JP3264354B2 - Permanent virtual circuit control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of a permanent virtual circuit in a switching system of a packet communication system, and more particularly to the setting and release of a permanent virtual circuit and the control of a permanent virtual circuit when a failure occurs.
Permanent, suitable for playing virtual circuits
It relates to a virtual circuit control method.

[0002]

2. Description of the Related Art Permanent communication in packet switching networks
Virtual Circuit (PermanentVirtual Circuit:
The method of providing a permanent virtual circuit is described in Section 4 of “Provision of Packet Switching Service in ISDN” (Technical Report of the Institute of Telecommunications Engineers, SE86-41, July 17, 1986). "
Is being considered. In this paper, the following two methods are used to connect the B-channel circuit-switched path on the I-interface.
There are two alternatives.

[Proposal A] A method in which a subscriber information path line used for a PVC service is fixedly connected at the time of contract.

[Plan B] Virtual Circuit (Virtua)
l Circuit: A method for connecting a subscriber line information path using a subscriber line signaling procedure, similarly to VC.

[0005] In the case A, the B channel used in PVC is always reserved for packet communication. Plan B
Is the ISD recommended by the CCITT, similar to VC.
N.Q. Although the 931 connection procedure can be used, this is contrary to the principle of PVC in which a fixed virtual circuit is always connected between terminals.

[0006]

In the above-mentioned paper, the method of making a fixed connection at the time of contract according to the plan A is described in Q.I.
The use of the 931 connection procedure is not considered. For this reason, when the plan B is adopted, the Q. 931 connection procedure based on the subscriber line information path connection program
In the case A, it is necessary to separately create a subscriber line information path connection program while the C call can be used. Further, a failure handling function in a VC call cannot be used for a failure that has occurred in a fixed information path of a PVC call.

[0007] It is an object of the present invention to provide VC calls for PVC calls.
An object of the present invention is to reduce the number of development steps of a call processing program by performing call processing by a mechanism similar to a call.

It is another object of the present invention to facilitate the development of a high reliability function by realizing a high reliability function against a failure in a PVC call by a method common to that in a VC call.

[0009]

In order to achieve the above object, according to the present invention, a virtual subscriber function, i.e., a virtual subscriber line link simulating a subscriber line signal link, is provided in an exchange accommodating a subscriber terminal receiving PVC service. Subscribers were established.

Further, in the present invention, the virtual subscriber is provided with a means for detecting a call release due to a failure, and a means for making a call again by triggering the detection of the call release.

Further, the present invention is provided with a means for setting a timing between each recall when it is necessary to execute the recall a plurality of times.

Furthermore, the present invention provides a means for collecting identifiers of used resources at the time of the first call and storing the collected identifiers, and a means for designating the resources to be used at the time of the re-call based on the stored identifiers. Provided.

[0013]

A virtual subscriber simulating a subscriber line signaling link is provided in an exchange accommodating a subscriber terminal receiving a PVC service. And / or send a call release signal to the PVC call processing program,
The PVC call processing program can set a fixed information path by the same processing as the call processing program of the VC call.

When a fault occurs and a call release signal sequence is executed, the sequence is detected by a call release signal from a PVC call processing program, and the detection of the call release signal is used as a trigger to change a call setting signal to a PVC. Since the call is transmitted to the call processing program, the PVC call processing program can deal with the failure by a normal call setting and / or call release program without creating a program corresponding to the failure.

Further, when a failure that requires resetting of many PVC calls at once occurs, the timing of a plurality of recalls is set to reduce the load on the exchange due to the recall processing. Can be dispersed.

Further, since the identifiers of the used resources of the PVC call are collected and stored, and the used resources are designated by using the stored identifiers at the time of re-calling, the used resources are the same as before the re-calling. The target information path can be set at the time of recall.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the permanent virtual circuit control system according to the present invention is applied to an ATM switch using fixed-length packets called cells will be described with reference to FIGS. FIG. 1 is a conceptual diagram showing an example in which virtual subscribers in a control method according to the present invention are arranged in an ATM switching network exchange. FIGS. 2 to 6 show PVC call processing procedures in the control method according to the present invention. FIG. 7 to FIG. 9 are diagrams showing a processing load occurrence situation and a distribution method thereof in an ATM switching network to which a control method according to the present invention is applied, and FIG. FIG. 8 is a diagram showing how to handle a used resource identifier in the control method according to the present invention.

