit to the standby RTP / RTCP processing unit. Both the active and standby RTP / RTCP processing units store the same time stamp value TS and sequence number SN in the RTP header, store voice data in the RTP payload portion, and output an RTP packet. The RTP packet is converted into an IP packet in both the active system and the standby system and output from the IP processing unit.
<Operation overview in packetization>
FIG. 4 shows an outline of an operation in which voice data in a TDM signal received from the telephone network 60 is voice-processed and then packetized and output to the packet network. Since the RTP / RTCP processing units of both systems perform processing for exchanging the time stamp value TS and the sequence number SN with each other, different operations are performed in the active system and the standby system.

  First, it is assumed that system switching is performed at a certain point in time, the gateway apparatus 10 is set from the standby system to the active system, and the gateway apparatus 20 is set from the active system to the standby system (step S1). The RTP / RTCP processing unit 102 of the gateway device 10 performs processing for converting the voice data supplied from the voice processing unit 105 into RTP packets and supplying the RTP packet to the IP processing unit 101. Upon packetization into the RTP packet, a time stamp value TS and a sequence number SN to be stored in the header part of the RTP packet are determined (step S2). The time stamp value TS and the sequence number SN are made to be continuous with the time stamp value TS and the sequence number SN determined by the gateway device 20 that was previously the active system during the period when the gateway device 10 is set as the standby system. To be determined.

  Next, the RTP / RTCP processing unit 102 sends the determined time stamp value TS and sequence number SN as the time stamp value TS and sequence number SN to the RTP / RTCP processing unit 202 of the standby gateway device 20. (Step S3). Next, the RTP / RTCP processing unit 102 generates an RTP packet, stores the audio data in the payload portion, and stores the previously determined time stamp value TS and sequence number SN in the header portion, thereby (Step S4).

  On the other hand, the RTP / RTCP processing unit 202 of the standby gateway apparatus 20 also performs processing of packetizing the voice data supplied from the voice processing unit 205 into RTP packets and supplying the packeted data to the IP processing unit 201. At this time, when packetizing into the RTP packet, the time stamp value TS and the sequence number SN to be stored in the header part of the RTP packet are the time stamp value TS and the sequence number SN sent from the active RTP / RTCP processing unit 102. The sequence number SN is used. The RTP / RTCP processing unit 202 generates an RTP packet, stores the voice data in the payload portion, and stores the time stamp value TS and sequence number SN determined by the operation system in the header portion, thereby storing the RTP packet. Processing is performed (step S5).

  The processing of the active RTP / RTCP processing unit 102 (steps S2 to S4) and the processing of the standby RTP / RTCP processing unit 202 (step S5) are repeated every time an RTP packet is generated. Since the time stamp value TS and the sequence number SN are continuous values, it is not always necessary to send the time stamp value TS and the sequence number SN from the active system to the standby system in some cases.

When system switching is performed again later, it is assumed that the gateway device 10 is changed from the active system to the standby system and the gateway device 20 is set from the standby system to the active system (step S6). The RTP / RTCP processing unit 202 of the gateway device 20 performs the same processing as in steps S2 to S4 described above (steps S7 and S8). Thereby, the same packet output in which both systems are completely synchronized becomes possible.
<Overview of operation in TDM signaling>
With reference to FIG. 1 again, a description will be given of an outline of the operation for synchronizing the processing of the active system and the standby system with respect to the process of processing the voice data in the packet received from the packet network, then converting it into a TDM signal and outputting it to the telephone network. In FIG. 1, the gateway device 10 and the gateway device 20 having a redundant configuration are examples in which the gateway device 10 is an active system and the gateway device 20 is a standby system.

  An arrival packet from the packet network 70 is input to the packet network interface unit 40. The packet network interface unit 40 outputs the input packet to the active system packet selection unit 100, duplicates the input packet, and uses the received packet confounding line PL to send the same packet to the standby system packet selection unit 200. Is output. The packet network interface unit 40 and the packet network interface unit 41 do not perform system switching at the same time as the gateway device, and always input packets from the packet network 70 to both the active packet selection unit 100 and the standby packet selection unit 200. Output for.

  The IP processing unit 101 and the IP processing unit 201 select only packets arriving at the self-redundant gateway system from among the IP packets input from the packet selection unit 100 and the packet selection unit 200 set in the active system. The data is output to the RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202. The RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 output the time stamp and sequence number SN of the input packets to the jitter buffer control unit 103 and the jitter buffer control unit 203, and the audio data is output to the jitter buffer 104. And output to the jitter buffer 204.

Writing to the jitter buffer 104 and the jitter buffer 204 is input in a state in which arrival fluctuations in the packet network and packet replacement occur. Next, the reading of the jitter buffer 104 and the jitter buffer 204 is output to the audio processing unit 105 and the audio processing unit 205 at a timing that matches the audio processing timing based on the processing timing signal S1. In the audio processing unit 105 and the audio processing unit 205, audio processing such as data generation for echo cancellation processing and encoding / decoding processing is performed, and the TDM processing unit 106 converts the audio data at a timing based on the processing timing signal S1. And output to the TDM processing unit 206. The TDM processing unit 106 and the TDM processing unit 206 output the audio data collected at the audio processing unit timing to the TDM exchange unit 30 as time division multiplexed data with the audio sampling timing as the frame timing. Based on the input signal from the control unit 50, the TDM exchange unit 30 outputs the TDM signal of the active gateway device among the TDM signals from the gateway device 10 and the gateway device 20 to the telephone network 60. In addition, the TDM signal of the standby gateway device is discarded in the TDM exchange unit 30.
<Details of operation in TDM signaling>
The detailed operation of the redundant gateway system will be described below with reference to FIGS. Here, the processing timing signal S1, the processing timing numbers # 1 to # 11, and the data input timings to the jitter buffer 104 and the jitter buffer 204 are the same timings as shown in FIGS. To do. Further, it is assumed that the jitter buffer 104 and the jitter buffer 204 operate as a cyclic buffer.

