JP2002044119A - Transmission unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission unit without any classification that simplifies the management of a network and does not destroy an asynchronous frame on the occurrence of a fault in a transmission line. SOLUTION: The transmission unit that executes exchange processing between an asynchronous frame and a synchronous frame, is provided with a division means that divides the asynchronous frame into cells to the cell header of which a transmission destination unit address is added, a frame extract means that receives the synchronous frame to extract a cell inserted to a prescribed band, a cell analysis means that discriminates whether or not the extracted cell is addressed to its own transmission unit on the basis of the transmission destination unit address of the cell header of the extracted cell to decide relay/ reception/abort of the cell, a frame insertion means that inserts the cells divided by the division means and relayed cells to a prescribed band of the synchronous frame and transmits the resulting synchronous frame, and an assembly means that assembles the cells addressed to its own transmission unit into asynchronous frames and transmits the asynchronous frames.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission unit for performing exchange processing between an asynchronous frame and a synchronous frame. In particular, synchronous transfer mode (Synchro mode) for transmitting data in a network by time division multiplexing using time slots
The present invention relates to accommodating an asynchronous frame such as Ethernet (registered trademark) in a transmission device adopting the nous Transfer Mode (STM) method.

[0002]

2. Description of the Related Art Generally, asynchronous data frames such as Ethernet are accommodated in a LAN and communication is performed between terminals. As a method of expanding a communication area in a corporate network or the like, an Ethernet frame is used. ST
There is a method of transmitting data in an M frame.

FIG. 23 is a diagram showing a network configuration accommodating a conventional Ethernet. As shown in FIG. 23, the conventional network includes a plurality of terminals 8 # ij (i = 1 to 3, j = 1, 2) connected to the Ethernet and a plurality of child units 2 # i (i = 1 to 3). ), Relay units 4 # A, 4 #
B, parent unit 6, system 0 STM transmission line 3 # 0 and system 1 S
It is composed of a TM transmission path 3 # 1. Each child unit 2 # i
(I = 1 to 3) accommodate a plurality of terminals 8 # ij (j = 1, 2) that transmit and receive Ethernet frames. Each child unit 2 # i is assigned a band of an STM frame in advance.

FIG. 24 is a configuration diagram of a conventional STM frame. As shown in FIG. 24, the STM frame includes an overhead (SOH) and a payload. In the payload, a band (path #i) indicated by a head position and a transmission rate (the number of time slots) is assigned to each child unit 2 # i (i = 1 to 3) in advance. For example, the band indicated by the path # 1 is assigned to the child unit 2 # 1, the band indicated by the path # 2 is assigned to the child unit 2 # 2, and the child unit 2
The band indicated by path # 3 is allocated to # 3.

FIG. 25 is a configuration diagram of a conventional child unit 2 # i. The physical interface unit 10 # i is connected to the terminal 8 # i
j receives the Ethernet frame transmitted from
Output to the system and system 1 transmission line insertion units 12 # 0 and 12 # 1.
The transmission line insertion unit 12 # ij (j = 0, 1) receives the Ethernet frame from the physical interface unit 10 # i, and the Ethernet frame is assigned to the STM frame, as indicated by a path #i in FIG. It is inserted into the band and output to TSW13 # ij (j = 0, 1). TS
W13 # ij (j = 0, 1) is the STM transmission path 3 # j
(J = 0, 1) and the transmission line insertion unit 12 # ij (j = 0,
The STM frame is received from 1), multiplexed into an STM frame, and transmitted to the STM transmission line 3 # j (j = 0, 1).

[0006] Thereby, for example, the terminal 8 # 3j (j =
The Ethernet frame transmitted from (1, 2) is inserted into the time slot corresponding to the path # 3 of the STM frame by the child unit 2 # 3, and the STM transmission path 3 # j (j =
0,1). The STM frame transmitted from the child unit 2 # 3 is inserted into the path # 3 of the STM frame by the child unit 2 # 2. Also, the terminals 8 # 21, 8
The Ethernet frame transmitted from # 22 is inserted into the path # 2 of the STM frame by the child unit 2 # 2. Similarly, Ethernet frames transmitted from terminals 8 # 11 and 8 # 12 are inserted into path # 1 of the STM frame. Thus, terminal 8 # ij (i = 1 to 3,
The Ethernet frame transmitted from j = 1, 2) is
It is inserted into the path i (i = 1 to 3) of the STM frame.
The relay unit 4 # A is connected to the STM transmission line 3 # j (j = 0,
1), the STM frame is received, and the STM frame is relayed to the STM transmission line 3 # j (j = 0, 1).

FIG. 26 is a configuration diagram of a conventional parent unit 6. TSW20 # j (j = 0, 1) is an STM transmission line 3 #
j (j = 0, 1), and outputs the STM frame to the transmission path extraction unit 24 # j (j = 0, 1) connected to the output terminal corresponding to the path # 1, # 2, # 3. I do. The transmission path extraction unit 24 # j (j = 0, 1) transmits each corresponding path #i (i
= 1 to 3), and outputs the data to the system selection unit 26. The system selection unit 26
The Ethernet frame switch unit selects the time slot data of each path #i (i = 1 to 3) output from the T-system transmission line extraction unit 24 # 0 or 1-system transmission line extraction unit 24 # 1 of the T system, and 20 to the corresponding terminal Pi (i = 1 to 3). The Ethernet frame switch unit 20 assembles the time slot data input from each of the input terminals Pi (i = 1 to 3) into an Ethernet frame. Then, based on the MAC DA address in the header of the Ethernet frame, the output terminal Pi corresponding to the child unit 2 # i to be the transmission destination
(I = 1 to 3). The transmission line insertion unit 22 # j (j
= 0, 1) inserts data output from each output terminal Pi (i = 1 to 3) of the Ethernet frame switch unit 20 into the corresponding STM frame, and sets the TSW 20 # j (j
= 0, 1). TSW20 # j (j = 0, 1)
Multiplexes the STM frame input from the transmission line insertion unit 22 # j (j = 0, 1), and
(J = 0, 1).

[0008] The relay unit 4 # C is connected to the STM transmission line 3 # j.
(J = 0, 1) to receive an STM frame
The signal is transmitted to the transmission path 3 # j (j = 01,). Each child unit 2 # i (i = 1 to 3) is connected to an STM transmission line 3 # j (j = 0,
From 1), the corresponding path #i of the STM frame (i = 1 to
The time slot data inserted in 3) is assembled into an Ethernet frame, and the terminal 8 # ij (j = 1 to 8)
Send to 2). The terminal 8 # ij (j = 1 to 2) sets the MAC DA address of the Ethernet frame to its own MA.
If the address matches the C address, an Ethernet frame is received. Thereby, terminal 8 # ij and terminal 8 # kl (i （
Communication can be performed between i) using an Ethernet frame.

[0009]

However, a conventional network accommodating Ethernet has the following problems.

