JP3203537B2 - Switching control method for ATM network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an asynchronous transfer mode (A
TM; Asynchronous Transfer
The present invention relates to a network (hereinafter referred to as an ATM network) for performing data transfer according to an ATM network, and particularly to an ATM network switching processing control method suitable for reducing the processor load associated with VPI / VCI determination, cell header conversion table setting, and bandwidth reservation. It is about.

[0002]

2. Description of the Related Art Broadband ISDN (Integrated Services Digital Network) for communication of multimedia information
vices Digital Network), for example, “Nikkei Communication Supplement ISDN Application Guide” (19
The ATM network control technology described on pages 168 to 177 of 1988 (Nikkei BP) has been developed. Hereinafter, the ATM network will be described with reference to FIGS.

In FIG. 16, 101 to 106 are terminals,
107 to 109 are ATM exchanges. Transmission links 110-1 between the terminal and the exchange and between the exchanges
It is tied by 18. Transmission links 110-118
Within one or more virtual paths (hereinafter referred to as VP; Virtua
l Pass), and one or more virtual connections (hereinafter referred to as VC; Virtual Connection) are accommodated in the VP. In an ATM network, all information is
The data is transferred in fixed-length block units called cells. The cell specifies (identifies) the VP in the cell header.
I, and a VCI specifying a VC in the VP,
The I and VCI identify which VC each cell carries information for. Also, in the cell header,
There is an area for distinguishing user information cells from other cells.

[0004] ATM exchanges include, for example, the ATM of FIG.
As shown in an exchange (described as Ex in the figure) 107, a cell header conversion table (TBL) 2 for determining a cell transfer destination
01 (also referred to as a mapping table) and a switch (denoted as SW in the figure) 20 for performing actual cell exchange processing
And a processor (described as CPU in the figure) 203 that performs signal processing for VPI / VCI determination, cell header conversion table setting, and bandwidth reservation. For example,
In FIG. 16, when communication is performed from terminal 101 to terminal 106, it is necessary to determine the VPI / VCI between the terminals, set the cell header conversion table on exchanges 107 and 109, and reserve the band between the terminals. Become. This bandwidth reservation is performed, for example, so that the amount of incoming cells does not exceed the transfer capacity of 150 Mb / s.
This is to secure in advance the transfer capacity corresponding to the inflow cell amount.

FIG. 1 shows how values are set in the cell header conversion tables of exchanges 107 and 109 in FIG.
7, shown in FIG. Cell header conversion table 2 in FIG.
01, the input transmission links 110 to 112 are a,
b, c, and the output transmission links 113, 114 are A,
In the cell header conversion table 301 of FIG. 18, the input transmission links 113 and 115 are denoted by a and b, and the output transmission links 117 and 118 are denoted by A and B. In FIG. 16, first, if it is determined that the VPI / VCI value of the cell header is output from the terminal 101 to the exchange 107 with, for example, “7” and “3”, the transmission link 110
17 in the cell header conversion table 201 of FIG.
The VPI / VCI value of the cell header is output to the corresponding output link A as (5, 4). The output link A is actually the transmission link 113, and the output cell is based on the cell header conversion table 301 shown in FIG. 18, and the exchange 109 sets the output transmission link A (that is, the transmission link 117) to VPI = 5 and VCI. = 7. As a result, this cell arrives at the destination terminal 106.

As described above, communication between terminals is performed by performing "VPI / VCI determination", "cell header conversion table setting", and "bandwidth reservation". Generally, in order for unspecified subscribers to communicate with each other, these processes are performed for each communication. At the end of each communication, "bandwidth release", "cell header conversion table setting release", "VPI / VC
Perform "I Release". These processes are performed not only by the ATM layer (providing a function to transfer cells) but also by the OS.
I (Open Systems Interconnection)
(3rd layer, network: determines a data transmission path), and is performed by software by the processors (203, 303).
Note that "VPI / VCI determination" and "cell header conversion table setting" are performed for each communication, but "Band reservation and release"
A technique has been proposed in which a "bandwidth reserved cell / released cell" is generated for each burst unit which is a block of cells. In this case, the "bandwidth reservation / release" can be performed in the ATM layer, and can be performed only by hardware without the intervention of a processor.

[0007]

The problem to be solved is that the conventional switching control technology of the ATM network is "VPI /
The processing for "VCI determination and cell header conversion table setting" occupies a large part of the processor load. An object of the present invention is to solve these problems of the prior art, to reduce or reduce the processing of the processor relating to "VPI / VCI determination, cell header conversion table setting", to make the ATM switch and the ATM network economical, and to realize the ATM switch. An object of the present invention is to provide an ATM network switching processing control method capable of improving the processing capacity.

[0008]