  FIG. 5 shows an outline of the write operation of the jitter buffer 104 and the jitter buffer 204. The RTP / RTCP processing unit 102 and the RTP / RTCP processing unit 202 are input in a state where arrival fluctuation or packet replacement in the packet network occurs, and data is input to the jitter buffer 104 and the jitter buffer 204 in the same state. . The jitter buffer 104 and the jitter buffer 204 divide the memory area for each audio processing unit, and manage by adding a pointer (address) to each area, thereby facilitating buffer management at the time of reading. Yes. Hereinafter, for ease of explanation, it is assumed that one input packet is one audio processing unit and the jitter buffer 104 and the jitter buffer 204 are eight regions.

  The operational jitter buffer control unit 103 receives the time stamp and sequence number SN as packet identification information from the RTP / RTCP processing unit 102, and compares it with the time stamp and sequence number SN of the previously received packet identification information. Based on the result, the write pointer (write pointer) of the operational jitter buffer 104 is determined. Here, the write pointer is determined so that the data order in the jitter buffer is continuous. As a result, the pointer at the time of reading can be set to a continuous value, and reading control can be facilitated.

  In the chart shown in FIG. 5, the data that is input immediately after the processing timing number # 5 has a sequence number SN of SN = 15, and is a continuous value from the sequence number SN = 13 of the previously input data. is not. This indicates that in the packet network 70, packet discard or packet order change occurred.

  In this case, assuming that writing to the operational jitter buffer 104 is continuously written in the order of the packet sequence number SN, if there is a free area where the input data can be written, The pointer value freed from the data writing area located at is determined as the writing pointer and writing is performed. Therefore, in this case, the write pointer WP of the data input immediately after the processing timing number # 5 is not WP = 7 obtained by adding 1 to the write pointer value WP = 6 of the previously input data, and WP = 0. The pointer value that frees the WP = 7 area as the SN = 14 writing area is determined. Subsequently input data is SN = 16 and WP = 1. The subsequent input data is SN = 14. In this case, if the input packet is not a packet at the timing after being read from the operational jitter buffer 104, it is determined that writing is possible, and the write pointer is determined to be WP = 7. Write.

  As a result of the above operation, data is written in the jitter buffer 104 in a continuous state. The write pointer determined in the active system is simultaneously transferred to the standby system and determined as the write pointer of the standby system jitter buffer 204. By transferring the write pointer from the active system to the standby system in this way, it becomes possible to make the data write states of the active system jitter buffer 104 and the standby system jitter buffer 204 completely coincide.

  FIG. 6 shows an outline of the reading operation of the jitter buffer 104 and the jitter buffer 204. The jitter buffer 104 and the jitter buffer 204 are operated by accumulating a predetermined amount of packets necessary to absorb packet arrival fluctuation and packet change occurring in the packet network 70, and the read data is a continuous data string. Operate to be. Therefore, at the start of a call, the read pointer RP is determined with a predetermined amount of pointer values to be accumulated in the jitter buffer 104 and operated with respect to the write pointer WP.

  Furthermore, since the data order is written in the jitter buffer 104 and the jitter buffer 204 as described above so that the data order is continuous, the read pointer (read pointer) at the next processing timing is set to the processing timing S1. Each time data is read out, 1 is added. The read pointer determined by the active gateway device 10 is simultaneously transferred to the standby gateway device 20 and determined as a read pointer for the standby jitter buffer 204. By transferring the read pointer from the active gateway device 10 to the standby gateway device 20 in this way, it becomes possible to completely match the output data contents of the active jitter buffer 104 and the standby jitter buffer 204, By reading out the active jitter buffer 104 and the standby jitter buffer 204 in accordance with the processing timing signal S1, the data timing output from the jitter buffer 104 in the active gateway device 10 and the jitter buffer in the standby gateway device 20 are read. It is possible to completely synchronize the data timing output from 204.

  Referring to the lower part of FIG. 6, the state of data retention in the active system jitter buffer 104 and the standby system jitter buffer 204 is shown. By referring to the processing timing number together with that in FIG. 5, the write and read data states of the operational jitter buffer 104 and the standby jitter buffer 204 and the operation states of the pointers can be clarified.

  FIG. 7 shows the operation when the write pointer and the read pointer are not transferred between the two systems. Here, it is assumed that the maintainer incorporates the standby gateway device 20 during the operation of the active gateway device 10. It is assumed that the processing timing signal S1, the processing timing number, and the input data timing to the jitter buffer 104 and the jitter buffer 204 are the same as those shown in FIGS. Further, the amount necessary to absorb the arrival fluctuation and packet change of the packet generated in the packet network 70 is set to 4 packets, and the jitter buffer 104 and the jitter buffer 204 are set with silent data as initial data. It shall be.

  First, it is assumed that the standby gateway apparatus 20 is incorporated and started to operate at the timing of processing timing number # 1. In standby gateway apparatus 20, data (sequence number SN = 10) input immediately after processing timing number # 1 is written from write pointer WP = 0 at the beginning of the buffer. Subsequently input data operates in the same manner as the above-described write operation. The amount of data that is input in bursts between processing timing numbers # 2 to # 4, and the amount required to absorb packet arrival fluctuations and packet switching that occur in the packet network at processing timing # 4 Since (4 packets) is satisfied, reading of data is started from processing timing number # 5.

