JP3145874B2 - Virtual path setting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an ATM (Asynchronous Transfer Mode). The present invention relates to a technology for shortening a virtual path (hereinafter, referred to as VP) setting time. The present invention relates to a VP setting method in which a VP setting time is independent of a network scale and the number of user terminal devices.

[0002]

2. Description of the Related Art In an ATM, a VP, which is a virtual transmission path, is set using an actually wired transmission path.
The VP divides this band so as not to exceed the maximum bandwidth of the transmission path, that is, the maximum bit rate that can be transmitted through the transmission path, and a plurality of VPs can share one transmission path. The VPs sharing one transmission line at the same time can flexibly change according to the traffic situation at that time.

In a communication network, a VP is transmitted in response to a request from a user.
At this time, it is necessary to grasp the surplus bandwidth of the transmission path in advance and determine whether or not this surplus bandwidth can be used when setting the VP.
A conventional example for this purpose will be described with reference to FIGS. FIG. 6 is a diagram showing the configuration of various tables in a conventional example.
FIG. 7 is a flowchart showing the procedure of the conventional example. Conventionally, surplus bandwidth information usable for each user VP is shown in FIG.
It is managed by the VP table shown in FIG. Here, a logical name of the VP and a usable surplus bandwidth value corresponding to the logical name are registered.

FIG. 7 shows the procedure. By waiting for message reception (S1), a VP setting request from the user is waited.
When a VP setting request from a user arrives, the surplus bandwidth value and the required bandwidth value are compared using the VP table, and if the surplus bandwidth value is larger than the required bandwidth value, it is determined to be “OK” and the surplus bandwidth value is determined to be the required bandwidth. If it is smaller than the value, it is determined to be "No" (S2).

In order to calculate a surplus bandwidth value managed by the VP table shown in FIG. 6A, a VP configuration table shown in FIG. A path table shown in FIG. 6C for managing the excess bandwidth value of the road is required. In the VP configuration table,
The logical name of the VP and the logical name of the transmission path through which the VP passes are registered. In the path table, the maximum value of the shared band corresponding to the logical name of the transmission path and the available surplus band value are registered. As a method of calculating the surplus bandwidth value managed by the VP table, the VP configuration table is searched to extract each transmission path through which the user VP passes (S
3) The required bandwidth value is subtracted from the surplus bandwidth value of the corresponding transmission line managed by the path table (S4). Next,
The VP configuration table is searched to list the VPs that are affected by subtracting the required bandwidth value from the surplus bandwidth value of the transmission path (S5). The transmission path accommodating the listed VP is obtained by searching the VP configuration table (S6). The minimum value of the surplus bandwidth value of each transmission line is obtained from the corresponding path table (S7), and the minimum value is set to the usable bandwidth value of the corresponding VP (S8). In this way, the band change is notified to each transmission path, and a response notification is transmitted to the user terminal device (Japanese Patent Laid-Open No. 4-150438).
Reference).

[0006]

In this conventional method,
When the availability determination result is “available”, it is necessary to update the bandwidth information managed by the VP table each time. Therefore, the number of accesses to the VP configuration table and the path table increases, and the response to the bandwidth change request increases. Time increases. Further, when the network scale becomes large, the effect of the band change of one user VP affects a large number of VPs, so that the processing time increases in the order of the number of VPs, and the response to the user terminal device is delayed. .

[0007] The present invention has been made in view of such a background, and an object of the present invention is to provide a VP setting method in which the VP setting time is independent of the network scale and the number of user terminal devices.

[0008]

SUMMARY OF THE INVENTION A first aspect of the present invention is as follows.
The VP setting device includes means for receiving a request including a destination and a transmission band value from a user, and means for setting a VP through which a cell to be transmitted according to the request.

Here, the feature of the present invention is that V
A VP configuration table in which actual transmission paths through which P can pass are recorded, and a path table in which the surplus bandwidth is recorded for each actual transmission path, and a VP that can be set for a destination included in the request. Means for selecting one of the VP configuration tables by referring to the VP configuration table, obtaining a surplus bandwidth value of the transmission line from the path table, and comparing the surplus bandwidth value with the transmission bandwidth value included in the request. A means for determining that setting is possible when there is a surplus, and another selection by the selecting means when it is determined that setting is impossible, and when it is determined that setting is possible, a band of the VP of the request is secured and Means for subtracting the bandwidth from the surplus bandwidth of the path table.

[0010] Thus, the processing can be sped up regardless of the network scale and the number of user terminal devices in the VP setting time.

