KR0175485B1 - Path Control Method Using Retry in Fully Distributed Asynchronous Transfer Mode Switching System - Google Patents

Abstract

The present invention relates to a method for controlling an originating and destination side using a retry algorithm in a fully distributed ATM switching system, which can perform efficient routing in a large-capacity fully distributed ATM switching system. In order to provide a method for controlling outgoing and called party paths using a retry algorithm, one-way by assigning an initial value to the variable B, the type of connection required, the variable S, and the switch link identifier, V Or a call processing step (100 to 119) for setting a switch link that satisfies the call request band according to the bidirectional connection type and requesting the called party to process and update the outgoing link band management table when receiving a response from the called party. The amount of band required by the call is variable B, the type of connection required is variable S, and the identifier of the switch link. Large-scale full distribution, including the called party processing steps (200 to 224) for updating the incoming link band management table by setting a switch link that satisfies the call request band according to the one-way or two-way connection type by assigning an initial value to the number V. In the ATM switching system, it is possible to perform efficient route setting.

Description

Path Control Method Using Retry in Fully Distributed Asynchronous Transfer Mode Switching System

1 is a block diagram of a fully distributed asynchronous transfer mode (ATM) switching system to which the present invention is applied.

2 is a flowchart of a path control method of a calling party in the present invention.

3 is a flowchart of a path control method of a called party according to the present invention;

The present invention relates to a path control method using retries in a fully distributed asynchronous transfor- mation switching (ATM) switching system. In particular, the present invention relates to a method of setting up an internal path of a fully distributed large-capacity ATM switching system. A route control method for establishing an internal route from a calling subscriber to a called subscriber.

Implementing a large capacity ATM switching system to provide broadband integrated communication services is essential, and an optimal routing function and resource management function are required for a large capacity ATM switching system that performs high-speed data processing and switching.

Therefore, there is a need for an efficient routing method for each depending on the method and shape of the ATM switching system.

In a fully distributed ATM switching system, many network resources, including links, are distributed by ATM Local Subsystem Subscriber-rype (ALS-S) or Relay Local Subsystem Trunk-rype (ALS-T). A centralized subsystem (ACS: ATM Cemtral Subsystem) contains functions necessary for service control, network resource control, and network resource management. Therefore, a routing algorithm distributed to each subscriber or relay line matching module is required. In addition, efficient routing can be achieved even when the system is expanded to a large capacity.

Accordingly, an object of the present invention is to provide a path control method through retrying to perform efficient path setting in a large-capacity fully distributed asynchronous transfer mode (ATM) switching system.

The present invention for achieving the above object is a unidirectional path control method applied to a fully distributed asynchronous transfer mode switching system, by referring to the transmission link band management table to determine the effective band more than the bandwidth required by the call input for all switch links Searching for a transmit switch link having a first step; A second step of determining a transmitting switch link having an effective band equal to or larger than the call request band retrieved in the first step as the calling party transmitting switch link, and transmitting information of the switch link determined to the called party; The called party searches for a receiving switch link having an effective band equal to or larger than a call request band for all switch links by referring to the receiving link band management table, and belonging to the same centralized subsystem (ACS) as the transmitting switch link determined at the calling party. The third step; A fourth step of transmitting a response message for requesting a retry of the path setting to the calling party if the receiving switch link is not satisfied in the third step; A fifth step of updating the determined bandwidth usage state of the determined reception switch link to the called party's receiving link band management table when the receiving switch link is satisfied in the third step, and transmitting a response message corresponding to the calling party; A sixth step of updating a bandwidth usage state of the determined transmission switch link in the transmission link band management table if the response message received from the called party is a message indicating normal processing; And a seventh step of returning to an initial state and repeating the first step or less if the response message received from the called party requests a retry.