(1) The STM network is a completely synchronous network,
It is necessary for each child unit to previously determine a head position and a width for inserting and extracting data with respect to a time slot (band) determined at a fixed cycle. That is, it is necessary to construct a fixed path. Therefore, the band used by one unit cannot be used by another unit for another purpose. When Ethernet communication is performed between three or more units, a parent unit having a role of cross-connecting (aggregating) a path from each child unit to another path is required. In order for the parent unit to aggregate the paths of the child units, a transmission line insertion unit and a transmission line extraction unit are required for each path, and the ports of the Ethernet frame switch unit increase with the number of paths, The circuit scale becomes large, and paths that can be aggregated in the parent unit are limited due to physical restrictions (such as circuit scale). That is,
The number of child units that can communicate is limited. When communication is performed between more child units, it is necessary to increase the number of parent units and to construct a path between the parent units. Therefore, the number of communication paths is limited due to the increase in the circuit scale, the path construction is complicated, the bandwidth for the number of paths is required, and the parent-child relationship is required for the units, and management is performed by increasing the number of unit types. There are the above problems.

(2) The STM transmission line has a duplex configuration from the viewpoint of improving reliability. However, the transmitting side to the STM transmission line sends out the STM frame containing the Ethernet frame transmitted from the containing terminal to the 0-system and 1-system STM transmission lines, and the receiving side operates normally based on the alarm information of the transmission line. The right route. However, the switching is performed on a band-by-band basis. That is, since the Ethernet frame included in the data is not considered, there is a possibility that the Ethernet frame is destroyed at the time of switching the route due to the transmission path alarm. In the case of a duplex transmission path, the data received from each path may have a different arrival time due to a difference in path length. For this reason, it is common to mask the data of the switched system for a fixed time (for example, the maximum delay time) so that the same data is not transmitted to the terminal when the route is switched. There is a problem that the Ethernet frame is discarded during the operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in view of the above circumstances. Therefore, a transmission unit which eliminates unit types, simplifies network management, and does not destroy asynchronous frames at the time of system switching at the time of transmission line failure. The purpose is to provide.

[0013]

FIG. 1 is a diagram illustrating the principle of the present invention. FIG. 1 is a diagram illustrating the principle of the present invention. As shown in FIG. 1, the transmission unit 30 includes a dividing unit 32, a frame extracting unit 34, a cell analyzing unit 36, a frame inserting unit 38, and an assembling unit 40.

The dividing means 32 in the transmission unit 30 converts the asynchronous frame including the source address, the destination address and the data transmitted by the terminal or the like into the destination unit address of the destination transmission unit based on the destination address in the cell header. Divide into cells added to.

[0015] The frame extracting means 34 receives the synchronous frame, and extracts cells inserted in a predetermined band allocated to accommodate the asynchronous frame. The cell analysis unit 36 determines whether the cell is addressed to the own transmission unit 30 in accordance with the destination unit address of the cell header of the cell extracted by the cell extraction unit 34, and determines the relay / reception / discard of the cell.

The frame inserting means 38 inserts the cell divided by the dividing means 32 and the cell determined to be a relay by the cell analyzing means 36 into a predetermined band of the synchronous frame, and sends out the synchronous frame. The assembling means 40 assembles the cells determined to be addressed to the own transmission unit 30 by the cell analyzing means 36 into an asynchronous frame, and sends out the asynchronous frame.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 2 is a configuration diagram of a network accommodating Ethernet according to a first embodiment of the present invention. This embodiment is applied to a company network or the like. In addition, the present invention is applicable not only to a network accommodating asynchronous frames but also to a network accommodating asynchronous frames. However, in the present embodiment, a network configuration accommodating an Ethernet frame is used as an example. Further, the network is applicable to various types of networks such as a ring configuration and a star configuration, but in the present embodiment, a ring configuration is used as an example. As shown in FIG.
The network includes a plurality of units 50 # i (i = 1 to
4), terminal 52 # ijk (i = 1 to 4, j = 1, 2, k
= 1 to n), a plurality of other units 54 # i (i = 1 to
2), a plurality of relay units 58 # i (i = 1 to 2), the Ethernet cable 60 # ij (j = 1, 2), the 0-system S
It comprises a TM transmission line 62 # 0 and a 1-system STM transmission line 62 # 1.

Each unit 50 # i has a unique unit address in the network and has the following functions.

The Ethernet cable 60 # ij (j
= 1,2) connected to the terminal 52 # ijk (k = 1 to
n) receives the Ethernet frame transmitted from
Divide into fixed length data. A header such as time information and control information, which will be described later, is added to the fixed-length data to make a cell (hereinafter, an IT (Integrated Transfer) cell).

An IT cell is inserted into a time slot of a pre-allocated band in an STM frame. In this embodiment, the bandwidth allocated to accommodate the Ethernet frame is a plurality of units 50 # i (i = 1 to 4).
Are the same band, and the start address and the number of time slots in the STM frame are the same. The bandwidth allocation will be described later in detail.

STM transmission line 62 # j (j = 0, 1)
And performs the following processing.

I) Regarding the time slot of the band allocated to accommodate the IT cell obtained by dividing the Ethernet frame in the STM frame, the relay / reception / reception / reception / reception from the cell header (described later) of the IT cell inserted in the time slot is performed. Decide to destroy.

When relaying an IT cell, the terminal 52 #
Prior to the Ethernet frame transmitted from ijk, the cell is inserted into the allocated band in the STM frame and transmitted to the STM transmission lines 62 # 0 and 62 # 1.

When receiving an IT cell, the IT cell extracted from the STM frame received from the STM transmission line 62 # j (j = 0, 1) is a frame obtained by adding a predetermined header to an Ethernet frame (hereinafter referred to as an Ethernet frame). , IT frame)
To decelerate. For the same Ethernet frame of the 0-system and the 1-system, the header is removed from the IT frame that is first decellularized, a necessary header portion is added, and the frame is converted into an Ethernet frame. The converted Ethernet frame is connected to the Ethernet cable 60 # ij (j = 1,
Send to 2).

Ii) Other data different from IT cells included in the time slot of the band allocated to the telephone terminal 56 #i (i = 1 to 2) other than the Ethernet frame in the STM frame is transmitted to the STM transmission line 62. #J (j = 0,
Relay to 1).

Each terminal 52 # ijk has a unique MAC address, and is accommodated in the unit 50 # i through the Ethernet cable 60 # ij. Other unit 54 #
i (i = 1 to 2) is a unit that accommodates a terminal that handles data other than the Ethernet frame, such as the telephone terminal 56 # i. The data transmitted from the telephone terminal 56 # i is
It is inserted into the band allocated to the TM frame. STM
The STM frame is received from the transmission line 62 # j (j to 0, 1), the time slot data of the band allocated to itself is transmitted to the telephone terminal 56 # i, and the data of the other band is transmitted to the STM transmission line 62 # j. #J (j = 0, 1).

The telephone terminal 56 # i is connected to another unit 54 # i
This is a terminal that transmits and receives data other than the Ethernet frame accommodated in. Relay unit 58 # i (i = 1 to
2) is performed from the STM transmission line 62 # j (j = 0, 1) to the ST
Upon receiving the M frame, the STM transmission line 62 # j (j =
0, 1). The reason why the relay unit 58 # i (i = 1 to 2) is provided is to compensate for deterioration of the signal level transmitted from the STM transmission line 62 # j (j = 0, 1).

