JP2005236423A - Ethernet (r) multiplexing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform control so as not to exceed the reception permission speed of an opposite Ethernet (R) terminal. <P>SOLUTION: MAC-PHY units 11 each accommodate an Ethernet line 10 and terminates a MAC frame with the Ethernet terminal. Buffer units 12 each include an FIFO for writing frame data output from the corresponding MAC-PHY unit. A multiplexing/demultiplexing unit 14 multiplexes frame data read from each of buffer units to generate multiplexed frames, and further inserts communication speed information of the Ethernet line to be output from the MAC-PHY unit into a predetermined data region. A MAC-PHY unit 15 transmits the multiplexed frames output from the multiplexing/demultiplexing unit to a concentration line 20. A speed control unit 13 detects opposite communication speed information from the opposite Ethernet line inserted into the predetermined region of the multiplexed frames, and outputs a reading control signal to the buffer unit. Also, the buffer unit transmits a pause frame if a buffer quantity exceeds a threshold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an Ethernet multiplexer, and more particularly to an Ethernet multiplexer that accommodates a line from an Ethernet terminal that performs point-to-point communication.

  The conventional flow control in this type of Ethernet multiplexing device has an automatic transmission rate adjustment function, and in an Ethernet switch having a port that supports various transmission rates, transmission of an external device connected to the port that supports the transmission rate. The speed is automatically set to match the transmission speed supported by the switch, the data transmitted between the external device and the switch is interfaced, and when the overflow occurs in the switch due to the data input from the external device, the line connection A control signal for decelerating the input data transmission rate to coincide with the data output transmission rate is output to the unit to adjust the input data transmission rate down (see, for example, Patent Document 1).

  Also, at the output port of the switching hub, congestion judgment is performed for each terminal group, and a congestion notification packet is output only to the group that is determined to be congested. The congestion determination is performed using the buffer for each group provided at the output port. Depending on the amount, the congestion state is judged in two stages, and flow control is performed for a single port or a plurality of ports (see, for example, Patent Document 2).

JP 2001-36559 (first page-second page, FIG. 3) JP 2002-223223 (first page-second page, FIG. 1)

  By the way, when performing point-to-point communication between Ethernet terminals, end-to-end (End-to-End) transmission speed automatic setting (Auto-negotiation) control cannot be performed via a dedicated network. Therefore, since there is no means for recognizing each other's communication speed in the above-described prior art, there is a possibility of communication at different communication speeds (10 Mbps or 100 Mbps) between Ethernet terminals. When this possibility is realized, frame data that exceeds the allowable reception range is transmitted from one Ethernet terminal to the opposite Ethernet terminal.

  For this reason, when transmitting a frame from the Ethernet multiplexer to the Ethernet terminal, the frame is discarded in the Ethernet terminal, or transmission from the Ethernet multiplexer is stopped by flow control from the Ethernet terminal, and unnecessary in the Ethernet multiplexer. There is a first problem that frames are discarded.

  Further, it is considered that a frame that is inevitably discarded is transmitted in the leased line network, and there is a second problem that the bandwidth of the leased line network is used inefficiently.

  Therefore, an object of the present invention is to avoid unnecessary frame discard and to efficiently reduce network bandwidth when performing point-to-point communication between end-to-end Ethernet terminals in an Ethernet-based dedicated line network. An object of the present invention is to provide an Ethernet multiplexer that can be used for the above.

  The invention according to claim 1 is an Ethernet multiplexing apparatus that accommodates a line from an Ethernet terminal (1, 5 in FIG. 1) that performs point-to-point communication via a leased line network (3 in FIG. 1). A first MAC-PHY unit (11 in FIG. 2), a buffer unit (12 in FIG. 2), and a speed control unit (in FIG. 2) that have a one-to-one correspondence with the Ethernet line (10 in FIG. 2) to which the terminal is connected. 13), a demultiplexing unit (14 in FIG. 2), and a second MAC-PHY unit (15 in FIG. 2). The first first MAC-PHY unit accommodates an Ethernet line. The MAC frame between the Ethernet terminal is terminated, and the buffer unit includes a FIFO for writing the frame data output from the corresponding first MAC-PHY unit, and the demultiplexing unit reads from each buffer unit Frame day And a communication speed information of the Ethernet line output from the first MAC-PHY unit is inserted into a predetermined data area, and the second MAC-PHY unit The multiplexed frame output from the demultiplexing unit is mapped to a Gigabit Ethernet or SDH frame and transmitted to an aggregated line (20 in FIG. 2) such as a Gigabit Ethernet line or an SDH line. The Ethernet multiplexing device is characterized in that it detects opposite communication speed information from the opposite Ethernet line inserted in a predetermined area and outputs a read control signal to the buffer unit.

