JP3100464B2 - Packet switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching system for establishing a communication state by mutually connecting a plurality of communication partners in a communication system.

[0002]

2. Description of the Related Art Generally, in a communication system, a communication state is established by mutually connecting a plurality of communication partners by an exchange.

In such an exchange, various failures occur due to aging and the like. As such a failure, there is a failure in the line accommodation device.

[0004] When a failure occurs in the line accommodating device, normal exchange processing is hindered, and erroneous communication is likely to be performed.

Therefore, when configuring an exchange, it is desirable to provide a function for handling a failure of the line accommodating device in addition to the exchange processing function.

[0006] An integrated service digital communication network (hereinafter referred to as "
In the packet switch provided in "ISDN", a function described in JP-A-2-59840 is conventionally known as a failure handling function as described above.

[0007] This document discloses a Q931 interface (hereinafter referred to as "ISD") when a failure occurs in a line accommodating device.
N protocol) and X25 protocol (hereinafter, referred to as "N protocol").
The call is disconnected based on a “packet protocol”).

According to such a fault processing configuration, even if a fault occurs in the line accommodating device, erroneous communication can be prevented.

FIG. 2 is a block diagram showing the configuration of the packet switch described in the above document. As the line accommodating device, there are a terminal line accommodating device accommodating a terminal line connecting the own station and the terminal, and a network line accommodating device accommodating a network line connecting the own station and the other station. Indicates a terminal line accommodation device as a representative.

In FIG. 2, reference numeral 100 denotes a packet switch provided in the ISDN. 200 and 300 are ISD
Terminals (TML1, TML2) having an I interface conforming to the N protocol and mutually connected by the packet switch 100.

In the packet switch 100, 101
Is a terminal line accommodating device (SLIC1) that accommodates the terminal line of the terminal 200 by the I interface. Similarly, the terminal 102 is connected to the terminal 30 by the I interface.
0 terminal line accommodation device (SLIC)
2).

Reference numeral 103 denotes a packet protocol processing device (PHM) that executes an exchange process for connecting the terminals 200 and 300 based on a packet protocol.
Reference numeral 104 denotes a time division switch (TSW) for exchanging time slots for connecting the terminal line accommodation devices 101 and 102 and the packet protocol processing device 103. 1
Reference numeral 05 denotes a centralized control device (SCM) for centrally controlling various processes (exchange, maintenance, operation, failure recovery, etc.) of the packet switch 100.

Reference numerals 106 and 107 denote time-division highways for connecting the terminal line accommodating devices 101 and 102 and the time-division switch 104, respectively. Reference numeral 108 denotes a time division highway that connects the time division switch 104 and the packet protocol processing device 103. 109 is the central control device 1
Centralized control bus (SCM-BU) that connects
S). 110 is a control bus for transmitting a call control signal.

In the above configuration, the failure handling operation will be described with reference to FIG. FIG. 3 shows that the terminals 200 and 300 are the terminal line accommodation devices 101 and 102 and the time division switch 10.
FIG. 4 is a diagram showing a failure processing sequence when a failure occurs in the terminal line accommodating apparatus 101 during performing packet communication via the packet protocol processing apparatus 103.

This fault processing sequence is started when the above fault is detected by the central control unit 105. This failure detection processing is performed by the central control device 105 periodically supplying a normality confirmation signal to the terminal line accommodation device 101.

That is, in such a configuration, if the terminal line accommodating device 101 is normal, the terminal line accommodating device 101 returns a normality confirmation response signal to the central control device 105. On the other hand, the terminal line accommodation device 101
Does not return the normality acknowledgment signal. Accordingly, the central control device 105 can determine whether or not a failure has occurred in the terminal line accommodation device 101 based on whether or not a response signal is returned.

The normality confirmation signal and the normality confirmation response signal are transmitted through the control bus 110. FIG. 3 shows a case where a failure occurs after the normality confirmation signal is output from the central control device 105 and before the terminal line accommodation device 101 outputs the normality confirmation response signal.

When a failure is detected as described above, a failure processing sequence is started. In the failure processing sequence, first, when a failure occurs, a process of determining whether packet communication has been performed via the terminal line accommodating device 101 is executed. This determination process is performed by the central control device 105. In the case of the present example, the terminal 200,
Since packet communication is being performed between the packets 300, it is determined that there is packet communication.

When it is determined that there is packet communication, processing for detecting a device involved in the packet communication is executed. This detection process is also performed by the central control device 105. In the case of the present example, the terminals 200 and 300, the terminal line accommodation devices 101 and 102, the packet protocol processing device 10
3. The time division switch 104 is detected.