  On the other hand, in the operational gateway device 10, the data (sequence number SN = 10) input immediately after the processing timing number # 1 is written from the middle write pointer WP = 3, and read at the processing timing number # 6. Has been started.

  As a result, the output data of the active system jitter buffer 104 and the output data of the standby system jitter buffer 204 are deviated, and when the system switching between the active system gateway device 10 and the standby system gateway device 20 is executed in this state, there is one Data loss for the audio processing unit will occur.

  FIG. 8 shows the operation when the write pointer and the read pointer are transferred between the two systems. Here, it is assumed that the maintainer incorporates the standby gateway device 20 during the operation of the active gateway device 10. It is assumed that the processing timing signal S1, the processing timing number, and the input data timing to the jitter buffer 104 and the jitter buffer 204 are the same as those shown in FIG. 5, FIG. 6, and FIG.

  When the standby gateway device 20 is installed at the timing of the processing timing number # 1 and the operation starts, the data (sequence number SN = 10) input immediately after the processing timing number # 1 is transferred and received from the active system The buffer is written from the write pointer WP = 3. Subsequently input data operates in the same manner as the write operation. Data is input in bursts between processing timing numbers # 2 to # 4, and at processing timing # 4, the location necessary to absorb packet arrival fluctuations and packet switching that occur in the packet network. Since the dose is satisfied, reading of data is started from processing timing number # 5. At this time, the read pointer transferred from the operational gateway device 10 and received is RP = 2, and the silent data of the initial data is output from the standby jitter buffer 204. The read pointer of processing timing number # 6 is RP = 3, the previously written data of sequence number SN = 10 is read, and the output data contents of the operational jitter buffer 104 and standby jitter buffer 204 are complete Matches.

In addition, the packet network interface unit 40 and the packet network interface unit 41 duplicate received packets and output packets having the same contents to both the connected packet selection unit 100 and the packet selection unit 200, thereby performing voice processing. In the echo cancellation processing in the unit 105 and the voice processing unit 205, the optimization condition for the echo cancellation processing optimal for the call session is held in both the active system and the standby system.
<Description of operational effects in the first embodiment>
In the first embodiment described above, by using the redundant gateway system according to the present invention, a series of processes of TDM processing, voice processing, RTP / RTCP processing, and IP processing is performed at a timing based on the frame clock of the TDM signal. However, it is performed in both the gateway device 10 and the gateway device 20 having a redundant redundancy configuration, and the same packet that is completely synchronized in both systems can be output to the packet network 70.

  In addition, by exchanging the time stamp value TS and the sequence number SN between the two systems, the identity and continuity of these values are guaranteed. Thereby, even when system switching occurs, the time stamp value TS and the sequence number SN can be set to continuous values. The receiving device on the communication partner side via the packet network 70 does not detect packet discontinuity, and is not affected by the instantaneous interruption in communication.

  In addition, the packet received from the packet network 70 is shared by both the active system and the standby system, and jitter buffer control is performed in accordance with the processing timing signal S1 generated by the timing signal generator 301, and the active system jitter buffer 104 and the standby system are Jitter buffer control by transferring the write pointer and read pointer of the system jitter buffer 204 allows the output data contents to be matched and the output timing synchronized between the active system jitter buffer 104 and the standby system jitter buffer 204 It becomes. As a result, the same voice data that is completely synchronized from the plurality of gateway devices 10 and 20 in a redundant configuration with respect to the telephone network 60 can be output to the telephone network 60. Therefore, there is no influence of voice data interruption or duplication in switching the operation system of the redundant apparatus.

Also, by maintaining optimization conditions for echo cancellation processing that are optimal for call sessions on both the active and standby systems, the time required to make the echo cancellation processing normal can be eliminated. It is possible not to be affected by the uncomfortable feeling of the call.
<Modification of the first embodiment>
In the above embodiment, the gateway devices 10 and 20 are provided with the timing signal generation unit 301 that generates the processing timing signal based on the clock of the TDM signal in the external TDM exchange unit 30, but the gateway devices 10 and / or 20 Alternatively, such a function may be provided in 20.

  In addition, although a form in which such a processing timing signal is supplied from the TDM switching unit 30 to the gateway devices of both systems is shown, the processing timing is added to the TDM signal itself supplied from the TDM switching unit 30 to the gateway devices of both systems. A series of processing in both systems may be performed in complete synchronization by incorporating a given signal.

  The reference processing timing signal S1 is generated with reference to the clock of the TDM signal, but a series of processing in both systems is performed using a reference timing having an arbitrary period supplied from inside or outside the gateway device 1020. May be performed in complete synchronization.

  In the first embodiment, the jitter buffer 104 and the jitter buffer 204 are divided into regions for each audio processing unit, and a pointer corresponding to the sequence number assigned to the packet is added to each region for management. The write pointer and the read pointer are transferred from the active system to the standby system to synchronize the output data. Instead of this sequence number, a pointer corresponding to the time stamp attached to the packet is added. And the write pointer and the read pointer may be transferred from the active system to the standby system to synchronize the output data.