Also, in the bidirectional symmetrical or asymmetrical path control method applied to a fully distributed asynchronous transfer mode switching system, a transmission switch link having an effective band greater than the bandwidth required by an input call for all switch links is searched by referring to the transmission link band management table. The first step to do; A second step of connecting a forward transmission link to a transmission link having an effective band equal to or greater than a band requested by the call retrieved in the first step; A third step of searching for a reception switch link having an effective band equal to or greater than a band required by an input call for all the switch links after performing the second step; A fourth step of determining a receiving switch link having an effective band equal to or greater than a band requested by the call retrieved in the third step as a reverse receiving link and transmitting information of the determined forward and reverse transmitting / receiving switch links to a called party; The called party searches for a receiving switch link having an effective band equal to or larger than the call request band for all switch links by referring to the receiving link band management table, and belonging to the same centralized subsystem (ACS) as the transmitting switch link determined at the calling party. The fifth step; A sixth step of transmitting a response message requesting a retry to a calling party if a receiving switch link that is satisfied in the fifth step is not found; A seventh step of determining a receiving link of the called party and a transmitting link of the calling party as a forward link when a receiving switch link satisfying the fifth step is found; After performing the seventh step, a transmission switch having an effective band equal to or greater than a call request band for all switch links with reference to the transmission link band management table, and belonging to the same centralized subsystem (ACS) as the receiving link determined by the originating party. An eighth step of retrieving the link; A ninth step of transmitting a response message requesting a retry to a calling party if a transmission switch link that is satisfied in the eighth step is not found; When the transmission switch link is found to be satisfied in the eighth step, the band usage state of the determined transmission switch link is updated in the called party transmission link band management table and the band usage state of the determined reception switch link is respectively updated in the reception link band management table. A tenth step of transmitting a response message corresponding to the sender; If the response message received from the called party is a message indicating normal processing, updating the determined band use statuses of the determined transmitting and receiving switch links in the transmitting and receiving link band management tables, respectively; And a twelfth step of repeating the first step or less of releasing the determined transmission and reception link bands, returning to an initial state, and searching for a valid switch link when the response message received from the called party requests a retry. Characterized by including.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a schematic diagram of an ATM switching system to which the present invention is applied, and is distributed in ATM local Ssubsystems (ALS) 1, which are independently configured subsystems. Each distributed subsystem is configured to be interconnected through an ATM central subsystem (ACS) 2.

When a call request is made from a subscriber, it is either a Broadband Subscriber Interface Module (BSIM) 3 or a Narrowband Subscriber Interface Module (NSIM) 4 which is a subscriber module in the ALS 1. It is detected and the signaling cell is converted into an inter-processor communication message and transmitted. The signaling cell entered through BSIM (3) which is a 155mps subscriber interface and NSIM (4) which is a medium and low speed subscriber interface. Cells entered through the BBSAL (Broad Physical Layer Hardware) block of the Access Switching Control Module (ACSM), a subscriber signal processing module (ASM), have an ATM Adaptation Layer (AAL). It is delivered to AASHH (AAL Signaling Handller) block, which is a signal processing layer.

In addition, the subscriber cell introduced through the 155 Mbps subscriber interface includes a Broadband Subscriber Physical Layer Hardware (BSPLH) block, which is the physical layer hardware of the BSIM 3, and a Broadband Subscriber ATM Layer Hardware (BSALH), which is an ATM layer processing hardware. Signals present in the ASCM (5) via the Access Link Interface Haredware (ALIH) block and the Access Switch Hardware (ASWH) block in the Access Switch Network Module (ASNM) 6 via the block. The processing block is delivered to the ATM Adaptive Layer Signal Processing Block (AASHH).

In the case of signals coming in through the medium to low speed subscriber interface, both interfaces survive at the same time. Cell for subscriber signal coming in through DSIE level link interface through Low Speed Interface Haredware (LSIH) block that handles DSIE level link interface, and cell for subscriber signal coming in through DS3 level interface ALIH, AS, and ASCM (Medium Speed Multiplexing and Demultiplexing Hardware Block (MMDXH), which multiplexes / demultiplexes medium and low speed subscriber cells through Medium Speed Interface Haredware (MSIH) blocks) 5) is passed to AASHH via BPALH.