When the detection process is completed, a process for disconnecting the call is executed. This call disconnection process includes a process of disconnecting a call on a packet protocol and a process of disconnecting a call on an ISDN protocol, and is executed in this order.

The call disconnection processing on the packet protocol is performed by the central control unit 105 by the packet protocol processing unit 103.
Is started by supplying a signal requesting that the call be disconnected. This packet call disconnection request signal is transmitted via the control bus 110.

As a result, the packet protocol processing device 103 first executes processing for internally releasing the call management state of the terminal 200 in the packet protocol. This is because signal failure between the terminal 200 and the packet protocol processing device 103 is impossible because a failure has occurred in the terminal line accommodation device 101.

When the release process is completed, a process for disconnecting the connection between the packet protocol device 103 and the terminal 200 in the packet protocol is executed. When the disconnection process is completed, a process of internally releasing the call management state of the terminal 300 on the packet protocol is executed. When the release processing is completed, the packet protocol processing device 103
Supplies the central control device 105 with a response signal indicating that the call disconnection has been completed. This call disconnect response signal is transmitted via the control bus 110.

With the above, the disconnection processing on the packet protocol is completed. When this process ends, a call disconnection process on the ISDN protocol is executed. This call disconnection process is performed by the central control device 105.

In the call disconnection process on the ISDN protocol, first, a process for releasing the call management state on the I interface of the terminal 200 is executed. This is because signal control between the terminal 200 and the centralized control device 105 is impossible because a failure has occurred in the terminal line accommodation device 101.

When the release processing is completed, a call disconnection processing on the ISDN protocol between the central control device 105 and the terminal 300 is executed. This call disconnection processing is performed on the control bus 1
10 and the terminal line accommodating device 102. When this call disconnection process ends, a process of releasing the call management state on the I interface of the terminal 300 is executed.

With the above, the call disconnection processing on the ISDN protocol is completed. As a result, the call between the terminals 200 and 300 is forcibly disconnected.

[0028]

As described above, in the conventional packet switch, when a failure occurs in the line accommodating device, the call during the packet communication is forcibly disconnected, so that such a failure is prevented. The resulting malfunction is prevented.

However, in such a fault processing configuration, there is a problem that the communication service to the terminal is stopped due to a factor on the exchange side, resulting in a decrease in the reliability of the exchange.

Therefore, the present invention provides an exchange which can prevent a decrease in reliability due to a failure by enabling a call to be rescued without disconnecting a call even if a failure occurs in the line accommodating apparatus. The purpose is to provide.

[0031]

In order to achieve the above-mentioned object, the present invention provides a packet switch having (1) an operation system and a backup system.
System, each system can accommodate the same line
Line handling for ISDN protocol processing with simple redundant configuration
Means, and (2) a plurality of lines accommodated in the line accommodation means
Exchange that establishes a communication state by connecting
Means and (3) a failure has occurred in the operation system of the line accommodation means.
Failure occurrence determination means for determining whether or not
If it is determined that a failure has occurred in the operation system of the
Switch the connection destination of the line from the operation system of the line accommodation unit to the standby system
And (5) the operation system of the line accommodating device.
Call determination method for determining whether an incoming call is occurring
And (6) the terminal connection based on the packet protocol.
Protocol processing means to perform exchange processing for
I can. Then, the packet protocol processing means has (1)
It is determined that a failure has occurred by the harm occurrence determination means,
In addition, it is determined that a call is occurring by the call occurrence determining means.
The connection destination of the exchange means from the operation system of the line accommodation means
Switch to the standby system and continue the call during packet communication.
(2) If the fault has occurred by the fault
Is determined and a call is generated by the call generation determination means.
If it is determined that the connection destination of the exchange means is not
In the operation system.

[0032]

According to the above configuration, failure in communication occurs
The protocol processor (Layer 2 or higher) continues the call
Change the line accommodating means (Layer 1) from the active system to the standby system
Switch. For this reason, the call is relieved without being disconnected, so that a drop in the reliability of the packet switch caused by the failure can be prevented.

On the other hand, if a failure occurs other than during communication
Has a protocol processing device (layer 2 or higher)
Is held in the operation system of the line accommodating means.

As a result, the fault is recovered while there is no call.
In this case, the switching back process can be performed quickly.

[0035]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention.

In FIG. 1, reference numeral 500 denotes a packet switch provided in the ISDN. 600 and 700 are I
Terminals (TML1, TML2) having an I interface conforming to the SDN protocol and interconnected by the packet switch 500.

The packet switch 500 is different from the packet switch 100 shown in FIG. 2 in that the line accommodating device has a duplex configuration including an operation system and a standby system, and these can be switched as appropriate.