In the first embodiment described above, a mode in which one packet is one audio processing unit is shown. As another modified example of the present invention, when the voice packetization period (packet length) of the input packet is longer than the voice processing unit, the voice data is divided according to the voice processing unit, and pointer management is performed. A new time stamp value TS may be added for each audio data to achieve synchronization of both systems, or a new identification such as adding a sequence number SN to each divided audio data to achieve synchronization. Synchronization may be realized by adding information. On the other hand, when the voice packetization cycle (packet length) of the input packet is shorter than the voice processing unit, the voice data is collectively managed by the pointer according to the voice processing unit, or a new time stamp is added for each voice data collected. Synchronization may be realized by adding new identification information such as adding value TS to achieve synchronization, or adding new sequence number SN for each collected audio data, etc. .
<Second embodiment>
FIG. 9 shows the second embodiment and shows the configuration of the redundant gateway system and the network connected thereto. Here, the redundant gateway system is provided between the packet network 160 and the packet network 261 in the redundant configuration of the current configuration and the standby configuration, and between the packet network 261 and the telephone network 50 as the TDM class. It includes at least two gateway devices 10 and gateway devices 20 configured to be multiplexed, a control unit 40, and a TDM exchange unit 30.

  In the second embodiment, the terms “working” and “standby” are used in place of the terms “active” and “standby” used in the first embodiment. This is because the two systems of the packet network and the gateway device are in an operable state at the same time, and both systems are premised on an operation form in which redundant processing is performed in parallel on packets having the same contents through different paths.

  The gateway device 10 and the gateway device 20 are respectively connected to the packet network 160 and the packet network 261 that are configured for active use and backup, and the gateway device 10 is for the packet network 160 and the gateway device 20 is for the packet network 261. Send and receive packets. For example, assuming that the packet network 160 is used as an active state and the packet network 261 is used as a standby state in the initial state, the gateway device 10 is used as the active state and the gateway device 20 is used as a standby state.

  When a system switching request is generated due to a system failure or maintenance work, the control unit 40 performs a system switching operation by automatic processing based on an external command operation or failure detection. Specifically, the control unit 40 supplies a control signal to the gateway devices 10 and 20, and alternatively sets each of the gateway devices 10 and 20 as active or standby. The control unit 40 is also required for connection to the packet network 160 and the packet network 261 as packet data such as the packet size and communication destination information in the RTP packetization of voice data as a pre-set for the gateway devices 10 and 20. Set a valid physical address and IP address.

  The TDM switching unit 30 is connected to the telephone network 50 and is always connected to the two gateway devices 10 and 20 regardless of the current and spare settings. However, the TDM switching unit 30 selects the voice data of the working gateway device that is one of the gateway device 10 and the gateway device 20 according to the setting from the control unit 40, and outputs the selected voice data to the telephone network 50. The TDM exchange unit 30 also includes a timing signal generation unit 301, and supplies the timing signal S1 in common to each of the gateway device 10 and the gateway device 20.

  The gateway device 10 and the gateway device 20 have the same internal configuration. The gateway device 10 includes a packet network interface unit 100, an IP processing unit 101, an RTP / RTCP processing unit 102, an own system reception buffer 103, an other system reception buffer 104, a reception buffer control unit 105, and a jitter buffer control. Unit 106, jitter buffer 107, voice processing unit 108, and TDM processing unit 109. Similarly, the gateway device 20 includes a packet network interface unit 200, an IP processing unit 201, an RTP / RTCP processing unit 202, an own system reception buffer 203, an other system reception buffer 204, and a reception buffer control unit 205. , A jitter buffer control unit 206, a jitter buffer 207, an audio processing unit 208, and a TDM processing unit 209.

  The gateway device 10 transmits / receives a packet to / from the packet network 160 by the packet network interface unit 100, and the gateway device 20 transmits / receives a packet to / from the packet network 261 by the packet network interface unit 200. Regardless of this, the communication state is always maintained for each packet network.

  The packet network interface units 100 and 200 are connected to the IP processing units 101 and 201, respectively. The IP processing units 101 and 201 are connected to the RTP / RTCP processing units 102 and 202, respectively. The RTP / RTCP processing units 102 and 202 have a function of duplicating the own system received packet. The RTP / RTCP processing unit 102 is connected to the own system reception buffer 103 and is connected to the other system reception buffer via the received packet confounding line PL. Connected to 204 and outputs the same packet to both sides. Similarly, the RTP / RTCP processing unit 202 is connected to the local reception buffer 203 and connected to the other reception buffer 104 via the reception packet confounding line PL, and outputs packets having the same contents to both. The RTP / RTCP processing units 102 and 202 are connected to the audio processing units 108 and 208, respectively.

  The jitter buffer controllers 106 and 206 are connected to each other across the systems, and perform jitter buffer operation by supplying a write pointer WP and a read pointer RP that are commonly used in the redundant gateway system from one to the other. Perform the operation to synchronize.

  The RTP / RTCP processing units 102 and 202 are mutually connected across the systems, and perform an operation of synchronizing the RTP / RTCP processing by supplying the time stamp TS and the sequence number SN from one to the other.

  The jitter buffers 107 and 207 are connected to the audio processing units 108 and 208, the audio processing units 108 and 208 are connected to the TDM processing units 109 and 209, and the TDM processing units 109 and 209 are connected to the TDM exchange unit 30, respectively. ing. The control unit 40 is connected to the gateway device 10, the gateway device 20, and the TDM exchange unit 30, respectively. The TDM exchange unit 30 is connected to the telephone network 50.