  According to a second aspect of the present invention, in the first aspect of the present invention, the buffer unit has a function of outputting a flow control signal to the first MAC-PHY unit when the frame data accumulation amount exceeds a set FIFO threshold. And the first MAC-PHY unit is an Ethernet multiplexer characterized in that it suppresses data transmission from the corresponding Ethernet terminal in response to the flow control signal.

  In the present invention, the Ethernet multiplexer detects the communication speed of the Ethernet terminal and notifies the opposite Ethernet multiplexer. In the opposite Ethernet multiplexer, the speed of reading frame data from the buffer unit is increased or decreased based on the notification.

  Also, the opposing Ethernet multiplexer performs control to suppress transmission of the connected Ethernet terminal by flow control using a pause frame or back pressure control based on the notification.

  According to the present invention, when performing point-to-point communication between end-to-end Ethernet terminals in an Ethernet-based leased line network, the Ethernet multiplexing apparatus does not exceed the reception allowable speed of the receiving-side Ethernet terminal. Since it is configured to control the transmission speed of the transmitting Ethernet terminal dynamically, it is possible to avoid unnecessary frame discard in the Ethernet multiplexer and to obtain an effect that the network bandwidth can be used efficiently. it can.

  The Ethernet multiplexer of the present invention is an Ethernet multiplexer that accommodates a line of an Ethernet terminal shell that performs point-to-point communication via a dedicated network, and is one-to-one with the Ethernet line to which the Ethernet terminal is connected. A corresponding first MAC-PHY unit, a buffer unit, a rate control unit, a demultiplexing unit, and a second MAC-PHY unit are configured.

  The first first MAC-PHY unit accommodates the Ethernet line and terminates the MAC frame with the Ethernet terminal. The buffer unit includes a FIFO for writing the frame data output from the corresponding first MAC-PHY unit. The demultiplexing unit multiplexes the frame data read from each buffer unit to generate a multiplexed frame, and further, the communication speed information of the Ethernet line output from the first MAC-PHY unit is a predetermined data area Insert into. The second MAC-PHY unit maps the multiplexed frame output from the demultiplexing unit to a Gigabit Ethernet or SDH frame, and transmits the frame to an aggregated line such as a Gigabit Ethernet line or an SDH line.

  The speed control unit detects counter communication speed information from the counter Ethernet line inserted in a predetermined area of the multiplex frame, and outputs a read control signal to the buffer unit.

  Hereinafter, specific description will be given with reference to the drawings. FIG. 1 shows a case where the Ethernet terminal 1 and the Ethernet terminal 5 perform point-to-point communication via an Ethernet-based dedicated line network 3 constructed in a MAN (metro area network) or the like. The Ethernet terminal 1 is located at the edge of the leased line network 3 and multiplexes a plurality of Ethernet lines and transmits the data to an aggregated line such as a Gigabit Ethernet line or a Synchronous Digital Hierarchy (SDH) line. It is connected to the device 2. The opposing Ethernet terminal 5 is also connected to a similar Ethernet multiplexer 4.

  Originally, when performing point-to-point communication between a terminal equipped with an Ethernet interface or an Ethernet connection device, the communication environment of 10 Mbps or 100 Mbps can be established with auto-negotiation control standardized by IEEE802.3u with the connection partner. Build and communicate. However, in the form of FIG. 1, since the Ethernet multiplexers 2 and 4 and the leased line network 3 are relayed, the auto-negotiation control cannot be performed directly between the Ethernet terminals 1 and 5, and the communication speed (10 Mbps or 100 Mbps) Point-to-point communication in different states.

