JP4365798B2 - Data frame transfer apparatus and data frame transfer method - Google Patents

Description

  The present invention relates to a data frame transfer apparatus and a data frame transfer method.

  2. Description of the Related Art Conventionally, in a data frame transfer apparatus constituting a data communication network, a method for avoiding frame discard by controlling frame transfer processing when traffic congestion occurs is known (Non-patent Document 1).

  The PAUSE function disclosed in Non-Patent Document 1 is to suppress frame discard when the reception buffer of the layer 2 switch or Ethernet (registered trademark) end station is congested.

  This PAUSE function is used when the traffic receiving side device (receiving side switch or end station) detects the congestion of the receiving buffer, this receiving side device becomes the traffic transmitting side device (sending side switch or end station). A PAUSE frame that stops data frame transmission is transmitted. Then, the transmission side apparatus that has received this PAUSE frame stops the transmission of the data frame. As a result, the transmission rate of the transmission side device is limited according to the congestion status of the reception side device, so that the congestion state of the reception buffer in the reception side device can be avoided.

  The DiffServ function shown in Non-Patent Document 2 determines the frame transmission order according to the priority class of the received data frame when congestion occurs in the receiving side device (IP router).

  When this DiffServ function is used, when congestion occurs in the IP router, the IP router preferentially discards the low priority class data frame. If congestion can be avoided by this data frame discard, the data frame belonging to the high priority class is not discarded by the IP router. As a result, even if congestion of the data frame transfer of the low priority class occurs in the IP router, the data frame transfer of the high priority class can be prevented from being affected by this.

  The Ethernet (registered trademark) priority processing function shown in Non-Patent Document 3 determines the frame transmission order according to the priority class to which the received frame belongs when congestion occurs in the receiving side device (Ethernet (registered trademark) switch). The purpose is to decide.

  If this Ethernet (registered trademark) priority processing function is used, the data frame transfer of the high priority class is not affected by the congestion of the data frame transfer of the low priority class as in the DiffServ function. be able to.

  The congestion control function using the Source Quench message shown in Non-Patent Document 4 suppresses frame discard when the reception buffer of the IP gateway apparatus or IP host is congested.

  When this function is used, when congestion is detected in the reception gateway of the traffic reception side IP gateway or the IP host, the reception side device sends a Source Quench message (to the transmission side device based on the transmission source IP address). (Congestion notification message including destination IP address information where congestion has occurred). Then, the transmission side apparatus that has received this Source Quench message limits the transmission rate of traffic addressed to the IP address included in this message.

  As a result, the transmission rate of the transmission-side apparatus is limited according to the congestion status of the reception-side apparatus, so that the congestion state of the reception buffer in the reception-side apparatus can be avoided.

lEEE802.3, “IEEE Standard for Information techno1ogy--Telecommunications and information exchange between Systems--Local and metropolitan area networks--Specific requirements--Part3: Carrier Sense Multiple Access With Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications " IETF RFC2475, "An Architecture for Differentiated Services", S.Blake, et al. (1998.12), [online], [searched on February 24, 2005], Internet <URL: http://www.ietf.org/ rfc / rfc2475.txt? number = 2475> 1EEE802.1D, “Information techno1ogy--Telecommunications and information exchange between systems--Local area networks--Media Access Control (MAC) bridges" IETF RFC792, "INTERNET CONTROL MESSAGE PROTOCOL DARPA INTERNET PROGRAM PROTOCOL SPECIFICAT10N", J Postel, (1981.9), [online], [searched February 24, 2005], Internet <URL: http://www.ietf.org /rfc/rfc2475.txt?number=792>

  However, in the congestion control method using the PAUSE function disclosed in Non-Patent Document 1, when congestion is detected in the traffic reception side device, the transmission side device transmits the data frame transferred to the reception side device. Stops all transmissions.

  Also, in the congestion control method using the priority control function disclosed in Non-Patent Document 2 and Non-Patent Document 3, when traffic congestion occurs in the receiving side device, transmission control is performed based on the priority class of the received frame. It's just what you do.

  That is, in any of the congestion control methods disclosed in Non-Patent Document 1 to Non-Patent Document 3, a device in which congestion occurs has a plurality of communication ports, and only a part of the traffic destined to the communication ports is in a congestion state. At this time, there is a possibility that frame discard may occur even in traffic destined for other communication ports where congestion has not occurred. That is, there is a possibility that traffic interference occurs between the transmission destination communication ports of the traffic receiving side apparatus.

  Further, in the congestion control method using the message shown in Non-Patent Document 4, transmission rate control is performed based on the destination IP address. When this method is applied to congestion control in a data transfer device that does not use an IP address, such as a layer 2 switch or an Ethernet (registered trademark) end station, the data transfer device that performs the congestion control performs traffic distribution processing by IP address. Therefore, the processing in the data transfer apparatus becomes complicated.

