JPH03187646A - Cell compound/decomposing system - Google Patents

Abstract

PURPOSE:To cope with versatile ATM cell formats by setting optionally information required for composition and decomposition of an ATM cell. CONSTITUTION:An ATM cell 60 includes a cell header 62 and a user information part 64 and required information such as virtual channel identification(VCI) information 66 and composition information 68 is stored in a cell header 62. A frame composition/decomposition device has a switch designating the length of the cell header 62, the length of a cell 60, the position of the VCI 66 and the position of the composition information 68. When a layer 2-frame 70 is decomposed into the cell 60, the frame 70 is decomposed into the cell 60 of a cell length accordingly depending on the setting state of the switch, and the VCI 66 and the composition information 68 are stored to respective positions in response to the header 62 with a relevant header length. Thus, the ATM cell 60 is composed/decomposed corresponding to an optional format in plural kids of ATM cell formats.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ATM communication device, and more particularly to an adaptation layer cell assembly and disassembly method for disassembling frames into cells and assembling cells into frames.

(Prior Art) Data transmitted between an ATM switch and its terminals is a layer 2 frame. When an ATM switch receives a layer 2 frame, it decomposes it into cells, which are transmission units of the ATM switching network, and sends the layer 2 frame to each cell.
A cell is formed by putting disassembly information into the division/assembly information field included in the M header. Furthermore, when assembling cells into layer 2 frames, the cells are assembled into frames according to division/assembly information in the ATM header of each cell.

Conventionally, as a method for assembling and disassembling cells in ATM communication equipment, for example, Shigeo Morita et al., "Study of integrated communication system in high-speed, high-bandwidth" IEICE Technical Report 5E87-104, pp. 55-60, Electronic Information There is a method disclosed in a publication published by the Communication Society of Japan (1987). In this method, layer 2 frames are decomposed into ATM cells and ATM cells are assembled into layer 2 frames according to a predetermined ATM self-format.

(Problem to be Solved by the Invention) In other words, in this conventional method, unless the ATM self-format is uniquely determined, it is not possible to disassemble layer 2 frames into ATM cells or assemble ATM cells into layer 2 frames. There was a problem. The reason for this is that when decomposing a layer 2 frame into ATM cells, the frame is divided into predetermined lengths and decomposed into cells, so if the cell length is not given, it cannot be decomposed into cells. . In addition, a cell header is added to the disassembled cell, and within this header is a verch cell channel identification fV.
It is configured to store necessary information such as cIl and assembly information. Therefore, unless the cell header length, the position of the VCI, and the position of the assembly information are determined, it is impossible to disassemble into cells.

Assembly of ATM cells into layer 2 frames is performed by removing cell headers. Therefore, if the cell header length was different from a predetermined value, the frame could not be assembled correctly. Furthermore, assembling into a frame is performed by adding a predetermined number of bytes of user data after the cell header. For this reason.

If the cell length was not uniquely determined, the frame could not be assembled.

Furthermore, frame assembly is performed in vCI units. Therefore, if the position of the VCI differs from a predetermined value, assembly cannot be performed.Furthermore, frame assembly is performed based on assembly information. Therefore, if the position of the assembly information is different from a predetermined value, the frame cannot be assembled.

Because of these format constraints, for example, if an ATM self-automated system is set up to be optimal for the field of use, each ATM system has the disadvantage that its own cell assembly/disassembly equipment is required.

The present invention solves the drawbacks of the prior art and enables various A
The purpose is to provide a cell assembly/disassembly method that is compatible with TM self-automation.

(Means for Solving the Problems) The present invention solves the above problems by configuring information necessary for disassembling and assembling ATM cells to be arbitrarily settable.

According to the present invention, the cell assembly/disassembly method for assembling ATM cells into layer 2 frames and disassembling layer 2 frames into ATM cells selectively sets one of the self-format of multiple fI types of ATM cells, According to this set self-format, ATM cells are assembled into layer 2 frames, or layer 2 frames are disassembled into ATM cells.

