JP2007174152A - Network congestion control system and method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that the transmission of the same physical port are entirely stopped because congestion control is executed in the unit of the physical port when a PAUSE frame defined in the IEEE802.3x standard as the congestion control of an L2 network is used. <P>SOLUTION: The network congestion control system having a network switch provided with a congestion detection means for detecting the congestion of transmission frames received from a plurality of input output ports, and a PAUSE frame transmission means for transmitting a PAUSE frame to the input output ports whose congestion is detected by the congestion detection means, includes an extended PAUSE frame transmission means, in place of the PAUSE frame transmission means, that uses an extended PAUSE frame resulting from attaching virtual LAN information to the PAUSE frame in place of the PAUSE frame and transmits the extended PAUSE frame to the input output port. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a network technology conforming to the IEEE 802.3x standard, and more particularly to a congestion control technology using a PAUSE frame.

  As one of the relay devices that make up the network such as the Internet, an L2 switch that determines the destination of a frame and transfers it in the data link layer, which is the second layer (Layer 2: L2) of the OSI (Open Systems Interconnection) model, is used. It has been broken. The protocol of the data link layer is based on the IEEE 802.3x standard widely known as Ethernet (registered trademark), and has a MAC (Media Access Control) function. Judging where to go.

  In an L2 network system that relays using such an L2 switch, there is a high QoS (Quality of Service) requirement, bandwidth control that limits the available line capacity (communication speed), and transmission frame transmission due to timeout. In order to protect from discarding, techniques such as priority control for preferentially transferring transmission frames with high importance are used. In particular, in order to realize a network system with high QoS, it is important to solve the problem of congestion due to concentration of communication traffic, and various ideas have been made so far.

  Conventionally, as a commonly used congestion control technique, the IEEE 802.3x standard defines a congestion control method for transmitting and receiving a PAUSE frame as a flow control function in full-duplex communication, and a congestion state occurs in a network switch. The PAUSE frame is sent to the transmitting side, and the transmitting side communication apparatus that receives the PAUSE frame avoids the congestion state by stopping the transmission.

Such a conventional technique will be described with reference to FIGS. FIG. 9 is a block diagram showing the configuration of a network switch of a congestion control system according to the prior art, FIG. 10 is an explanatory diagram for explaining the contents of a PAUSE frame used in the prior art, and FIG. 11 uses a conventional congestion control system. It is a block diagram which shows the structure of the whole network.
First, the configuration of the entire network in FIG. 11 will be described. In FIG. 11, 301 is a connection line to an upper network (IP network), 152 is an upper switch using the network switch described in FIG. 9, and 153, 154 and 155 are lower circuits using the network switch described in FIG. Switches 156 to 162 are terminals connected to the network, and 163 is a line connecting the upper switch 152 and the lower switch 153.

  Terminals 156 and 157 indicate a part of terminals connected to the lower switch 153, terminals 158, 159 and 160 indicate a part of terminals connected to the lower switch 154, and terminals 161 and 162 connect to the lower switch 155. Each of the terminals to be used is shown. The lower switches 153, 154, and 155 represent a part of the lower switches connected to the upper switch 152, and the terminals 156 to 162 are connected to the upper switch 152 via any of the lower switches 153 to 155. The upper IP network can be accessed via the connection line 301.

  Next, FIG. 10 shows the configuration of a PAUSE frame used in the prior art, 251 is a PAUSE frame, 202 is a preamble (PA) for frame synchronization, 203 is a delimiter (SFD) indicating the start of the frame, 252 is the header part of the PAUSE frame, 205 is the MAC address (DMAC) of the destination (DMAC = 01-80-C2-00-00-01 is a special address indicating that it is a PAUSE frame), 206 is the source MAC address (SMAC), 208 is a frame type (0x8808 is a special value indicating a MAC control frame (0x indicates a hexadecimal number)), 209 is data, 210 is an error detection flag (FCS) is shown. The data 209 is determined to be configured as follows when the frame is a PAUSE frame. In the data 209, 253 indicates a MAC control operation code (OPCODE = 0x0001 indicates a PAUSE frame), 254 indicates an interruption time (0x0002 indicates a multiple of 512-bit transmission time, and in this case, the time is doubled) ) And 255 respectively indicate future expansion parts (filled with 0).