In the Subscriber Call Processor Haredware (SCPH) block in the ASCM (5) in the originating ALS (1), a Virtual Path Connection Identifier (VPCI) / Virtual Channel Identifier (VCI) is sent to the subscriber who sent the signaling cell. It allocates the link band between the Virtual Channel Identifier and the subscriber and the network, and finds the destination ALS (1) through number translation.

After determining the number of the incoming ALS (1), in conjunction with the ASCM (5) in the incoming ALS (1), the ALIH from the calling subscriber, the ASWH of the calling ALS (1), and the central link interface hardware (CLIH) The path to the called party is established through the block, the Central Switch Hardware (CSWH) block, and the Access Switch Hardware (ASWH) block, which is a switch of the destination ALS 1.

Each module commonly uses a Broadband Subscriber Physical Layer Hardware (BSPLH) block for physical layer processing, a Broadband Subscriber ATM Layer Hardware (BSALH) block for ATM layer processing, and various signaling cells. Blocks composed of a combination of AAL Signaling Handler Hardware (AASHH) blocks for ATM adaptation layer processing are present in BSIM 3, NSIM 4, ASCM 5, and OMCM 10, respectively.

In addition, BSIM (3) for 155 Mbps subscriber link interface and NSIM (4) for medium to low speed subscriber link interface have UPCH (Usage Parameter Control Hardware) block. Supervised user parameter control is performed.

In addition, an operation and maintenance processor hardware (OMPH) block in the OMCM 10 provides an interface between a system operator and an ATM switching system, performs tasks related to operation and maintenance of the system, and provides various devices. To control.

Network Synchronization Modules (NSMs) 7 and 11 present in the ALS 1 and the ACS 2 receive a timing signal transmitted from the outside and supply a timing signal inside the system.

Local Timing Generation Hardware (LTGH) block in NSM (7) inside ALS receives local timing signal and generates Local Timing related signal used by the system itself, and NSM (AC) inside ACS (2) The Network Synchronization Handling Hardware (NSHH) block in 11) receives timing signals from the LTGH of the ALS 1 and distributes timing sources to all systems in the ACS 2.

2 is a flow chart of an embodiment of a path control method of a calling party according to the present invention.

The amount of band required by the new call is assigned to variable B, the type of connection required, variable S, and the initial value of the switch link identifier to variable V (100).

The type of connection is expressed as Uni_d for unidirectional connection and Bi_d for bidirectional symmetrical and asymmetrical connection, and the identifier of the switch link has a value between 0 and any maximum switch link value (MaxVV) for each link group.

The type of connection is checked through a variable S value representing the type of connection among the variables substituted as described above (101).

If the connection type is Uni_d indicating a one-way connection, the effective band of the initial switch link assigned to the variable V indicating the switch link identifier is referred to the variable BW_tx by referring to the source transmission (Tx) link band management table. The identifier variable V of the switch link representing the number of cycles is increased by one (102).

Then, the band B required by the call is compared with the effective band BW_tx of the currently selected switch link (103).

As a result of the comparison in step 103, if the effective band BW_tx of the switch link is smaller than the band B required by the call, the currently selected switch link cannot be used. Therefore, it is checked whether the currently selected switch link is the last link. 104).

If it is not the last link in step 104, in order to select another link, it is substituted into variable V representing the switch link identifier by referring to the source transmission link band management table, and then assigns the effective band of the switch link into variable BW_tx, Step 102 or less is repeated to increase the variable V representing the number by one.

This step is performed for all switch links until a switch link with at least the call request band is found, and if the switch link with at least the band requested by the call is not found until the last switch link is found, the currently requested call is processed. Since it cannot be done, it ends after abnormal processing.

If the effective band BW_tx of the switch link is greater than or equal to the band B required by the call in step 103, since the switch link satisfies the band required by the call, the switch link is determined as the calling party valid transmission link (105).

The switch link information and the like selected by the calling party are sent to the called party to request the incoming call (106).

Wait for a response message to be received from the called party (107). If a response message is received, the received response message is analyzed.