According to the present invention, the frame assembling device that receives ATM cells, assembles the ATM cells into layer 2 frames, and outputs the frames includes a selection means for selectively setting one of a plurality of types of self-formatting of the ATM cells; assembling means for receiving the cells and assembling the ATM cells into layer 2 frames according to the set seven file formats.

Furthermore, according to the present invention, a frame disassembly device that receives a layer 2 frame and disassembles the layer 2 frame into ATM cells includes a selection means for selectively setting one of a plurality of types of self-formatting of the ATM cell; It receives the frame and decomposes the layer 2 frame into ATM cells according to the set self-format.

According to the present invention, the frame assembly and disassembly device for assembling AT&I cells into layer 2 frames and disassembling layer 2 frames into ATM cells is configured to selectively set one of a plurality of types of self-formatting of ATM cells. means for receiving the ATM cells and assembling the ATM cells into layer 2 frames according to the set self-format; assembling means for receiving the layer 2 frames and disassembling the layer 2 frames into ATM cells according to the set self-format.

- (Function) In the cell assembly/disassembly method according to the present invention, one of a plurality of types of self-automation of an ATM cell is selectively set. According to this set self-automation, ATM
Assemble cells into layer 2 frames, and decompose layer 2 frames into ATM cells.

The frame disassembly device according to the present invention disassembles a frame according to the information set in the selection means, includes the user information in a cell of a set cell length, adds a cell header, and adds, for example, assembly information and VCI to the header. Form an ATM cell. Further, the frame assembling device extracts, for example, VCI i3 and assembly information from the header of the ATt4 cell according to the information set in the selection means, and assembles the user information part of the cell into a layer 2 frame according to the assembly information for each VCl, and outputs the frame. .

(Example) Next, an example of the cell assembly/disassembly method according to the present invention will be described in detail with reference to the accompanying drawings. First, an outline of the assembly and disassembly of the frame in this embodiment will be explained with reference to FIG. The four-cell M cell 60 includes a cell ladder 62 and a user information section 64. The cell ladder 62 includes a vertical cell channel identification (VCII 66) and assembly information 68.
Necessary information such as the following information is stored. As will be described later, the frame assembly/disassembly apparatus of this embodiment includes a switch for specifying the length value of the ladder 62, the length value of the cell 60, the position of the VCl 66, and the position of the assembly information 68 to the cell. has.

When decomposing a layer 2 frame 70 into cells 60, as shown by arrow A, the frame 70 is decomposed into cells 60 with a corresponding cell length according to the setting status of those switches, and the frame 70 is divided into cells 60 with a corresponding header length. VCI 66 and assembly information 68 at their respective positions on the ladder 62.
Store. When assembling the cell 60 into the layer 2 frame 70, as shown by arrow B, the assembly information 68 and VCI 66 are extracted from the corresponding position of the cell 60 according to the setting state of the switch, and according to the corresponding cell length and cell header length. Extract information and frame 70
Assemble to. In this way, it is possible to assemble and disassemble ATM cells corresponding to any one of a plurality of types of ATM self-automated cells.

The frame assembly/disassembly apparatus of this embodiment includes a frame disassembly section 50 and a frame assembly section 80. FIG. 1 is a functional block diagram of a frame decomposition unit 50 in an embodiment of the present invention. The layer 2 frame 70 is input to the frame decomposition circuit 17 from the input terminal 1. The frame decomposition circuit 17 converts the layer 2 frame 70 into the ATM cell 6
This is a circuit that decomposes into 0.

The frame decomposition unit 50 has switches 2 to 5, which are used for selective setting to select a more desired format from among a plurality of available ATM self-format formats under the control of a higher-level device (not shown). It is a circuit. Parameters that can be specified as self-format are the length of the cell 60, the position 2 of the VCI 66, the position of the assembly information 68, and the length of the cell header 62 in this embodiment.

