JPH1070544A - Communication equipment and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transmission quality without a data loss by detecting a virtual path of a transmission destination communication equipment and sending data to a communication equipment connected to a same path when the idle capacity is not sufficient for cell transmission so as to effectively utilize the transmission channel. SOLUTION: A capacity notice cell processing section 40 writes a used capacity of a set virtual path to a virtual path capacity notice cell and informs it to a communication equipment. The communication equipment writes it to a capacity management table 32 of its own equipment to update the contents. Then a virtual path 11 of the transmission destination communication equipment is detected by a routing table 31 and a virtual path capacity control section 50 discriminates whether or not the idle capacity is sufficient for cell transmission. When not sufficient, a capacity management table 32 is referenced and whether or not the capacity is to be increased is discriminated. When the increase is possible, the cells are sent to a communication equipment connecting to a same virtual path. Thus, the transmission channel is effectively utilized and transmission quality is improved without a data loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device, and more particularly to an asynchronous transfer mode (ATM) transmission network.
It has a mechanism to notify other communication devices of the used capacity and / or free space of the received virtual path of the own communication device to other communication devices, performs virtual path capacity management by the communication device, and uses the virtual path capacity management information of the own device to perform virtual path The present invention relates to a communication device and a system that enable efficient and economical use of resources in a network by changing the capacity of a network.

[0002]

2. Description of the Related Art ATM (Asynchronous Transfer Mode)
The technology transmits information in an information transmission unit called an ATM cell having a fixed length of 53 bytes. FIG.
Shows the configuration of the ATM cell. FIG. 9 shows a configuration diagram of the ATM cell header. A virtual path (Virtual Pat) is used as a logical path for transmitting ATM cells in an ATM transmission network.
h) has been proposed. FIG. 10 shows a conceptual diagram of the virtual path. The capacity of the virtual path can be defined by the number of cells transmitted per unit time. When setting a virtual path between communication devices in an ATM transmission network,
A fixed capacity virtual path (CBR-VP) is used. Usually, one virtual path is set between a plurality of communication devices.

[0003] ABR (Available Bit Rate) is a technology for changing the capacity of a virtual channel or virtual path depending on the use condition of a transmission path and the like.
Discussions are underway at T and ATM Forum.

[0004]

However, when a virtual path to a certain communication apparatus is set as a fixed capacity virtual path and only one path is set, it is necessary to prepare the maximum capacity that can be transmitted. Uneconomical,
If the maximum capacity is not prepared, information may not be transmitted.

[0005] Further, in the ABR technology, each terminal and each device in the network must have a function of handling ABR, and it is necessary to replace all terminals and network devices currently used with those corresponding to ABR. It is difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and notifies other communication apparatuses of a virtual path capacity, a virtual path free capacity, or both a virtual path capacity and a free capacity periodically or when a capacity change occurs. By performing the virtual path capacity management on the own device, if there is not enough free space on the virtual path, the own device determines whether or not the capacity of the virtual path can be increased. It is an object of the present invention to provide a communication device and a system capable of increasing the capacity of a virtual path based on a device database and efficiently using a transmission path.

[0007]

FIG. 1 shows the principle of the present invention. The present invention relates to an asynchronous transfer mode, in which a virtual channel is accommodated in a virtual path.
In the M cell processing unit, from the header information of the input cell,
The switch unit has a function of transmitting the ATM cell to a target outgoing path based on the routing table of the own device, and a virtual path capacity table for managing the used capacity of the virtual path and the free capacity, and capacity information of the virtual path. In the communication device having a function of notifying the communication device of the present invention and a function of changing the capacity of the virtual path, the virtual path capacity table shows the free space of the virtual path with respect to the virtual path to the communication device to which the input ATM cell is to be transferred. When there is sufficient capacity to transmit the ATM cell, the ATM cell is transferred to the virtual path. When there is not enough free capacity, the capacity management table is searched and the capacity of the virtual path is changed. It is determined whether the capacity of the virtual path can be increased, and if the capacity of the virtual path can be increased, the capacity of the virtual path is increased. AT received to Ri該 virtual path
M cells can be transmitted.

FIG. 2 is a diagram showing the operation of the present invention. The figure shows a case where there are four communication devices of the present invention,
A virtual path is set between communication devices via a cross-connect device. It is assumed that information on which transmission path each virtual path has passed is known in advance.