If the received response message is a response message indicating a normal processing result, the band transmission state of the determined switch link is updated (108) in the outgoing transmission link band management table, and the process ends. On the other hand, if the result of analyzing the response message from the called party is a request for rerouting due to a failure in establishing the called party's path, the process returns to the initial stage and searches for a valid link.

If the variable S indicating the connection type is a bidirectional symmetric or asymmetric connection request in step 101, the effective band of the first switch link is substituted into the variable BW_tx by referring to the source transmission link band management table, and the switching link indicating the number of purifying Increment an identifier variable V of 1 by one (109).

Then, the band B required by the call is compared with the idle band BW_tx of the currently selected switch link (110).

If the effective band BW_tx of the switch link currently selected in step 110 is smaller than the call request band B, it is checked whether the switch link compared now is the last link (111).

In step 111, if it is not the last link, it is assigned to the identifier variable V of the switch link with reference to the source transmission link band management table to select another link, and then assigns the effective band of the switch link to the variable BW_tx and Step 109 is repeated to increase the variable V representing the number by one.

This step is performed for all switch links until a switch link with a band above the call request band is found, and if the switch link with the band of band shift required by the call is not found by searching until the last switch link, the currently requested Since the call cannot be processed, it ends after the abnormal processing.

If the effective band BW_tx of the switch link currently selected in step 110 is greater than or equal to the call request band, there is a switch link that satisfies the band required by the call.

In order to find the reverse switch link of the calling party, the effective band of the first switch link is substituted into the variable BW_tx by referring to the calling party receiving link band management table, and the variable V representing the number of cycles is increased by one (113).

Then, the band B required by the call is compared with the effective band BW_tx of the currently selected switch link (114).

As a result of the comparison of step 114, when the effective band BW_tx of the currently selected switch link is smaller than the call request band B, the currently selected switch link cannot be used. Substituting the effective band of the first switch link to the variable BW_tx and repeating step 113 or less by increasing the variable V representing the number of cycles by one.

This step is repeated 115 for all switch links until a switch link having a band above the call request band is found.

Similarly, if a switch link having a band greater than or equal to the call request band is not found, the current call cannot be processed, and thus terminates after abnormal processing.

If the effective band BW_tx of the reverse switch link currently selected in step 114 is equal to or greater than the call request band, there is a switch link that satisfies the band required by the call.

The forwarding and reverse switch link telegrams selected by the calling party are sent to the called party to request incoming processing (117).

Wait for a response message to be received from the called party (118). If a response message is received from the called party, the received response message is analyzed.

As a result of the analysis, if the received response message is a message indicating a normal processing result, the bandwidth reason state of the forward and reverse switch links determined in the source transmitting and receiving link band management tables is updated (119), and the process ends.

On the other hand, if the response message of the called party is a request for resetting the path due to the failure of the called party's path setting, the process returns to the initial state and searches for a valid switch link on the transmitting end.

Figure 3 shows a flowchart of an embodiment of a called party path control method according to the present invention.

As in the calling party, the number of bands required by the call is assigned to variable B, the type of connection required, variable S, and the initial value of the switch link identifier to variable W (200).

Here, the type of connection represents a unidirectional connection as Uni_d, bidirectional symmetrical or asymmetrical connection as Bi_d, and the identifier of the switch link has a value between 0 and any maximum switch link value MaxW.

The type of the connection is checked through a variable S value indicating the type of the connection among the assigned initial values (201).

If the variable S representing the type of connection is Uni_d representing a one-way connection, the transmitting switch link of the calling party transmitted from the calling party is assigned to the calling party transmitting (Tx) link (202), and the called party receiving link band management table is set. The effective band of the first switch link is assigned to the variable BW_rx, and the variable W representing the number of cycles is increased by one (203).

Then, the band B requested by the call is compared with the effective band BW_rx of the currently selected switch link (204).

If the effective band BW_rx of the switch link is smaller than the band B required by the call in step 204, it is determined whether the switch link compared in order to find another switch link is the last switch link (205).

If it is not the last switch link in step 205, in order to find a new called party receiving link, the effective band of the next switch link is substituted into the variable BW_rx with reference to the called party receiving link band management table, and a variable W representing the number of cycles is obtained. Repeat step 203 and incrementing by one.