The switch 2 is a switch that specifies the cell length, and its output 90 is connected to the frame decomposition circuit 17. The cell header register 18 is a temporary storage circuit that stores the data of the cell header 62 sent from the host device, and its output 92 is connected to the cell header creation section 19. Switch 3 is a setting circuit that sets the position of VCI G6, and switch 4 is a switch that sets the position of assembly information 68.

The output 94 of switch 3 and the output 96 of switch 4 are
It is connected to the cell header creation section 19. Switch 5 is a switch that sets the cell header length, and its output 98
is connected to the frame decomposition circuit 17 and the ATM cell creation section 20.

The frame decomposition circuit 17 converts the layer 2 frame 70 into AT
It disassembles into M cells 60, outputs its user information part 64 to ATM cell creation part 20, and assembles information 68 and VCI 6.
6 is output to the cell header section 19. In FIG. 1, the reference numerals of the signal lines are indicated by the same reference numerals as the information transferred by the signal lines (FIG. 3). The cell header creation unit 19 is a functional unit that creates a ladder 62 for a cell and outputs it to the ATM cell creation unit 20. The ATM cell creation section 20 has a function of adding a cell header 60 to user information 64 to form an ATM cell 60, and outputting this to its output terminal 6.

Next, the operation of the frame decomposition unit 50 will be explained.

When the layer 2 frame 70 arrives at the input terminal l, the frame decomposition circuit 17 calculates the length of the user information section 64 according to the cell length 90 set in the switch 2 and the cell header length 98 set in the switch 5. The frame 70 is then divided by this length and outputted as the user information section 64 to the cell creation section 20. At the same time, the division conditions for dividing the frame 70 are output to the cell header creation unit 19 as assembly information 68, and
The VCI 66 extracted from 0 is output to the cell header creation section 19.

The cell header creation unit 19 adds a VCI 6 to the cell header data 92 input from the cell register 18 to a position corresponding to the VCI position 94 set in the switch 3.
6 and the assembly information 68 is stored in a position corresponding to the assembly information position 96 set in the switch 4 to create the cell header 62. The created cell ladder 62 is output to the cell creation section.

The ATM cell creation section 20 creates an ATM cell 60 by combining the user information section 64 from the frame decomposition circuit 17 and the cell/ladder 62 from the cell header creation section 19, and outputs this to the terminal 6. At this time, the length of the header 62 depends on the header length specified by the switch 5.

FIG. 2 is a functional block diagram of the frame assembly section 80 in the same embodiment. The frame assembly unit 80 has a delay register 2
6, which is an ATM input from the input terminal 21.
The cell 60 is delayed and converted into parallel data, and its output 1
This is a register circuit that outputs signals from 04 to 105 to selection circuits 37 and 39. The frame assembly section 80 also includes switches 22-25, which are selectively used to select the format of the input cell 60 from among a plurality of available self-format formats under the control of a higher-level device (not shown). This is a setting circuit. The switch 22 is a setting circuit that sets the position of the VCI 66, and the switch 23 is a switch that sets the position of the assembly information 68. switch 2
The output 100 of switch 2 and the output 102 of switch 23 are connected to selection circuit 38. Further, the switch 24 is a switch for setting the cell header length, and its output 10
8 is connected to a selection circuit 39. Also, switch 2
5 is a switch that specifies the cell length, and its output 110
is connected to the frame assembly circuit 42.

The selection circuit 37 has the function of extracting the VCI 66 and assembly information 68 from the cell 60 and outputting them to the MCI register 40 and assembly information register 41, respectively. The selection circuit 38 is a circuit that selects data indicating the position of the VCI 66 and data indicating the position of the assembly information 68, and outputs the selected data to the selection circuit 37. Further, the selection circuit 39
This circuit extracts the user information part 64 from the cell 60 and outputs it to the frame assembly circuit 42. VCI register 4
0 holds the VCI 66, and the assembly information register 41 is a temporary storage circuit that stores assembly information.The outputs 112 and 114 of both are connected to the frame assembly circuit 42. The frame assembly circuit 42 includes a VCI register 40, an assembly information register 41 . This circuit assembles the ATM frame 70 according to information given from the selection circuit 39 and the switch 25, and the assembled frame 70 is output to its output terminal 13.