  The IP processing units 101 and 201, the RTP / RTCP processing units 102 and 202, the jitter buffer control units 106 and 206, the jitter buffers 107 and 207, the voice processing units 108 and 208, and the TDM processing units 109 and 209 And each have the same function as in the first embodiment. These are supplied with the timing signal S1 from the timing signal generation unit 301 of the TDM exchange unit 30, and perform synchronized operations at the audio processing timing according to the timing signal S1. Therefore, operations relating to synchronization of jitter buffer operation, RTP / RTCP processing, and voice processing timing are the same as in the first embodiment.

  Self-system reception buffer 103 and other-system reception buffer 104 included in gateway device 10 are connected to reception buffer control section 105, and are received by the other-system packet network received from voice data from local system packet network 160 and reception packet confounding line PL. The audio data from 261 is supplied. The reception buffer control unit 105 is connected to the local reception buffer 103 and the other reception buffer 104 for the control of writing and reading.

  The own-system reception buffer 203 and the other-system reception buffer 204 included in the gateway device 20 are connected to the reception buffer control unit 205, and the other-system packet network 160 received by the data from the own-system packet network 261 and the received packet confounding line PL. Supply data from. The reception buffer control unit 205 is connected to the local reception buffer 203 and the other reception buffer 204 and controls writing and reading thereof. The reception buffer controllers 105 and 205 are also connected to the jitter buffer controllers 106 and 206 and the jitter buffers 107 and 207, respectively, and supply the received audio data thereto. The reception buffer control unit 105 and the reception buffer control unit 205 are connected to each other through the reception buffer control signal line CL across the systems, and supply the buffer pointer BP from one to the other, thereby receiving the local reception buffer. 103 and 203 and other system reception buffers 104 and 204 are synchronized.

  10 to 13 show the operation of the redundant gateway system in the second embodiment in a time chart format with the horizontal axis as time. The operation of the redundant gateway system will be described below with reference to the components shown in the block diagram of FIG.

  As a premise, the redundant gateway system receives the same packet from the packet network 160 and the packet network 261 in parallel, converts the packet into voice data in the TDM signal format, and outputs it to the telephone network 50. And

  The packet network interface units 100 and 200 receive packets from the packet network 160 and the packet network 261, respectively, receive only packets addressed to their own physical addresses preset by the control unit 40, and IP processing units 101 and 201, respectively. The received packet is supplied. The IP processing capitals 101 and 201 receive only the packets addressed to their own IP addresses set in advance by the control unit 40 from the supplied packets, and check the header information and the normality of the data as necessary. Then, only valid packets are supplied to the RTP / RTCP processing units 102 and 202, respectively.

The RTP / RTCP processing units 102 and 202 extract packet discrimination information, that is, information such as a port number, a sequence number, a time stamp, and a synchronization source identifier (SSRC) from the supplied packets, To generate audio data. The RTP / RTCP processing unit 102 further supplies the generated audio data to the local reception buffer 103 and also supplies it to the other reception buffer 204 via the reception packet confounding line PL. Similarly, the RTP / RTCP processing unit 202 supplies the generated audio data to the own system reception buffer 203 and also supplies it to the other system reception buffer 104 connected via the reception packet confounding line PL.
<Write operation of receive buffer>
Referring to FIG. 10, the write operation of the reception buffer controllers 105 and 205 with respect to the local reception buffers 103 and 203 and the other reception buffers 104 and 204 is shown. Here, the local reception buffers 103 and 203, the other reception buffers 104 and 204, and the reception buffer controllers 105 and 205 all have a four-sided memory configuration in which pointers are individually assigned. The actual memory configuration should be determined according to network conditions.

  First, at timing t0, the voice data (SN = 10) input from the RTP / RTCP processing unit 102 of the working gateway device 10 to the local reception buffer 103 is received by the local buffer by the write pointer management of the reception buffer control unit 105. It is written to the pointer 0 of the buffer 103. On the other hand, the same voice data (SN = 10) is input from the RTP / RTCP processing unit 102 to the other-system reception buffer 204 via the reception packet confounding line PL. At the same time, the write pointer of the own system reception buffer 103 is transferred from the working gateway device 10 to the backup gateway device 20. In response to this, the voice data (SN = 10) is written to the pointer 0 of the other system reception buffer 204 of the backup gateway device 20 by the write pointer management of the reception buffer control unit 205 of the backup gateway device 20.

  Next, at timing tl, the audio data (SN = 11) input to the local reception buffer 103 is similarly written to the pointer 1 of the local reception buffer 103 and input to the other reception buffer 204. The same audio data (SN = 11) is written in the pointer 1 of the other system reception buffer 204 in the same manner. Thereafter, the same audio data is written to the same pointer in the local reception buffer 103 and the other reception buffer 204 by the same operation.

  On the other hand, at timing t0, the voice data (SN = 10) input from the RTP / RTCP processing unit 202 of the backup gateway device 20 is also supplied to the local reception buffer 203 and the received packet confounding line PL is set. To the other-system reception buffer 104. The audio data (SN = 10) supplied to the local reception buffer 203 is written to the pointer 0 of the local reception buffer 203 by the write pointer management of the reception buffer control unit 205 of the backup gateway device 20, and the other system The audio data (SN = 10) supplied to the reception buffer 104 is written into the other system reception buffer 104 pointer 0 by the write pointer management of the reception buffer control unit 105 of the working gateway device 10. Thereafter, the same operation is performed in the same manner as the operation for the voice data input from the RTP / RTCP processing unit 102 of the working gateway device 10 described above.