In the case of the last switch link in step 205, since there is no receiving switch link that satisfies the bandwidth required by the call, and service cannot be performed, a response message requesting retry is transmitted to the calling party (206), and the process ends.

If the effective band BW_rx of the switch link is greater than or equal to the bandwidth required by the call in step 204, the ATM centralized subsystem (ACS) having the same receiving (Rx) link and transmitting (Tx) link of the called party satisfying the bandwidth required by the call is the same. Check whether it is via the module (207).

If not in step 207 through the same ACS module to repeat the step 205 to check whether the switch link that is compared now is the last switch link to find the receiving switch link through the same ACS module.

On the other hand, in step 207, the determined switch link of the called party is used to use the selected called party receiving (Rx) link (W) and the calling party transmitting (Tx) link (V) as a path between originating parties when passing through the same ACS module. The status of the band usage is displayed in the incoming reception link band management table and updated (208). Then, the destination processing result is transmitted (209) to the calling party. Then, the incoming processing ends.

On the other hand, if the last switch link is found and the receiving switch link belonging to the same ACS module as the transmitting switch link of the calling party is not found, a response message requesting retry is transmitted to the calling party (206).

In step 201, if the connection is a bidirectional symmetric or asymmetric connection, the transmit / receive (Tx / Rx) link selected and selected by the calling party for forward / reverse connection of origination and destination is forward-transmitting (Tx) link and reverse direction. Each of them is assigned to an originating side Rx link (211).

Then, the effective band of the first switch link is substituted into the variable BW_rx with reference to the receiving side reception link band management table to determine the forward receiving and reverse transmitting links of the called party, and the variable W representing the number of cycles is increased by one ( 212).

Then, the band B required by the call is compared with the effective band BW_rx of the currently selected switch link (213).

If the effective band BW_rx of the currently selected switch link is smaller than the band B required by the call in step 213, it is checked whether the switch link compared now to find another switch link is the last switch link (214).

In step 214, if there is no last switch link, the effective band of the next switch link is substituted into the variable BW_rx with reference to the destination Rx link band management table to find a new destination Rx link. Repeat step 212 to increase the number W representing the number by one.

On the other hand, in the case of the last switch link in step 214, since there is no link that satisfies the bandwidth required by the call, the transmitter transmits a response message requesting retry to the calling party (215) and terminates.

If the effective band BW_rx of the switch link is greater than or equal to the band required by the call in step 213, it is checked whether the currently selected destination (Rx) link and the source (Tx) link of the called party pass through the same ACS module (216).

If the same ACS module is not used in step 216, the step 214 is repeated to check whether the switch link compared now is the last switch link.

On the other hand, in step 216, via the same ACS module, the selected destination receiving link W and the originating transmission link V are determined as forward paths between the originating call (217).

In order to find the reverse path, the effective band of the first switch link is substituted into the variable BW_tx by referring to the called party transmission bandwidth management table, and the variable W representing the number of cycles is increased by one (218).

Thus, the band B required by the call is compared with the switch effective band BW_tx (219).

If the effective band BW_tx call of the switch link is smaller than the required band in step 219, it is determined whether the switch link compared now is the last switch link (220).

In step 220, if the last switch link is aryl, the effective band of the next switch link is substituted into the variable BW_tx by referring to the destination transmission link band management table to find a new destination transmission link. Repeat steps 1 and 218 below increasing.

On the other hand, in the case of the last switch link in step 220, since there is no link that satisfies the bandwidth required by the call, after releasing the determined band of the forward switch link and transmitting a response message requesting retry to the calling party (221). Ends,

If the effective band BW_tx of the switch link is greater than or equal to the bandwidth required by the call in step 219, it is determined whether the transmitting link of the called party and the receiving link of the originating party satisfying the band requested by the call are the same ACS module (222).

When not passing through the same ACS module in step 222, the step 220 is repeated to check whether the switch link compared now is the last switch link.

