JP2740433B2 - Dynamic Bandwidth Allocation Method for Trunk Line in Asynchronous Transfer Mode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dynamically allocating a trunk line in an asynchronous transfer mode.

[0002]

2. Description of the Related Art Conventional asynchronous transfer mode (hereinafter referred to as ATM)
In a communication network, a virtual path provided on a trunk line of an ATM communication system (here, a virtual path is a direct link logically defining a route and a band between arbitrary ATM exchanges on a physical transmission network). The transmission capacity of the virtual path is determined at the time of designing the network irrespective of the occurrence of the call, and the admission judgment of the call is performed by calculating the bandwidth based on the traffic report value from the user at the time of the call occurrence, and This is done by comparing with the free space.

[0003] Next, in order to ensure the quality of the received call, priority control of transfer processing is performed according to the attribute of the terminal or the medium of the communication information, or a call connected to a new virtual path is bypassed. , Quality control.

[0004]

In the conventional asynchronous transfer mode communication method, the transmission capacity of a virtual path provided in a communication network is determined at the time of designing the network, so that the bandwidth usage for each virtual path is not constant. If the trunk line is not used effectively and if the transmission capacity of the virtual path is set in consideration of the statistical multiplexing effect and more cells are sent out, the effect of quality degradation such as the cell discard rate will be affected by the entire trunk line. Problem.

[0005]

According to the present invention, there is provided a dynamic bandwidth allocation system for a trunk in an asynchronous transfer mode, which is used in an electronic exchange accommodating a trunk in an asynchronous transfer mode communication system and a terminal of an arbitrary communication system. Virtual path setting means for setting a plurality of virtual paths on the trunk line, band allocation means for allocating a band for each virtual path, and a virtual path group obtained by bundling the plurality of virtual paths into two groups, which are classified according to communication quality. Attribute adding means for adding an attribute to the virtual path, virtual path selecting means for selecting a virtual path belonging to the virtual path group according to the attribute of the terminal or the media characteristics of the communication information when a call is generated, and assigning the virtual path to the virtual path. Call admission rejection means for deciding to reject the call based on the allocated bandwidth, and the relay according to the sum of the bandwidths pre-allocated to the respective virtual paths included in the respective virtual path groups. Group bandwidth allocating means for proportionally allocating a band to the virtual path group, cell transmitting means for transmitting a cell to the trunk according to the priority given to the virtual path group, and Communication amount monitoring means for counting the number of passing cells to monitor the transmission amount of communication information, cell waiting means for temporarily waiting for the cell when the trunk line is blocked, and waiting for the virtual path group A congestion monitoring unit that measures the number of cells and a waiting time to monitor congestion of the virtual path group, and a communication amount suppression unit that suppresses a communication amount transmitted from the virtual path group to the trunk line to a group bandwidth or less. A group bandwidth changing unit that changes the group bandwidth of each virtual path group when the virtual path group is congested,
It is characterized in that a band can be allocated such that the sum of the bands of the virtual path exceeds the transmission band of the trunk line.

The communication quality for classifying the attribute information added to the virtual path group includes a cell delay time and a cell discard rate.

[0007]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an electronic exchange showing one embodiment of the present invention, FIG. 2 is a functional layout diagram of the electronic exchange shown in FIG. 1, and FIGS. 3, 4, and 5 are virtual path groups from virtual path settings in FIG. FIG. 3 is a flowchart showing a processing flow leading to a band change, FIG. 3 shows a flow from setting of a virtual path to addition of an attribute, FIG. 4 shows a flow of processing from a call generation to a call connection following the flow of FIG. Shows the flow of processing from cell transmission to group band change.

As shown in FIG. 1, in this embodiment, the ATM
In the electronic exchanges 11 and 12 having the communication methods of
Virtual paths 51, 52, 53, 54 are connected to the ATM trunk line 41.
Is set (step 301 shown in FIG. 3).

A bandwidth is allocated to each virtual path (step 302), and the virtual paths 51, 52 and 5 are assigned.
3 and 54 are bundled into two virtual path groups 71 and 72 (step 303), and an attribute classified according to communication quality is added to the bundled virtual path group (step 304).