Means for Solving the Problems] To achieve the above object, exchange control method in the ATM network of the present invention, (1) through
VPI / VCI determination and cell header change
When the communication table is set, the VPI /
Release VCI and release setting of cell header conversion table
In an ATM network switching processing control method for performing cell transfer in an asynchronous transfer mode (ATM), communication is started.
Before the start of communication between the two network elements, the VPI / VCI used for cell transfer between the two network elements arbitrarily selected is determined and the cell header conversion table is set. Specifies a cell for which a band is to be reserved and a cell for which a band is to be released according to the VPI / VCI set in the cell header conversion table.
Flow between two network elements while converting, VPI / VCI
Is determined and released and the setting and release of the cell header conversion table are not performed, but only the reservation and release of the band are performed. (2) Determination of VPI / VCI when starting communication
And set the cell header conversion table, and end the communication.
Release of VPI / VCI and cell header conversion table
In the switching control method of the ATM network for performing the data transfer in the asynchronous transfer mode (ATM), the VPI / VCI is released when the communication between the network elements accommodated in the ATM network is terminated, and without releasing the cell header conversion <br/> table performs only release the band,
At the start of the next communication between the network elements, the cell for which the bandwidth is to be reserved flows between the two network elements while performing VPI / VCI conversion according to the VPI / VCI set in the cell header conversion table in the previous communication. Features. (3) In the switching control method for an ATM network described in (2), the VPI / VCI between two network elements is
Determine and release and set and release cell header conversion table
When the number of times of the communication with the network element reaches a predetermined number, the switching process control only for the release of the band at the end of the communication between the two network elements is performed. (4) A according to any of (1) to (3) above;
In the switching control method of the TM network, the frequency of communication of a cell to which a VPI / VCI is determined and set in the cell header conversion table to a transfer destination network element is counted, and the VPI between network elements exceeds a predetermined number. When the / VCI is determined and the cell header conversion table is set, VPI / VCI between network elements is assigned to communication between new network elements in the order of lowest counted communication frequency. (5) A according to any of (1) to (3) above;
In the switching processing control method of the TM network, when determining the VPI / VCI between network elements exceeding a predetermined number and setting the cell header conversion table, the VPI / VCI between the network elements is determined in the order of the oldest communication occurrence date and time. It is characterized in that it is assigned to communication between new network elements. (6) A according to any one of the above (1) to (5).
In the switching processing control method of the TM network, each network element
The cell flow on the PI / VCI is monitored, and when a VPI / VCI in which no cells flow for a predetermined time or more is detected, a cell for releasing the band of the VPI / VCI is transmitted. (7) A according to any one of the above (1) to (6)
In the switching processing control method of the TM network, each network element
Monitor the cell flow on the PI / VCI, detect and store the VPI / VCI in which no cells have flowed for a predetermined period,
When a shortage of VPI / VCI occurs for a new communication request between network elements accommodated in the ATM network, the stored V
It is characterized in that PI / VCI is assigned to a new communication request. (8) A according to any one of (1) to (6) above.
In the switching control method of the TM network, the network element
It monitors the cell flow on the I / VCI, detects and stores the VPI / VCI in which no cells have been flowing for a predetermined time or more, releases the bandwidth allocated to the stored VPI / VCI, and When a shortage of VPI / VCI occurs in response to a new communication request between network elements accommodated in the ATM network, one VPI is stored from the stored VPI / VCI.
/ VCI, release the selected VPI / VCI, and release the setting in the cell header conversion table.
The released VPI / VCI is allocated to a new communication request. (9) A according to any one of the above (1) to (6).
In the switching control method of the TM network, the network element
The cell flow on the I / VCI is monitored, and every time a VPI / VCI in which no cells flow for a predetermined time is detected, a cell in a band allocated to the detected VPI / VCI is detected.
, Release of VPI / VCI, and release of setting of the cell header conversion table. (10) In the switching control method for an ATM network according to any one of the above (7) to (9), a VPI / IP communication method is used for a new communication request between network elements accommodated in the ATM network.
When VCI shortage occurs, the VPI used for the oldest communication
/ VCI is selected and assigned to a new communication request. (11) In the switching processing control method for an ATM network according to any one of (1) to (10), the VPI / VC
With the configuration of the I determination and cell header conversion table, between the <br/> network element allocates bandwidth for any amount in advance, and performing the communication between network elements within the band amount this assignment . (12) The switching control method for an ATM network according to any one of (1) to (11), wherein each switching control is performed between a calling terminal and a called terminal as network elements. I do. (13) The switching control method for an ATM network according to any one of the above (1) to (3), characterized in that the switching control is performed between switches as network elements. (14) In the switching control method for an ATM network according to any one of the above (1) to (11), each switching process control is performed between exchanges as network elements, and the exchange and the network element as network elements are controlled. Start communication between the calling and called terminals
Of VPI / VCI and Cell Header Conversion Table
Header conversion table for setting and communication termination
And performing conventional exchange process control for release.

[0009]

According to the present invention, it is necessary to determine the VPI / VCI and the cell header conversion table prior to the cell transfer on the ATM network. This requires software processing (upper layer), and thus becomes a processor load. Note that, for example, “VPI / VCI determination” and “cell header conversion table setting” are performed in advance between specific network elements such as terminals and exchanges that frequently communicate. It should be noted that, in the calling terminal, the called terminal for which “VPI / VCI determination” and “cell header conversion table setting” have been performed in advance is registered as “registered destination”. In the communication to the registered destination, only the reservation and release of the band are performed by hardware processing at the time of communication request and at the end of communication. Alternatively, only bandwidth reservation is performed by hardware processing when a communication request is made, and bandwidth release is performed by monitoring the network (monitoring whether cells are flowing for a predetermined time or more). In this way, software processing can be reduced.
As a result, an increase in the amount of communication that can be processed by a single exchange and utilization of high-speed hardware can be expected.

Also, in the case of communication using a network element that has not been registered, upon termination of communication according to the conventional technique, only band release is performed, and VPI / VCI release and the cell header conversion table are not performed. By leaving the "VCI determination" and "cell header conversion table setting", the same processing can be performed for a user who is not registered as a registered destination. Also, only when a predetermined number of communications have been performed, by leaving "VPI / VCI determination" and "cell header conversion table setting", it is possible to efficiently specify a network element to which the present invention is applied. it can.