On the other hand, in the case of passing through the same ACS module in step 222, the selected destination transmitting link (W) and the source receiving link are determined as the reverse path between the originating and receiving and transmitting (Tx / Rx) link band management of the destination. The bandwidth usage statuses of the forward and reverse switch links currently determined in the table are updated (223), and a response message corresponding to the sender is transmitted (224), and the incoming call distance is terminated.

On the other hand, if it does not find the receiving switch link belonging to the same ACS module as the transmitting switch link by searching the last switch link, it transmits a response message requesting retry to the calling party.

The present invention as described above has the effect that can be efficiently performed in the large-capacity fully distributed ATM switching system.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited to the drawing.

Claims (2)

A unidirectional condensation control method applied to a fully distributed asynchronous transfer mode switching system, comprising: a second link retrieving a transmission switch link having an effective band equal to or larger than a bandwidth required by an input call for all switch links by referring to a transmission link band management table; Step: determining a transmitting switch link having an effective band equal to or greater than the call request band retrieved in the first step as the calling party transmitting switch link, and transmitting the information of the determined switch link to the called party. The called party manages the receiving link band. A third step of searching for a receiving switch link having an effective band equal to or greater than a call request band for all switch links with reference to the table, and belonging to the same centralized subsystem (ACS) as the transmitting switch link determined at the calling party; If no matching receive switch link is found in step 3, A fourth step of transmitting a response message requesting re-establishment of rerouting to the mobile station: if the receiving switch link is satisfied in the third step, the band reception state of the determined receiving switch link is updated in the reception destination link band management table of the destination receiver. And a fifth step of transmitting a response message corresponding to the calling party, if the response message received from the called party is a message indicating normal processing, updating the determined bandwidth usage state of the determined transmission switch link in the transmission link band management table. In step 6 and if the response message received from the called party is a message requesting a retry, the method returns to an initial state and includes a seventh step of repeating the first step or less. One way path control method. In the bidirectional symmetric or asymmetric path control method applied to a fully distributed asynchronous transfer mode switching system, a transmission switch link having an effective band greater than that required by an input call for all switch links is searched by referring to a transmission link band management table. The first step is to disconnect the transmission switch link having a valid band or more than the band requested by the call retrieved in the first step to the forward transmission link. After performing the second step, all the steps are referred to by referring to the reception link band management table. A third step of searching for a receiving switch link having an effective band equal to or greater than a band requested by the call input for the switch link: determining a receiving switch link having an effective band equal to or greater than the band requested by the call retrieved in the third step as a reverse receiving link; Forward and backward transmission / reception as determined above by the called party. Step 4: Transmitting location link information: The called party has an effective band equal to or greater than the call request band for all switch links by referring to the reception link band management table, and also has the same centralized subsystem as the transmit switch link determined at the calling party. A fifth step of searching for a reception switch link belonging to the ACS; if a reception switch link satisfied in the fifth step is not found, a sixth step of transmitting a response message requesting a retry to the calling party; satisfactory in the fifth step If a receiving switch link is found, the receiving link of the called party and the transmitting link of the calling party are determined to be forward links. After performing the seventh step, all the switch links are referred to with reference to the transmission link band management table. Has an effective band of more than the required band, and is the same as the receive switch link determined at the originating side Eighth step of searching for a transmission switch link belonging to a centralized subsystem (ACS): If a transmission switch link is not satisfied in the eighth step: transmitting a response message requesting retry to the calling party; In step 8, if the transmission switch link is found to be satisfied, the band usage state of the determined transmission switch link is updated in the called party transmission link band management table, and the band usage state of the determined reception switch link is updated in the reception link band management table. Step 10: transmitting a corresponding response message to the calling party; if the response message received from the called party is a message indicating normal processing, a band of the determined transmitting and receiving switch links of the calling party is determined in the transmitting and receiving link band management table. Step 11 of updating the use status respectively: and from the called party And a twelfth step of releasing the determined transmission and reception switch link bands if the received response message is a message requiring retry, and repeating the first and subsequent steps of returning to an initial state and searching for a valid switch link. A bidirectional path control method in a fully distributed asynchronous transfer mode switching system, characterized in that.