When a call is generated, a call processing unit (hereinafter referred to as a CP) 96 shown in FIG.
L101, 102, 201, 202), data terminal (D
TE 103, 104, 203, 204)) The virtual path group is selected in accordance with the attribute of the communication information and the medium of the communication information, and the CP 96 determines whether or not the call can be accepted based on the bandwidth allocated to the virtual path. According to the connection method, for example, a connection call 61 between the TEL 101 and the virtual path 51 in FIG.
5 between the TEL 102 and the virtual path 52
Between the TEL 202 and the virtual path 52
Between the DTE 103 and the virtual path 53
Between the DTE 203 and the virtual path 53
Between the DTE 104 and the virtual path 54
Is set between the DTE 204 and the virtual path 54, respectively.

According to the flow shown in FIG.
And the TEL 201, the TEL 102 and the TEL 202, the DTE 103 and the DTE 203, and the DTE 104 and the DTE 204, respectively.

In FIG. 1, the bandwidth is proportionally allocated to two virtual path groups 71 and 72 set in the trunk line 41 in accordance with the sum of the bandwidths previously allocated to the respective virtual paths (step 305 shown in FIG. 3). .

Next, in FIG. 2, the electronic exchange 10 accommodates the terminal 100 in a terminal interface (hereinafter, U-IF) 81 and accommodates a trunk line 400 in the asynchronous transfer mode in a trunk line interface (hereinafter, N-IF) 82. ing.

The cross connect mechanism 30 of the electronic exchange 10
, A cross-connect processing unit (hereinafter referred to as XP) 97 activates a virtual path switch control unit (hereinafter referred to as VPCTL) 93, and the VPCTL 93 operates as a virtual path switch (hereinafter referred to as VPSW) of an asynchronous transfer mode switch (hereinafter referred to as ATMSW) 84.
86, a communication path called a virtual path is set between the N-IF 82 and a virtual path interface (hereinafter, V-IF) 83.

When the exchange mechanism 20 of the electronic exchange 10 receives a call request from the terminal 100 (step 401) following step 305 in FIG.
A virtual path is selected based on the attributes of the information and the media characteristics of the communication information (step 402).

Next, it is determined whether or not the corresponding path exists (step 4).
03), if there is a corresponding path, a request for communication quality is received from the terminal 100 that transmitted the communication (step 404), and the communication quality (cell delay time, cell discard rate) according to the medium of the communication information.
Is determined, and a virtual path is selected according to the communication quality, and acceptance or rejection is determined based on the bandwidth allocated to the virtual path (step 405).

If the reception is possible (YES in step 406), the channel switch control unit (hereinafter, CHCTL) 92 is started by a known exchange means, and the CHCTL 92 is started.
Is the channel switch of ATMSW84 (CHSW)
85 by connecting the U-IF 81 and the V-IF 83
A communication path called a connection call is set up between them (step 407).

According to the flow shown in FIG. 4, the terminal 100 can communicate via the trunk 400 in the asynchronous transfer mode (step 408).

When there is no corresponding path in step 403, or when the reception is rejected in step 406, the transmission is prohibited by a known means (step 409), and no call connection is made (step 410).

Next, in FIG. 2, the trunk line 400 is
A virtual path is selected in accordance with the attribute of “00” or the media characteristic of the communication information, and the CP 96 determines whether to accept the call based on the bandwidth of the selected virtual path.

Signal processing units (hereinafter referred to as SPs) 94 and 95 are connected to the trunk line 40 in accordance with the priority given to the selected virtual path group.
The cell is transmitted to 0 (step 501).

In the SPs 94 and 95, the trunk line 40
The number of zero cells is measured to monitor the amount of communication to be transmitted (step 502), and when the blockage of the trunk line 400 is detected (YES in step 503), a cell waiting process is temporarily performed (step 504). ).

The virtual path group 71 of the trunk line 41 shown in FIG.
72 is monitored (step 505), and when trunk line congestion is detected (YES in step 506), the bandwidth proportional to the virtual path groups 71 and 72 is changed (step 507).