However, in the second embodiment, each write pointer is transferred from the working gateway device 10 to the backup gateway device 20 to achieve uniformity of operation management. That is, the reception buffer control unit 105 of the working gateway device 10 determines and controls the write pointers of the local reception buffer 103 and the remote reception buffer 104 by itself. On the other hand, the reception buffer control unit 205 of the backup gateway device 20 controls the write pointers of the local reception buffer 203 and the other reception buffer 204 according to the write pointer transferred from the active gateway device 10.
<Reading operation of receive buffer>
Referring to FIG. 11, a read operation by the reception buffer control unit 105 with respect to the own system reception buffer 103 and the other system reception buffer 104 of the working gateway device 10 is shown. Here, each of the local reception buffer 103 and the other reception buffer 104 is always monitored by the reception buffer control unit 105 to determine whether or not the audio data is held. Control is performed to perform a read operation. The read target buffer and the read pointer are determined in a unified manner by the reception buffer control unit 105 of the working gateway device 10. The reception buffer read operation is controlled by the reception buffer control unit 105 using a read enable signal so that reading from both the local reception buffer 103 and the other reception buffer 104 is not performed simultaneously. The middle part of FIG. 11 shows a read enable signal for the local reception buffer 103 and the other reception buffer 104 and an audio data string to be output.

  First, immediately after timing t 0, the audio data (SN = 10) input to the local reception buffer 103 is written into the local reception buffer 103 by the reception buffer control unit 105 after the writing to the local reception buffer 103 is completed. It is detected that data is held, is read from the local reception buffer 103, and is supplied to the reception buffer control unit 105. Thereafter, the audio data (SN = 10) input to the other-system reception buffer 104 is also read from the other-system reception buffer 104 and supplied to the reception buffer control unit 105 in the same manner. Here, since the audio data supplied to the reception buffer control unit 105 is supplied from both the packet network 160 and the packet network 261, double data rate processing is required. In an actual circuit, a circuit configuration in which the data bus width is multiplied is used to improve the processing rate.

  The reception buffer control unit 105 extracts packet discrimination information, that is, information such as a boat number, a sequence number, a time stamp, and a synchronization source identifier (SSRC) from the supplied audio data, and the audio data has been supplied previously. It is determined whether or not the audio data is the same as the audio data. If it is determined that the audio data is previously input, the audio data is discarded as duplicate audio data. Here, among the voice data received in the past, the previous voice data necessary for such determination is that the arrival fluctuation time of the packet network 160 is ± α hours and the arrival fluctuation time of the packet network 261 is ± β hours. In this case, the audio data received at least before “α + β + maximum delay time when reading the buffer” from the present time is determined.

  The lower part of FIG. 11 shows audio data output as a result of the discard processing described above in the reception buffer control unit 105. Only the audio data read out first of either the local reception buffer 103 or the other reception buffer 104 is supplied as valid audio data to the subsequent jitter buffer 107 and the jitter buffer control unit 106.

  Although the operation of the working gateway device 10 has been described in FIG. 11, the operation of the backup gateway device 20 is basically performed in the same manner. However, when reading the own system reception buffer 203 and the other system reception buffer 204 in the standby gateway apparatus 20, the reception buffer control unit 105 for the own system reception buffer 103 and the other system reception buffer 104 of the current gateway apparatus 10 described above. The read target buffer and the read pointer determined by are transmitted to the reception buffer control unit 205 via the reception buffer control signal line CL. The reception buffer control unit 205 controls the read operation for the other-system reception buffer 204 and the own-system reception buffer 203 in synchronization with the read operation of the active gateway device 10 in response to the reception of the read target buffer and the read pointer. In this case, after the read pointer of the own system reception buffer 103 of the working gateway device 10 is replaced with the read pointer of the other system reception buffer 204 of the backup gateway device 20, the reading to the other system reception buffer 204 is performed, and the working gateway After the read pointer of the other-system reception buffer 104 of the device 10 is replaced with the read pointer of the own-system reception buffer 203 of the backup gateway device 20, the reading to the own-system reception buffer 203 is performed. As a result of the above operation, the same audio data that is completely synchronized is stored in the jitter buffer control unit 106 and the jitter buffer 107 in the working gateway device 10 and the jitter buffer control unit 206 and the jitter buffer 207 in the backup gateway device 20. Will be supplied.

  Referring to FIG. 12, when the standby gateway device 20 is newly incorporated during the operation of the working gateway device 10, the write buffer read / write pointer of the reception buffer by the reception buffer control signal line CL is “when no transfer is performed”. Operation is shown. Here, it is assumed that backup gateway device 20 is incorporated in a state where voice data (SN = 19) that has not been read is held in own reception buffer 103 of active gateway device 10.

  First, immediately after the timing t10, the input voice data (SN = 20) is written into the pointer 2 of the own system reception buffer 103 of the working gateway device 10. Similarly, the voice data (SN = 20) is also input to the other-system reception buffer 204 of the backup gateway device 20 previously incorporated via the reception packet confounding line PL and written to the initial pointer 0.

  When the voice data is read from the local reception buffer 103 and the other reception buffer 204 after the completion of the writing of the voice data (SN = 20), the active gateway device 10 holds the data in the local reception buffer 103 first. Audio data (SN = 19) is read out. On the other hand, the backup gateway device 20 reads the voice data (SN = 20). That is, the same audio data that is completely synchronized is not supplied to the jitter buffer control unit 106 and jitter buffer 107 in the working gateway device 10 and the jitter buffer control unit 206 and jitter buffer 207 in the backup gateway device 20. become. As a result, the jitter buffer described in the first embodiment cannot be synchronized.