Next, the operation of the frame assembly section 60 will be explained. First, when an ATM cell 60 is inputted from the input terminal 21, it is delayed by the delay register 26 and outputted to the output lines 104-105 as parallel data in units of bytes. Position data 100 of VCI 66 set in switch 22
．． and assembly information 68 set in switch 23
The position data 102 of is selected by the selection circuit 38 and transferred to the selection circuit 37 in series. The selection circuit 37 selects VCI G from the delay data output from the delay register 36.
615 and assembly information 68 as output 1 from the selection circuit 38
16 and supplies them to the VCI register 40 and assembly information register 41, respectively. The VCI register 40 receives and holds VCI B6, and the assembly information register 41 receives and holds assembly information.

The selection circuit 39 removes the cell header 62 from the cell data received from the delay register 26 based on the cell header length 108 also supplied to the switch 24, extracts only the user information part 64, and outputs it to the frame assembly circuit 42. The frame assembly circuit 42 extracts user information up to the cell length 110 set by the switch 25 for each value held in the VCI register 40 according to the assembly information in the assembly information register 41, and thereby assembles the ATM frame 70. is its output terminal 1
3 is output.

(Effects of the Invention) As described above, according to the present invention, ATM cells can be assembled into layer 2 frames according to any one of a plurality of types of self-organized frames, and layer 2 frames can be assembled into AT
It can be decomposed into M cells.

Therefore, an ATM switch is provided that is capable of exchanging cells according to various types of formats. Furthermore, it is possible to select the most suitable ATM self-automation for various systems. For example, a cell length suitable for conditions such as system traffic and a cell header structure suitable for system characteristics can be selected. Furthermore, for example, if there is a change in self-automation that involves a change in information used in a device external to the frame assembly/disassembly device, it can be effectively dealt with.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a functional block diagram showing a configuration example of a frame disassembly section in an embodiment of the cell assembly/disassembly method according to the present invention, and FIG. FIG. 3 is an explanatory diagram illustrating the cell assembly and disassembly method in the same embodiment. 2.22. Main part, Frame decomposition circuit 18, Cell header register 19, 20, 26, 37-39° 40, 41, . 42, , 50, , 60, , 62, , 64, , 66, , 68, , 70, , 80, Cell to ivy creation section ATII Cell creation section creation - register selection circuit VCI Register assembly information Register frame assembly circuit Frame disassembly section ATM cell To cell User information section VCI Assembly information Layer 2 frame Frame assembly section

Claims (1)

[Claims] 1. In a cell assembly/disassembly method in which ATM cells are assembled into layer 2 frames and layer 2 frames are disassembled into ATM cells, the method selects one of a plurality of cell formats of ATM cells. according to the configured cell format, assemble the ATM cells into layer 2 frames, or assemble the layer 2 frames into ATM
A cell assembly/disassembly method characterized by disassembling into cells. 2. A frame assembling device that receives ATM cells, assembles the ATM cells into layer 2 frames, and outputs them,
The device includes: a selection means for selectively setting one of a plurality of cell formats for ATM cells; and an assembling means for receiving an ATM cell and assembling the ATM cell into a layer 2 frame according to the set cell format. A frame assembly device comprising: 3. Receive layer 2 frame and send the layer 2 frame to A
A frame disassembly device for disassembling into TM cells, the device includes a selection means for selectively setting one of a plurality of types of cell formats of an ATM cell; A frame disassembly device that disassembles a frame into ATM cells according to a cell format. 4. A frame assembly and disassembly device for assembling ATM cells into layer 2 frames and disassembling layer 2 frames into ATM cells, the device comprising: a selection means for selectively setting one of a plurality of cell formats of ATM cells; and assembling means for receiving ATM cells and assembling the ATM cells into layer 2 frames according to the set cell format; and receiving layer 2 frames and disassembling the layer 2 frames into ATM cells according to the set cell format. A frame assembly and disassembly device characterized by: