JPH0715470A - Packet line backup system and packet exchange system - Google Patents

Abstract

PURPOSE:To improve the reliability of line backup on the occurrence of a line fault by decreasing the number of backup lines. CONSTITUTION:Data terminal equipments 11, 11a are respectively connected td terminal accommodation equipments 110, 111 by terminal equipment lines 12, 13 and connected semi-fixedly to packet protocol processing units 130, 131 via a time division switch 120 to form communication paths A, B reaching a packet switch 140. The usual packet communication is executed via the communication paths. When a line fault detected by the terminal accommodation devices 110, 111 and the packet protocol processing units 130, 131 is informed to a central controller 181, the controller 181 sets one of backup communication paths C, D, E and F reaching the packet switch 140 via network interface processing units 160, 161, a time division switch 120, and packet protocol processing units 170, 171. A packet is transferred via the set backup path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet line backup system and a packet switch system for setting a backup line when a line failure occurs in the packet switch system.

[0002]

2. Description of the Related Art A conventional packet switching system has, for each terminal line connecting a data terminal, a subscriber line connecting to this terminal via a circuit switching network. A backup method is adopted in which a packet is transferred to a data terminal, and when the terminal line fails, the subscriber line is used to transfer the packet to the other data terminal. Similarly, the data terminal of the opposite side is connected to the terminal line and the subscriber line, and performs packet communication with each other via the exchange system.

In this conventional packet switching system, a terminal accommodating device which connects to a terminal line to process the interface and detects a failure of the terminal line, and an interface of a circuit switching network connected to a subscriber line are provided. And a network interface processing device for processing, and these devices are connected to the packet protocol processing device via the line switching control device. The line switching control device normally selects and connects the terminal accommodating device, and selects the network interface processing device and switches the connection when the terminal line fails. The packet protocol processing device connected to the packet switch under normal conditions and faults performs call setup with the data terminal, data link level and packet level processing, and sends the assembled fixed-length packet to the packet switch. The packet is transferred to the packet protocol processing device of the destination address. The control of these packet transfers is performed by the control of the central control unit of the packet switching system.

In this packet switching system, for example, at a normal time when there is no abnormality in the terminal line, a communication path from the data terminal to the terminal accommodating device, the line switching control device and the packet protocol processing device is formed, and two data terminals are provided. For communication between them, packet communication is performed via a packet switch from the first communication path and the second communication path to which each data terminal is connected. At this time, if a failure occurs in the terminal line of the second communication path, the terminal accommodation device issues a backup connection instruction to the network interface processing device. When the network interface processing device receives this connection instruction, it connects to the data terminal device via the circuit switching network and notifies the central control processing device of line switching completion.
As a result, the packet switching system can carry out packet communication through the circuit switched subscriber line.

[0005]

However, in the conventional packet switching system, in order to cope with the line backup at the time of the terminal line failure, the same number of backup subscriber lines as this terminal line, the network interface processing device, Since it is necessary to provide the line switching control device, there is a problem that the device scale of the packet switching system increases. Further, there is a problem that the terminal line cannot be backed up if a failure occurs in the backup line or the device corresponding to this backup line when the terminal line fails.

The present invention solves the above-mentioned drawbacks of the prior art, reduces the number of backup lines, reduces the system scale, and eliminates the possibility of connection failure due to a double failure during backup. An object is to provide a line backup method and a packet switching system.

[0007]

In order to solve the above-mentioned problems, a packet line backup system according to the present invention accommodates a terminal line accommodating a terminal line to which a plurality of terminal devices for exchanging packets according to a predetermined protocol process are connected. In a packet line backup method in a packet switching system including a device and a network interface processing device that accommodates a backup line to which a terminal device is connected via a circuit switching network, the system uses a network interface processing device as a terminal device. If multiple shared terminals are provided and a terminal line failure is detected, a network interface processing device that can be used normally is selected, and the selected network interface processing device is connected by a time division switch for line backup. Is characterized by.

In this case, this system may select a network interface that can be used normally, based on the management data indicating the status of the backup line.