[0011] When the number of registrations exceeds the number that can be registered, "VPI / VCI determination" and "cell header conversion table setting" are always left for communication with high communication frequency or communication close to the latest communication. . As a result, a specific network element can be efficiently selected. In particular, since the selection can be made based on the date and time of occurrence of communication, it is effective when the communication partner has a high correlation with the recent communication partner. Also,
By monitoring the cell flow, network elements with low communication frequency can be discriminated, the band can be released by the terminating terminal or the exchange, and when the VPI / VCI is insufficient, "VPI / VCI release" and "cell header conversion table setting release" are released. Can be selected and VPI / VCI can always be used up. Further, by performing the switching processing control of the present invention between the exchanges accommodating the originating terminal and the destination terminal, respectively, the processor load of the transit exchange can be reduced and the VPI / VCI can be used more effectively. Also, by dividing the bandwidth for each destination node (exchange), the use efficiency of the bandwidth is reduced, but it is not necessary to reserve and release the bandwidth at the relay node.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 4 are flowcharts showing a first embodiment of an ATM network switching control method according to the present invention.
The operation between the terminal 101 and the terminal 106 in the ATM switching network having the configuration shown in FIG. 16 will be described with reference to FIGS. In the present embodiment, it is assumed that the terminal 101 in FIG. 16 communicates with the terminal 106 at a high frequency. First, the terminal 106 is determined in advance as a registration target (step 101), and the cell between the terminals 101 and 106 is determined. Determine the VPI / VCI to be used (step 102).

For example, as described in the background art, the terminal (101) and the exchange 107 are numbered (7, 3),
Is determined as (5,4) between the exchange 109 and the exchange 109, and as (5,7) between the exchange 109 and the terminal 106. Then, the terminal 101 stores the terminal 106 as “VPI / VCI determined, cell header conversion table set destination” (hereinafter referred to as “registered destination”), and stores the VPI / VCI to be written in the cell for this terminal 106. It is stored as shown in FIG. 19 (step 103). Further, the cell header conversion tables 201 and 301 of the exchanges 107 and 109 on the way are set (step 104). For example, the cell header conversion table 201
In the cell header conversion table 301, the input a (7, 3) and the output A (5, 4)
(5, 7) is set. Then, the terminal 106 is notified that it has been registered as a destination terminal (step 105).

When the terminal 101 actually communicates with the terminal 106 (incoming call request), the subscriber who uses the terminal 101 inputs the incoming call address corresponding to the terminal 106 (step 106). Terminal 101 refers to the contents of FIG. 19 to determine whether the address is already included in the registered destination (step 107). If it is not included, communication is performed by the function of the upper layer of the prior art (step 108). In this example, however, the terminal 106 is included in the registered destinations as shown in FIG. The cell to be performed (discriminated from the user information cell by the cell header) corresponds to the terminal 106 as VPI / VCI (7, 3).
And sends it out on the output transmission link 110 (step 109).

Next, the exchange 107 receiving this cell
Recognizes that the cell is a band reservation cell (step 11).
0), the required bandwidth amount and VPI / VCI written in a predetermined area of the cell are read (step 111), and the value of the reserved bandwidth corresponding to the corresponding VP on the transmission link 113 (see FIG. 20) When the required bandwidth amount is added and the value exceeds the VP bandwidth (step 112), a cell for notifying that the bandwidth cannot be reserved is returned to terminal 101 (step 113).
If not, the value is newly written to the bandwidth management table in the exchange as a reserved bandwidth value (see FIG. 20) (step 114). Thereafter, according to the cell header conversion table 201 in FIG. 17 (input a “7, 3”,
Output A “5,4”), VPI / VCI conversion of the band reservation cell,
The data is transmitted to the exchange 109 via the transmission link 113 (step 115).

As described above, the entire process from reception to transmission of the band reservation cell in the exchange 107 is performed by hardware without the intervention of the processor 203. Here, the necessary bandwidth amount is described in the bandwidth reservation cell, but the VC bandwidth may be stored in advance for each registered destination and not described in the bandwidth reservation cell. Next exchange 109
, The same processing from reception of a reserved band cell to transmission as in the exchange 107 is performed (steps 116 to 116).
119), the band reservation cell is transmitted to the destination terminal 106 (step 120).

The terminal 10 that has received the band reservation cell
6 (step 121), if the user information can be received (step 122), the receivable cell is transmitted in the opposite direction to the band reservation cell (step 124). Receivable cells are
It is provided to the terminal 101 via the exchanges 109 and 107 (steps 125 and 126). If the reception is not possible in step 122, the cell for notifying the reception is exchanged with the exchange 1
The terminal 101 is notified via the terminals 09 and 107 (step 123). The terminal 101 that has received the receivable cell (step 127) flows the user information cell and performs communication with the terminal 106 (step 128). At the end of the communication, terminal 101 instructs exchange 107 to release the band by transmitting a band release cell (which is distinguished from the user information cell in the cell header) to line 110 with VPI = 7 and VCI = 3 (step). 129).

Further, the exchange 107 receiving this cell
Recognizes that the cell is a band release cell (step 13).
0), read the released bandwidth amount written in a predetermined area of this cell (if the bandwidth reservation cell has no description of the bandwidth amount, the released cell does not need to describe the bandwidth) and VPI / VCI (step). 131), the value of the reserved bandwidth for the corresponding VP on the transmission link 113 is reduced by the released bandwidth area, and
7 is written into the bandwidth management table shown in FIG. 20 (step 132). After that, according to the cell header conversion table 201 of FIG. 17, this band release cell is VPI / VCI converted,
The data is transmitted to the exchange 109 via the line 113 (step 133). From reception of such a band released cell to transmission thereof, it can be performed by hardware without the intervention of the processor 203.

In the next exchange 109, the exchange 10
7, the processing from reception of the released cell to transmission is performed (steps 134 to 137). Exchange 109
The terminal 106 which has received the band release cell from the terminal transmits the release end cell in the opposite direction to the band release cell (step 13).
8). The cell is connected to the terminal 1 via the exchanges 109 and 107.
01 (steps 139-141). FIG. 21 shows the cell transmission / reception operation by the above processing.