  Next, a conventional network switch that constitutes the upper switch 152 and the lower switches 153, 154, and 155 of FIG. 11 will be described with reference to FIG. In FIG. 9, 901 is a network switch, 102 is an input / output port on the concentrator side, 103 is a transmission / reception buffer on the concentrator side, and 104 is matched with the MAC address 205 of the receiving destination between the concentrator side and the terminal side for each transmission frame. Switch control unit for allocating frames; 105, 106 and 107 are transmission / reception buffers; 905, 906 and 907 are input / output ports; 902 is a congestion state when the usage capacity of the transmission / reception buffers 105, 106 and 107 becomes a certain amount or more The congestion detection unit 903 determines that the congestion detection signal is output, and 903 generates the PAUSE frame 251 shown in FIG. 10 based on the congestion detection signal of the congestion detection unit 902, and inputs / outputs corresponding to the transmission / reception buffers in the congestion state The PAUSE frame generated from the port is sent out.

  For example, assume that the network switch 901 in FIG. 9 shows the configuration of the upper switch 152 in FIG. 11, and the lower switch 153 is connected to the input / output port 905 via the line 163. When the input of the transmission frame of the terminal 157 input from the input / output port 905 of the upper switch 152 becomes extremely large and exceeds a certain capacity in the transmission / reception buffer 105 of the upper switch 152, the congestion detection unit 902 Upon detecting the congestion state, the PAUSE frame generation / transmission unit 903 generates the PAUSE frame 251 in FIG. 10 and transmits the PAUSE frame 251 from the input / output port 905 corresponding to the transmission / reception buffer 105. The PAUSE frame 251 sent from the upper switch 152 in FIG. 11 is input to the lower switch 153 via the line 163 in FIG.

  Next, description will be made assuming that the network switch 901 in FIG. 9 shows the configuration of the lower switch 153 in FIG. When the PAUSE frame 251 sent via the line 163 is input to the transmission / reception buffer 103 from the input / output port 102 on the concentrating side of the lower switch 153, the PAUSE frame detection control unit 904 detects the arrival of the PAUSE frame 251. The input / output port 102 on the line collecting side of the lower switch 153 is closed. Alternatively, as another method, the input / output ports 905 to 907 on the terminal side may be closed, or the PAUSE frame 251 may be transmitted as it is to all terminals connected to the lower switch 153 and the transmission is stopped on the terminal side. It may be. In any case, in such a conventional technique, the communication device that has received the PAUSE frame 251 stops all transmissions. Therefore, when a plurality of communication terminals are connected to the communication device, all communication terminals are connected. It falls into a state where it cannot communicate. For example, in FIG. 11, if the upper switch 152 sends a PAUSE frame 251 to the lower switch 154 via the line 164, all of the terminals 158 to 160 cannot be transmitted. That is, congestion can be controlled only in units of physical ports of the upper switch 152.

In order to solve such a problem, the “congestion control device in an Ethernet switch” described in Patent Document 1 uses the above-described PAUSE frame and uses a predetermined priority according to the received PAUSE frame. There is described a technique for suppressing congestion in an environment where a plurality of Ethernet switches are connected by providing suppression means for suppressing transmission traffic from the transmission queue according to the degree.
JP 2004-104427 A

In the current L2 network system, there is a high demand for the QoS function, and there is a demand for a high-quality network system that makes full use of bandwidth control and priority control of transmission frames, and solving congestion due to traffic concentration is an important issue. ing.
In addition, a PAUSE frame defined in the IEEE 802.3x standard may be used as congestion control for the L2 network. However, in the IEEE 802.3x standard specification, the congestion control unit is a physical port unit, so priority should be given to that port. Even if a transmission frame exists, there is a problem that transmission of a priority transmission frame cannot be performed because congestion control is performed in units of physical ports.

In order to solve these problems, in Patent Document 1 described above, the PAUSE frame is used so that traffic can be controlled according to the priority. The details were not described in detail.
In order to provide a high-quality network, the present invention provides a congestion control system and method capable of performing fine congestion control using an extended PAUSE frame that extends an existing PAUSE frame without providing a special standard. To do.