That is, in the packet switch 500, an operation terminal line accommodating device (A-SL) 501 accommodating the terminal line of the terminal 600 through the I interface.
IC1). Reference numeral 502 denotes a standby terminal line accommodating device (S-SLI) accommodating the terminal line of the terminal 600.
C1). Reference numeral 503 denotes an operation terminal line accommodating device (A-SLIC2) for accommodating the terminal line of the terminal 700 by the I interface. 504 is also the terminal 7
This is a standby terminal line accommodating device (S-SLIC2) accommodating the terminal line of No. 00.

Reference numeral 505 denotes a switching device (SEL1) for connecting the terminal line of the terminal 600 to one of the terminal line accommodating devices 501 and 502. 506 is the terminal 700
Is a switching device (SEL2) for connecting the terminal line of any one of the terminal line accommodation devices 503 and 504.

Reference numeral 507 denotes a packet protocol processing device (PHM) for executing a switching process for connecting the terminals 600 and 700 based on the packet protocol.
Reference numeral 508 denotes a time division switch (TSW) for exchanging time slots for connecting the terminal accommodation devices 501 to 504 and the packet protocol processing device 507. 509
Is a centralized controller (SC) that centrally controls various processes (exchange, maintenance, operation, failure recovery, etc.) of the packet switch 100.
M). Reference numeral 510 denotes a switching control device (COV) that controls the connection state of the switching devices 505 and 506.

Reference numerals 511 to 514 denote time division highways (HW) for connecting the terminal line accommodating apparatuses 501 to 504 and the time division switch 508, respectively. Reference numeral 515 denotes a time division highway (HW) connecting the time division switch 508 and the packet protocol processing device 507. 516
Is a centralized control bus (SCM-BUS) for connecting the centralized control device 509 and each device. 517 is a control bus (S-BUS) for transmitting a call control signal. A line control bus 518 controls the switching devices 505 and 506.

The terminals 600 and 700 are connected to the terminal line accommodating devices 501 and 503 when no failure occurs in the active terminal line accommodating devices 501 and 503.
And when a failure occurs, it is set in the standby terminal line accommodation devices 502 and 504. This control is performed by the switching control device 510 under the control of the central control device 509.

The connection destination of the time division switch 508 is as follows.
Only when a failure occurs in the active terminal line accommodating devices 501 and 503 and a call is generated through these, the standby terminal line accommodating devices 502 and 504 are set. Terminal line accommodating devices 501 and 50
Set to 3. As a result, the connection destination of the time division switch 508 is held in the active terminal line accommodating devices 501 and 503 as it is, even if a failure occurs and if no call occurs.

The connection destination of the time division switch 508 is switched by the central control unit 509 by the time division switch 5.
This is performed by controlling the process of exchanging the 08 time slot.

In the above configuration, the failure handling operation will be described with reference to FIG. FIG. 4 shows an active terminal line accommodating device while terminals 600 and 700 are performing packet communication via the active terminal line accommodating devices 501 and 503, the time division switch 508, and the packet protocol processing device 507. FIG. 5 is a diagram illustrating a failure processing sequence when a failure has occurred in 501;

The fault processing sequence is also started when the fault is detected by the central control unit 105, as in the packet switch of FIG. This failure detection is also performed based on the normality confirmation procedure described with reference to FIG.

In this failure processing sequence, first, the connection destination of the terminal line of the terminal 600 is changed from the terminal line accommodating device 501 of the active system to the terminal line accommodating device 502 of the standby system.
Is performed. This switching process is started when a switching request signal is supplied from the centralized control device 509 to the switching control device 510. This switching request signal is transmitted via the central control bus 516.

Thus, the switching control device 510 executes a process of switching the connection state of the switching device 505 via the line control bus 518. As a result, the connection destination of the terminal line of the terminal 600 is switched from the active terminal line accommodating device 501 to the standby terminal line accommodating device 502.

Upon completion of the switching process, a response signal indicating that the switching process has been completed is returned from switching control device 510 to centralized control device 509. This response signal is also transmitted via the central control bus 516.

When the return process is completed, the process of switching the connection destination of the terminal line of the terminal 600 from the active terminal line accommodating device 501 to the standby terminal line accommodating device 502 is terminated.

When this switching process is completed, a process for determining whether or not a call has been made via the terminal line accommodating device 501 is executed. This determination processing is performed by the central control device 5
09. In the case of the present example, the terminals 600 and 70
Since packet communication is being performed between 0, it is determined that a call is occurring.

When it is determined that a call has occurred, a process of detecting a packet protocol processing device involved in the packet communication from a plurality of packet protocol processing devices is executed. This processing is also performed by the central control device 509. In the case of the present example, the packet protocol processing device 507 is detected.