  The present invention solves the above-described problem, and in a data frame transfer apparatus having a plurality of communication ports, when congestion occurs only in traffic destined to some communication ports, the traffic distribution process using the IP address is not performed. It is an object of the present invention to provide a data frame transfer apparatus or the like that does not affect the traffic of a communication port that is not congested by controlling the transmission rate of traffic destined for the communication port that is congested.

In order to solve the above-described problems, the present invention is to communicate with a core network communication port connected to a core network for performing communication between data frame transfer apparatuses and an external data communication network different from the core network. A data frame transfer apparatus that includes one or more external communication ports and performs data frame transfer, and is written in the header of the data frame received from the external communication port, the core network communication port, and the external communication port A transmission destination communication port resolution unit that identifies identification information of a transmission destination external communication port of the transmission destination data frame transfer device of the data frame in accordance with the information and resolves the transmission destination external communication port; and a transmission destination of the transmission destination data frame transfer device For each external communication port identification information, this communication port Given a storage unit for storing transmission rate setting table showing the transmission rate of the data frame, measures the queue length of each destination external communication port in the buffer of the data frame of its own data frame transfer device, the queue length When there is a communication port exceeding the threshold value, it is determined that congestion has occurred in the communication port, the congestion occurrence communication port identification information that is identification information of the communication port in which congestion has occurred , and other data frames Generates a congestion notification data frame including a transmission rate control duration, which is a time from when the transmission rate of the data frame transmitted to the congestion occurrence communication port is lower than the initial value to when the transfer device returns to the initial value. The congestion notification data frame generation unit and the generated congestion notification data frame are connected to the core network communication port. When a congestion notification data frame is received from another data frame transfer device via a data frame transmission / reception unit that transmits data to another data frame transfer device via the core network communication port, congestion occurs in this congestion notification data frame. Congestion notification data frame analysis unit that reads out communication port identification information and writes the transmission rate of the data frame to this congestion occurrence communication port in the transmission rate setting table, and a data frame to be transmitted to the congestion occurrence communication port based on the transmission rate setting table possess a data frame transmission rate control unit for controlling the delivery rate of the congestion notification data frame analysis unit, the transmission rate setting table, when writing the transmission rate of the data frames to congestion communication port, as transmission rate Write a value lower than the initial value and After the elapse of the transmission rate control duration included in the congestion notification data frame, the initial value is restored . Other configurations will be described in embodiments described later.

  According to the present invention, when a network is configured by connecting a plurality of data frame transfer apparatuses, congestion occurs when only traffic of some communication ports of the data frame transfer apparatus is in a congestion state. It is possible to transfer a frame that is not affected by congestion to other communication ports that are not connected. As a result, the throughput of the entire network can be improved.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the overall configuration of a system to which the data frame transfer device (edge node of the core network) of the present embodiment is connected (accommodated). The overall configuration of the system according to the present embodiment will be described with reference to FIG. Here, a case where the core network 10 of the IP networks (external data communication networks) 4 to 9 is an Ethernet (registered trademark) network will be described as an example. A core network is a large-capacity backbone communication line that connects networks. For example, a line that connects connection bases in an Internet service provider, a provider and another provider, or an IX (Internet eXchange, business operator) Lines connecting the interconnection points). In the present embodiment, the case where the external data communication networks to which the core network 10 is connected is the IP networks 4 to 9 will be described as an example, but the present invention is not limited to this.

  The system according to the present embodiment connects the IP networks 4 to 9, the core network 10, the data frame transfer apparatus 1 that connects the IP networks 4 and 5, and the core network 10, and the IP networks 6 and 7 and the core network 10. And a data frame transfer device 3 that connects the IP networks 8 and 9 and the core network 10.

  The data frame transfer apparatuses 1 to 3 transfer the data frames received via the IP networks 4 to 9 to the data frame transfer apparatuses 1 to 3 as the transmission destination via the core network 10. For example, when the data frame transfer device 1 receives a data frame addressed to the IP network 6 via the IP network 4, the data frame transfer device 1 transfers data to the data frame transfer device 2 via the core network 10.