The conceptual diagram shown in FIG. 1 shows, as an example of an ATM communication system to which the control method according to the present invention is applied, subscriber terminals (161, 162) receiving a service of a permanent virtual circuit, and A to contain
TM subscriber exchanges (101, 103), ATM transit exchanges (102), information paths (141) established between these subscriber terminals and exchanges, and signal links (151, 15).
2) is shown. Permanent virtual circuit (PVC)
The fixed information path that receives the service of
It corresponds to 1). Each ATM exchange (101-10
3) is controlled by software (111-113), respectively, and in each software, a PVC call processing program (121-123) for controlling call setting and / or call release is arranged. Virtual subscriber (171, 172) in the control method according to the present invention
Are arranged in the software (111, 113) of the ATM local exchange (101, 103) and interface with the call processing programs (121, 123) and the interfaces (181, 18).
Have 2). This virtual subscriber (171, 172)
Simulates a subscriber line signaling link through this interface (181, 182). That is, the virtual subscriber sets up and / or releases a call according to a terminal that handles a call for setting an information path for each communication (hereinafter referred to as a virtual circuit call) (ie, a call setup signal sequence and / or a call release). Signal sequence). Each of the virtual subscribers (171, 172) has a maintenance system (1).
91, 192).

FIG. 2 shows the virtual subscriber (17) shown in FIG.
1 and 172) are associated with respective call processing programs (12
1, 123) to the subscriber line link (181, 1).
FIG. 82 is a processing sequence diagram illustrating an example of a processing sequence for emulating (82). In FIG. 2, the service order (PVC registration: PVRG, PCV disconnection: PVCL, 231, 23) from the maintenance person via the maintenance system (191) is shown.
2) An example is shown in which a call setting and / or call release process of PVC is activated by input. The ATM subscriber exchanges (101, 103) execute a service order program (201, 2) for receiving a service order from a maintenance person.
02). Here, the service order (2
The virtual subscriber (171) arranged in software on the side of the ATM local exchange (101) to which 31) is inputted.
And the PVC call processing program (121), and the calling virtual subscriber (211) and the PVC calling call program (2).
21) and the other ATM local exchange (10
3) The virtual subscriber (172) and the call processing program (123) arranged in the software on the side are shown as a destination virtual subscriber (212) and a PVC destination call processing program (222). . In FIG. 2, the ATM transit exchange (102) shown in FIG. 1 is omitted.

In FIG. 2, a service order (PVRG, 231) triggers a PVC call setup from a maintenance person.
Is received, the service order program (201) that has received the notification notifies the calling virtual subscriber (211) of the PVC call. The calling-side virtual subscriber having received the notification will thereafter call the PVC calling-side call processing program (221).
To simulate the subscriber line signal. That is, SETUP-P (PVC calling signal) and CONN-P (P
VC response signal) is transmitted and received between the two. During this time, the PVC originating call processing program is divided into the PVC destination call processing program (222) and the call setting signal IAM-P (PVC
An address signal), ACM-P (PVC address completion signal), and ANM-P (PVC response signal) are transmitted and received to perform call setting processing. On the other hand, the PVC destination call processing program also
Along with the signal transmission and reception with the PVC originating call processing program,
Destination virtual subscriber (212), SETUP-P, CONN
-Send and receive P signals. In FIG. 2, a PVC originating call processing program (221) and a PVC destination call processing program (22)
2) Signals IAM-P and ACM-
P and ANM-P are shown following the call setup signal in the common channel signaling system. When such a call setting signal sequence proceeds and the PVC call is normally completed and the setting of the fixed information path is completed, a notification to that effect to the maintenance person (2)
41, 243).