By implementing the flow shown in FIG. 5, it is possible to allocate a band such that the sum of the bands of the virtual path exceeds the transmission band of the trunk line.

If the answer is NO in Step 503, Step 504 is skipped and the process proceeds to Step 505. If the answer is NO in Step 506, Step 507 is skipped.

[0026]

As described above, according to the present invention, a plurality of virtual paths are provided on a trunk line of a communication system of an asynchronous transfer mode,
A band is allocated to each virtual path, a plurality of virtual paths are bundled into two, and an attribute classified according to communication quality is added to the bundled virtual paths. By changing the group band, there is an effect that a band can be allocated such that the sum of the bands of the virtual path exceeds the transmission band of the trunk line.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic exchange according to an embodiment of the present invention.

FIG. 2 is a functional layout diagram of the electronic exchange shown in FIG.

FIG. 3 is a flowchart showing a flow of processing from virtual path setting to attribute addition in FIG.

FIG. 4 is a flowchart showing a flow of processing from a call generation to a call connection following the flow of FIG. 3;

FIG. 5 is a flowchart showing a flow of processing from cell transmission to group band change.

[Explanation of symbols]

10, 11, 12 Electronic exchange 20, 21, 22 Switching mechanism 30, 31, 32 Cross-connect mechanism 41, 400 Trunk line 51, 52, 53, 54 Virtual path 61, 62, 63, 64, 65, 66, 67, 68
Connection call 71, 72 Virtual path group 81 Terminal interface (U-IF) 82 Trunk line interface (N-IF) 83 Virtual path interface (V-IF) 84 Asynchronous transfer mode switch (ATMSW) 85 Channel switch (CHSW) 86 Virtual Path switch (VPSW) 91 Switch control unit (SWCTL) 92 Channel switch control unit (CHCTL) 93 Virtual path switch control unit (VPCTL) 94, 95 Signal processing unit (SP) 96 Call processing unit (CP) 97 Cross connector processing unit (XP) 100 terminal 101, 102, 201, 202 voice terminal (TE
L) 103, 104, 203, 204 Data terminal (DT
E)

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-119845 (JP, A) JP-A-4-150439 (JP, A) Transactions of the Institute of Electronics, Information and Communication Engineers, VOL. J 72-BI, NO. 11 (1989-11-25), PP. 904-916

Claims (2)

(57) [Claims] 1. An electronic exchange accommodating a trunk of an asynchronous transfer mode communication scheme and a terminal of an arbitrary communication scheme, a virtual path setting means for setting a plurality of virtual paths on the trunk, Bandwidth assigning means for assigning a bandwidth to a plurality of virtual paths, attribute adding means for adding an attribute classified according to communication quality to a virtual path group obtained by bundling a plurality of the virtual paths, attribute and communication of a terminal when a call is generated Virtual path selecting means for selecting a virtual path belonging to the virtual path group according to the media characteristics of the information, call acceptance rejecting means for determining rejection of the call based on a band allocated to the virtual path, Group bandwidth allocating means for allocating a bandwidth to the virtual path group on the trunk line in proportion to the sum of the bandwidth pre-allocated to each virtual path included in each virtual path group, Cell transmission means for transmitting cells to the trunk line according to the priority given to the path group, communication amount monitoring means for counting the number of passing cells for each virtual path group and monitoring the transmission amount of communication information, Cell waiting means for temporarily waiting for the cell when the trunk line is blocked, and congestion for monitoring the number of waiting cells and waiting time of the virtual path group and monitoring congestion of the virtual path group. A monitoring unit, a communication amount suppressing unit that suppresses a communication amount transmitted from the virtual path group to the trunk line to a group band or less, and changes the group band of each virtual path group when the virtual path group is congested. A dynamic band allocation method for a trunk in an asynchronous transfer mode, characterized by comprising: a group bandwidth changing unit, wherein a bandwidth such that the sum of the bandwidths of the virtual paths exceeds the transmission bandwidth of the trunk is enabled. . 2. The dynamic bandwidth of a trunk in an asynchronous transfer mode according to claim 1, wherein said communication quality for classifying attribute information added to said virtual path group includes a cell delay time and a cell discard rate. Assignment method.