In order to solve the above problems, the packet switching system according to the present invention is such that a plurality of terminal devices for switching packets according to a predetermined protocol process are connected to a terminal accommodation device accommodating a terminal line, In a packet switching system that accommodates a backup line configured by connecting to a circuit switching network, this system
Terminal accommodating means for performing packet transfer with the terminal device via the terminal line, network interface processing means for performing packet transfer with the terminal device via the subscriber line, and packet processing in accordance with the packet processed by the terminal accommodating means. First packet protocol processing means for controlling the procedure, second packet protocol processing means for controlling the packet procedure according to the packet processed by the network interface processing means, terminal accommodating means, and first packet protocol Switch means for connecting the processing means, the time division switch means for selectively connecting the network interface processing means and the second packet protocol processing means in a time division manner, the first packet protocol processing means and the second packet protocol processing means. Connected to the packet protocol processing means, Packet switching means for packet transfer, and terminal lines connected to the first terminal device and the second terminal device for packet communication, respectively, to a terminal accommodating means, a packet switch, and a first packet protocol processing means. And a control means for setting the first communication path and the second communication path.
Includes a terminal line fault detecting means for detecting a fault in the first communication path to which the terminal device is connected, the network interface processing means includes a subscriber line fault detecting means for detecting a fault in the subscriber line, and the control means Sets a backup line corresponding to the first terminal device when a failure in the first communication path is detected, and the backup line, the network interface processing means, the packet switch, and the second packet from the first terminal device are set. It is characterized in that a normal backup communication path to the protocol processing means is set and control is performed so that packet communication is performed via the backup communication path and the second communication path.

In this case, the control means has a backup line selecting means for selecting a backup line, and the backup line selecting means may select the backup communication path based on the management data for selecting the backup line. .

In this case, further, the management data includes a selection pattern for selecting a terminal line group of the backup line, a detour table for defining the priority order of the network interface for each selection pattern, and an open / closed block indicating the open / closed state of the network interface. It may be composed of a table and a network interface failure table indicating a failure or normality of the network interface.

Further, the first packet protocol processing means and the second packet protocol processing means may each include a failure detection processing means for detecting a failure in the packet.

Further, the control means may switch the backup communication path to another normal communication path by controlling the time division switch means when detecting a failure during communication on the backup communication path.

Further, the terminal device receives the fault notification from the packet switching system, the line side control means for performing the packet communication through the terminal line, the network side control means for performing the packet communication through the subscriber line, It is preferable to provide terminal control means for switching the packet communication from the line side control means to the network side control device.

[0015]

According to the packet line backup system and the packet switching system of the present invention, a plurality of backup lines are provided so as to be shared by a plurality of terminal devices according to the traffic frequency at the time of failure, so that the number of backup lines can be increased. It can be significantly reduced over numbers.

By connecting a plurality of network interface processing means connected to the backup line group to a plurality of packet protocol processing means via the time division switch means, these backup communication paths for performing backup processing are multiplexed. Therefore, it is possible to prevent a situation in which backup cannot be performed due to a failure in the backup communication path. Furthermore, by dividing the terminal line and the backup line into groups, and selecting the backup line group that can be used normally from the terminal line group with high priority,
Priority backup of the priority terminal line and reliable packet line backup can be performed.

[0017]

Embodiments of the packet line backup system and packet switching system according to the present invention will now be described in detail with reference to the accompanying drawings. Referring to FIG. 1, there is shown an embodiment of a packet switching system to which the packet line backup method of the present invention is applied. This packet switching system 10 is, for example, a system that accommodates a plurality of data terminals via terminal lines and transfers data transmission / reception between these data terminals as packets. It should be noted that in the description of the embodiments, the illustration and description of parts that are not directly related to the present invention are omitted.

In the figure, the packet switching system 10, the data terminal 11 and the data terminal 11a are connected via terminal lines 12 and 13, respectively.
Packets are transferred through these terminal lines 12 and 13. Further, the packet switching system 10 uses these terminal lines 12
When 13 and 13 are faulty, terminal 11 and terminal 11 are used by using circuit switching network 14 such as INS1500 as a backup circuit.
This is a system in which a and a are connected by a circuit switched subscriber line 15 (or circuit switched subscriber line 16) and a circuit switched subscriber line 17, respectively.

In the packet switching system 10, the terminal accommodating devices 110 and 111 to which the terminal lines 12 and 13 are connected respectively have a failure detecting section 115 for detecting a line failure of the terminal lines 12 and 13, respectively. Also, the packet is transmitted / received to / from the data terminal 11a by the layer 1 interface, and the packet is transferred to the packet protocol processing devices 130 and 131 connected via the time division switch 120.