  The congestion control system for a network according to the present invention includes a congestion detection means for detecting congestion of a transmission frame input from a plurality of input / output ports, and a PAUSE frame for sending a PAUSE frame to the input / output port where the congestion detection means detects the congestion. In a congestion control system having a network switch having a sending means, an extended transmission frame in which virtual LAN information is added instead of the transmission frame, and an extended PAUSE in which virtual LAN information is added to the PAUSE frame instead of the PAUSE frame And an extended PAUSE frame sending means for sending the extended PAUSE frame to the input / output port instead of the PAUSE frame sending means.

  The network switch is provided with an extended PAUSE frame detecting means and a filter means for deleting the extended transmission frame in accordance with the virtual LAN information for each of the plurality of input / output ports. The detection of the extended PAUSE frame sent from the network switch is transmitted to the filter means, and the filter means deletes the extended transmission frame corresponding to the virtual LAN information described in the extended PAUSE frame. .

In particular, the virtual LAN information is a VLAN-ID value of a VLAN tag conforming to the IEEE 802.3x standard.
Alternatively, the virtual LAN information is used as a priority value of a VLAN tag of the IEEE 802.3x standard.
Further, a network comprising congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports, and PAUSE frame transmission means for sending PAUSE frames to the input / output ports where the congestion detection means has detected congestion. In a congestion control system having a switch, an extended transmission frame with virtual LAN information added instead of the transmission frame, and an extended PAUSE frame with virtual LAN information added to the PAUSE frame instead of the PAUSE frame, Filter means for deleting the extended transmission frame according to the virtual LAN information for each of a plurality of input / output ports, and filter control means for controlling the operation of the filter means instead of the PAUSE frame sending means Features.

  The network congestion control method according to the present invention also includes a congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports, and a PAUSE frame is transmitted to the input / output port where the congestion detection means detects the congestion. In a congestion control method for stopping transmission of the transmission frame by transmitting the PAUSE frame in a network including PAUSE frame transmission means, an extended transmission frame to which virtual LAN information is added instead of the transmission frame; An extended PAUSE frame in which virtual LAN information is added to the PAUSE frame is used instead of the PAUSE frame, and an extended PAUSE frame transmitting unit is provided instead of the PAUSE frame transmitting unit, and the extended PAUSE frame transmitting unit includes the congestion detection unit. Detects congestion It characterized in that the input and output ports detected congestion when sending the extended PAUSE frame.

  Alternatively, in a network comprising congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports, and PAUSE frame transmission means for sending PAUSE frames to the input / output ports where the congestion detection means has detected congestion. In the congestion control method for stopping transmission of the transmission frame by transmitting the PAUSE frame, an extended transmission frame to which virtual LAN information is added instead of the transmission frame, and a virtual transmission in the PAUSE frame instead of the PAUSE frame. A filter unit that uses an extended PAUSE frame to which LAN information is added, and deletes the extended transmission frame according to the virtual LAN information for each of the plurality of input / output ports; and the filter unit instead of the PAUSE frame sending unit Controls the operation of The filter control means has virtual LAN information described in the extended PAUSE frame by the filter means for each input / output port that has detected congestion when the congestion detection unit detects congestion. The extended transmission frame is deleted.

  In the congestion control according to the prior art using a PAUSE frame, since the unit of control is a physical port unit, it becomes impossible to transmit all transmission frames regardless of whether or not a priority transmission frame exists in the port. However, in the network congestion control system and method according to the present invention, the extended PAUSE frame to which the virtual LAN information for specifying the frame to be subjected to congestion control is used instead of the conventional PAUSE frame. It is possible to stop only the transmission frames.

In particular, by using a VLAN tag as virtual LAN information, it is possible to perform fine congestion control such as congestion control for each VLAN-ID value and congestion control for each priority value.
As described above, the network congestion control system and method of the present invention provide a high-quality network within the range of the IEEE 802.3x standard without newly providing a unique frame configuration for congestion control. Is possible.

(First embodiment)
A first embodiment of the network congestion control system of the present invention will be described in detail with reference to FIGS. FIG. 1 is a block diagram showing the configuration of a network switch in the network congestion control system of the present invention, FIG. 2 is an explanatory diagram for explaining the contents of an extended PAUSE frame used in the present invention, and FIG. 3 is the congestion of this embodiment. It is a block diagram which shows the structure of the whole network using a control system.