FIG. 3 shows an example of a virtual path capacity management table. FIG. 4 shows a configuration example of the capacity notification cell. Each communication device transmits the capacity information to the communication device connected to each virtual path by using the capacity notification cell for all the reception virtual paths of the own device. When each communication device receives the virtual path capacity notification cell transmitted from another communication device, each communication device updates the corresponding part of the capacity management table of its own device.

When an ATM cell arrives at the communication device # 1, a communication device to which the ATM cell is to be transmitted is searched from a routing table. The capacity status of the virtual path to the partner communication device is checked in the capacity management table of the own device, and if the free capacity of the virtual path is sufficient to transmit the arrived ATM cell, the ATM cell is transmitted.

If there is not enough free space in the virtual path, check the free space in all the transmission paths accommodating the virtual path from the capacity management table of the own device, and determine whether the capacity of the virtual path can be increased. Determine whether or not. If the capacity of the virtual path can be increased, the capacity of the virtual path is increased, and a virtual path capacity notification cell is sent to another communication device related to the increase in the capacity of the virtual path, and the capacity of the virtual path is increased. After notifying the increase,
The ATM cell is transmitted.

[0012]

FIG. 5 is a diagram of a first embodiment of the present invention, and shows a configuration of one of the communication devices of the present invention described with reference to FIGS. In FIG. 5, 10, 1
Are virtual paths on the subscriber side, 11, 11, ... are virtual paths on the network side, 20, 20, ... are virtual channels, 30 is a switch unit, 31 is a routing table, 32 is a capacity management table, and 40,. Are capacity notification cell processing units, and 50, 50, ... are virtual path capacity control units. In the routing table 31, a route to which an arriving ATM cell should be transmitted is set in advance. The virtual path capacity table 32 indicates the own device and the virtual path 11.
6 is a table that holds the capacity of a virtual path accommodated in another communication device connected by the communication device. The capacity notification cell processing unit 50, the virtual path capacity control unit 50, the routing table 31, and the capacity management table 32 can be realized by software and hardware such as a storage device in a computer system provided in a communication device, for example.

The capacity notification cell processing unit 4 is provided between the communication devices.
0, the used capacity of the set virtual path 11 (or the free capacity or both the used capacity and the free capacity)
Is written in the virtual path capacity notification cell (see FIG. 4), and the communication path connected to the virtual path 11 is notified of the virtual path capacity. The virtual path capacity notification cell is transmitted at a predetermined time interval. When the communication device receives the virtual path capacity notification cell, the communication device updates the corresponding item in the capacity management table 32 of the own device.

FIG. 6 is a diagram showing a configuration example of the capacity management table 32 held by each of the communication devices # 1 to # 4 in the communication system shown in FIG. Virtual path capacities are held in the columns of the transmission paths # 1 to # 5 through which the virtual paths # 1 to # 6 pass. In the column of the transmission path that does not pass, a description indicating that the transmission does not pass is held. The capacity management table 32 holds the transmission path capacity, calculates the difference between the sum of the capacities of all the virtual paths accommodated in the own transmission path and the own transmission path capacity, and holds the difference as transmission path free capacity data.

In the configuration shown in FIG. 5, the destination of the ATM cell is checked by the routing table 31 from the header of the ATM cell received by the communication device. When the virtual path 11 to the communication device to be transmitted is known, the virtual path
It is determined whether or not the free capacity of the virtual path is sufficient to transmit the ATM cell.
Send the TM cell to the virtual path.

If the virtual path free capacity for transmitting the ATM cell is not sufficient, it is determined whether or not the virtual path capacity can be increased by referring to the capacity management table 32 of the communication device. If the virtual path capacity can be increased,
The virtual path capacity notification cell is transmitted to a communication device connected to another related virtual path accommodated in the same transmission path as the virtual path. The communication device that has received the virtual path capacity notification cell reads the contents of the virtual path capacity notification cell, and changes the corresponding virtual path capacity in its own capacity management table. When the processing related to the change of the capacity of the virtual path is completed, the ATM cell is transmitted to the virtual path after the capacity is increased.