Next, another embodiment according to the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing the second embodiment of the ATM network switching control method according to the present invention. In this example, the band is released by the destination terminal.
After the processing in steps 106 to 128 in FIG.
The destination terminal monitors the cell flow (step 20).
1) If a cell has not been transferred for a certain period of time (step 202), a band release cell is generated and transmitted;
Release the bandwidth for communication with the calling terminal (step 20)
3).

Next, another embodiment according to the present invention will be described with reference to FIG. FIG. 6 is a flowchart showing a third embodiment of the ATM network switching control method according to the present invention. In this example, the bandwidth is released by each exchange, and the VPI / VCI in which cells have not been transferred for a predetermined time or more is released from the cell header conversion table. In particular,
Terminal 101 in ATM switching network having the configuration shown in FIG.
Step 1 in FIG.
17 shows an operation example when the destination terminal corresponding to the communication request at 07 is not included in the registered destinations.

If the destination terminal corresponding to the communication request is not included in the registered destinations, communication according to the prior art is performed (step 306). In that case, the network first determines the VPI / VCI used by the cell between the terminals 101 and 106. For example, as described in the prior art, the terminal 101 and the exchange 107 are numbered (7, 3), the exchanges 107 and 109 are numbered (5, 4), and the exchange 109 and the terminal 106 are (5, 7).
Decide the turn. Then, the cell header conversion tables 201 and 301 of the exchanges 107 and 109 on the way are set. For example, in the cell header conversion table 201, the input a (7,
3), output A (5, 4), cell header conversion table 30
At 1, an input a (5, 4) and an output A (5, 7) are set. The terminal 101 sets the terminal 106 to “registered destination”
(VIP / VCI determined, cell header conversion table set destination) and the VPI / VCI to be assigned to the cell for the terminal is stored (see FIG. 19). As a result, terminal 1
06 is a registered destination.

As described above, when a communication request is issued to a destination that is not included in the registered destinations, the VPI / VCI is determined and the cell header conversion table is set by the conventional technique. VPI / VCI release processing is not performed after the communication processing control by. Therefore V
CI is exhausted. In order to cope with such a problem, as shown in FIG. 6, in the present embodiment, between the processes of step 128 and step 133 described in FIGS. The flow is monitored (step 301), and V
C (step 302) and stored in the processor as a dormant VC list (see FIG. 23) (step 30).
3) Subtract the VC band from the reserved band list (see FIG. 20) (step 304). Therefore, a user who does not want to release a band in which user information is interrupted needs to occasionally transmit an OAM cell or the like while not transmitting user information.

In the state where the dormant VC list is registered in this way, for example, it is assumed that the VCI at VPI = 5 in the transmission link 113 shown in FIG. 17 has been used up (step 305). Is assumed to be as shown in FIG. 23 (step 30).
7), the transmission link 113 is connected to the exchange 1 as described above.
07, the transmission link “A”, and VCI = 4 for VPI = 5 in this transmission link is a dormant VC.
, Input (a, 7, 3) and output (A, 5, 4) corresponding to the same VCI are deleted (step 309),
Release cells of this VC (VCI = 4) are forwarded in the forward direction of the VC,
Transmission is performed in the reverse direction (step 310). Step 3
If the VCI is not insufficient in 05, communication control is performed by the function of the upper layer according to the prior art (step 306). In step 307, the pause VC
If there is no list, call loss or detour processing is performed (step 308).

In step 310, the exchange 1 that has received the VC release cell transmitted from the exchange 107 that lacks the VCI.
09, the cell header conversion table 301 shown in FIG.
From the input (a, 5, 4) and the output (A,
5, 7), and release the cell of the VC to the terminal 1.
06 (step 311). The terminal 106 that has received the VC release cell releases the corresponding VCI from the registered destination list and returns a release end cell (step 312). The release end cell is notified to the exchange 107 via the exchange 109. (Step 313). still,
The terminal 101 that has received the release cell of the VC transmitted from the exchange 107 receives the VC release table from the cell header conversion table.
And its destination (destination 106, VPI
= 7, VCI = 3), and transmits a release end cell to the exchange 107. As a result, the VP on the transmission link 113
Since VCI = 4 in I = 5 can be used for another VC, the exchange 107 allocates this VCI to a new communication request by the conventional technique.

The above processing operation is also shown in FIG. In the third embodiment, the release of the VCI is performed when a communication request for a destination not included in the registered destination occurs and the VCI becomes insufficient. However, the release may be performed at regular intervals. . Also, the newly assigned VC
At the end of the communication using I, terminal 101 transmits a band release cell to terminal 106, as in step 129 in FIG. 3 (at this time, exchanges 107 and 109 perform only transfer of the band release cell). Or, similarly to the processing of steps 201 to 203 in FIG.
Monitors the cell flow, detects that no cell has flowed for a certain period of time, and secures a band. In any case, the exchange does not activate the band release processing and the VPI / VCI release processing by any notification processing.

Next, another embodiment according to the present invention will be described with reference to FIGS. 7 to 11 show the AT of the present invention.
14 is a flowchart illustrating a fourth embodiment of a method for controlling switching of an M network. FIGS. 7 to 11 show examples of communication according to the present invention between the exchanges 904, 906 and 907 in the ATM switching network having the configuration shown in FIG. On the exchange 904 in FIG. 24, a table indicating the determined VPI / VCI and the registered destination nodes is stored (FIG. 2).
5). The cell header conversion table on the exchange 905 is as shown in FIG. Here, the transmission link 909 is an input transmission link a on the cell header conversion table, the transmission link 910 is an output transmission link A, and the transmission link 912 is an output transmission link B.

Therefore, in exchange 904, VPI =
1, the cell transmitted on the transmission link 909 with VCI = 1 is transmitted to the exchange 905 on the transmission link 910 by the VCI.
It is sent out with PI = 1 and VCI = 1 and delivered to the exchange 906. In the exchange 904, VPI = 1, V
The cell transmitted on the transmission link 909 with CI = 3 is transferred to the exchange 905 on the transmission link 912 by the VPI =
1, VCI = 1, and delivered to the exchange 907.