The Ethernet cable 60 # ij (i = 1
-4, j = 1, 2) are transmission media for transmitting Ethernet frames, and are 10BASE-5 and 10BASE-
2,10BASE-T and the like. Unit 50 # i (i
= 1 to 4) accommodates the Ethernet cable 60 # ij
Although the number of (j = 1, 2) is not particularly limited, it is two in the present embodiment. STM transmission line 62 # j (j = 0,
1) is a transmission medium for transmitting an STM frame. S
TM transmission line 62 # 0 is 0 system, STM transmission line 62 # 1 is 1
System. In the present embodiment, in order to improve reliability, ST
Although the M transmission line is duplicated with the 0 system and the 1 system, it has a ring configuration. As shown in FIG. 2, the 0-system STM transmission line 6
2 # 0 is clockwise and 1-system STM transmission line 62 # 1 is counterclockwise.

FIG. 3 shows a unit 50 # i (i = 1) in FIG.
FIG. As shown in FIG. 3, each unit 50 # i includes a transformer 70 # ij (j = 1, 2), a physical interface unit 72 # ij (j = 1, 2), an Ethernet switch unit 74 # i, and an Ethernet frame process. Unit 78 # i, processor unit 80 # i, boot ROM 82
#I, work RAM 84 # i, processor bus 86 #
i, transmission dual port RAM 90 # ij (j = 0,
1), celling section 92 # ij (j = 0, 1), selecting section 94
#Ij (j = 0, 1), the transmission control unit 96 # ij (j =
0, 1), relay buffer 98 # ij (j = 0, 1),
STM frame insertion unit 100 # ij (j = 0,1), band setting unit 102 # ij (j = 0,1), STM frame extraction unit 104 # ij (j = 0,1), cell analysis unit 106
#Ij (j = 0, 1), decellularizing section 108 #ij (j =
0, 1), dual port RAM 110 # ij for reception
(J = 0, 1) and TSW112 # ij (j = 0, 1)
Having.

The transformer 70 # ij interfaces between the Ethernet cable 60 # ij and the physical interface unit 72 # ij. Physical interface unit 72 # i
j performs processing at the Ethernet frame level and checks the normality of the frame and the status of various alarms.
The Ethernet switch unit 74 # i performs switching of the Ethernet frame using the buffer 76 # i. In the present embodiment, the Ethernet switch unit 74 # i
Performs switching of three ports (A, B, C).

The switch unit 74 # i is simply a port A,
A hub having a hub function of multiplexing the Ethernet frame input from B and outputting the multiplexed Ethernet frame to port C and multicasting the Ethernet frame input from port C to ports A and B may be used. Also, the MAC SA address set in the Ethernet frame is stored, the MAC address of the terminal 52 # ijk to be accommodated is learned, and the terminal 52 # ijk (j = 1, 2, k = 1 to n) is learned. The Ethernet frame to be communicated is the STM transmission line 62 # 0,6.
Ethernet cable 60 without transmitting to 2 # 1
It may have a bridge function for transmitting to #ij.

When the bridge device is used, the Ethernet frame transmitted to the STM transmission line 62 # j (j = 0, 1) is after the filtering by the MAC address. STM transmission line 62 # j (j
= 0, 1). This is because the STM transmission line 62 # j (j = 0,
1) It leads to the reduction of the above traffic. The Ethernet frame processing unit 78 # i has an interface function of an Ethernet frame with the processor unit 80 # i. When an Ethernet frame is received from the Ethernet switch unit 74 # i, the Ethernet frame is notified to the processor unit 80 # i to request reading of the frame. When an Ethernet frame is received from the processor unit 80 # i, it is transmitted to the Ethernet switch unit 74 # i.

FIG. 4 is a functional block diagram relating to the transmission of an Ethernet frame by the processor unit 80 # i in FIG. As shown in FIG. 4, a block related to Ethernet frame transmission includes an Ethernet frame receiving unit 120 #.
i, time information obtaining unit 122 # i, time information adding unit 124
#I, the unit DA address management table 126 # i,
A unit DA acquisition unit 128 # i, a unit SA address register 130 # i, a unit SA acquisition unit 132 # i,
DA, SA, CNT adding section 136 # i, CRC adding section 1
36 # i, 0 system writing unit 138 # i0 and 1 system writing unit 13
8 # i1.

FIG. 5 is a diagram showing an Ethernet frame, an IT frame, an IT cell, and an STM frame. Upon receiving the notification from the Ethernet frame processing unit 78 # i, the Ethernet frame receiving unit 120 # i receives the Ethernet frame. As shown in FIG. 5, the IT frame includes an Ethernet frame and a header. Here, a part of the header part such as Preamble and SFD of the Ethernet frame is deleted from the IT frame. This is because these are fixed values,
This is because these are deleted from the frame and the Ethernet frame is efficiently accommodated in the IT cell. The IT frame is divided into fixed-length data, and the header is added to the IT frame.
Housed in a cell.

The header of the IT frame is composed of units DA,
It is composed of units SA, CNT, LENGTH, and TIME. In this header, CNT, unit DA, and unit SA are set in the header of the IT cell in which the IT frame is accommodated. This is because it is necessary to determine the relay / reception / discard of the IT cell.

The unit DA is a unit 50 # j accommodating the terminal 52 # ljk to which the Ethernet frame is to be transmitted.
Unit address / unit group address / broadcast unit address. The unit address is an address for uniquely specifying each unit 50 # i (i = 1 to 4). In the present embodiment, the unit DA address is an address unique to the unit. The group address is an address assigned to each unit by classifying the units 50 # i (i = 1 to 4) into groups. The broadcast unit address is an address specified in the case of broadcast communication with all units 50 # i (i = 1 to 4) as communication partners.
A mode using a group unit address will be described in a second embodiment, and a mode using a broadcast unit address will be described in a third embodiment. Unit SA
Is the unit address of the own unit 50 # i that is the transmission source. This is required to control the circulating cell.

CNT is control information for controlling relay / reception of an Ethernet frame.
D, DL, RE, and GP. USD is a field indicating whether the IT frame is a valid frame or an invalid frame. For example, USD = '1' is a valid cell, and USD = '0' is an invalid cell. DL indicates the number of cells in which the IT frame is accommodated. RE is a field that indicates whether the unit that has received the cell performs relaying. For example, if RE = '1', relaying is performed even after receiving a cell. This is for performing group communication, broadcast communication, and the like between the units 50 # i (i = 1 to 4). The group communication and the broadcast communication will be described in the second embodiment and the third embodiment. In the present embodiment, point-to-point communication is performed by setting a unit address to the unit DA address instead of group communication or broadcast communication (one-to-one communication).
Communication between units). GP is a field indicating whether or not the unit DA address is a group address. LENGTH is a field for specifying the length of the IT frame. TIME is a field indicating time information. CRC is the CRC of the IT frame.

The time information obtaining section 122 # i obtains current time information. The time information is information on the current time, for example, the current time or a counter value. The time information adding unit 124 # i sets time information in the TIME field of the header of the IT frame.

FIG. 6 is a diagram showing the unit DA address management table 126 # i in FIG. The unit DA address management table 126 # i is a table for obtaining a unit address of a unit accommodating a terminal having the MAC address from the MAC DA address of the Ethernet frame. As shown in FIG. 6, the MAC address of each terminal accommodated in the network and the unit address of the unit accommodating the terminal are registered in the unit DA address management table 126 # i.

