JP2001086123A - Mini-cell multiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a transmission delay of a mini-cell with high delay priority. SOLUTION: An ATM cell assembly means 4 reads mini-cells from a storage means 3 by priority in the order of higher priority, assembles mini-cells into ATM cells and provides an output. An ATM cell assembly control means 6 inhibits succeeding assembling of the ATM cells until a designated time elapses after the output of the ATM cells when the storage means 3 by priority stores only delay non priority mini-cells only. After a lapse of a designated time or when the storage means 3 by priority stores delay priority mini-cells, assembling of succeeding ATM cells is permitted. Thus, even when delayed priority mini- cells arrive just after many delay non priority mini-cells reach in a burst way, accumulation of delayed cells can be prevented when traffic shaping is applied to the ATM cells.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network for transmitting low-speed data, such as voice, whose delay quality is strict, with a low delay using a mini-cell (according to ITU-T I.363.2) shorter than an ATM cell. The present invention relates to a mini-cell multiplexer for assembling into cells to realize interconnection with an ATM network.

[0002]

2. Description of the Related Art Conventionally, minicell multiplexing apparatuses have been
The one using the method shown in UT I.363.2 is known. FIG. 4 is a diagram showing a conventional minicell multiplexer. In FIG. 4, 101 is an incoming line, 102 is a cell length L
A minicell receiving unit that receives an octet (an integer that satisfies L <48) minicell, a priority storing unit 103 stores minicells by priority, a minicell assembling unit 104 assembling minicells into ATM cells, and an output line 105 is there.

The operation of the conventional mini-cell multiplexing apparatus configured as described above will be described. Minicell receiver 10
2 receives the mini-cell from the incoming line 101 and stores the received mini-cell by priority in the storing unit 103 according to priority.
The cell assembling section 104 reads out the specified number of minicells from the minicell storage section 103 in the order of higher priority, and
Assemble into M cells and output to outgoing line 105. Departure line 105
If the number of minicells stored in the priority-based storage unit 103 is less than the number required for ATM cell assembly even after a certain time has elapsed after the output of the ATM cells, the ATM cell assembly unit 104 After reading all the minicells from 103 and adding invalid data to make the number necessary for assembling the ATM cells, assembling them into ATM cells and then outputting 105
Output to

As described above, even in the conventional minicell multiplexing apparatus, all minicells received from the incoming line 101 are transmitted by the AT.
It can be assembled into M cells and output to outgoing lines.

[0005]

However, in the conventional minicell multiplexer, as shown in the operation explanatory diagram (timing chart) of FIG. 5, minicells (a1 to a6) having a low delay priority are arranged in a burst. Arrives, AT
Immediately after assembling and outputting the M cells (A1 to A3), when the minicells (b1, b2) having a high delay priority are assembled into the ATM cell (B1) and output, the minicells (a1 to a6) having a low delay priority are output. ATM cells (A1 to A
3) Traffic shaping (input ATM
(The output interval of the cell is adjusted to the specified time interval T), the delay is accumulated, and the accumulated delay is added to the subsequent ATM cells including the mini-cell having a high delay priority. There is a problem that the transmission delay of a high minicell increases.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a mini-cell multiplexer capable of reducing the transmission delay of a mini-cell having a high delay priority.

[0007]

SUMMARY OF THE INVENTION The present invention provides priority-based storage means for storing minicells by delay priority, ATM cell assembly means for reading minicells in descending order of delay priority and assembling them into ATM cells, AT controlling assembly of ATM cells according to minicell storage state of separate storage means
M cell assembling control means, wherein the storing means for each priority stores mini cells received from the incoming line for each priority, and the ATM cell assembling means has a higher priority for mini cells than the storing means for each priority. The ATM cell assembling control means, when the priority-specific storage means stores only the delay non-priority mini cells, outputs the next ATM cell until the designated time elapses after the output of the ATM cell. The cell assembling is prohibited, and the next ATM cell is allowed to be assembled after a specified time has elapsed or when the priority-specific storage unit stores the delay priority minicell. According to such a configuration, even when the delay-priority minicell arrives immediately after a large amount of the delay-nonpriority minicell arrives in a burst, the output time interval of the ATM cell assembled only with the delay-nonpriority minicell is set to the designated time ( By setting the time interval equal to or longer than the time interval corresponding to the shaping rate, it is possible to prevent accumulation of delay due to traffic shaping of ATM cells assembled only with delay non-priority mini cells.

The present invention further comprises shaping means for performing traffic shaping on the ATM cell, wherein the shaping means adjusts the ATM cell at a designated time interval and outputs the ATM cell to an outgoing line. The assembling control means prohibits the assembly of the ATM cell before the designated time interval elapses after outputting the ATM cell to the outgoing line, and permits the assembly of the next ATM cell after the elapse of the designated time interval T. According to such a configuration, even when the delay priority minicell arrives immediately after the delay nonpriority minicell arrives in a burst, the ATM including the delay priority minicell can be used.
The traffic shaping can be performed on the ATM cell and output without increasing the cell delay.

[0009]

(Embodiment 1) FIG. 1 is a block diagram showing Embodiment 1 of a minicell multiplexer according to the present invention. In FIG. 1, 1 is an incoming line, 2 is a minicell receiving unit that receives minicells having a cell length of L octets (an integer satisfying L <48), 3 is a storing unit for storing minicells by priority, and 4 is a minicell. A mini-cell assembling section for assembling into ATM cells, 5 is an outgoing line, and 6 is an ATM cell assembling control section for controlling assembling of ATM cells.