In the process of FIG. 2, the PVC from the maintenance person
Service order (PVC disconnect:
Similarly, when the virtual subscribers (PVCL, 232) are turned on, a DISC-P (PVC disconnection signal), a REL-P (PVC) between the virtual subscribers (211 and 212) and the call processing programs (221 and 222). The disconnection signal) is transmitted and received, and REL- is transmitted between the call processing programs (221.222).
P and RLC-P (PVC disconnection completed) signals are transmitted and received. As a result, the call release processing is executed, and the maintenance person is notified (242, 244) that the processing has been completed.

In the example shown in FIG. 2, the call processing program (221, 222) for PVC exchanges call processing signals with the subscriber line signal link and the trunk line signal link simulated by the virtual subscriber. This is similar to a call processing program for a VC call in that it operates in a manner similar to that of a call processing program for a VC call. The software interface between the virtual subscribers (211 and 212) and the call processing programs (221 and 222) may be defined in accordance with the protocol definition of the subscriber line signal link. I can do it.

FIG. 3 shows that the ATM transit exchange 102 restarts during the execution of the PVC call setup sequence after the service order (231) is input from the maintenance person as in FIG. The example which executed the accompanying call release sequence is shown. In FIG. 3, when the PVC calling process is performed from the PVC calling process program (221), A
When resumption occurs in the TM transit exchange (102),
The relay station sends a GRS-P to the adjacent ATM exchange.
(PVC reset signal, 301), and upon receiving this, the ATM switching center sends REL-P (P
(VC disconnection signal). Upon receiving the call release signal REL-P or GRS-P transmitted by the restart, the call processing program (221, 222) generates a signal RELCOMP which simulates the virtual subscribers (211 and 212) and the subscriber line signal link, respectively. -Send and receive P (PVC path forced disconnection signal). The virtual subscriber (21) receiving this
1, 212) detects that the call setting signal sequence is abnormally terminated, and notifies the maintenance person of the abnormality (302, 3).
03). In the example shown in FIG. 3, even in the abnormal sequence, the call processing program (221, 222) and the virtual subscriber (211, 212) are in accordance with the interface specification on software according to the protocol specification of the subscriber line signal link. It is shown that it can work.

FIG. 4 shows a case in which a service order (231) is input from a maintenance person as in FIG. 2, and after the PVC call setup sequence is completed, an ATM transit exchange is restarted. And a sequence in which the reproduction of the fixed information path is started. In FIG.
Call release signal REL-P or G transmitted by resumption
Upon receiving the RS-P (401), the PVC call processing program (221, 222) sends the virtual subscriber (211,
212) and a signal DISC-P simulating the subscriber line signal link, respectively. Upon receiving this signal, the virtual subscribers (211 and 212) detect that the call release signal sequence has been executed due to the cause of the abnormality, and notify the maintenance person of the abnormality (403 and 404). Thereafter, the originating virtual subscriber (211) activates a new call setup signal sequence to regenerate the fixed information path,
A calling signal SETUP-P (402) is sent to the PVC originating call processing program (221) to urge recall processing.
Thereafter, the same signal sequence as the call setup signal sequence shown in FIG. 2 is executed, and the fixed information path is reproduced. In the example shown in FIG. 4, the PVC call processing program (221, 222) performs normal call release and / or call setup for processing of call release due to an abnormal factor and call setup for resetting a fixed information path. The calling virtual subscriber (211) may perform a simple operation of executing the call setting signal sequence after the termination of the call disconnection signal sequence.

Although FIGS. 3 and 4 show the case where a failure occurs in the ATM transit exchange, the control of PVC using the virtual subscriber according to the present invention is also performed when the failure occurs in the ATM subscriber exchange. It is possible to do. This is shown in FIGS.

In FIG. 5, after the service order (PVRG, 231) is input from the maintenance person as in FIG.
An example in which an abnormality occurs in the ATM local exchange (103) during the execution of the call setup sequence of (1), and a call release sequence is executed accordingly. In FIG. 5, ATM
After an abnormality (501) occurs in the service order program (202) of the destination local exchange (103), a call release sequence is activated by the destination virtual subscriber (212).