When a communication request is actually made between the terminals 901 and 903 (step 401), the terminal 901 makes a communication request to the exchange 904 using the function of the upper layer according to the prior art (step 402). The exchange 904 recognizes that this communication request is a communication request to the terminal 903 (step 403), and as a destination node, the exchange 90
6 is selected (step 404), and the registered destination node table is searched (step 405).
VPI / VC whose registered destination node corresponds to the exchange 906
One of I that is not in use, for example, VPI = 1,
VCI = 1 is selected (step 406), and the VP (VP
It is determined whether or not a value obtained by increasing the value of the reserved band corresponding to I = 1) by the amount of band required for this communication exceeds the VP band, and if so, a call loss or bypass process is performed. (Step 408). If the value does not exceed the VP band, the value is newly set as the value of the reserved band and written in a table (see FIG. 20) for performing band management in the exchange (step 409).

Then, the selected VPI = 1, VCI = 1
Is set in the cell header conversion table on the exchange 904 (step 410), and the band reservation cell is set to the transmission link 909.
The data is sent upward as VPI = 1 and VCI = 1 (step 411). FIG. 27 shows the setting contents of the cell header conversion table after the processing of step 410. The exchange 905 that has received the band reservation cell recognizes that the cell is a band reservation cell (step 412), and reads the required band amount and VPI / VCI written in a predetermined area of the cell (step 413). ), The relevant VP on the transmission link 910 (VP
If the value obtained by increasing the value of the reserved band corresponding to I = 1) by the amount of band necessary for this communication does not exceed the VP band (step 414), the value is newly set as the value of the reserved band and the exchange The data is written in the table for performing the band management in (step 416). If the bandwidth exceeds the VP band, a time-out is returned due to the return of the non-reservable cell or the discard of the band reserved cell (step 415).

Then, according to the cell header conversion table,
The bandwidth reservation cell is transmitted to the transmission link 910, VPI = 1, VCI
= 1, and transmits to the exchange 906 (step 417).
The procedure from reception to transmission of the band reservation cell is performed by the exchange 9
In 05, no software processing or upper layer processing by the processor is required. The exchange 906 that has received the band reservation cell (step 418) sends an incoming request to the terminal 903 using the function of the upper layer according to the related art (steps 419 to 422).

Thereafter, processing based on the prior art is performed. That is, the terminal 903 that has received the incoming call request (step 423) determines whether or not the user information can be received (step 424), notifies that the reception has not been possible (step 425), and accepts if the user information has been received. A possible notification is sent (step 426). The exchange 906 which has received the acceptance notification from the terminal 903 generates a receivable cell and transmits it to the exchange 904 via the exchange 905 (step 427). The exchange 904 having received the receivable cell transmits a receivable notification to the terminal 901 (step 428). After receiving the reception enable notification (step 429), terminal 901 transmits user information (step 430).

At the end of the communication, the terminal 901 notifies the exchange 904 of the end using the function of the upper layer according to the conventional technique (step 431). The exchange 904 analyzes this notification by the processor, recognizes that it is the end-of-call notification (step 432), and changes the contents of the cell header conversion table (see FIG. 27) corresponding to the VC into “input (a, 1,
1), output (A, 1, 1) "(step 43).
3), the in-use display of the corresponding part (switch 906, VPI = 1, VCI = 1) of the registered called node (see FIG. 25) is returned to "not used" (0) (step 43).
4). Then, the corresponding VP (VPI) on the transmission link 909
= 1), the value of the reserved bandwidth is reduced by the release bandwidth amount, the bandwidth management table is updated (step 435), and the bandwidth release cell is placed on the transmission link 909 by VPI = 1, VCI
= 1 and instructs the exchange 905 to release the band (step 436).

The exchange 905 recognizes that the received cell is a band release cell (step 437), and reads the release band amount and VPI / VCI written in a predetermined area of the cell (step 438). Then, the value of the reserved bandwidth for the corresponding VP (VPI = 1) on the transmission link 910 is reduced by the released bandwidth amount, and the bandwidth management table (see FIG. 20) is updated (step 439). After that, according to the cell header conversion table, this band release cell is VPI / VCI converted,
The message is transmitted to the exchange 906 (step 440). Exchange 9
At 05, from the reception of this band release cell to the transmission.
Perform without software processing or higher layer processing in the processor.

The exchange 906 receives the band release cell from the exchange 905 (step 441), reads the release band amount and VPI / VCI written in a predetermined area of the cell (step 442), In the management table, the value of the reserved bandwidth for the corresponding VP on the transmission link 911 is subtracted by the bandwidth to be released (step 443). Thereafter, using the function of the upper layer according to the prior art, the terminal 9
03, a notification of the end of call is given, and the corresponding part on the cell header conversion table is released (step 44).
4).

Next, another embodiment according to the present invention will be described with reference to FIGS. FIGS. 12 to 15 are flow charts showing a fifth embodiment of the ATM network switching control method according to the present invention. Based on FIGS. 12 to 15, FIG.
Exchanges 904, 90 in the ATM switching network having the configuration shown in FIG.
6 and 907. On the exchange 904 in FIG. 24, a table indicating the determined VPI / VCI and the registered destination node (see FIG. 25), the total available bandwidth of each VC corresponding to the registered destination node, and the time There is a table (see FIG. 28) for storing the sum of the used bands.

The cell header conversion table on the exchange 905 is as shown in FIG. Here, the transmission link 909 in FIG. 24 is the input transmission link a on the cell header conversion table shown in FIG.
Is an output transmission link A, and transmission link 912 is an output transmission link B. Therefore, VPI =
1, the cell transmitted on the transmission link 909 with VCI = 1 is sent to the exchange 905 on the transmission link 910 by the V
It is sent out with PI = 1 and VCI = 1 and delivered to the exchange 906.