The means for selecting one is preferably selected from VPs having a small number of actual transmission paths.

A second aspect of the present invention is an ATM communication network provided with this VP setting device.

[0013]

In setting a VP requested by a user, a transmission line accommodating the VP is determined. Subsequently, the surplus bandwidth value of the transmission path is compared with the required bandwidth value of the VP. As a result, when the surplus bandwidth value is larger than the required bandwidth value, the required bandwidth of the VP is secured, and the bandwidth is subtracted from the surplus bandwidth. This result is notified to the user and communication is started.

Usually, there are many N transmission paths, but in this case, the excess band value of the transmission path and the VP
, And the securing of the required VP bandwidth and the subtraction of the required bandwidth from the surplus bandwidth are repeated N times. As for the order, it is preferable to perform the order sequentially from the VP of the shortest path.

As described above, since the VP setting time does not depend on the network scale and the number of user terminal devices, even if the network scale and the user scale increase, the VP setting time can be increased quickly.
P can be set.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of an embodiment of the present invention. FIG. 2 is a block diagram of the VP setting device.

The present invention provides a user terminal device CPE (Custome
r VP (Variable Bandwidth Allocation Controller) including means for receiving a request including a destination and a transmission band value from the r Premise Equipment, and means for setting a VP through which a cell to be transmitted in accordance with the request.
ler).

Here, the feature of the present invention is, as shown in FIG. 2, a VP configuration table 1 in which actual transmission paths through which a VP can pass are recorded, and a surplus bandwidth for each actual transmission path. And a path table 2 in which is stored a VP.
Means for selecting one of them by referring to the P configuration table 1, obtaining a surplus bandwidth value of this transmission line from the path table 2, comparing the surplus bandwidth value with the transmission bandwidth value included in the request, A means for determining that the setting is possible at a certain time, and another selection by the selecting means when it is determined that the setting is impossible, and the VP of the request when the setting is determined to be possible.
And a means for securing the bandwidth and subtracting the bandwidth from the surplus bandwidth of the path table in the VP setting unit 4. The means for selecting one of the VP setting units 4 selects from VPs having a small number of actual transmission paths.

Each user terminal device CPE performs communication between the user terminal devices CPE via a user VP in the ATM network. Further, each CPE of the user terminal device is a VP setting device VA.
C has a communication line (control VP in FIG. 1). When the user terminal device CPE sends a band change request to the VP setting device VAC, the VP setting device VAC
E responds to the request of E
Subscriber termination device SLT (Subscriber Loop
Terminal) is notified of the updated bandwidth. The cross connect switch XC is a switch for performing VP exchange connection.

Next, the procedure of the method according to the embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram showing a table configuration used in the embodiment of the present invention. FIG. 4 is a flowchart showing the procedure of the embodiment of the present invention. From the message waiting state (A1), the VP setting device VAC that has received the requested band value (Breq) as a VP band increase request from the user terminal device CPE subscribed to the band variable service is shown in FIG.
(A2) is searched from the VP configuration table shown in FIG. Comparing the size with the shared spare band (Bmin) managed by each transmission line, and when the requested band value is smaller than the surplus band value (Breq <Bm
in) is determined to be “OK”, and if the requested bandwidth value is larger than the surplus bandwidth value (Breq ≧ Bmin), it is determined to be “NO” (A3).
This determination process is repeated by the number of transmission paths through which the control target VP passes (hereinafter, this is referred to as the number of hops).
The request bandwidth value is subtracted from the surplus bandwidth value of the transmission path managed by the path table searched in (A4) (A4), and an availability notification (affirmation) is transmitted as a response to the user terminal device CPE that has issued the VP bandwidth increase request. If it is determined as “No” at least once during the determination process for several hops, the determination process is interrupted, and an availability notification (negation) is transmitted as a response to the user terminal device CPE. In this way, a response notification is made to the VP band increase request from the user terminal device CPE determined to be “permitted”.

Next, the conventional method and the method of the present invention will be compared using the processing time of the VP setting device VAC. Define the parameters as follows: The number (N) of transmission paths through which the user VP to be subjected to the band change passes, and all the VPs sharing the transmission path through which the user VP to be subjected to the band change passes
Number (LV), the average number of hops (LP) of the transmission path through which the user VP passes, and the reading and writing time (T) of one table in the VP setting device VAC. Table 1 shows the table access processing times of the conventional method and the method of the embodiment of the present invention.