The time division switch 120 is a terminal accommodation device 110.
And 111 and the packet protocol processor 130 and
131 is semi-fixedly connected, and normal communication paths A and B in the exchange corresponding to the terminal lines 12 and 13 are set between the two terminals. Packet protocol processors 130 and 131
Performs layer 2 (data link level) and layer 3 (packet level) processing on the packet transferred from the time division switch 120 to control the packet procedure between the data terminals 11 and 11a, and to transfer the packet to the packet switch 14
Transfer to 0. The packet switch 140 transfers packets between the packet protocol processors 130 and 131. In addition, the packet protocol processing devices 130 and 131
Has a fault detection unit 135 that detects a fault in the terminal lines 12 and 13 at the data link level.

The time division switch 120 connects the network interface processing devices 160 and 161 connected to the circuit switched subscriber lines 15 and 16 and the packet protocol processing devices 170 and 171 connected to the packet switch 140. It has a plurality of backup paths C, D, E and F, and a plurality of multiplexed backup paths are configured.

When the terminal lines 12 and 13 connected to the terminal accommodating devices 110 and 111 fail in the normal communication paths A and B in the time division switch 120, one of the backup paths is selected. The network interface processing devices 160 and 161 corresponding to this route have a fault detecting unit 165 for transmitting / receiving a packet to / from a data terminal through a layer 1 interface and detecting a fault in the circuit switched subscriber lines 15 and 16, respectively. .

Packet protocol processing devices 170 and 17
1 is connected to the packet switch 140 and is a time division switch
The packet transferred from 120 is processed at layer 2 (data link level) and layer 3 (packet level), and the processed packet is transferred to the packet switch 140. In addition, the packet protocol processing devices 170 and 17
1 has a fault detecting unit 175 for detecting a fault in the circuit switched subscriber lines 15 and 16 in the data link level processing.

The central control unit 181 comprises the terminal accommodating units 11 and 111, the time division switch 120, the packet protocol processing units 130, 131, 170 and 171 and the packet switch.
A control bus 181 that connects the 140 and the network interface processing device 160, respectively, is connected to each device and controls the processing in these devices. For example, the central controller 18
1 sets the normal communication paths A and B through the time division switch 120, and causes the communication paths A and B to perform normal packet communication on the terminal lines 12 and 13.

In addition, the central controller 18 in this embodiment
1 has a backup line selection unit 185 and a backup setting control unit 186 for performing a backup process for the terminal lines 12 and 13 in the event of a terminal line failure. Specifically, the backup line selection unit 185 selects the normal switched subscriber line 15 or 16 as the backup line. The backup setting control unit 186 controls the network interface processing devices 160 and 161, sets a backup line between the network side control device 220 of the data terminal 11 and the network interface processing devices 160 and 161, and notifies the terminal of the failure. , One of the plurality of backup communication paths C to F in the time division switch 120 is set. Further, the packet switch 140 controls the destination addresses of the packets transferred between the communication paths A and B during normal communication, and between the paths A and B and the backup communication paths C to F when a line failure occurs.

The line side control unit 210 of the data terminal 11 is normally operated under the control of the central control unit 200.
A packet communication is performed by connecting to the terminal accommodation device 110 of the packet switch 10 via the. Further, when the terminal line 12 becomes a failure, the network side control device 220 causes the packet switching system via the circuit switching subscriber line 17 connected to the circuit switching network 14.
A failure notification is received from 10 via the circuit switching network 14, and under the control of the central controller 200, backup call setting is performed and communication is started.

In the packet switching system 10, while the data terminal 11 and the data terminal 11a are communicating via the routes A and B, for example, the terminal line 12 to which the data terminal 11 is connected.
When a line failure occurs in the central processing unit 181 connected to the control bus 180, the failure detection unit 115 of the terminal accommodation device 110 or the failure detection unit 135 of the network interface processing unit 130 on the path A detects this line failure. Notify the line failure. The central control unit 180 notified of the line failure starts the backup process.