When a communication request between the terminals 901 and 903 actually occurs (step 501), the terminal 901 makes a communication request to the exchange 904 by using the function of the upper layer according to the prior art (step 502). The exchange 904 recognizes in the processor that this communication request is a communication request to the terminal 903 (step 503), and the exchange 906.
Is selected as the terminating exchange (step 504). The registered destination node table is searched (step 50).
5), the registered destination node corresponds to the exchange 906
One of VPI / VCI that is not in use, for example, VPI
= 1, VCI = 1 (step 506), and in the bandwidth management table (see FIG. 28), the registered destination node is exchange 9
If the difference between the available bandwidth and the bandwidth in use corresponding to 06 is equal to or greater than the required bandwidth of the communication request (step 507), the value of the bandwidth in use is increased by the required bandwidth of the communication request. The value is updated (step 509), and is set in the cell header conversion table on the exchange 904 as shown in FIG. 27 (step 510). Step 50
If NO in step 7, a call loss or bypass process is performed (step 508).

After that, the exchange 904 sends out a band reservation cell with the terminal 903 (which is distinguished from the user information cell by the header) on the transmission link 909 according to the cell header conversion table (step 511). The exchange 905, which is the transit exchange, recognizes that this cell is a band reservation cell, and immediately transfers the cell to the exchange 906, which is the terminating exchange, according to the cell header conversion table (step 512). The processing of the exchange 905 can be performed only by hardware. The exchange 906, having received the cell from the exchange 905, recognizes that this cell is a band reservation cell with the terminal 903 (step 513), and uses the function of the upper layer according to the prior art to terminate the call at the destination terminal 903. Request (step 514).

The terminal 903 that has received the incoming call request (step 515) determines whether or not the user information can be received (step 516), notifies that the user information cannot be received (step 517). Exchange 906 for notification of acceptance
(Step 518) using the upper layer of the prior art. The exchange 906 that has received the acceptance notification from the terminal 903 generates a receivable cell and transmits it to the exchange 905 (step 519). Exchange 905
Transmits the received receivable cell to exchange 904 (step 520). The exchange 904 that has received the receivable cell releases the time-out of the bandwidth reservation (step 5).
21) Send a reception enable notification to the terminal 901 using the upper layer of the conventional technique (step 522). After receiving the reception enable notification (step 523), the terminal 901
Transmits user information (step 524).

At the end of the communication, the terminal 901 notifies the exchange 904 of the end using the function of the upper layer according to the conventional technique (step 525). The exchange 904 analyzes this notification by the processor, recognizes that it is the end-of-call notification (step 526), cancels the contents of the cell header conversion table corresponding to the VC (step 527), The corresponding part (exchange 906, VPI =
1, the VCI = 1) is returned to "not in use" (step 528), and the value of the used band corresponding to the registered destination node in FIG. 28 is changed by the band required for the communication. It is reduced and stored (step 529). at the same time,
The band release cell is transmitted to the exchange 905 (step 530), and the exchange 905 transfers the received band release cell to the exchange 906 (this is only transfer and can be handled by hardware processing). The exchange 906 that has received this band release cell recognizes that this cell is a band release cell (step 532), and notifies the terminal 903 of the release using the function of the upper layer according to the related art (step 533). ).

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 29 is a flowchart showing a sixth embodiment of the ATM network switching control method according to the present invention. If there is a communication request (step 601). It is determined whether this communication request is for a registered destination (step 602). If not, communication using the function of the upper layer of the prior art is started (step 603), and communication of user information is performed (step 604). At the end of the communication, it is determined whether or not the destination network element has the function according to the present invention (step 605).

If the result of this determination is negative, the communication is terminated by the function of the upper layer of the prior art (step 606), but it has the function and, by this communication, the same destination network element If the number of communications has reached a predetermined number (step 607), only the release of the band is performed without releasing the VPI / VCI and releasing the cell header conversion table (step 608). Is registered as a registered destination (step 609). If this registration is more than the number that can be registered in the source network element, the oldest communication history destination among the registered destinations is deleted, and this destination network element is replaced with the latest one. Register as a communication destination. In step 602, if the communication request is for a registered destination, the communication with the destination network element is updated to the latest one, and the communication history of the registered network element is updated (step 61).
0) Then, the processing after step 109 shown in FIGS. 1 to 4 is performed.

As described above with reference to FIGS. 1 to 29, in the switching processing control method of the ATM network according to each embodiment, for example, specific network elements such as terminals and exchanges which communicate frequently are used. "VPI / VCI determination" and "cell header conversion table setting" are performed in advance. Then, in the communication to the specific destination (registered destination), only the reservation and release of the band are performed by hardware processing at the time of communication request and at the end of communication. Alternatively, only bandwidth reservation is performed by hardware processing when a communication request is made, and bandwidth release is performed by monitoring the network (monitoring whether cells are flowing for a predetermined time or more). In this way, software processing can be reduced. As a result, an increase in the amount of communication that can be processed by a single exchange and utilization of high-speed hardware can be expected.

Also, in the case of communication using a network element that has not been registered, upon termination of the communication according to the conventional technique, only the band is released, the VPI / VCI release and the cell header conversion table are not released. By leaving the "VCI determination" and "cell header conversion table setting", the same processing can be performed for a user who is not registered as a registered destination. Also, only when a predetermined number of communications have been performed, by leaving "VPI / VCI determination" and "cell header conversion table setting", it is possible to efficiently specify a network element to which the present invention is applied. it can.