The operation of the minicell multiplexing apparatus according to the present invention having the above configuration will be described. Minicell receiver 2
Receives mini-cells with different delay priorities from incoming line 1,
The minicells received by the priority-based storage unit 3 are stored by delay priority, and the ATM cell assembling unit 4 reads out a specified number of minicells from the priority-based storage unit 3 in the order of priority and assembles them into ATM cells. And output to outgoing line 5.

The ATM cell assembling control unit 6 determines that if the storage cells in the priority storage unit 3 are only delay non-priority mini cells,
Until the designated time elapses after the output of the ATM cell to the outgoing line 5, the ATM cell assembling unit 4 is prohibited from assembling the next ATM cell. When the ATM cell assembly control unit 6 stores the delay-priority mini-cell after the specified time elapses after the output of the ATM cell to the outgoing line 5 or even before the specified time elapses, the ATM cell assembling unit 3 Part 4
Is permitted to assemble the next ATM cell.

As described above, according to the first embodiment, as shown in the operation explanatory diagram (timing chart) of FIG.
Even if the delay priority mini-cells (b1, b2) arrive immediately after the delay non-priority mini-cells (a1 to a6) arrive in bursts, the ATM cell assembling control unit 6 assembles only the delay non-priority mini-cells. (A1 to A3)
Is controlled so as to be equal to or longer than a designated time T (a time interval corresponding to the shaping speed) to prevent the cumulative delay from being added to the ATM cell (B1) including the delay-priority minicell. The delay of the ATM cell assembled using the received delay priority minicell can be reduced.

(Embodiment 2) FIG. 3 is a block diagram showing Embodiment 2 of a minicell multiplexer according to the present invention. In FIG. 3, 11 is an incoming line, 12 is a minicell receiving unit that receives minicells having a cell length of L octets (an integer that satisfies L <48), 13 is a priority storing unit that stores minicells by priority, and 14 is a minicell storing unit. A mini-cell assembling section for assembling into ATM cells, 15 is an outgoing line, 16 is an ATM cell assembling control section for controlling ATM cell assembly, and 17 is a shaping section for performing traffic shaping on ATM cells.

The operation of the minicell multiplexing apparatus according to the present invention having the above-described configuration will be described. Minicell receiver 1
2 receives minicells having different delay priorities from the incoming line 11, stores the minicells received by the priority-specific storage unit 13 for each delay priority, and the ATM cell assembling unit 14 stores the specified number of minicells with the higher priority. The ATM cells are sequentially read from the priority storage unit 13, assembled into ATM cells and output, and the shaping unit 17 adjusts the ATM cells to a specified time interval T and outputs the adjusted ATM cells to the outgoing line 15. ATM cell assembly control unit 1
6 outputs the ATM cell to the outgoing line 15, prohibits the assembly of the ATM cell before the lapse of the designated time interval T, and permits the assembly of the next ATM cell after the lapse of the designated time interval T. As described above, according to the second embodiment, even when a delay-priority mini-cell arrives immediately after a delay non-priority mini-cell arrives in a burst, the delay of the ATM cell including the delay-priority mini-cell is increased without increasing the delay. On the other hand, traffic shaping can be performed and output.

[0015]

According to the present invention, the priority storing unit stores the minicells received from the incoming line by priority, and the ATM cell assembling unit reads the minicells from the priority storing unit in descending order of priority. And assemble it into an ATM cell and output it.
When the ATM cell assembly control unit stores only the delay non-priority minicell in the priority-specific storage unit, the ATM cell assembly control unit prohibits the next ATM cell assembly until a specified time has elapsed after the output of the ATM cell, and after the specified time has elapsed, or When the priority-based storage unit stores the delay-priority minicell, the next ATM cell is allowed to be assembled. Therefore, even if the delay-priority minicell arrives immediately after the delay non-priority minicell arrives in a burst, the delay can be reduced. ATM assembled only with non-priority minicells
By setting the cell output time interval to be equal to or longer than the specified time, it is possible to prevent the cumulative delay from being added to subsequent cells during traffic shaping, and to reduce the delay of ATM cells including delay priority mini cells.

[Brief description of the drawings]

FIG. 1 is a block diagram of a minicell multiplexing apparatus according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram of an operation of the minicell multiplexing apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a minicell multiplexing apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a block diagram of a conventional minicell multiplexer.

FIG. 5 is a diagram illustrating the operation of a conventional minicell multiplexer.

[Description of Signs] 1,11 incoming line 2,12 minicell receiving unit 3,13 priority storing unit 4,14 ATM cell assembling unit 5,15 outgoing line 6,16 ATM cell assembling control unit 17 shaping unit

Claims (2)

[Claims] 1. Priority storing means for storing mini cells by delay priority, ATM cell assembling means for reading mini cells in descending order of delay priority and assembling them into ATM cells;
ATM cell assembly control means for controlling the assembly of ATM cells in accordance with the minicell storage state of the priority-based storage means, wherein the priority-based storage means stores the minicell received from the incoming line by priority, The ATM cell assembling means reads out the minicells from the priority-based storage means in ascending order of priority, assembles them into ATM cells, and outputs the ATM cells. When the ATM cell is output, the assembly of the next ATM cell is prohibited until the designated time has elapsed since the output of the ATM cell. After the designated time has elapsed, or when the priority-specific storage unit stores the delay priority minicell, the next ATM cell is stored. A mini-cell multiplexing device which permits assembly. 2. A shaping means for performing traffic shaping on an ATM cell according to claim 1, wherein said shaping means adjusts the ATM cell at a designated time interval and outputs the adjusted ATM cell to an outgoing line. A mini-cell multiplexing apparatus wherein the assembly control means inhibits assembly of an ATM cell before a designated time interval elapses after outputting an ATM cell to an outgoing line, and permits assembly of a next ATM cell after a designated time interval elapses. .