The backup line selection unit 185 is shown in FIG.
The control data for selecting the backup line shown in (d) to (d) is provided, and the control for selecting the backup line shown in FIG. 2 is performed. For example, when a failure occurs in the terminal line 12, the backup line selection unit 185 sets the line group number of the failed terminal line in the failure detection units 115 and 135.
Received from (S100) and selected from the selection pattern table for selecting the group of terminal lines shown in Fig. 3 (a), the priority of the backup line such as circuit switched subscriber lines 15 and 16 for each terminal line group number In step S101, a selection pattern for selecting the corresponding network interface processing device 160 or 161 is acquired.

Next, a TRK group is acquired in accordance with the priority order indicating the order for selecting the TRK group representing the group of network interface processing devices for each selected pattern shown in the TRK detour table of FIG. 3B. (S102). When the TRK group is acquired, the usage status of the network interface processing unit is shown to be empty according to the TRK mounting space block table corresponding to each TRK group shown in Fig. 3 (c) and the TRK failure table shown in Fig. 3 (d). , And a TRK number representing a normal network interface processing device in which no failure has occurred is acquired (S103), and the circuit-switched subscriber line 15 as a backup line connected to the normal network interface processing device 160 is selected. It In this case, in step 102, for example, the first TR
When all the network interface processing devices in the K group are faulty or blocked and cannot be selected, the TRK groups from the second TRK group on the TRK detour table are acquired, and the network interface processing devices are processed in the same procedure as in step 102 and step 103. The backup line corresponding to is selected.

When the backup line is selected, the network interface processing device 160 corresponding to the selected circuit switching subscriber line 15, the packet protocol processing device 170, and
One of them 171 is connected by a time divisional switch 120 to set a backup path. At this time, the backup setting control unit 186 performs the backup line setting process based on the setting sequence shown in FIG.

(A) The packet switch 10 sends out a call setup message (SETUP) from the network interface processor 160 selected by the backup line selection processor 185, and this call setup packet is sent via the circuit switched network 14. The network side control device 220 of the data terminal 11 to which the faulty terminal line is connected.
Next, the network-side control device of the data terminal 11 sends a call admission message (CALLPROC) to the interface via the circuit switching network.
The response message (CON
N) send.

(B) The packet switch 10 sets the backup communication path C in the time divisional switch 120 connecting the network side control device 220 and the packet protocol processing device 170, for example, based on the set backup path.

(C) The data terminal 11 sends an asynchronous balanced mode frame (SABM) from the network side controller 220, reaches the other side data terminal 11a via the packet switching system 10,
The data link is established. The partner data terminal 11a returns an unnumbered frame (UA) to the data terminal 11. The network-side controller 220 of the data terminal 11a sends a restart request (S
Q) and receive the response (SF) from the data terminal 11,
Packet communication becomes possible.

During circuit backup or during regular testing of the backup circuit, circuit switched subscriber lines 15,1
If 6 fails, the network interface processor 16
0,161 and packet protocol processing devices 170,171
The failure is detected by the failure detection units 165 and 175 and notified to the central controller 181. The central controller 181 is shown in FIG.
A fault is registered in the TRK number of the TRK fault table shown in (d), and the TRK number representing a normal and normal network interface processing device is acquired by the procedure shown in FIG. 2, and the multiplexed backup communication path C is obtained. It is possible to reset a normal backup path from the middle of F to F. When the central control device 181 detects a failure in the network interface processing devices 160, 161 and the packet protocol processing devices 170, 171 as well, a normal route except for the failed device is reset.

As described above, an appropriate number (TRK number) of network interface processing devices can be provided in view of the line failure occurrence rate and reliability. As a result, the number of backup lines can be greatly reduced, and the device configuration of the packet switching system can be made small. For example, when a failure occurs in a terminal line, a normal network interface processing device is selected and connected when backing up the communication of the corresponding line. Therefore, the backup network interface processing device and the subscriber of the circuit switching network are connected. The number of line facilities can be reduced, and the reliability of the packet switching system 10 is dramatically improved.

[0036]

As described above, according to the present invention, a plurality of network interface processing devices for accommodating a backup line are shared by the terminal device, and the network interface can be normally used when a failure of the terminal line is detected. A processor is selected, and a backup communication path is set by a time division switch to perform line backup. Therefore,
By sharing a backup line, the number of backup lines can be significantly reduced as compared with the conventional one. Therefore, the device of the packet switching system becomes smaller, and the reliability of line backup is improved by multiplexing the backup communication path. In addition, since a backup line group that can be used normally is selected, highly reliable packet line backup can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a packet switching system to which a packet line backup method according to the present invention is applied.