  First, the configuration of the entire network in FIG. 3 will be described. 3, 302 is an upper switch using the network switch described in FIG. 1, 303, 304 and 305 are lower switches using the network switch described in FIG. 1, and 306 to 312 are VLAN-IDs described later. 313, 315 and 315 are lines connecting the upper switch 302 and the lower switches 303, 304 and 305, 316 is a line connecting the lower switch 303 and the terminal 307, and 317 is the line connecting the lower switch 304 and the terminal 310. Each line to be connected is shown. Terminals 306 and 307 indicate a part of terminals connected to the lower switch 303, terminals 308, 309, and 310 indicate a part of terminals connected to the lower switch 304, and terminals 311 and 312 connect to the lower switch 305. Each of the terminals to be used is shown. Lower switches 303, 304, and 305 indicate a part of lower switches connected to the upper switch 302, and the terminals 306 to 312 are connected to the upper switch 302 via any of the lower switches 303 to 305. It is possible to access the upper IP network.

  In the present embodiment, a VLAN tag function, which is an option of the IEEE 802.3x standard, is used. FIG. 2 shows a frame structure in which a virtual LAN VLAN tag option defined by IEEE802.1Q is added to the IEEE802.3x standard frame format. 2, 201 indicates an extended PAUSE frame, 204 indicates a header portion of the extended PAUSE frame 201, and 207 indicates a VLAN tag. The description of the same reference numerals as those described in FIG.

  In the VLAN tag 207, 211 indicates a frame type (TPID) (TPID = 0x8100 indicates a VLAN tag), and 212 indicates VLAN tag control information (TCI). Further, in the TCI 212, 213 indicates a user priority (PRI) indicating priority, 214 indicates a format (CFI), and 215 indicates a VLAN identifier (VLAN-ID: VID) indicating a VLAN ID.

  The communication apparatus on the network can identify whether the DMAC 205 is 01-80-C2-00-00-01 or not, whether it is a PAUSE frame. Furthermore, in the present invention, since the VLAN tag is used, it is possible to identify whether or not the frame is an extended frame to which the VLAN tag is added depending on whether or not the TPID 211 of the VLAN tag 207 is 0x8100.

In FIG. 3, terminals 306 to 312 are terminals that use the VLAN tag described above. The terminal 306 has VID = 1, the terminal 307 has VID = 3, the terminal 308 has VID = 6, the terminal 309 has VID = 8, and the terminal. 310 is pre-assigned VID = 10, terminal 311 is pre-assigned VID = 13, and terminal 312 is pre-assigned VID = 15.
Next, network switches constituting the upper switch 302 and the lower switches 303, 304, and 305 in FIG. 3 will be described with reference to FIG. In FIG. 1, 101 is a network switch, 108, 109 and 110 are input / output ports having a VID filter function for stopping the input of the specified VLAN-ID, and 111 is congestion by looking at the used capacity of the transmission / reception buffers 105, 106 and 107. A congestion detection unit for determining the state and outputting the congestion transmission / reception buffer position and the VLAN-ID of the frame in the congestion state as a congestion detection signal, 112 generates the extended PAUSE frame shown in FIG. An extended PAUSE frame generation / transmission unit that transmits an extended PAUSE frame generated from the input / output port corresponding to the transmission / reception buffer that becomes the above, 113 is an extended PAUSE frame detection unit that detects the extended PAUSE frame of the transmission / reception buffer 103, and 114 is an input / output port 108, 109 and 110 The filter control unit for controlling the operation of the VID filter respectively show.

  For example, assume that the network switch 101 in FIG. 1 shows the configuration of the upper switch 302 in FIG. 3 and the lower switch 303 is connected to the input / output port 108 via the line 313. When the input of the transmission frame having VID = 3 input from the input / output port 108 of the upper switch 302 becomes extremely large and exceeds a certain capacity (for example, 80% of the total capacity) in the transmission / reception buffer 105, congestion occurs. The detection unit 111 detects that the transmission / reception buffer 105 is in a congested state, and outputs VID = 3 of the stagnated transmission frame to the extended PAUSE frame generation / transmission unit 112. In response to this, the extended PAUSE frame generation / transmission unit 112 generates an extended PAUSE frame 201 in which VID = 3 is set in the VLAN identifier 215 in FIG. 2 and transmits it from the input / output port 108 corresponding to the transmission / reception buffer 105. In this way, the extended PAUSE frame 201 with VID = 3 sent from the upper switch 302 in FIG. 3 is input to the lower switch 303 via the line 313 in FIG.