  The data frame transfer apparatus 1 includes an edge node (edge router, L2SW (layer 2 switch), etc.) of the core network 10 that includes at least one communication port of the IP network 4 or 5 and one or more communication ports of the core network 10. ). Here, the data frame transfer apparatuses 1 to 3 are communication ports connected to the core network 10 (core network communication ports in claims) and communication ports connected to any of the IP networks 4 to 9 (external communication in claims). Ports) are each provided as one or more. The data frame transfer apparatus 1 includes a communication port 11 connected to the core network 10 and communication ports 12 and 13 connected to the IP networks 4 and 5. Similarly, the data frame transfer apparatus 2 includes a communication port 21 connected to the core network 10 and includes communication ports 22 and 23 connected to the IP networks 6 and 7. Similarly, the data frame transfer apparatus 3 also includes a communication port 31 connected to the core network 10 and communication ports 32 and 33 connected to the IP networks 8 and 9. When the core network 10 is Ethernet (registered trademark), the communication ports 11, 21, 31 are communication ports for Ethernet.

  For example, when the data frame transfer apparatus 1 of FIG. 1 receives a data frame via the IP network 4 and the communication port 12, it outputs this data frame to the core network 10 via the communication port 11. Then, the data is input from the core network 10 to the data frame transfer device 2 via the communication port 21 and output to the IP network 6 via the communication port 22.

  The number of data frame transfer apparatuses 1 to 3, the IP networks 4 to 9 and the core network 10 and the number of communication ports of the data frame transfer apparatuses 1 to 3 are not limited to the numbers shown in FIG.

(Data frame transfer device)
Next, the configuration of the data frame transfer apparatuses 1 to 3 will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the data frame transfer apparatus of FIG.
Since the configuration of the data frame transfer apparatus 1 in FIG. 1 is the same as that of the data frame transfer apparatuses 2 and 3, the configuration of the data frame transfer apparatus 1 will be described here as a representative.

  As shown in FIG. 2, the data frame transfer apparatus 1 includes communication ports 11 to 13 for the IP networks 4 and 5 and the core network 10, and a CPU (Central Processing Unit) 14 and a main memory 16 which is a storage area when the CPU 14 performs various arithmetic processes. The main memory 16 stores a data frame transfer program 120, a destination communication port resolution table 109, a transmission rate setting table 110, and a congestion determination table 111.

The CPU 14 executes the data frame transfer process of the present embodiment based on the data frame transfer program 120 while referring to the transmission destination communication port resolution table 109, the transmission rate setting table 110, and the congestion determination table 111. Details of the data frame transfer program 120, the destination communication port resolution table 109, the transmission rate setting table 110, and the congestion determination table 111 will be described in detail with reference to FIG.
Instead of executing the data frame transfer program 120 by the CPU 14, the data frame transfer process of the present embodiment may be executed by dedicated hardware.
By doing in this way, the data frame transfer process by the data frame transfer apparatuses 1-3 can be sped up. Of course, a part of the data frame transfer process may be executed by dedicated hardware, and a part may be executed by the CPU 14 and the data frame transfer program 120.

  FIG. 3 is a block diagram illustrating the functions of the data frame transfer apparatus of FIG. The function of the data frame transfer apparatus 1 will be described with reference to FIGS. 1 and 2 as appropriate and with reference to FIG.

  The data frame transfer apparatus 1 includes communication ports 11 to 13 that are input / output interfaces with the core network 10 and the IP networks 4 and 5, and a control unit that executes transfer processing of data frames input via the communication ports 11 to 13. And a storage unit 140 that stores a destination communication port resolution table 109, a transmission rate setting table 110, and a congestion determination table 111. The storage unit 140 corresponds to the main memory 16 shown in FIG.

  The control unit 130 includes a data frame transmission / reception unit 101 that transmits / receives data frames via the communication ports 11 to 13, and congestion notification data that determines whether or not a data frame (congestion notification data frame) including a congestion notification has been received. Data received by referring to the frame reception determination unit 102, the congestion notification data frame analysis unit 103 that analyzes the congestion notification data frame and sets the transmission rate in the transmission rate setting table 110, and the destination communication port resolution table 109 A transmission destination communication port resolution unit 104 that performs resolution (specification) of a transmission destination communication port of a frame, a transmission data frame generation unit 105 that generates a transmission data frame to be transmitted via the data frame transmission / reception unit 101, and a transmission rate setting table 110 The transmission data frame of the generated transmission data frame with reference to FIG. A data frame transmission rate control unit 106 that controls the communication, and a congestion determination unit (congestion determination unit) for each destination communication port that determines whether or not congestion has occurred in the communication ports 12 and 13 with reference to the congestion determination table 111 107 and a congestion notification data frame generation unit 108 that generates a congestion notification data frame when congestion occurs in the communication ports 12 and 13.

  These components are realized by the CPU 14 executing the data frame transfer program 120 while referring to the transmission destination communication port resolution table 109, the transmission rate setting table 110, and the congestion determination table 111.

  Next, each component of the control unit 130 will be described. Here, both the case where the data frame transfer apparatus 1 is a data frame reception side and the case where it is a transmission side will be described together.