FIG. 6 shows a case where a service order (231) from a maintenance person is entered as in FIG. 2 and the ATM originating local exchange is restarted after the PVC call setup sequence is completed. 4 shows an example of a release sequence and a sequence in which reproduction of the fixed information path is started. In FIG. 6, A
After the TM originating local exchange restart (601) occurs, the call release sequence is activated by the originating virtual subscriber (211), and after this is completed, the call setting sequence is again executed by the originating virtual subscriber (211). Is started.

Next, a method of distributing the processing load of the exchange accompanying the call setting signal sequence for reproducing the fixed information path will be described with reference to FIGS. FIG. 7 is a diagram showing an example of a load generation state due to a call setting signal sequence for reproducing the fixed information path. In this example, the restarted ATM transit exchange (701) is connected to ATM subscriber exchanges (711-714) accommodating subscriber terminals receiving PVC service. When the resumption of the fixed information path occurs in the ATM exchange (701), a release signal sequence is activated via this for a plurality of PVC calls that set up the fixed information path. When each release signal sequence is completed, the call setup signal sequence for reproducing the fixed information path described with reference to FIG.
4) Activated from the virtual subscriber located. As a result, a simultaneous call (721) is made to the restarting ATM transit exchange (701). That is, the restarted ATM exchange becomes a bottleneck in the processing capacity of the entire network.

In order to avoid such a problem, it is desirable to distribute the load on the ATM switch which caused the restart of the fixed information path as shown in FIG. In FIG. 8, FIG.
The call setting signal sequence for reproducing the fixed information path described with reference to FIG.
814) activates a call setup signal sequence at regular intervals within a fixed delay time according to the number of virtual subscribers arranged corresponding to the fixed information path. As a result, in the restart-occurring ATM switch (801), a load equally distributed is applied within a fixed delay time.

FIG. 9 is a state transition diagram of the virtual subscriber showing a processing method in the ATM subscriber exchange for performing load distribution as shown in FIG. In FIG. 9, a normal state (S1)
When a call release signal due to resumption is received (S11), a counter for counting the number of call setting signal sequences to be started for reproducing the fixed information path is cleared (S21).
Then, the state transits to the state of continuing the count (S2). Thereafter, when the call release signal due to the restart is received (S14), the counter is counted up (S26). Since the reception of the series of call release signals is completed after a certain period of time, this is monitored by a timer, and when a time-out (S12) is detected, the delay time shown in FIG. Then, a call setting signal sequence activation cycle is obtained by dividing by (S23), and the state transits to a state (S3) in which the call setting signal sequence is activated at regular time intervals. After this,
Timeout in the call setting signal sequence activation cycle (S1
Every time 3), a call setting signal sequence activation is performed (S
24). After repeating the timeout (S13) and the execution of the call setting signal sequence activation (S24), it is determined that the call setting sequence activation for the counter is completed (S
25), ending a series of call setting signal sequence activations,
The state transits to the normal state (S1). Thus, each AT
The M subscriber exchange can perform load distribution as shown in FIG.

Next, a method of calculating the constant delay time used in FIGS. 8 and 9 will be described. (A) PV that can be set simultaneously in one ATM exchange
The number of C calls is 100,000, (A) the processor performance of the ATM switch is 10 MIPS, and (C) one PVC
Assuming that the processing step required for call setting of a call is 50 Kstep / (one call) and (E) the percentage of the processor performance that can be spent on call setting for PVC is 80%, the ATM switch executes the call setting process per hour. The number of PVC calls that can be made is as follows.

1,000,000 × 10 (Mips) × 6
0 (second) × 60 (minute) × 0.8 (%) ÷ (50 × 1,0
00) = 576,000 (BHCA)

Thus, the time required to handle 100,000 PVC calls is 100,000 ÷ 576,00
0 = 0.17 (time) = 10.5 (minutes), and the constant delay time may be about 10 minutes 30 seconds.