  Next, description will be made assuming that the network switch 101 in FIG. 1 shows the configuration of the lower switch 303 in FIG. The extended PAUSE frame 201 sent via the line 313 is input from the input / output port 102 on the line concentration side of the lower switch 303 to the transmission / reception buffer 103. Here, the extended PAUSE frame detection unit 113 always checks whether the frame received by the transmission / reception buffer 103 is an extended PAUSE frame. When the extended PAUSE frame is received, this is detected and notified to the filter control unit 114. The filter control unit 114 operates the VID filter of each input / output port corresponding to the VLAN-ID described in the received extended PAUSE frame. In this example, since the congested frame has VID = 3, only the frame with VID = 3 is not allowed to pass. That is, only the line 316 for inputting the terminal 307 having VID = 3 in FIG. 3 is stopped.

  As with the PAUSE frame, the extended PAUSE frame is also applied with the interruption time 254 of FIG. 10, and transmission is resumed when the time set for the interruption time 254 has elapsed. Of course, when extended PAUSE frames are continuously transmitted within the time set as the interruption time 254, the stop state is continued until the transmission is completed. Alternatively, if Pause Time = 0x0000 is set at the interruption time 254 and transmission is performed, transmission is resumed immediately.

In this embodiment, the upper switch and the lower switch are configured in two stages. However, even if the network switch having the same configuration as the network switch 101 shown in FIG.
As described above, since it is possible to stop transmission of only a transmission frame transmitted from a terminal having a specific VLAN-ID causing congestion, for example, the upper switch 302 in FIG. When the extended PAUSE frame having VID = 10 is sent, the lower switch 304 can only stop transmission of the transmission frame of the terminal 310 connected via the line 317, and therefore, the lower switch 305 via the line 314. Since transmission of transmission frames from a terminal with a different VLAN-ID is not stopped even if the terminal is connected to another terminal or a terminal connected to the lower switches 303 and 304, even if the same physical port is used. Communication can be performed.

(Second Embodiment)
Next, a second embodiment of the network congestion control system of the present invention will be described in detail with reference to FIGS. FIG. 4 is a block diagram showing the configuration of the network switch in the network congestion control system of the second embodiment, and FIG. 5 is a block diagram showing the configuration of the entire network using the congestion control system of this embodiment.

  First, the configuration of the entire network in FIG. 5 will be described. In FIG. 5, 502 is an upper switch using the network switch described in FIG. 4, 503, 504 and 505 are also lower switches using the network switch described in FIG. 4, and 506 to 512 are VLAN tag priorities described later. Each terminal has a value. Terminals 506 and 507 indicate a part of terminals connected to the lower switch 503, terminals 508, 509, and 510 indicate a part of terminals connected to the lower switch 504, and terminals 511 and 512 connect to the lower switch 505. Each of the terminals to be used is shown.

  Here, the priority value of the VLAN tag is the portion indicated by PRI 213 in FIG. 2 described in the first embodiment, and the higher the number, the higher the priority. For example, it is determined in advance that a transmission apparatus that transmits data having strong real-time properties such as images and sounds is transmitted with a higher priority. In FIG. 5, terminals 506 to 512 are terminals that use the VLAN tag. The terminal 506 has PRI = 1, the terminal 507 has PRI = 3, the terminal 508 has PRI = 6, and the terminal 509 has PRI = 8. , Terminal 510 is pre-assigned to PRI = 10, terminal 511 is pre-assigned to PRI = 13, and terminal 512 is pre-assigned to PRI = 15.

  In FIG. 4, the same reference numerals as those in FIG. 1 of the first embodiment have the same functions and are not described here, but 401 is a network switch that performs congestion control using the priority value of the VLAN tag, 402 Is a congestion detection unit, 403 is an extended PAUSE frame generation / transmission unit that generates an extended PAUSE frame in which a priority value is set and transmits it from the corresponding input / output port, and 404 is an extended PAUSE frame detection unit that detects an extended PAUSE frame including the priority value. , 405 is a filter control unit 405, 406, 407 and 408 for controlling the operation of the PRI filter attached to the input / output ports 406 to 408 according to the priority value output from the extended PAUSE frame detection unit 404. Output port it It is shows.