When the number of registrations exceeds the number that can be registered, "VPI / VCI determination" and "cell header conversion table setting" are always left for communication with high communication frequency or communication close to the latest communication. . As a result, a specific network element can be efficiently selected. In particular, since the selection can be made based on the date and time of occurrence of communication, it is effective when the communication partner has a high correlation with the recent communication partner. Also,
By monitoring the cell flow, network elements with low communication frequency can be discriminated, the band can be released by the terminating terminal or the exchange, and when the VPI / VCI is insufficient, "VPI / VCI release" and "cell header conversion table setting release" are released. Can be selected and VPI / VCI can always be used up.

Further, by performing the switching processing control of the present invention between the exchanges accommodating the originating terminal and the destination terminal, respectively, the processor load on the transit exchange can be reduced and the VPI / VCI can be used more effectively. Also, by dividing the bandwidth for each destination node (exchange), the use efficiency of the bandwidth is reduced, but it is not necessary to reserve and release the bandwidth at the relay node. The present invention is not limited to the embodiment described with reference to FIGS. 1 to 29, and can be variously modified without departing from the gist thereof.

[0048]

According to the present invention, the processing of the processor relating to "VPI / VCI determination, cell header conversion table setting" can be reduced or reduced, and the ATM switch and the ATM network can be made more economical.
In addition, it is possible to improve the processing capacity of the ATM switch.

[Brief description of the drawings]

FIG. 1 is a quarter of a flowchart showing a first embodiment of a method for controlling switching processing of an ATM network according to the present invention.

FIG. 2 is a 2/4 part of a flowchart showing the first embodiment of the ATM network switching control method of the present invention;

FIG. 3 is a 3/4 part of a flowchart showing the first embodiment of the ATM network exchange processing control method of the present invention;

FIG. 4 is a 4/4 part of a flowchart showing the first embodiment of the ATM network switching processing control method of the present invention;

FIG. 5 is a flowchart showing a second embodiment of the ATM network switching control method according to the present invention;

FIG. 6 is a flowchart showing a third embodiment of the ATM network switching control method according to the present invention;

FIG. 7 is a 1/5 part of a flowchart showing a fourth embodiment of the ATM network exchange processing control method of the present invention;

FIG. 8 is a 2/5 part of the flowchart showing the fourth embodiment of the ATM network switching control method of the present invention;

FIG. 9 is a 3/5 part of a flowchart showing a fourth embodiment of the ATM network exchange processing control method of the present invention;

FIG. 10 shows a fourth embodiment of the ATM network switching control method according to the present invention.
5 is a 4/5 part of a flowchart showing the embodiment of FIG.

FIG. 11 shows a fourth example of the ATM network switching control method according to the present invention.
6 is a 5/5 portion of the flowchart showing the embodiment.

FIG. 12 shows a fifth embodiment of the ATM network switching control method according to the present invention;
4 is a quarter of a flowchart showing the embodiment of FIG.

FIG. 13 shows a fifth embodiment of the ATM network switching control method according to the present invention;
5 is a 2/4 part of a flowchart showing the embodiment of FIG.

FIG. 14 shows a fifth embodiment of the ATM network switching control method according to the present invention.
5 is a 3/4 part of a flowchart showing the embodiment of FIG.

FIG. 15 shows a fifth embodiment of the ATM network switching control method according to the present invention.
5 is a 4/4 part of a flowchart showing the embodiment.

FIG. 16 is a block diagram showing a first configuration example of an ATM network.

17 is a block diagram showing an example of the internal configuration of the exchange accommodating the calling terminal in FIG.

18 is a block diagram showing an example of the internal configuration of the exchange accommodating the receiving-side terminal in FIG.

19 is an explanatory diagram showing an example of registered contents of a registered destination table according to the present invention in the exchange shown in FIG. 16;

FIG. 20 is an explanatory diagram showing registered contents of a band management table according to the present invention in the exchange in FIG. 16;

FIG. 21 is a sequence diagram showing an example of cell transmission / reception operations in the ATM network having the configuration of FIG. 16 by the processing in FIGS. 1 to 4;

FIG. 22 shows an AT having the configuration of FIG. 16 by the processing in FIG. 6;
FIG. 9 is a sequence diagram illustrating an example of a cell transmission / reception operation in the M network.

FIG. 23 is an explanatory diagram showing an example of registered contents of a dormant VC list according to the present invention.

FIG. 24 is a block diagram showing a second configuration example of the ATM network.

FIG. 25 is an explanatory diagram showing an example of registered contents of a registered destination table according to the present invention in the exchange in FIG. 24;

FIG. 26 is an explanatory diagram showing an example of setting contents of a cell header conversion table according to the present invention in the exchange in FIG. 24;

FIG. 27 is an explanatory diagram showing another example of the setting contents of the cell header conversion table in the exchange in FIG. 24 according to the present invention.

FIG. 28 is an explanatory diagram showing an example of registered contents of a bandwidth management table according to the present invention in the exchange in FIG. 24;

FIG. 29 shows a sixth embodiment of the ATM network switching control method according to the present invention;
It is a flowchart which shows the Example of FIG.