  Therefore, for example, when the communication speed / method of the Ethernet terminal 1 is 100 Mbps / full duplex and the communication speed of the Ethernet terminal 5 is 10 Mbps, the Ethernet multiplexer 2 indicates that the communication speed of the Ethernet terminal 1 is 100 Mbps. The device 4 is notified as opposite communication speed information. Further, the Ethernet multiplexer 4 notifies the Ethernet multiplexer 2 as opposite communication speed information that the communication speed of the Ethernet terminal 5 is 10 Mbps.

  Now, when the MAC frame 6 is transmitted from the Ethernet terminal 1 to the Ethernet terminal 5, the Ethernet multiplexer 2 has the communication speed of the Ethernet terminal 5, that is, the opposite communication speed information is 10 Mbps. The reading speed is 10 Mbps. As a result, a MAC frame at a speed exceeding 10 Mbps is not transmitted to the Ethernet terminal 5.

  In addition, when the amount of data stored in the FIFO of the buffer unit exceeds the threshold value S, the Ethernet multiplexer 2 sends a pause frame 7 to the Ethernet terminal 1. The pause time Tp at this time is Tp = 2k / 10 Mbps = 200 ms when the threshold value S = 2 kbit, and transmission from the Ethernet terminal 1 stops only during this time.

  With the above configuration, the communication speed from the Ethernet terminal 1 to the Ethernet terminal 5 is constantly 10 Mbps.

  FIG. 2 is a detailed view of the Ethernet multiplexers 2 and 4. These Ethernet multiplexers include a MAC-PHY unit 11, a buffer unit 12, a speed control unit 13, a demultiplexing unit 14, and a MAC-PHY unit 15 that are in one-to-one correspondence with the Ethernet line 10 to which the Ethernet terminal is connected. It consists of and.

  Each MAC-PHY unit 11 accommodates an Ethernet line 10 and terminates a MAC (Media Access Control) frame 6. The buffer unit 12 has a FIFO for writing the frame data output from the corresponding MAC-PHY unit 11, and outputs a flow control signal 18 to the MAC-PHY unit 11 when the set FIFO threshold is exceeded. It has the function to do.

  The demultiplexing unit 14 multiplexes the frame data read from each buffer unit 12 to generate a multiplexed frame, and further transmits Ethernet line communication speed information 16 (10 Mbps or 100 Mbps) output from the MAC-PHY unit 11. Insert into a predetermined data area. The MAC-PHY unit 15 maps the multiplexed frame output from the demultiplexing unit 14 to a Gigabit Ethernet or SDH frame, and transmits the frame to a centralized line 20 such as a Gigabit Ethernet line or an SDH line.

  On the other hand, the demultiplexing unit 14 separates the MAC frame addressed to the Ethernet line 10 from the multiplexed frame received by the MAC-PHY unit 15. The speed control unit 13 detects the counter communication speed information 19 from the counter Ethernet line inserted in a predetermined area of the multiplex frame, and outputs a read control signal 17 to the buffer unit 12.

  Next, the operation of the Ethernet multiplexer of FIG. 2 will be described.

  First, data multiplexing processing from the Ethernet line 10 to the central line 20 will be described. The MAC-PHY unit 11 performs physical layer (PMD, PMA, PCS) and MAC processing on the input stream of each Ethernet line 10 to extract MAC frames, and the buffer unit 12 writes the MAC frame data to the FIFO. . Whether the communication speed of the Ethernet terminal 1 connected to the MAC-PHY unit 11 is 10 Mbps or 100 Mbps is recognized by the set value in the case of the auto-negotiation control or the forced mode, and the demultiplexing unit 14 transmits the communication speed. Output as information 16.

  The demultiplexing unit 14 multiplexes the MAC frame data read from the buffer unit 12 with overhead, generates a multiplexed frame, and outputs the multiplexed frame to the Gigabit Ethernet or SDH MAC-PHY unit 15. Further, the communication speed information 16 is inserted into a predetermined area within this overhead. The MAC-PHY unit 15 maps the multiplexed frame to a Gigabit Ethernet or SDH frame, and relays the concentrated line 20 to transmit it to the opposing Ethernet multiplexer.