  For example, assume that the network switch 401 in FIG. 4 shows the configuration of the upper switch 502 in FIG. 5 and the lower switch 503 is connected to the input / output port 406 via the line 513. When the number of transmission frames having PRI = 1 input from the input / output port 406 of the upper switch 502 becomes extremely large and exceeds a specified capacity (for example, 80%) in the transmission / reception buffer 105, the congestion detection unit 402 Detects that the transmission / reception buffer 105 is in a congested state, and outputs PRI = 1 of the delayed transmission frame to the extended PAUSE frame generation / transmission unit 403. Receiving this, the extended PAUSE frame generation / transmission unit 403 generates an extended PAUSE frame 201 in which PRI = 1 is set in the user priority 213 in FIG. 2 and transmits it from the input / output port 406 corresponding to the transmission / reception buffer 105.

  Next, description will be continued assuming that the network switch 401 in FIG. 4 shows the configuration of the lower switch 503 in FIG. Now, assuming that the extended PAUSE frame 201 sent via the line 513 has received an extended PAUSE frame having PRI = 1 from the input / output port 102 on the concentrating side of the lower switch 503, the transmission / reception buffer 103 uses the extended PAUSE frame. The detection unit 404 detects the reception of the extended PAUSE frame, and notifies the filter control unit 405 of PRI = 1 of the frame, and the filter control unit 405 that has received this signal sets the PRI filters of the input / output ports 406 to 408 to PRI = 1 or less. Is controlled not to pass. Accordingly, the lower switch 503 in FIG. 5 stops only transmission from the terminal 506 having PRI = 1, and the terminal 507 having PRI = 3 having higher priority can continue transmission.

  Even if the same physical port is used in this way, it is possible to suppress only frames with a priority lower than that causing congestion and transmit frames with higher priority without stopping. When the third upper switch 502 sends an extended PAUSE frame having PRI = 8 to the lower switch 504 via the line 514, the lower switch 504 stops transmitting the transmission frame of the terminal with PRI = 8 or lower. Terminals 508 and 509 connected to 504 cannot transmit, but terminal 510 with PRI = 10 higher than PRI = 8 can continue to transmit. In addition, since the extended PAUSE frame is not transmitted to other terminals connected to the lower switch 505 connected via the line 515, the transmission is not stopped.

In this embodiment, transmission frames having a priority equal to or lower than the priority value set in the extended PAUSE frame are filtered. For example, only transmission frames having a specific priority value such as PRI = 8 are filtered. You may make it filter.
(Third embodiment)
Next, a third embodiment of the network congestion control system of the present invention will be described with reference to FIGS. FIG. 6 is a block diagram showing the configuration of the network switch in the network congestion control system of the third embodiment, and FIG. 7 is a block diagram showing the configuration of the entire network using the congestion control system of this embodiment. First, the configuration of the entire network in FIG. 7 will be described.

  In FIG. 7, reference numeral 702 denotes an upper switch using the network switch described in FIG. 6, reference numerals 703, 704 and 705 denote lower switches using the network switch described in FIG. 6, and reference numerals 706 to 712 denote extended PAUSE frames using VLAN tags. The terminal corresponding to is shown. Terminals 706 and 707 indicate a part of terminals connected to the lower switch 703, terminals 708, 709 and 710 indicate a part of terminals connected to the lower switch 704, and terminals 711 and 712 connect to the lower switch 705. Each of the terminals to be used is shown. Also, terminal 706 has VID = 1, terminal 707 has VID = 3, terminal 708 has VID = 6, terminal 709 has VID = 8, terminal 710 has VID = 10, terminal 711 has VID = 13, and terminal 712 has VID = 15. Are pre-assigned.