[Explanation of symbols]

 101-106, 901-903 Terminals 107-109, 904-907 Switch 110-118, 908-913 Transmission link 201,301 Cell header conversion table 202,302 Switch 203,303 Processor

Continuation of the front page (56) References JP-A-6-132973 (JP, A) JP-A-6-197127 (JP, A) JP-A-7-231322 (JP, A) JP-A-6-338918 (JP) , A) IEICE Technical Report SS E94-5 (April 4, 1994) IEICE Technical Report IN 93-110 (January 28, 1994) IEICE Transactions BI Vol. J76-BI No. 11 pp. 869-881 (November 25, 1993) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/28 H04L 12/56

Claims (14)

(57) [Claims] 1. A VPI / VCI used for transferring a user information cell when starting communication in response to a new communication request.
Make decisions and setting a cell header conversion table performs unset the VPI / VCI of the release and the cell header conversion table when you exit the through <br/> Shin, ATM network to perform cell transfer by the asynchronous transfer mode In the switching processing control method of the first aspect, a pre- selection between the first and second two network elements is selected .
Place the setting to fit the VPI / VCI of the decision and the cell header conversion table row Do I, the first, the new communication requests between the second two net elements
At the start of the corresponding communication and at the end of the communication, a cell for performing band reservation and a cell for releasing band are
According to VPI / VCI previously determined between the first and second network elements and set in the cell header conversion table, V
It flows between the first and second network elements while performing PI / VCI conversion, and responds to a new communication request between network elements that are not selected in advance.
ATM network switching characterized in that only the reservation and release of the bandwidth are performed without determining and releasing the VPI / VCI and setting / releasing the cell header conversion table at the start of the corresponding communication and at the end of the communication. Processing control method. 2. A replacement processing control method in the ATM network performing cell transfer by asynchronous transfer mode, a new passage between two network elements contained in the ATM network
When starting communication in response to a communication request, the user information cell
Determination of VPI / VCI used for transfer and cell header conversion
To set and bandwidth reservation of Buru, to terminate the above-mentioned communication
Without unsetting of the VPI / VCI-released our good beauty above SL cell header conversion table of the time that performs only release the band corresponding to the next new communication requests between the two net elements hand
At the start of the communication, the cell for which the bandwidth is to be reserved is set to the cell header conversion table which has been set in the cell header conversion table in the previous communication.
A switching control method for an ATM network, characterized in that a flow is performed between the two network elements while performing VPI / VCI conversion according to PI / VCI. 3. The switching control method for an ATM network according to claim 2, wherein the VPI / VPI / VPI communication between the two network elements is performed.
When communication involving determination and release of the VCI and setting and release of the cell header conversion table has reached a predetermined number of times,
An ATM characterized by performing a switching control of only a bandwidth release upon termination of the communication between the two network elements.
Network switching processing control method. 4. The switching processing control method for an ATM network according to claim 1, wherein said VPI /
The communication frequency of the cell to which the VCI is determined and set in the cell header conversion table to the transfer destination network element is counted, and the VPI / VCI between the network elements exceeding a predetermined number is determined and the cell header conversion table is checked. An ATM network switching processing control method, wherein, when setting is performed, VPI / VCI between the network elements is allocated to communication between new network elements in order of the counted communication frequency being the lowest. 5. The switching control method for an ATM network according to claim 1, wherein the determination of VPI / VCI between said network elements exceeding a predetermined number and the setting of a cell header conversion table are performed. An ATM network exchange processing control method, wherein, when performing, the VPI / VCI between the network elements is assigned to communication between the new network elements in the order of the oldest communication occurrence date and time. 6. The switching control method for an ATM network according to claim 1, wherein each of the network elements monitors a cell flow on each of the VPI / VCIs and monitors the cell flow for a predetermined time or more. A switching control method for an ATM network, characterized in that when a VPI / VCI in which no cell flows is detected, a cell for releasing the band of the VPI / VCI is transmitted. 7. The switching control method for an ATM network according to claim 1, wherein each of said network elements monitors a cell flow on each of the VPI / VCIs and monitors the cell flow for a predetermined period or more. The VPI / VCI in which no cell flows is detected and stored, and when a shortage of the VPI / VCI occurs in response to a new communication request between the network elements accommodated in the ATM network, the stored VPI / VCI is stored. A switching control method for an ATM network, wherein a VCI is assigned to the new communication request. 8. The switching processing control method for an ATM network according to claim 1, wherein said network element monitors a cell flow on each VPI / VCI, and selects a cell for at least a predetermined time. Detects and stores the VPI / VCI that does not flow, releases the bandwidth allocated to the stored VPI / VCI, and responds to new communication requests between network elements accommodated in the ATM network. On the other hand, VPI / V
When the shortage of CI occurs, the stored VPI / VCI
One VPI / VCI from the selected VPI
/ VCI release and setting in the cell header conversion table are performed, and the released VPI / VCI is allocated to the new communication request. 9. The switching processing control method for an ATM network according to claim 1, wherein said network element monitors a cell flow on each VPI / VCI, and monitors a cell flow for a predetermined time or more. Each time a VPI / VCI that does not flow is detected, the release of the band allocated to the detected VPI / VCI based on the cell, the release of the VPI / VCI, and the setting of the cell header conversion table are released. ATM network switching processing control method. 10. The ATM network switching processing control method according to claim 7, wherein:
For new communication requests between network elements accommodated in the network,
A switching control method for an ATM network, characterized in that when the shortage of the VPI / VCI occurs, the VPI / VCI used for the oldest communication is selected and assigned to the new communication request. 11. The ATM network switching processing control method according to claim 1, wherein the VP
Along with the determination of the I / VCI and the setting of the cell header conversion table, an arbitrary amount of bandwidth is allocated in advance between the network elements, and communication between the network elements is performed within the allocated bandwidth amount. An ATM network switching control method. 12. The switching control method for an ATM network according to claim 1, wherein said switching control is performed between a calling terminal and a called terminal as said network element. ATM network exchange processing control method. 13. An ATM network switching processing control method according to claim 1, wherein said switching processing control is performed between exchanges as said network elements. Exchange processing control method. 14. The switching processing control method for an ATM network according to claim 1, wherein said switching processing control is performed between exchanges as said network elements, and said exchange and said network elements are controlled by said switching element. A conventional exchange process control for determining the VPI / VCI at the start of the communication, setting the cell header conversion table, and releasing the cell header conversion table at the end of the communication is performed between the calling terminal and the destination terminal. A switching control method for an ATM network.