The unit DA acquisition unit 128 # i checks whether or not the frame is a broadcast frame from an Ethernet frame. If the frame is not a broadcast frame, the unit DA acquisition unit 128 # i uses the MAC DA address of the Ethernet frame as an index to store the unit DA address management table 1
26 # i is retrieved to obtain the unit DA address. The unit SA address register 130 # i is a register that stores the unit address of the own unit 50 # i. The unit SA acquisition section 132 # i
The unit address of 0 # i is obtained from the unit SA address register 130 # i.

The DA, SA, and CNT adding sections 134 # i
Unit DA, unit SA,
Set CNT and LENGTH. For CNT, USD = '1', DL = number of cells, RE = 'if the Ethernet frame is a broadcast frame
1 ', unit DA address = broadcast address, if not a broadcast frame, RE ='
0, GP = '0'. CRC adding section 136 # i
Calculates the CRC of the IT frame and adds C
Set RC. The 0-system writing unit 138 # i0 writes the IT frame into the transmission dual port RAM 90 # i0. The 1-system writing unit 138 # i1 writes the IT frame into the transmission dual port RAM 90 # i1.

FIG. 7 is a functional block diagram relating to the reception of an Ethernet frame by the processor unit 80 # i in FIG. As shown in FIG. 7, the blocks related to the Ethernet frame reception of the processor unit 80 # i include a data read unit 140 # i, a CRC check unit 142, a time information comparison unit 144 # i, and an Ethernet frame creation unit 146 # i.
It is composed of The data reading unit 140 # i receives a signal from the decelerating unit 108 # i0 or 108 # i1
When receiving the notification of the writing of the T frame, the receiving dual port RAM 110 # i0 or 11
The IT frame is read from 0 # i1.

The CRC checking section 142 # i checks the CRC of the IT frame, checks the validity of the IT frame, and discards the IT frame if the CRC is abnormal. The time information comparing unit 144 # i uses the T
The time information set in the IME field is extracted. Then, it is checked whether the same time information as the extracted time information is written in the work RAM 84 # i. If the same time information has been written in the work RAM 84 # i, the IT frame is discarded. If the same time information has not been written to the work RAM 84 # i, the time information is written to the work RAM 84 # i. As a result, a frame in which a correct IT frame is decelerated earlier is received, and an abnormal IT frame or a late-arriving frame is discarded.

Therefore, the STM transmission line 62 # 0 or 62
When an STM frame is not input due to a failure in # 1, for example, when an IT cell is decellularized into an IT frame, a subsequent I
Even if the T cell is no longer input due to a failure in the STM transmission line 62 # 0 or 62 # 1, the normal STM transmission line 6
STM frame is input from 2 # 1 or 62 # 0,
An Ethernet frame contained in the STM frame is received. Ethernet frame creation unit 146 # i
Removes the header from the IT frame and creates a Preambl
A header part such as e is added to assemble into an Ethernet frame and transmitted to the Ethernet frame processing unit 78 # i.

The boot ROM 82 # i is a ROM for storing a program executed by the processor unit 80 # i. The work RAM 84 # i stores the time information R
AM. The processor bus 86 # i is a bus that connects the transmission dual port RAM 90 # ij (j = 0, 1) and the like. Dual port RAM for transmission 90 # ij
(J = 0, 1) is a dual port RAM for storing IT frames. The reason for dual port RAM is
Writing from the processor unit 80 # i and the cell unit 92 # i
This is because reading from j (j = 1, 2) can be performed simultaneously.

Upon receiving the notification of the writing of the pseudo-Enet frame from the processor unit 80 # i, the cell unit 92 # ij (j = 0, 1) receives the transmission dual port RAM 9
An IT frame is read from 0 # ij (j = 0, 1). The read IT frame is divided into fixed lengths. I which is obtained by adding a header shown below to each divided fixed length part
Create a T cell. Transmission control unit 96 # ij (j = 0,
According to the instruction of 1), the selection unit 94 # ij (j = 0, 1)
Output an IT cell. As shown in FIG. 6, the cell header includes a CNT field, a unit DA field, a unit SA field, a LIFE field, and an HEC field. The CNT field, the unit DA field, and the unit SA field are the same as those in the header of the IT frame. In the LIFE field, an initial value, for example, the maximum number of relays is set to prevent the IT cell from circulating indefinitely.
Each time i (i = 1 to 4) relays an IT cell, the value is decremented. And if relayed more than a certain amount,
For example, when the field value becomes 0, the IT cell is discarded. HEC is set in the HEC field.

The selector 94 # ij (j = 0, 1) receives an instruction from the transmission controller 96 # ij (j = 0, 1) and receives a command from the cell generator 92 # ij (j = 0, 1) or Relay buffer 9
8 # ij (j = 0, 1) is selected as an IT cell. The transmission control unit 96 # ij (j = 0, 1) gives priority to the relay buffer 98 # ij (j = 0, 1) if the relay buffer 98 # ij (j = 0, 1) has an IT cell. 1)
Read the IT cell from the relay buffer 98 # ij
If there is no IT cell at (j = 0,1), the transmission dual port RAM 90 # ij (j = 0,1) is stored in the cell unit 92.
Instruct #ij (j = 0, 1) to output an IT cell.

STM frame insertion unit 100 # ij (j =
(0, 1) obtains the band information, that is, the start address of the STM frame and the band (the number of time slots) from the band setting unit 102 # ij (j = 0, 1), and then selects the selecting unit 94 #.
ij (j = 0, 1) is inserted into the time slot specified by the band information at the bit rate indicated by the band to create an STM frame, and the TSW 11
2 # ij (j = 0, 1). Band setting unit 102
#Ij (j = 0, 1) is assigned to all terminals 52 #ijk (i = 1 to
The bandwidth information for accommodating the Ethernet frame of (4, j = 1, 2, k = 1 to n) is output.

FIG. 8 is a diagram showing the structure of an STM frame. In the present embodiment, the band for accommodating the Ethernet frame in the STM frame is indicated by a path # 1 as shown in FIG. 8, for example, and is allocated from the beginning of the payload. Then, all the units 50 # i (i =
The bandwidths for accommodating the Ethernet frames for the items 1 to 4) are the same. Terminal 5 accommodated by unit 50 # i (i = 1 to 4) in a time slot corresponding to this band
Ethernet frame sent from 2 # ijk is IT
It will be housed in the form of a cell. The band corresponding to the other data is a band accommodating data other than the Ethernet frame such as the telephone terminal 56 # I (i = 1 to 2). ST
The M frame extraction unit 104 # ij (j = 0, 1) uses the TSW
112 # ij (j = 0, 1) is received, and the band setting unit 102 # ij (j = 0, 1) receives the STM frame.
A time slot corresponding to the band set in 1) is extracted.