In FIG. 6, reference numeral 601 denotes a network switch according to the third embodiment that performs congestion control using the VLAN-ID value of the VLAN tag, and reference numerals 608, 609, and 610 denote input / output ports. In addition, since the thing of the same code | symbol as FIG. 1 of 1st Embodiment has the same function, description is abbreviate | omitted.
For example, assume that the network switch 601 in FIG. 6 shows the configuration of the upper switch 702 in FIG. 7 and the lower switch 703 is connected to the input / output port 608 via the line 713. When the input of a transmission frame having VID = 3 input from the input / output port 608 of the upper switch 702 becomes extremely large and exceeds a prescribed capacity (for example, 80%) in the transmission / reception buffer 105, the congestion detection unit 111 Detects that the transmission / reception buffer 105 is in a congested state, and outputs VID = 3 of the stagnated transmission frame to the extended PAUSE frame generation / transmission unit 112. Receiving this, the extended PAUSE frame generation / transmission unit 112 generates an extended PAUSE frame in which VID = 3 is set, and transmits it from the input / output port 608 corresponding to the transmission / reception buffer 105. The operation up to this point is exactly the same as in the first embodiment, but the input / output ports 608 to 610 are different from the first embodiment in that they do not have a VID filter function.

  In the case of this embodiment, it is assumed that the terminals 706 to 712 shown in FIG. 7 are terminals corresponding to the extended PAUSE frame used in the present invention, and corresponds to the VID of the extended PAUSE frame transmitted by the extended PAUSE frame generation / transmission unit 112. The terminal that recognizes itself recognizes itself and operates to stop transmission. A terminal that does not support the VID of the extended PAUSE frame transmitted by the extended PAUSE frame generation / transmission unit 112 operates without stopping transmission.

  As described above, if only the terminal corresponding to the extended PAUSE frame is used, the extended PAUSE frame describing the VID in which the upper switch 702 in FIG. 7 is congested is sent to the lower level via the lines 713, 714 and 715. For example, if VID = 3 and VID = 10 are designated by sending to the switches 703, 704 and 705, the terminals 707 and 710 recognize this and each terminal stops transmission itself. Can be simplified as compared with the first embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the network congestion control system of the present invention will be described with reference to FIG. FIG. 8 is a block diagram showing the configuration of a network switch in the network congestion control system of the fourth embodiment. In FIG. 8, reference numeral 801 denotes the configuration of a network switch based on filter control according to the fourth embodiment, and the other individual components are the same as those in FIG. 1, but are different from the first embodiment. 1 includes a filter control unit 114 instead of the extended PAUSE frame generation / transmission unit 112 in FIG. 1, and there is no extended PAUSE frame detection unit as in the third embodiment. In addition, only a connection differs from FIG. 1, and the thing of the same code | symbol has the same function.

  If the input of the transmission frame having VID = 3 input from the input / output port 108 in FIG. 8 becomes extremely large and exceeds the specified capacity in the transmission / reception buffer 105, the congestion detection unit 111 is congested in the transmission / reception buffer 105. It is detected that the state has been reached, and VID = 3 of the stagnated transmission frame is output to the filter control unit 114. Receiving this, the filter control unit 114 sets the VID filters of the input / output ports 108 to 110 to VID = 3, and controls to filter frames having VID = 3. When the congestion detection unit 111 stops detecting congestion, the filter control unit 114 cancels the filtering and operates to pass a frame with VID = 3.

As described above, by not passing a frame having a VLAN-ID causing congestion until congestion is eliminated, congestion control can be easily performed, and the configuration of the network switch can be simplified.
The first to fourth embodiments related to the network congestion control system and method according to the present invention have been described above. However, the third and fourth embodiments control the congestion only by the VLAN-ID of the VLAN tag. As described above, control may be performed by priority values as in the second embodiment, or VLAN-ID values and priority values may be combined and controlled. That is, by providing both the VID filter and the PRI filter at the input / output port, only the VID = 3 and PRI = 5 or less are stopped, or the transmission frame of PRI = 8 or less and VID = 1 is not stopped. It becomes possible to perform fine congestion control.

  As described above, in the present invention, by using an extended PAUSE frame having a VLAN tag, it becomes possible to control congestion of terminals accommodated in the same physical port, which was difficult in the prior art, and a special frame configuration is used for congestion control. Without providing a new network, it is possible to provide a high-quality network within the range of the IEEE 802.3x standard.