Next, referring to FIG. 10, at the time of reproducing the fixed information path according to claim 4, the same ATM as before the reproduction is used.
A method of reproducing the fixed information path so as to use the same resource via an exchange will be described.

FIG. 10 shows a PVC according to claim 4 of the present invention.
FIG. 7 is a diagram showing an example of a mechanism in which an identifier of a resource used for a call is stored in the virtual subscriber by a call setting signal. FIG.
Medium, ATM between subscriber terminals (1041, 1042)
When the information path (1071) of the PVC call via the exchanges (1001, 1002, 1003, 1004) is set, the resources (1) used by each ATM exchange
The identifiers (POS # 1 to POS # 6) of (021 to 1023) and (1031 to 1033) are taken over by the parameters (1011 to 1013) of the call setting signal and stored as data in the virtual subscriber (1051). . The reason why different resource identifiers are given to the uplink and the downlink is A
This is in line with the fact that line resources in the TM exchange can be managed separately for uplink and downlink. The identifier data (1061) of the used resource thus obtained is set as a parameter of the call setting signal for reproducing the fixed information path, and each ATM exchange refers to this parameter, and is designated by the parameter. By using the resources again, it is possible to set the fixed information path using the same resources on the same path as before the reproduction.

[0036]

As described above, according to the present invention,
Set up a virtual subscriber in the software of the ATM switch and
Since the subscriber line signal is simulated with respect to the call processing program for the VC call, the setting or release of the fixed information path by the PVC call or the reproduction of the fixed information path when a failure occurs is performed in the same manner as the normal call processing. I can do it.

Further, when a large number of fixed information paths are reproduced at the time of occurrence of a restart in the exchange, the call setting signal sequence is started at a timing corresponding to the processing performance of the restarted exchange. The load required for processing can be distributed over time, and the fixed information path can be efficiently reproduced.

Further, the used resource identifier of the call is collected and stored in the call setting signal sequence, and the stored resource identifier is used in the call setting signal sequence when the fixed information path is reproduced. Is re-designated, it is possible to set the same fixed information path in which the resources used are the same as before the reproduction, thereby preventing disturbance of the switching network due to the reproduction.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement of virtual subscribers in an ATM switching network according to the present invention.

FIG. 2 is a diagram showing an example of a sequence in which a virtual subscriber according to the present invention simulates a subscriber line signaling link with a call processing program.

FIG. 3 is a diagram showing an example of a call release sequence that occurs when a restart occurs in an ATM transit exchange during execution of a PVC call setup sequence.

FIG. 4 shows the AT after the PVC call setup sequence is completed.
FIG. 9 is a diagram showing an example of a call release signal sequence and a call setup signal sequence accompanying the restart of the M relay exchange.

FIG. 5 is a diagram showing an example of a call release sequence that occurs when a restart occurs in the ATM local exchange while a PVC call setup sequence is being executed.

FIG. 6 illustrates an AT after a PVC call setup sequence is completed.
FIG. 6 is a diagram showing an example of a call release signal sequence and a call setup signal sequence accompanying the restart of the M local exchange;

FIG. 7 is a view showing a state of occurrence of a load due to a call setting signal sequence for reproducing the fixed information path.

FIG. 8 is a diagram showing how a load is distributed by a call setting signal sequence for reproducing the fixed information path.

FIG. 9 is a state transition diagram at the virtual subscriber for distributing a load by a call setting signal sequence for reproducing the fixed information path.

FIG. 10 is a diagram showing an example of a mechanism in which an identifier of a resource used for a PVC call is stored in the virtual subscriber by a call setting signal.