FIG. 9 shows a cell analyzer 106 # ij in FIG.
It is a block diagram of (j = 0,1). As shown in FIG. 9, the cell analysis unit 106 # ij includes a cell input unit 150 # ij, a cell header extraction unit 152 # ij, and an HEC check unit 154.
#Ij, a unit DA determination unit 156 # ij, a cell relay unit 158 # ij, and a cell drop unit 160 # ij. The cell input unit 150 # ij is the STM frame extraction unit 1
Input an IT cell from 04 # ij. Cell header extraction section 152 # ij extracts a cell header. The HEC check unit 154 # ij calculates the HEC of the cell header, and
If a C error occurs, the IT cell is discarded.

FIG. 10 is a diagram showing criteria for judging reception / relay / discard of a cell. Unit DA determination unit 156 # ij
Performs determination of reception / relay / discard of an IT cell according to the determination criteria shown in FIG. In the present embodiment, point-to-point communication or multicast communication (when the Ethernet frame is a multicast frame) is used, and the group communication using the group unit address is not performed. However, it is possible to process normally even when group communication is specified.

(1) If USD = '0', the IT cell is discarded.

(2) If the error is a HEC error, the IT cell is discarded.

(3) If LIFE = "0", the IT cell is discarded.

(4) If SA = unit address of own unit 50 # i, it is a circulating cell, and the IT cell is discarded.

(5) If DA = 0, it is determined that the cell is an invalid cell, and the IT cell is discarded.

(6) When USD = “1”, SA ≠ own unit address and GP = “0”, DA = own unit address, RE = “0”, and LIFE ≠ “0”, IT
Determine the reception of the cell.

(7) When SD = “1” and SA ≠ own unit address and GP = “0”, DA = own unit address, RE = “1” and LIFE ≠ “0”, reception and relay of IT cells To determine.

(8) If USD = “1” and SA ≠ own unit address and GP = “0”, DA ≠ own unit address and RE = “0” and LIFE ≠ “0”, IT
Determine the cell relay.

(9) If USD = “1” and SA ≠ own unit address and GP = “0” and DA ≠ own unit address and RE = “1” and LIFE ≠ “0”, IT
Determine the cell relay.

(10) USD = “1” and SA ≠ own unit address and GP = “0” and DA = 0 or All ′
If F 'and RE =' 0 'and LIFE ≠' 0 ', then I
Determine T cell reception.

(11) USD = “1” and SA ≠ Local unit address and GP = “0” and DA = 0 or All ′
If F 'and RE =' 1 'and LIFE ≠' 0 ', then I
Determine T cell reception and relay.

(12) USD = “1” and SA ≠ own unit address and GP = “1” and DA = 0 or All ′
If F 'and LIFE ≠' 0 ', it is an invalid cell and IT
Discard the cell.

(13) When USD = “1” and SA ≠ local unit address and GP = “1”, DA = local group unit address, RE = “0” and LIFEＬ “0”, reception of an IT cell is performed. decide.

(14) When USD = “1” and SA ≠ own unit address and GP = “0” and DA ≠ own group unit address and RE = “1” and LIFE ≠ “0”, the reception of the IT cell is performed. decide.

(15) If USD = “1” and SA ≠ own unit address and GP = “1” and DA ≠ own group unit address and RE = “0” and LIFE ≠ “0”, the relay of the IT cell is performed. decide.

(16) If USD = “1”, SA ≠ own unit address and GP = “1”, DA ≠ own group unit address, RE = “1”, and LIFE ≠ “0”, reception of an IT cell is performed. decide.

In the case of a relay cell, the cell relay unit 158 # ij updates the HEC after decrementing the LIFE field value of the relay cell by 1 and updates the HEC.
Write the relay IT cell to ij. Cell drop section 160
#Ij outputs the IT cell to the decellularizing unit 108 # ij.

Decellularizing section 108 # ij (j = 0, 1)
Inputs an IT cell from the cell analysis unit 106 # ij (j = 0, 1) and deletes the header of the IT cell. Assemble into an IT frame according to the DL field of the header of the IT frame. Perform a CRC check on the IT frame,
If normal, reception dual port RAM 110 # i
Write an IT frame to j (j = 0, 1). When the writing is completed, the processor unit 80 # i is notified via the processor bus 86 # i. Dual port R for reception
AM110 # ij (j = 0, 1) is a dual port RAM for storing IT frames. Dual port RA
The reason why M is set is that the decelerating unit 108 # ij (j = 0, 1)
And reading from the processor unit 80 # i can be performed at the same time.

TSW112 # ij (j = 0, 1) is
The STM frame is received from the TM transmission line 62 # j (j = 0, 1), and the STM frame extraction unit 104 # ij (j =
0, 1). STM frame insertion unit 100 # i
FIG. 8 of the STM frame output from j (j = 0, 1)
The data of the band indicated by the path # 1 in the middle and the STM transmission line 62 #
j (j = 0, 1), multiplexes the data of the time slot in which the other DATA shown in FIG. 8 is accommodated in the STM frame into the STM frame, and
j (j = 0, 1).

The operation of the network shown in FIG. 2 will be described below.

(1) Terminal 52 # 111 accommodated in unit 50 # 1 and terminal 5 accommodated in unit 50 # 3
When performing communication with 2 # 311 The terminal 52 # 111 sets the MAC address of its own terminal to the MAC address.
The SA address and the MAC address of the terminal 52 # 311 are represented by the MAC DA address, LENGTH, DATA, FC
S, Preamble, SFD, etc. are set in the Ethernet frame, and the Ethernet frame is transmitted to the Ethernet cable 60 # 11. Transformer 70 # 11
Receives the Ethernet frame and sends it to the physical interface unit 72 # 11. Physical interface unit 7
2 # 11 establishes a data link with the terminal 52 # 111 and checks the normality of the Ethernet frame and the status of various alarms. If abnormal, the terminal 52 # 111 is requested to retransmit. If it is normal, it outputs to the port A of the Ethernet switch unit 74 # 1.

The Ethernet switch section 74 # 1 receives the terminal 52 # 1jk (j = 1, 2, k = 1 to 1) based on the MAC SA address of the input Ethernet frame.
learning the MAC address of n). If the DA MAC address of the Ethernet frame input from the ports A and B is the address of a terminal accommodated in the same port as the input ports A and B, the Ethernet frame is discarded. If the address is a terminal accommodated in another port A or B, an Ethernet frame is output to that port. Otherwise, output to port C. Here, the DA address of the Ethernet frame is
Since the address is not # 1jk (j = 1, 2, k = 1 to n), the Ethernet frame processing unit 78 #
Output to 1. Ethernet frame processing unit 78 # 1
, Upon receiving the Ethernet frame, notifies the processor unit 80 # 1.

FIG. 11 is a flowchart for transmitting an Ethernet frame by the processor unit 80 # 1. Step S2
, An Ethernet frame is received from the Ethernet frame processing unit 78 # 1. In step S4, the current time information is obtained and added to the Ethernet frame as shown in FIG. In step S6, referring to the unit DA address management table 126 # 1, if the Ethernet frame is not a broadcast frame, the unit address is obtained from the DA MAC address and set in the unit DA address field. If the frame is a broadcast frame, '0' or all 'F' is set in the unit DA address field. In the CNT field, USD = '1', D
L, RE = '0', GP = '0' are set. LENG
Set the data length in the TH field.