  On the other hand, at the time of data processing from the concentrated line 20 to the Ethernet line 10, the MAC-PHY unit 15 performs stream termination from the concentrated line 20 and outputs a multiplexed frame to the demultiplexing unit 14. The demultiplexing unit 14 demultiplexes the MAC frame data multiplexed in the multiplexed frame for each Ethernet line 10 and outputs the MAC frame data to the MAC-PHY unit 11 corresponding to each Ethernet line 10. Also, the opposite communication speed information 19 of the opposite Ethernet terminal inserted in a predetermined area in the overhead added at the time of multiplexing is read and output to the speed control unit 13.

  Next, in this Ethernet multiplexing apparatus, in order not to transmit the MAC frame data exceeding the reception allowable speed of the opposite Ethernet terminal, the transmitting-side Ethernet terminal connected by the flow control using the pause frame or the back pressure control is used. A means for suppressing the transmission of will be described.

  First, the frame data reading speed from the FIFO in the buffer unit 12 is controlled. As a means for this, the speed control unit 13 recognizes the communication speed of the opposite Ethernet terminal from the counter communication speed information 19 and outputs the read control signal 17 from the FIFO in the buffer unit 12 at that communication speed.

  The buffer unit 12 monitors the amount of frame data stored in the FIFO, and outputs a flow control signal 18 to the MAC-PHY unit 11 when the amount of storage exceeds a set threshold value S. The MAC-PHY unit 11 uses the flow control signal 18 as a trigger to transmit a pause frame when the Ethernet line accommodated to the transmitting-side Ethernet terminal is full duplex.

  The Ethernet terminal that has received the pause frame stops transmission for the pause time in the pause frame according to IEEE802.3u. The pause time = Tp is Tp = S / Y seconds assuming that the opposite communication speed information = Ybps and the FIFO threshold = S bits. By stopping the transmission for the time Tp, all the frame data stored in the FIFO is read without being discarded.

  When the Ethernet line is half-duplex, back pressure control is performed on the transmitting Ethernet terminal by forced collision, and transmission during that time is stopped.

The figure which illustrates the network to which this invention is applied Configuration diagram of Ethernet multiplexer of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ethernet terminal 2 Ethernet multiplexer 3 Dedicated line network 4 Ethernet multiplexer 5 Ethernet terminal 6 MAC frame 7 Pause frame 10 Ethernet line 11 MAC-PHY part 12 Buffer part 13 Speed control part 14 Demultiplexing part 15 MAC-PHY part 16 Communication speed information 17 read control signal 18 flow control signal 19 facing the communication speed information 20 concentrate line

Claims (2)

In an Ethernet multiplexer that accommodates a line from an Ethernet (registered trademark) terminal that performs point-to-point communication via a dedicated line network,
It is composed of a first MAC-PHY unit, a buffer unit, a speed control unit, a demultiplexing unit, and a second MAC-PHY unit, one-to-one correspondence with the Ethernet line to which the Ethernet terminal is connected,
The first first MAC-PHY unit accommodates an Ethernet line and terminates a MAC frame with the Ethernet terminal;
The buffer unit includes a FIFO for writing frame data output from the corresponding first MAC-PHY unit,
The demultiplexing unit multiplexes frame data read from each buffer unit to generate a multiplexed frame, and communication speed information of the Ethernet line output from the first MAC-PHY unit is predetermined. Insert into the data area,
The second MAC-PHY unit maps the multiplexed frame output from the demultiplexing unit to a Gigabit Ethernet or SDH frame, and transmits the frame to an aggregated line such as a Gigabit Ethernet line or an SDH line.
The Ethernet is characterized in that the speed controller detects opposite communication speed information from an opposite Ethernet line inserted in a predetermined area of the multiplex frame, and outputs a read control signal to the buffer. Multiple device equipment. The buffer unit has a function of outputting a flow control signal to the first MAC-PHY unit when a frame data accumulation amount exceeds a set FIFO threshold;
The Ethernet multiplexing apparatus according to claim 1, wherein the first MAC-PHY unit suppresses data transmission from a corresponding Ethernet terminal in response to the flow control signal.

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