[0022]

[Table 1] (Conventional example method) Availability judgment time T Path table bandwidth information update (1) Search for transmission path accommodating target VP N × T (2) Band read and subtraction processing of the transmission path N × T (3 ) Write the subtraction value of the above transmission path N × T VP table bandwidth information update processing (1) List processing of related VP LV × T (2) Search for transmission path accommodating related VP LV × LP × T (3) Related Calculation of minimum value of transmission path through which VP passes 0 (4) Writing of minimum value LV × T processing time Total ((LP + 2) LV + 3N + 1) T (method of the embodiment of the present invention) Availability judgment time (1) Accommodates target VP Retrieve transmission path to be performed T Update path table bandwidth information (1) Read bandwidth of above transmission path, subtraction processing N × T (2) Write subtraction value of above transmission path N × T processing time Total (2N + 1) T [Table 1] When the total processing time is shown based on, in the case of the conventional method, (( For P + 2) × LV + 3N + 1) × T ... (Equation 1) The present invention inventive method, the (2N + 1) × T ... (Equation 2). The processing time difference between the conventional method and the method of the present invention is ((LP + 2) × LV + N) × T (Equation 3). From Equation 3, it can be seen that the conventional method takes extra processing time than the method of the present invention, and the processing time difference increases in proportion to LV. FIG. 5 is a graph showing the processing time of the conventional method and the method of the embodiment of the present invention, using LV as a variable based on this. FIG. 5 is a graph in which the processing time is obtained by using as a variable the total number of VPs (LV) sharing the transmission path through which the user VP to be changed in bandwidth passes.
The horizontal axis indicates LV, and the vertical axis indicates processing time. While the conventional method increases in proportion to the LV, the method of the present invention increases the LV.
Is constant regardless of Accordingly, the processing time difference between the conventional method and the method of the present invention increases in proportion to LV. When the network scale increases and the number of user terminals increases, LP, LV, and N also increase in (Equation 3), so that the processing time difference also increases.

[0023]

As described above, according to the present invention,
It is possible to realize a VP setting method in which the VP setting time is independent of the network scale and the number of user terminal devices.
As a result, the VP setting time can be shortened even if the network scale and the number of user terminal devices increase.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a VP setting device.

FIG. 3 is a diagram showing a table configuration used in the embodiment of the present invention.

FIG. 4 is a flowchart showing the procedure of the embodiment of the present invention.

FIG. 5 is a graph in which a processing time is obtained by using the number of all VPs sharing a transmission path through which a user VP to be changed in bandwidth shares as a variable;

FIG. 6 is a diagram showing the configuration of various tables in a conventional example.

FIG. 7 is a flowchart showing a procedure of a conventional example.

[Explanation of symbols]

 1 VP Configuration Table 2 Path Table 3 Interface 4 VP Setting Unit CPE User Terminal Device VAC VP Setting Device SLT Subscriber Termination Device XC Cross Connect Switch

Continuation of front page (72) Inventor Hiromi Ueda 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-5-268240 (JP, A) JP-A-2-192246 JP-A-8-51432 (JP, A) JP-A-4-150438 (JP, A) JP-A-7-231322 (JP, A) JP-A-62-178048 (JP, A) Kaisho 63-104540 (JP, A)

Claims (3)

(57) [Claims] 1. A virtual path setting device disposed in a network for setting and managing a virtual path for a user terminal device and a subscriber terminal device that stores a user terminal device based on a request from a user terminal device that stores a user. Comprising means for receiving a request including a destination and a transmission bandwidth value from a user, and means for setting a virtual path through which a cell to be transmitted according to the request is transmitted, and wherein a real transmission through which the virtual path can pass is provided. A virtual path configuration table in which a path is recorded, and a path table in which a surplus bandwidth is recorded for each actual transmission path, wherein the virtual path configuration is selected from among virtual paths that can be set for a destination included in the request. Means for selecting one of them by referring to a table, obtaining a surplus bandwidth value of the transmission line from the path table, and including the surplus bandwidth value in the surplus bandwidth value and the request. Comparing the transmission band values
To determine whether there is a surplus.
Means for determining that setting is possible when there is a surplus performed by the number of transmission paths through which the virtual paths pass , and another means for selecting when the setting is impossible is performed by the selecting means. Means for securing the bandwidth of the requested virtual path and subtracting the bandwidth from the surplus bandwidth of the path table. 2. The virtual path setting device according to claim 1, wherein said means for selecting one selects a virtual path having a small number of actual transmission paths. 3. An ATM communication network comprising the virtual path setting device according to claim 1.