In step S 8, C is added to the IT frame.
RC added, dual port RAM 90 # for system 0 transmission
Write an IT frame to 10. In step S10, the fact that the writing of the IT frame is completed is indicated by the
Notify 0. In step S12, an IT frame is written into the 1-system transmission dual port RAM 90 # 11. In step S10, the fact that the writing of the IT frame has been completed is notified to the 1-system cell forming section 92 # 11.

Upon receiving notification of the end of the data writing from the processor unit 80 # 1, the cell unit 92 # 1j (j = 0, 1) transmits the dual port RAM 90 # 1j (j
= 0, 1) to read an IT frame. Divide the IT frame into fixed lengths. An IT cell is generated by adding a header shown in FIG. 5 to each fixed-length data. The IT cell is written into a buffer (not shown).

FIG. 12 shows the transmission control section 96 # 1j in FIG.
6 is an operation flowchart of (j = 0, 1). The transmission control unit 96 # 1j (j = 0, 1) is connected to the relay buffer 98 #
1j (it monitors the writing of IT cells to j = 0.
In step S20, the relay buffer 98 # 1j
It is determined whether there is an IT cell at (j = 0, 1). I
If there is a T cell, the process proceeds to step S22. If there is no IT cell, the process proceeds to step S26. In step S22, the IT cell is read. In step S24, the selection unit 94 # 1j (j = 0, 1) is instructed to select the output from the relay buffer 98 # 1j (j = 0, 1). In step S26, the cell unit 92 # 1j
Instruct (j = 0, 1) to output an IT cell. In step S28, the selection unit 94 # 1j (j = 0, 1) is instructed to select the output of the cell unit 92 # 1j (j = 0, 1). Here, control is performed so that another IT frame is not mixed in the middle of the IT cell. The cell unit 92 # 1j (j
= 0, 1) outputs an IT cell upon receiving the instruction.
The selection unit 94 # 1j (j = 0, 1) is connected to the transmission control unit 96 #
1j (j = 0, 1), an IT cell is selected, and the STM frame insertion unit 100 # 1j (j = 0, 1) is selected.
Output to

STM frame insertion section 100 # 1j (j =
(0, 1) obtains the start address and the number of time slots from the band setting unit 102 # ij (j = 0, 1), and allocates the allocated band, for example, the path # as shown in FIG.
1 time slot, the selection unit 94 # 1j (j = 0,
1) Insert the IT cell output from step 1). And TS
W112 # 1j (j = 0, 1). TSW11
2 # 1j (j = 0, 1) corresponds to the STM transmission line 62 # j (j
= 0, 1) to input an STM frame from other than the Ethernet and the STM frame insertion unit 100 #
1j (j = 0, 1) are multiplexed, and the STM frame shown in FIG.
2 # j (j = 0, 1).

Unit 50 # 1 to 0-system STM transmission line 6
The STM frame transmitted to 2 # 0 is
Received in # 2. The relay unit 58 # 2 receives the STM frame from the STM transmission line 62 # 0, and
The data is transmitted to the transmission path 62 # 0. The other unit 54 # 2 has 0
The STM frame is received from the system STM transmission line 62 # 0, and if other data is inserted in the time slot of the band allocated to the telephone terminal 56 # 2 shown in FIG. It is sent to the telephone terminal 56 # 2. When data is input from the telephone terminal 56 # 2, the telephone terminal 5
6 inserts data into the band assigned to # 2, and inserts the data contained in path # 1 of the STM frame received from the 0-system STM transmission line 62 # 0 into path # 1.
The M frame is transmitted to the 0-system STM transmission line 62 # 0. Unit 50 # 3 performs the same process as unit 50 # 1, and transmits an STM frame to unit 50 # 2. 1
Similarly, the STM frame transmitted from the unit 50 # 1 to the 1-system STM transmission line 62 # 1 is transmitted to the relay unit 58 # 1 and the other unit 5 #.
The signal is received by the unit 50 # 2 via 4 # 1.

TSW112 # 2j in unit 50 # 2
(J = 0, 1) corresponds to the STM transmission line 62 # j (j = 0,
1) to receive the STM frame and output it to the STM frame extraction unit 104 # 2j (j = 0, 1). The STM frame extraction unit 104 # 2j (j = 0, 1) acquires the start address and the number of time slots from the band setting unit 102 # 2j (j = 0, 1), and assigns the start address and the number of time slots to the time slot in which the Ethernet frame is accommodated. The inserted IT cell is extracted.

FIG. 13 is a flowchart of the relay / reception of a cell. Cell analyzer 106 # 2j (j = 0, 1)
Inputs an IT cell in step S40. In step S42, a cell header is extracted. In step S44, USD is checked. USD = '
If it is 0 ', the process proceeds to step S60. If USD = '1', the process proceeds to step S46. In step S46, a CRC check is performed. If the CRC is abnormal, the process proceeds to step S60. If the CRC is normal, step S48
Proceed to.

In step S48, LIFE is checked. If LIFE = '0', the process proceeds to step S60. If LIFE ≠ 0, the process proceeds to step S49. In step S49, the unit SA address is checked. If unit SA address = own unit address, the process proceeds to step S61. If unit SA address ≠ own unit address, the process proceeds to step S50. In step S50, the GP is checked. G
If P = '1', the process proceeds to step S52. GP = '
If it is 0 ', the process proceeds to step S62. In this example, the GP
= “0” and point-to-point communication, so the process proceeds to step S62.

In step S52, the unit group DA address is checked. If unit group address = own unit group address, step S
Proceed to 54. Unit group address "0" or A
If ll'F ', the process proceeds to step S60. If unit group address = other unit group address,
Proceed to step S59. In step S54, an IT cell is output to decellularizing section 108 # 2j (j = 0, 1) (cell reception). In step S56, the LIFE is decremented by 1, and the relay buffer 98 # 2j (j =
Write the IT cell to (0, 1) (cell relay).

In step S59, cell relay is performed.
In step S61, the cell is a revolving cell,
Since it is considered that learning of the MAC address of 2 # 2jk (j = 1, 2, k = 1 to n) has not been completed, an IT cell is received. In step S62, the unit DA
Check the address. If unit DA address = own unit address, the process proceeds to step S64. If unit DA address ≠ own unit address, the process proceeds to step S70. In step S64, an IT cell is received. In step S66, the RE is checked. If RE = '1', the process proceeds to step S68. In step S68, the IT cell is relayed. Step S
At 70, the IT cell is relayed. In this example, the terminal 5
Since the unit DA address of the IT cell accommodating the Ethernet frame from 2 # 111 to the terminal 52 # 211 is the address of the unit 50 # 2, the IT cell is received. Also, since RE = '0', no IT cell is relayed. As a result, unnecessary relay is eliminated, so that traffic can be reduced.

Upon receiving the IT cell, the decellularizing section 108 # 2j (j = 0, 1) assembles it into an IT frame as shown in FIG. 5 based on the CNT DL of the cell header and the LENGTH of the header of the IT frame. . Write to the dual port RAM for reception 110 # 2j (j = 0, 1). When the writing is completed, through the processor bus 86 # 2,
Notify the processor unit 80 # 2.