  Referring to FIG. 13, when the backup gateway device 20 is newly incorporated during the operation of the active gateway device 10, the operation of “when transfer is performed” of the write / read pointer of the reception buffer by the reception buffer control signal line is performed. It is shown. Here, as in the case of FIG. 12, the backup gateway device 20 is incorporated with the voice data (SN = 19) not read in the local reception buffer 103 of the working gateway device 10 being held. And

  First, immediately after the timing t10, the input voice data (SN = 20) is written into the pointer 2 of the own system reception buffer 103 of the working gateway device 10. Similarly, it is also input to the other system reception buffer 204 of the backup gateway device 20 previously incorporated via the reception packet confounding line PL in accordance with the write pointer value 2 input via the reception buffer control signal line CL. The voice data (SN = 20) is written to the pointer 2.

 When the voice data is read from the local reception buffer 103 and the other reception buffer 204 after the completion of the writing of the voice data (SN = 20), the active gateway device 10 holds the data in the local reception buffer 103 first. Audio data (SN = 19) is read out. On the other hand, the spare gateway device 20 reads the empty area of the pointer 1 according to the transferred read pointer value 1, but the audio data output when no audio data is written is silenced. By using the data, data having no influence is supplied to the audio processing unit 208 in the subsequent stage.

Next, when audio data (SN = 20) is read from the own system reception buffer 103, the audio data (SN = 20) is also read from the other system reception buffer 204. That is, the same audio data that is completely synchronized is supplied to the jitter buffer control unit 106 and the jitter buffer 107 in the working gateway device 10 and the jitter buffer control unit 206 and the jitter buffer 207 in the backup gateway device 20. It will be. As a result, as described in the first embodiment, the jitter buffer control units 106 and 206 for controlling the jitter buffer 107 and the jitter buffer 207, the audio processing units 108 and 208, and the TDM processing units 109 and 209, respectively, are used as a reference. Processing can be performed in complete synchronization according to the timing signal sl.
<Description of operational effects in the second embodiment>
In the second embodiment described above, the gateway devices 10 and 20 can communicate with both the packet network 160 and the packet network 261 in a redundant configuration, in place of the configuration described in the first embodiment. Each of the gateway devices 10 and 20 extracts a series of valid packets that do not overlap from all packets including packets received by other systems and holds them in common.

  In the configuration of the first embodiment, when the packet network 160 and the packet network 261 are in a redundant configuration and these are system switched, the timing of the system switching and the system switching of the gateway device in the redundant configuration is used. Note that packet loss cannot be avoided due to a difference. On the other hand, in the configuration of the second embodiment, it is possible to perform uninterruptible system switching without causing loss of received packets even in system switching including the packet network 160 and the packet network 261 in a redundant configuration. It becomes.

Since each of the gateway devices 10 and 20 extracts a series of valid packets from all packets including packets received by other systems and holds them in common, the packet network 160 and the packet network in a redundant configuration It is possible to separately execute the system switching of 261 and the system switching of the gateway devices 10 and 20 in the redundant configuration. For this reason, it is possible to easily perform uninterruptible switching without using a special network switch device. This action not only improves the maintainability of the gateway device, but also greatly improves the maintainability of the packet network because there is no need to make the gateway device aware of whether the packet network is currently used or reserved.
<Modification of Second Embodiment>
As described above, in the second embodiment, packet discrimination information, that is, information such as a boat number, a sequence number, a time stamp, and a synchronization source identifier (SSRC) is obtained from the audio data supplied from the reception buffer in the reception buffer control unit 105. Extract and determine whether the audio data is the same as the previously supplied audio data. If it is determined that the audio data is previously input, the audio data is discarded as duplicate audio data. However, a function related to the jitter buffer control units 106 and 206 may be provided.

  From the audio data supplied from the reception buffer in the jitter buffer control units 106 and 206, packet discrimination information, that is, information such as the boat number, sequence number, time stamp, and synchronization source identifier (SSRC) is extracted, and the audio data is If it is determined that the audio data is the same as the audio data previously written in the jitter buffer, the audio data is determined as duplicate audio data. Then, the jitter buffer write enable signal may be controlled to a non-write state.

  In the above embodiments, a gateway apparatus that accommodates a telephone and performs voice processing has been described as an example. However, in a redundant gateway system that performs data communication using not only voice but also a packet network, switching without interruption is necessary. It can be widely used.

  Further, in the above-described embodiments, the description has been given by taking the communication mode for transferring on the IP protocol as an example. However, the transfer protocol to be used is not limited to the IP protocol, but is such as ATM (Asynchronous Transfer Mode) or FR (Frame Relay). The present invention can also be applied to other packet protocols.

  In the above embodiment, one voice channel has been described. However, the redundant gateway system according to the present invention can also be applied to a gateway device that processes a plurality of channels.

It is a block diagram which shows the Example of this invention and shows the whole structure containing a redundant gateway system. It is a chart figure which shows the structural example of a TDM signal. It is a chart figure which shows the input / output timing of the audio | voice data in both systems, and a packet. It is a flowchart figure which shows the operation | movement outline | summary which packetizes a TDM signal. It is a chart figure which shows the write-in outline | summary of the jitter buffer in both systems. It is a chart figure which shows the read-out outline | summary of the jitter buffer in both systems. It is a chart figure which shows operation | movement when not transferring a write pointer and a read pointer between both systems. It is a chart figure which shows the operation | movement in the case of performing transfer of a write pointer and a read pointer between both systems. It is a block diagram which shows a 2nd Example and shows the structure of the network connected with a redundant gateway system. It is a time chart which shows about the write-in operation | movement with respect to an own system receiving buffer and an other system receiving buffer. It is a time chart which shows the read-out operation | movement with respect to the own system reception buffer and other system reception buffer of an active gateway apparatus. 10 is a time chart showing an operation of “when no transfer is performed” of a write / read pointer of a reception buffer when a spare gateway device is newly installed. FIG. 10 is a time chart showing an operation in the case of “transfer” of a write / read pointer of a reception buffer when a spare gateway device is newly installed. FIG.