When the detection process is completed, the time division switch corresponding to the detected packet protocol processing device 507, that is, the connection destination of the time division switch 508 is changed from the active terminal line accommodating device 501 to the standby terminal line. Processing for switching to the accommodation device 502 is executed.

As described above, the terminals 600 and 700 are the terminal line accommodating devices 501 and 503 of the operation system and the time-division switch 5.
08: While performing packet communication via the packet protocol processing device 507, the failure processing sequence when a failure occurs in the active terminal line accommodating device 501 ends.

Thus, even if a failure occurs, the call is maintained without being disconnected. As a result, the packet communication is continued without interruption.
In this case, there is a possibility that a packet may be lost at the time of system switching, but since the packet switch has a packet retransmission function, this loss can be compensated.

In the above description, of the terminal line accommodating devices 501 and 503 of the operation system, the terminal line accommodating device 50
Although the case where a failure has occurred has been described, similar processing is performed when a failure has occurred in the terminal line accommodation device 503.

In the above description, the case where a call is generated at the time of occurrence of a failure has been described. However, when no call has occurred, the connection destination of the time division switch 508 is directly connected to the terminal line of the operation system. It is held in the device 501. Thereafter, before the failure is recovered, if a call is generated, the connection destination is switched, but if no call is generated, this switching is not performed at all.

According to this embodiment described in detail above, the following effects can be obtained.

(1) The terminal line is accommodated in a duplex configuration, and when a failure occurs , packets involved in packet communication
The packet protocol processor (PHM) call continues
Since the terminal line accommodating device is switched from the active system to the standby system in the same state, even if a failure occurs during packet communication, it can be relieved without disconnecting the call. As a result, it is possible to prevent the reliability of the packet switch 500 from deteriorating due to the failure of the terminal line accommodation devices 501 and 503.

(2) The process of switching from the active system to the standby system is divided into the process of switching the connection destination of the terminal line and the process of switching the connection destination of the time-division switch 508. When the error does not occur, the latter switching process is not performed, so that a failback process can be quickly performed when a failure is recovered without generating a call.

Although one embodiment of the present invention has been described in detail, the present invention is not limited to such an embodiment.

(1) For example, in the above embodiment, the case where the present invention is applied to the failure processing of the terminal line accommodating apparatus has been described. However, the present invention can be applied to the failure processing of the network line accommodating apparatus. it can.

(2) In the above embodiment, the case where the present invention is applied to a packet switch has been described. However, the present invention can be applied to a storage switch and a circuit switch other than the packet switch.

(3) In addition, it goes without saying that the present invention can be variously modified and implemented without departing from the scope of the invention.

[0065]

As described in detail above, according to the present invention ,
Even if a failure occurs in the line accommodating device during communication, it can be relieved without disconnecting the call, so that a highly reliable packet switch for the failure can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional packet switch.

FIG. 3 is a diagram for explaining a failure processing operation of a conventional packet switch.

FIG. 4 is a diagram for explaining a failure processing operation of the packet switch according to the embodiment;

[Explanation of symbols]

500: packet switch, 600, 700: terminal, 50
1 to 504: terminal line accommodating device, 505, 506: switching device, 507: packet protocol processing device, 508
... time-division switch, 509 ... centralized control device, 510 ... switching control device, 511-515 time-division highway, 51
6: Centralized control bus, 517: Control bus, 518: Line control bus

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04L 12/56 H04L 12/28 H04L 12/02 H04Q 3/42

Claims (1)

(57) [Claims] 1. A packet switching system for establishing a communication state by connecting a plurality of communication partners to each other, comprising a working system and a standby system, each having a redundant ISDN protocol processing capable of accommodating the same line. To
A line accommodating unit to perform, a switching unit for establishing a communication state by interconnecting a plurality of lines accommodated in the line accommodating unit, and whether a failure has occurred in an operation system of the line accommodating unit. and determining failure occurrence determination means for, when a failure in the operation system of the line accommodating means is determined to have occurred, El destination switch the connection destination of the line to the backup system from the operation system of the line accommodating means Switching means, call generation determining means for determining whether or not a call has occurred through the operation system of the line accommodation device, and switching for terminal connection based on a packet protocol.
A packet protocol processing unit for performing processing, wherein the packet protocol processing unit determines that a failure has occurred by the failure occurrence determination unit, and determines that a call has occurred by the call occurrence determination unit Once, Ete switch the connection destination of said switching means to the backup system from the operation system of the line accommodating unit, said call in a packet communication relay
The failure occurrence determination means determines that a failure has occurred.
And a call is generated by the call generation determining means.
If not, the connection destination of the switching means is set to the line.
A packet characterized by being held in the operation system of the accommodation means
Exchange .