FIG. 14 is a flow chart of the ethersat frame reception of the processor section 80 # 2 in FIG. In step S80, a notification that the data has been written to the receiving dual port RAM 110 # 2j is received from the decelerating unit 108 # 2j. In step S82, an IT frame is read from the receiving dual port RAM 110 # 2j of the system that has been notified. Check the CRC of the IT frame. If the CRC check is correct, the time information in the header of the IT frame is compared with the time information in the work RAM 84 # 2.

In step S86, the work RAM
It is checked whether or not 84 # 2 has the same time information as that of the IT frame. If the same one already exists, the process proceeds to step S92. If not, the process proceeds to step S88. In step S88,
The time information is written to the work RAM 84 # 2. In step S90, the header is deleted from the IT frame,
Instead, Preamble and SFD are added to assemble into an Ethernet frame and passed to the Ethernet frame processing unit 78 # 2. As a result, a normal IT frame that arrives first is received and processed.

FIG. 15 is a time chart relating to the reception of an Ethernet frame. As shown in FIG. 15, if both the 0-system and 1-system STM transmission lines 62 # j (j = 0, 1) are normal, the normal IT frame (decelified frame) that arrives early is received and the processor unit 80 # i. However, for example, the 0-system STM transmission line 62 # 0
, A normal STM frame cannot be received from the 0-system STM transmission line 62 # 0. for that reason,
The IT frame received from the 1-system STM transmission line 62 # 1 is output from the processor unit 80 # i. Thereby, ST
Even if the M transmission lines 62 # 0 and 62 # 1 become faulty, they are correctly received without destroying the Ethernet frame.

The Ethernet frame processing unit 78 # 2
An Ethernet frame is received from the processor unit 80 # 2 and output to the Ethernet switch unit 74 # 2. When an Ethernet frame addressed to the terminal 52 # 211 is input, the Ethernet switch unit 74 # 2 receives the terminal 52 # 2.
11, the physical interface unit 72 # 21 and the transformer 70
The data is transmitted to the Ethernet cable 60 # 21 through # 21. If the MAC address of the terminal 52 # 211 has not been learned, the Ethernet frame is transmitted from the ports A and B through the physical interface unit 72 # 2j (j = 1, 2) and the transformer 70 # 2j (j = 1, 2). The data is transmitted to the Ethernet cable 60 # 2j (j = 1, 2).
Terminal 52 # 211 receives the Ethernet frame,
Since the own MAC address is set as the DA MAC address, the Ethernet frame is processed.

(2) When terminal 52 # 111 accommodated in unit 50 # 1 sends out a broadcast frame Assume that terminal 52 # 111 sends out a broadcast Ethernet frame. The unit 50 # 1 sets its own unit address as the unit SA address, All'F ', GP =' 0 ', RE =' 1 ', etc. as the unit DA address, and accommodates the Ethernet frame in the STM frame. The STM transmission line 62 # j (j = 0, 1)
Send a frame. Each unit 50 # 2, 50 # 3
50 # 4 is unit DA address = All'F ', G
Since P = '0' and RE = '1', it receives the IT cell and relays the cell. The relay cell is accommodated in the STM frame and received by the unit 50 # 1. Since the unit DA address of the relay cell is its own unit address, it is determined to be a circulating cell and cell relay is not performed. Thus, the broadcast frame is also correctly relayed.

As described above, according to the first embodiment, communication is performed between units having the same band set by converting an Ethernet frame into cells and performing cell-level processing on the STM transmission line. Can be. Further, in the related art, a parent unit having a role of aggregating data from each child unit is indispensable. However, the use of cells allows all units to stand at equal positions. As a result, only one path needs to be set for transmission, and the path management and the like in the construction of the network become very easy. Further, since the destination unit address is directly used, 1: 1 communication with the opposing unit can be realized. This can be used as a repeater to extend between Ethernet. Further, the route switching processing in the duplex transmission path is not performed in the conventional route collective unit, but can be switched in Ethernet frame units by using time information, so that the reliability of the network is also improved.

Second Embodiment FIG. 16 is a configuration diagram of a network accommodating Ethernet according to a second embodiment of the present invention. Components that are substantially the same as the components in FIG. 2 are given the same reference numerals. are doing. The unit 180 # i (i = 1 to 4) in FIG. 16 differs from the unit 50 # i (i = 1 to 4) in FIG. 2 in performing point-to-point communication in performing inter-group communication.

FIG. 17 is a block diagram of the unit 180 # i in FIG. 16. Components that are substantially the same as those in FIG. 3 are given the same reference numerals. Processor section 190
In order to perform group communication between the units 180 # i (i = 1 to 4), #i has a unit group DA address in the unit DA address of the IT frame and GP = 'in the CNT.
1 and RE = '1' are different from the processor unit 80 # i in FIG.

FIG. 18 shows the processor section 190 # in FIG.
FIG. 5 is a functional block diagram relating to Ethernet frame transmission of i, in which components that are substantially the same as the components in FIG. 4 are denoted by the same reference numerals.

FIG. 19 shows the unit group DA in FIG.
FIG. 3 is a configuration diagram of an address management table 200 # i. Figure 1
As shown in FIG. 9, the unit group DA address management table 200 # i includes the MAC address and the unit group D of the unit accommodating the terminal having the MAC address.
The A address is stored. Unit 180 # i (i
= 1 to 4) are grouped, and a group unit address is assigned to each group. The grouping is performed based on the physical arrangement (for example, adjacent units) of the units 180 # i (i = 1 to 4) or the logical arrangement (for example, for each department in a corporate network or the like). The number of group unit DA addresses registered in the unit group DA address management table 200 # i may be one or more. 1
As an application form in the case of the number of terminals, a communication form in which the terminal 52 # ijk performs inter-group communication only between terminals accommodated in the same group as the unit 180 # i can be considered. Also,
As an application form in the case of a plurality of terminals, a form in which the terminal 52 # ijk performs inter-group communication with a terminal accommodated in a unit of an arbitrary group can be considered.

Unit group DA acquisition section 202 # i
Is a unit group DA address management table 200 # i based on the MACDA address of the Ethernet frame.
To obtain the unit group address. D
The A, SA, and CNT adding unit 204 # i stores the unit group DA address and the unit SA in the unit DA address.
Unit address in address, GP in CNT = '
1 ', RE =' 0 'is set. The setting values of the other fields are the same as in the first embodiment.

Thus, for example, when an Ethernet frame addressed to terminal 52 # 211 is transmitted from terminal 52 # 111, unit 180 # 1 receives the unit 180 # 1 containing terminal 52 # 211 from the MAC DA address of the Ethernet frame. The unit group address of # 2 is obtained, and the unit group address is set in the unit DA address of the cell header. If the unit group address corresponding to the MAC DA address is not registered, for example, a broadcast unit address is set. A cell is received by a unit having a unit group address. Then, it is assembled into an Ethernet frame. The assembled Ethernet frame is transmitted over the Ethernet cable. The terminal receives the Ethernet frame from the Ethernet cable and processes the Ethernet frame if the MAC DA address is its own MAC address. In this way, the terminal can perform inter-group communication.

As described above, the same effects as in the second embodiment can be obtained. In addition, by using inter-group communication, units using the same band can be divided into groups, and one type of virtual LAN can be constructed in a unit that sets the same band on the STM. .