In the first embodiment, the virtual path capacity notification cell is transmitted at a predetermined time interval. However, as the second embodiment of the present invention, the same cell as that of the first embodiment is used. In the configuration, it is possible to transmit the virtual path capacity notification cell when the capacity change occurs. Other configurations of the second embodiment can be the same as those of the first embodiment.

According to a third embodiment of the present invention, a virtual path capacity notification cell is transmitted when a transmission request for a virtual path capacity notification cell comes in a configuration similar to that of the first embodiment. It is also possible. Otherwise, the configuration is the same as that of the first embodiment.

FIG. 7 is a diagram of a fourth embodiment of the present invention. This embodiment is different from the first embodiment in that a virtual path capacity monitoring unit 60 is newly provided and the virtual path 1
The free space of 0 is monitored, and when the free space of the virtual path is equal to or larger than a predetermined value, the capacity of the virtual path is reduced to a predetermined value, and the change in capacity is notified by the virtual path capacity notification cell. It is characterized by the following. Otherwise, the content is the same as that of the first embodiment.

As a fifth embodiment of the present invention, in the second embodiment, the free space of the virtual path is monitored in the same manner as in the fourth embodiment, and the free space of the virtual path is set to a predetermined value. In the case described above, the capacity of the virtual path may be reduced to a predetermined value, and the capacity change may be notified by the virtual path capacity notification cell. Otherwise, the content is the same as that of the second embodiment.

According to a sixth embodiment of the present invention, in the third embodiment, the free space of the virtual path is monitored in the same manner as described above, and when the free space of the virtual path is equal to or larger than a predetermined value. May reduce the capacity of the virtual path by a predetermined value, and notify the capacity change by a virtual path capacity notification cell. Otherwise, the content is the same as that of the third embodiment.

[0022]

As described above, according to the present invention,
In a state where a virtual path is set between a plurality of the present invention apparatuses, each communication apparatus transmits the virtual path capacity to the communication apparatus to which each virtual path is connected by using the virtual path capacity notification cell for all of the reception virtual paths of the own apparatus. When the capacity of the virtual path for transmitting the arriving ATM cell to the target device is insufficient, the capacity of the virtual path may be increased. It is determined whether or not transmission is possible, and if the capacity can be increased, the capacity of the virtual path is increased, so that the transmission path can be used effectively, and furthermore, data loss and the like can be prevented. Quality improvement can be expected.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a diagram illustrating the operation of the present invention.

FIG. 3 is a diagram illustrating an example of a capacity notification cell.

FIG. 4 is a diagram illustrating a configuration example of a capacity management table.

FIG. 5 is a diagram of the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration example of a capacity management table according to the first embodiment of this invention.

FIG. 7 is a diagram of a fourth embodiment of the present invention.

FIG. 8 is a diagram of a configuration of an ATM cell.

FIG. 9 is a diagram showing a configuration of an ATM cell header.

FIG. 10 is a conceptual diagram of a virtual path.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Virtual path 11 Virtual path 20 Virtual channel 30 Switch part 31 Routing table 32 Capacity management table 40 Capacity notification cell part 50 Virtual path capacity control part 60 Virtual path capacity monitoring part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideyuki Tsuboi 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Hiroyuki Fujiwara 3- 192-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo No. Japan Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. In an asynchronous transfer mode (ATM), a plurality of communication devices are connected by a virtual path, and A
When transmitting and receiving TM cells, there are a plurality of devices having an ATM cell processing unit, a switch unit, a routing table, a capacity management function of each virtual path, a virtual path capacity change function, and a virtual path capacity notification function. In this case, when the path of the virtual path to be transmitted from one device to a certain device is set in advance, the used capacity or free space of the receiving virtual path of the own communication device or both used and free space are connected by the virtual path Has a function of managing the virtual path free space of the other communication device by notifying the other communication device that has been entered, and transmitting the input ATM cell to the other communication device,
It checks the free space of the virtual path set to the destination communication device of the ATM cell, and if there is enough free space to send the ATM cell, sends the ATM cell to the virtual path. If there is not enough free space in the virtual path capacity management function, the own device determines whether the capacity of the virtual path can be increased,
If the capacity can be changed, the communication apparatus changes the capacity of the virtual path and transmits the ATM cell. 2. A communication system comprising a plurality of communication devices according to claim 1, wherein said plurality of communication devices are connected by a virtual path to transmit and receive ATM cells between said devices.