Explanation of symbols

10, 20 Gateway device
30 TDM exchange
40, 41 Packet network interface
50 Control unit
60 Telephone network
70 packet network
100 packet selector
101 IP processor
102 RTP / RTCP processor
103 Jitter buffer controller
104 Jitter buffer
105 Audio processor
106 TDM processing section
200 packet selector
201 IP processor
202 RTP / RTCP processor
203 Jitter buffer controller
204 Jitter buffer
205 Audio processor
206 TDM processing section
301 Timing signal generator
S1 Processing timing signal
TS timestamp value
SN sequence number
WP write pointer
RP read pointer

Claims (7)

A plurality of gateway devices configured to be multiplexed between the packet network and the TDM network, the gateway device performs TDM conversion processing on the plurality of packets supplied from the packet network, and the obtained TDM signal is converted to the TDM signal. A redundant gateway system for supplying to a network,
The same packet supply means for supplying the same content packet to a plurality of the gateway devices by generating a copy of the packet;
A common write pointer generating means for generating a common write pointer corresponding to the time stamp TS and / or sequence number SN attached to the packet for each packet, and supplying the common write pointer to the plurality of gateways ;
Selective supply means for selectively switching any one of the plurality of gateway devices and supplying only the TDM signal obtained from the one gateway device to the TDM network;
Including
Each of the plurality of gateway devices is
At least one jitter buffer;
Means for generating a read pointer of the jitter buffer;
For each supplied packet, the packet is written into the jitter buffer according to a common write pointer corresponding to the packet, and the written packet is sequentially read out from the jitter buffer according to the jitter buffer read pointer to perform the TDM conversion processing. Jitter buffer control means for use in
Only including,
The common write pointer generation means and the read pointer generation means are provided in each of the plurality of gateway devices, and only one gateway device according to an operation command generates all of the write pointer and the read pointer while generating them. A redundant gateway apparatus, characterized in that the redundant gateway apparatus is commonly supplied to the gateway apparatus.   Including a processing timing signal generating means for generating a common processing timing signal of a predetermined period, and all of the plurality of gateway devices perform write and read operations on a jitter buffer included in the gateway device in synchronization with the common processing timing signal. The redundant gateway system according to claim 1, wherein:   3. The redundant gateway system according to claim 2, wherein the processing timing signal generation unit generates a common processing timing signal having a period synchronized with the TDM signal as the predetermined period. Including a plurality of gateway devices configured to be multiplexed between a plurality of packet networks configured to be multiplexed and one TDM network, and performing a TDM conversion process on the plurality of packets supplied from the packet network by the gateway device A redundant gateway system for supplying the obtained TDM signal to the TDM network,
Generating a common write pointer corresponding to the time stamp TS and / or sequence number SN attached to the packet for each packet, and supplying the common write pointer to the plurality of gateways ;
Selective supply means for selectively switching any one of the plurality of gateway devices and supplying only the TDM signal obtained from the one gateway device to the TDM network;
Including
Each of the plurality of gateway devices is
At least one receive buffer;
At least one jitter buffer;
Means for generating a read pointer of the jitter buffer;
The same packet supply means that takes in a packet supplied from only one of the packet networks, generates a packet having the same content by duplicating the packet, and supplies the packet to another gateway device other than itself.
A reception buffer control means for sequentially writing and reading out both the packet taken in by the gateway device itself and the packet supplied from other than the self to the reception buffer;
Only valid packets are supplied to the jitter buffer by discarding, as invalid packets, packets with the same contents that have been read out later as valid packets while making the packets previously read from the reception buffer valid. An effective packet supply means;
For each packet supplied by the valid packet supply means, the packet is written into the jitter buffer according to a common write pointer corresponding to the packet, and the written packet is sequentially written from the jitter buffer according to the jitter buffer read pointer. Jitter buffer control means for reading out to the TDM conversion process,
Only including,
The common write pointer generation means and the read pointer generation means are provided in each of the plurality of gateway devices, and only one gateway device according to an operation command generates all of the write pointer and the read pointer while generating them. A redundant gateway apparatus, characterized in that the redundant gateway apparatus is commonly supplied to the gateway apparatus. Including a processing timing signal generating means for generating a common processing timing signal of a predetermined period, and all of the plurality of gateway devices perform write and read operations on a jitter buffer included in the gateway device in synchronization with the common processing timing signal. The redundant gateway system according to claim 4, wherein: 6. The redundant gateway system according to claim 5, wherein the processing timing signal generation unit generates a common processing timing signal having a period synchronized with the TDM signal as the predetermined period. Each of the gateway devices includes means for generating a write pointer and a read pointer for the reception buffer for each packet, and only one gateway device according to an operation command can write and read as a common write pointer for the reception buffer. A pointer is generated and supplied to all gateway devices in common, and all reception buffer control means of the gateway device writes or reads packets to or from the reception buffer to be controlled according to the supplied write pointer and read pointer. 5. The redundant gateway apparatus according to claim 4 , wherein the redundant gateway apparatus is controlled.

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