Third Embodiment FIG. 20 is a configuration diagram of a network accommodating Ethernet according to a third embodiment of the present invention. Components that are substantially the same as the components in FIG. 2 are given the same reference numerals. are doing. Unit 50 # in FIG. 2 that performs point-to-point communication in that unit 210 # i (i = 1 to 4) in FIG. 20 performs broadcast communication between units 210 # i (i = 1 to 4). i (i = 1 to 4).

FIG. 21 is a block diagram of the unit 210 # i in FIG. 20. Components that are substantially the same as those in FIG. 3 are given the same reference numerals. Processor section 220
#I is the unit DA address of the IT frame = All'F 'and the CNT G
The point that P = '0' and RE = '0' are set is different from the processor unit 80 # i in FIG.

FIG. 22 shows the processor section 220 # in FIG.
FIG. 5 is a functional block diagram relating to Ethernet frame transmission of i, in which components that are substantially the same as the components in FIG. 4 are denoted by the same reference numerals. The DA, SA, and CNT adding unit 230 # i outputs the unit DA address = All'F ',
A unit address is set as the unit SA address, and GP = “0” and RE = “1” in the CNT are set. The setting values of the other fields are the same as in the first embodiment.

Thus, for example, when an Ethernet frame addressed to terminal 52 # 211 is transmitted from terminal 52 # 111, unit 210 # 1 sets All'F 'in the unit DA address of the cell header. All units 210 # i (i = 1 to 4) receive the IT cell,
Assemble into Ethernet frame. The assembled Ethernet frame is connected to the Ethernet cable 60 # ij (i
= 1 to 4, j = 1, 2). Each terminal 52 # ij
k receives an Ethernet frame from the Ethernet cable 60 # ij. Terminal 52 # 211 has MAC D
Since the A address is its own MAC address, it processes the Ethernet frame. In this way, broadcast communication becomes possible.

In this embodiment, all Ethernet frames are broadcast. However, in the first and second embodiments, the unit address and the unit group address are stored in the unit DA address management table and the unit group DA address management table. If it is not registered, for example, if a destination unit is newly added, broadcast communication may be performed. Thereby, flexible communication can be performed.

As described above, the third embodiment has the same effects as the first embodiment. Each unit can communicate by broadcast communication without knowing the unit address or unit group address of another unit.

[0105]

As described above, according to the present invention,
Asynchronous frames are converted into cells, and cell-level processing is performed on synchronous frames, so that communication can be performed between units in which the same band is set. Further, by setting the relay value in the cell and updating the cell every time the cell is relayed, the cell is discarded when the relay value reaches a certain value, so that the traffic is not increased more than necessary and the traffic does not increase. Further, the route switching processing in the duplex transmission path is not performed in the conventional route collective unit, but can be switched in Ethernet frame units by using time information, so that the reliability of the network is also improved.

[Brief description of the drawings]

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

FIG. 2 is a network configuration diagram according to the first embodiment of the present invention.

FIG. 3 is a unit configuration diagram in FIG. 2;

FIG. 4 is a functional block diagram related to Ethernet frame transmission of a processor unit in FIG. 3;

FIG. 5 is a diagram showing an Ethernet frame and cell data.

FIG. 6 is a configuration diagram of a unit DA address management table in FIG. 4;

FIG. 7 is a functional block diagram relating to reception of an Ethernet frame by a processor unit in FIG. 3;

FIG. 8 is an STM frame configuration diagram.

FIG. 9 is a functional block diagram of a cell analysis unit in FIG. 3;

FIG. 10 is a diagram showing criteria for receiving / relaying / discarding a cell.

11 is an Ethernet frame transmission flowchart of the processor unit in FIG. 3;

FIG. 12 is an operation flowchart of a transmission control unit in FIG. 3;

FIG. 13 is a flowchart of cell relay / reception.

FIG. 14 is a flowchart of receiving an Ethernet frame by the processor unit in FIG. 3;

FIG. 15 is a time chart related to Ethernet frame reception.

FIG. 16 is a network configuration diagram according to a second embodiment of the present invention.

FIG. 17 is a unit configuration diagram in FIG. 16;

FIG. 18 is a functional block diagram relating to Ethernet frame transmission of a processor unit in FIG. 17;

19 is a configuration diagram of a unit group DA address management table in FIG.

FIG. 20 is a network configuration diagram according to a third embodiment of the present invention.

FIG. 21 is a unit configuration diagram in FIG. 20;

FIG. 22 is a functional block diagram related to Ethernet frame transmission of the processor unit in FIG. 21;

FIG. 23 is a network configuration diagram accommodating a conventional Ethernet.

FIG. 24 is a configuration diagram of a conventional STM frame.

FIG. 25 is a configuration diagram of a conventional child unit.

FIG. 26 is a configuration diagram of a conventional parent unit.

[Explanation of symbols]

 Reference Signs List 30 transmission unit 32 dividing means 34 frame extracting means 36 cell analyzing means 38 frame inserting means 40 assembling means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K030 HA08 HB28 HB29 HC14 HD06 JA06 LC18 MD02 5K033 CB15 CC01 CC02 DA05

Claims (3)

[Claims] 1. A transmission unit for exchanging an asynchronous frame including a source address, a destination address, and data between an asynchronous frame and a synchronous frame, wherein the asynchronous frame is transmitted to a destination transmission unit based on the destination address. Division means for dividing a destination unit address into cells added to a cell header; andframe extraction means for receiving the synchronous frame and extracting cells inserted in a predetermined band allocated to accommodate the asynchronous frame, Cell analysis means for determining whether the cell is addressed to its own transmission unit based on the destination unit address of the cell header of the extracted cell and determining relay / reception / discard of the cell; The cell divided by the dividing means and the cell determined to be a relay by the cell analyzing means are Frame insertion means for inserting the synchronous frame into the predetermined band and transmitting the synchronous frame; and assembling a cell determined to be addressed to the own transmission unit by the cell analyzing means into an asynchronous frame, and transmitting the asynchronous frame. A transmission unit, comprising: 2. The method according to claim 1, wherein the dividing unit sets a relay value in the cell header, and the cell analyzing unit determines discarding of the cell based on the relay value of the cell header. The transmission unit according to claim 1, wherein the relay numerical value is updated. 3. The transmission path for transmitting the synchronization frame is 0.
The system is redundantly configured as a system and a system, wherein the dividing unit sets time information in a cell into which each of the asynchronous frames is divided, and the frame inserting unit converts the synchronous frame into which the cell is inserted into the 0 system and the Sending to the transmission line of system 1;
The frame extracting unit receives the synchronous frame from each of the transmission lines of the 0-system and the 1-system and extracts a cell, and the assembling unit extracts the time information set in the cell related to the transmitted asynchronous frame. When the cells extracted from the 0-system and 1-system synchronous frames are stored in a memory and assembled into an asynchronous frame, if the same time information as the time information of the cell is stored in the memory, the asynchronous frame is stored in the memory. 2. The method according to claim 1, wherein when the same time information as the time information of the cell is not stored in the memory, the asynchronous frame is transmitted and the time information related to the asynchronous frame is written in the memory. Transmission unit as described.