1 is a block diagram illustrating a network switch 101 according to a first embodiment. It is explanatory drawing explaining the extended PAUSE frame used by this invention. 1 is a block diagram illustrating an entire system according to a first embodiment. It is a block diagram which shows the network switch 401 of 2nd Embodiment. It is a block diagram which shows the whole system of 2nd Embodiment. It is a block diagram which shows the network switch 601 of 3rd Embodiment. It is a block diagram which shows the whole system of 3rd Embodiment. It is a block diagram which shows the network switch 801 of 4th Embodiment. It is a block diagram which shows the network switch 901 by a prior art. It is explanatory drawing explaining the PAUSE frame of a prior art. It is a block diagram which shows the whole system by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Network switch 105 ... Transmission / reception buffer 108 ... Input / output port with VID filter 111 ... Congestion detection unit 112 ... Extended PAUSE frame generation / transmission unit 113 ... Extended PAUSE frame detection unit 114 ..Filter control unit 201 ... extended PAUSE frame 207 ... VLAN tag 213 ... user priority (PRI)
215 ... VLAN identifier (VLAN-ID: VID)
251 ... PAUSE frame

Claims (7)

Congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports;
PAUSE frame sending means for sending a PAUSE frame to the input / output port where the congestion detecting means has detected congestion;
In a congestion control system having a network switch with
An extended transmission frame with virtual LAN information added instead of the transmission frame;
An extended PAUSE frame in which virtual LAN information is added to the PAUSE frame instead of the PAUSE frame;
Use
A congestion control system comprising extended PAUSE frame sending means for sending the extended PAUSE frame to the input / output port instead of the PAUSE frame sending means. The congestion control system according to claim 1,
An extended PAUSE frame detection means in the network switch;
Filter means for deleting the extended transmission frame according to the virtual LAN information for each of the plurality of input / output ports;
Provided,
The extended PAUSE frame detection means informs the filter means of detection of the extended PAUSE frame sent from another network switch.
The network congestion control system according to claim 1, wherein the filter means deletes the extended transmission frame corresponding to the virtual LAN information described in the extended PAUSE frame. In the congestion control system according to any one of claims 1 and 2,
A network congestion control system, wherein the virtual LAN information is a VLAN-ID value of a VLAN tag of IEEE802.3x standard. In the congestion control system according to any one of claims 1 and 2,
A congestion control system for a network, wherein the virtual LAN information is used as a priority value of a VLAN tag of IEEE802.3x standard. Congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports;
PAUSE frame sending means for sending a PAUSE frame to the input / output port where the congestion detecting means has detected congestion;
In a congestion control system having a network switch with
An extended transmission frame with virtual LAN information added instead of the transmission frame;
An extended PAUSE frame in which virtual LAN information is added to the PAUSE frame instead of the PAUSE frame;
Use
Filter means for deleting the extended transmission frame according to the virtual LAN information for each of the plurality of input / output ports;
Filter control means for controlling the operation of the filter means instead of the PAUSE frame sending means;
The congestion control system characterized by providing. Congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports;
PAUSE frame sending means for sending a PAUSE frame to the input / output port where the congestion detecting means has detected congestion;
In a congestion control method for stopping transmission of the transmission frame by sending the PAUSE frame in a network comprising:
An extended transmission frame with virtual LAN information added instead of the transmission frame;
An extended PAUSE frame in which virtual LAN information is added to the PAUSE frame instead of the PAUSE frame;
Use
In place of the PAUSE frame sending means, an extended PAUSE frame sending means is provided,
The extended PAUSE frame transmission means transmits the extended PAUSE frame to an input / output port that detects congestion when the congestion detection unit detects congestion. Congestion detection means for detecting congestion of transmission frames input from a plurality of input / output ports;
PAUSE frame sending means for sending a PAUSE frame to the input / output port where the congestion detecting means has detected congestion;
In a congestion control method for stopping transmission of the transmission frame by sending the PAUSE frame in a network comprising:
An extended transmission frame with virtual LAN information added instead of the transmission frame;
An extended PAUSE frame in which virtual LAN information is added to the PAUSE frame instead of the PAUSE frame;
Use
Filter means for deleting the extended transmission frame according to the virtual LAN information for each of the plurality of input / output ports;
Filter control means for controlling the operation of the filter means instead of the PAUSE frame sending means;
Provided,
The filter control unit deletes the extended transmission frame having the virtual LAN information described in the extended PAUSE frame by the filter unit for each input / output port that has detected congestion when the congestion detection unit detects congestion. A network congestion control method characterized by the above.

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