FIG. 2 is a diagram showing a backup line selection processing flow in this embodiment.

FIG. 3 is a diagram showing management data for backup line selection processing in this embodiment.

FIG. 4 is a diagram showing a setting sequence for setting a backup line in this embodiment.

[Explanation of symbols]

 10 Packet switching system 11 Data terminal 12,13 Terminal line 14 Circuit switching network 15,16 Circuit switching subscriber line 110,111 Terminal accommodation device 120 Time division switch 130,131 Packet protocol processing device 140 Packet switch 160,161 Network interface processing device 115,135,165,175 Fault detection unit 180 Control bus 181,200 Central control unit 185 Backup line selection unit 186 Backup setting control unit 210 Line side control unit 220 Network side control unit

Claims (8)

[Claims] 1. A terminal accommodation device accommodating a terminal line to which a plurality of terminal devices for exchanging packets according to a predetermined protocol process are connected, and a backup line to which the terminal device is connected via a circuit switching network. In a packet line backup method in a packet switching system including a network interface processing device, the system is provided with a plurality of the network interface processing devices shared by the terminal device, and when a failure of the terminal line is detected, a normal operation is performed. A packet line backup method characterized in that a network interface processing device that can be used for is selected, and the selected network interface processing device is connected by a time division switch for line backup. 2. The packet line backup method according to claim 1, wherein the method selects the normally usable network interface based on management data indicating the status of the backup line. Packet line backup method. 3. A backup line constructed by connecting a plurality of terminal devices for exchanging packets in accordance with a predetermined protocol process to a terminal accommodation device accommodating a terminal line and connecting the terminal device to a circuit switching network. In the packet switching system, the system includes terminal accommodating means for performing packet transfer with the terminal device via the terminal line, and network interface processing means for performing packet transfer with the terminal device via the subscriber line, A first packet protocol processing means for controlling a packet procedure according to a packet processed by the terminal accommodating means, and a second packet protocol control means for controlling a packet procedure according to a packet processed by the network interface processing means. Packet protocol processing means, said terminal accommodating means and first packet protocol processing Switch means for connecting the stages, the time division switch means for selectively connecting the network interface processing means and the second packet protocol processing means in a time division manner, the first packet protocol processing means and the first packet protocol processing means. Two
From the terminal line connected to each of the first terminal device and the second terminal device, which are connected to the packet protocol processing means for performing packet transfer between the packet protocol processing means, and the first terminal device and the second terminal device for performing packet communication. Accommodating means, the packet switch, and control means for setting a first communication path and a second communication path to the first packet protocol processing means, wherein the terminal accommodating means is connected to a first terminal device. A terminal line fault detecting unit that detects a fault in the first communication path, the network interface processing unit includes a subscriber line fault detecting unit that detects a fault in the subscriber line, and the control unit includes When a failure in the first communication path is detected, the backup operation corresponding to the first terminal device is performed. A line is set, and a normal backup communication path from the first terminal device to the backup line, the network interface processing means, the packet switch, and the second packet protocol processing means is set, and the backup communication path and the second A packet switching system characterized by performing control for packet communication via a communication path. 4. The packet switching system according to claim 3, wherein the control means has a backup line selecting means for selecting a backup line, and the backup line selecting means has management data for selecting a backup line. A packet switching system, wherein the backup communication path is selected based on the above. 5. The packet switching system according to claim 4, wherein the management data includes a selection pattern for selecting a terminal line group of the backup line and a detour table that defines a network interface priority for each of the selection patterns. And a network interface failure table representing a failure or normal state of the network interface, and a packet line backup method. 6. The packet switching system according to claim 3, wherein the first packet protocol processing means and the second packet protocol processing means each include failure detection processing means for detecting a failure in the packet. A packet switching system characterized in that 7. The packet line backup system according to claim 3, wherein said control means controls said time division switch means to detect another backup communication path when another failure is detected during communication on said backup communication path. A packet switching system characterized by switching to a normal communication path. 8. The packet switching system according to claim 3, wherein the terminal device has a line side control means for performing packet communication through a terminal line, and a network side control for performing packet communication through the subscriber line. And a terminal control means for switching packet communication from the line side control means to the network side control device in response to a failure notification from the packet switching system.