[Explanation of symbols]

101-103, 1001-1004 ATM switch 111-113 Switch software 121-123, 221, 222 Call processing program 131-133 Switch 141 Information path 151, 152 Signal link 161, 162 Subscriber terminal 171, 172, 211, 212, 1051 virtual subscriber 181, 182 interface 191, 192 maintenance system 201, 202 service program 231, 232 service order 241-244, 302, 303, 403, 404 maintenance person report 301, 401 call release signal 402 call setting signal 501 program abnormality 601 ATM switch restart 701, 801 ATM transit switch 711-714, 811-814 ATM subscriber switch 721 Simultaneous call 1011-1013 Parameter of call release signal 1021 to 1023 uplink channel resources 1031 to 1033 downstream line resources 1041 and 1042 the subscriber terminal 1061 resource identifier hold data S1~S3 state S11~S14 event S21~S26 process

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Haruo Oboshi 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd.In the Information and Communication Division (72) Inventor Hiroto Uno 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Address: Hitachi, Ltd., Information and Communication Division (72) Katsuhiko Taruya, Inventor Katsuhiko 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd. Information and Communication Division (72) Inventor: Koichi Seino 1-1-1, Uchisaiwai-cho, Chiyoda-ku, Tokyo No. 6 Nippon Telegraph and Telephone Corporation (72) Inventor Masaya Okubo 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12 / 56

Claims (4)

(57) [Claims] 1. A network system such as a maintenance system which provides a subscriber exchange and a transit exchange and an interface for performing maintenance operations on them using a packet switching system for decomposing and transferring information into packets. A so-called permanent in which an information path is fixedly set between the subscriber terminals in a packet-switched network composed of subscriber terminals that perform communication by utilizing, and call setup and / or call release is omitted. In a control method of a service form called a virtual circuit, a virtual subscriber function (hereinafter, referred to as a virtual subscriber) is provided inside a subscriber exchange accommodating the subscriber terminal, and the virtual subscriber is provided with each communication. According to a terminal that handles a call that sets an information path to a terminal (hereinafter referred to as a virtual circuit call for a permanent virtual circuit call) Controlling the fixed information path by simulating a setup and / or a call release (ie, a call setup and / or a call release signal sequence).
Circuit control method. 2. When a hardware or software failure occurs in an exchange or a transmission device through an information path between subscriber terminals during a service of a permanent virtual circuit, the exchange detects the occurrence of the failure. Activating the call release signal sequence, and transmitting and receiving a call release signal according to the subscriber terminal of the virtual circuit call to the virtual subscriber during the call release signal sequence in the subscriber exchange accommodating the transmitting / receiving terminal. Do
2. The method according to claim 1, wherein the virtual subscriber, which detects that the fixed information path is released based on the call release signal, activates a call setup signal sequence to reproduce the fixed information path. Permanent virtual circuit control method described. 3. A call release signal for a large number of permanent virtual circuits simultaneously due to a restart of an exchange in the switching network or a failure of a line and a line device in which information paths of a plurality of permanent virtual circuit calls are set. When the sequence is activated, the call release signal is provided with a parameter for identifying that a number of calls have been released at the same time, and the virtual subscriber who has received the call release signal allows a number of permanent virtual Detecting a simultaneous activation of a call release signal sequence for a circuit call, and initiating a call setup signal sequence to regenerate said fixed information path, a number of permanent virtual circuit calls released; A number of call setup signal sequences corresponding to 3. The permanent virtual system according to claim 1, wherein processing of the exchange accompanying the call setup signal sequence is distributed in time.
Circuit control method. 4. A call setting signal includes a parameter indicating an exchange through which the fixed information path passes and an identifier of a resource used by the fixed information path in the exchange. The parameters are set in each exchange that executes the setting signal sequence, the parameters are collected in the subscriber exchange accommodating the subscriber terminal, the intermediate exchanges and the identifiers of the resources are stored, and the fixed information path reproduction is performed. In the call setting signal sequence at the time, the stored data is set to the parameter in the call setting signal in the local exchange accommodating the subscriber terminal,
In each exchange that executes the call setup signal sequence, by selecting, based on the parameters, an exchange through which the fixed information path passes and an identifier of a resource used by the fixed information path in the exchange, the same as before reproduction is performed. 4. The permanent virtual circuit control system according to claim 1, wherein said fixed information path is reproduced so as to use the same resource via an exchange.