  The data frame transmission / reception unit 101 outputs the data frame received from the communication port 11 to the congestion notification data frame reception determination unit 102. The data frame transmission / reception unit 101 refers to the header information of the data frame output from the data frame transmission rate control unit 106 and outputs the data frame to any one of the communication ports 11 to 13. The data frame transmitted at this time is a normal data frame (a data frame other than the congestion notification data frame) or a congestion notification data frame.

  The congestion notification data frame reception determination unit 102 determines whether or not the data frame received from the data frame transmission / reception unit 101 is a congestion data frame, and if the received data frame is a congestion notification data frame, The data is output to the congestion notification data frame analysis unit 103. On the other hand, if the received data frame is not a congestion notification data frame, the received data frame is output to the destination communication port resolution unit 104. Here, whether or not the received data frame is a congestion notification data frame is determined based on whether or not the value of the data frame type identifier is a value indicating the congestion notification data frame.

  The congestion notification data frame analysis unit 103 analyzes the congestion notification data frame output from the congestion notification data frame reception determination unit 102, and acquires congestion occurrence communication port identification information from this data frame. Then, a set of the congestion generation communication port identification information and the transmission rate is set in the transmission rate setting table 110 so as to limit the transmission rate of the data frame addressed to the congestion generation communication port.

The transmission rate setting table 110 will be described with reference to Table 1. Table 1 is an example of the transmission rate setting table 110.

  As shown in Table 1, the transmission rate setting table 110 is a destination data frame transfer device (for example, in the case of the transmission rate setting table 110 of the data frame transfer device 2 in FIG. ) Shows the transmission rate (transmission rate) to the communication port of the transmission destination data frame transfer apparatus for each identification information of the transmission destination communication port which is an external communication port. That is, the transmission rate setting table 110 shows the transmission rate to the communication port for each external communication port identification information in the receiving side data frame transfer apparatus.

  For example, in Table 1, information “500 Mbps” is set as the transmission rate of the data frame addressed to the communication port of the transmission destination communication port identification information “a” in the transmission rate setting table 110, and the transmission destination communication port identification information “b”. , “E” and “f” indicate that information “1 Gbps” is set as the transmission rate of the data frames addressed to the communication ports. In addition, the transmission rate information includes a predetermined value (for example, 1 Gbps) in the initial state, and every time the congestion notification data frame analysis unit 103 receives the congestion notification data frame, the congestion notification data frame analysis unit 103 It is updated to a value (for example, 500 Mbps or 0 Mbps) lower than this value (1 Gbps). When the congestion notification data frame is not received for a predetermined time or more, the transmission rate information is updated to the initial value (1 Gbps) for each destination communication port identification information.

  Incidentally, when the value of the transmission rate in the transmission rate setting table 110 is set to 0 Mbps, the data frame transfer device 1 stops transmission (transfer) of the data frame addressed to the communication port of the transmission destination data frame transfer device.

  In the above-described embodiment, the transmission rate setting table 110 is set (updated) at the timing when the congestion notification data frame is received. For example, the data frame transfer apparatus 1 has congestion related to the congestion-occurring communication port. The notification data frame may be set (updated) when a predetermined number of notification data frames are received within a predetermined time.

  The destination communication port resolution unit 104 resolves the destination external communication port based on the destination IP address (routing information in the claims) included in the data frame output from the congestion notification data frame reception determination unit 102, that is, the destination The identification information of the communication port (destination external communication port) is specified. Specifically, first, the destination IP address included in the congestion notification data frame is read. Next, the destination communication port identification information of this data frame is searched from the destination communication port resolution table 109 using this IP address as a key. Then, the destination communication port resolution unit 104 assigns the searched destination communication port identification information to the data frame and outputs the data frame to the transmission data frame generation unit 105.

Here, the destination communication port resolution table 109 will be described using Table 2. Table 2 is a table illustrating the destination communication port resolution table 109.

  As shown in Table 2, for each destination IP address of the data frame, the destination communication port resolution table 109 transmits the communication port identification information (transmission) of the destination data frame transfer device when transmitting the data frame addressed to the IP address. (Destination communication port identification information).

  For example, when a data frame having a destination IP address “192.168.1.0/24” is received, this data frame is transmitted to the communication port “a” of the transmission destination data frame transfer device, and “192.168 .. When the data frame of “2.0 / 24” is received, it indicates that the data frame is transmitted to the communication port “b” of the transmission destination data frame transfer apparatus. In other words, when the destination communication port resolution unit 104 receives the data frame of the destination IP address “192.168.1.1”, the destination communication port identification information “a” of the data frame is changed to the data frame. And output to the transmission data frame generation unit 105.

  The transmission data frame generation unit 105 generates a transmission data frame in accordance with the type of the transmission destination communication port for the data frame output from the transmission destination communication port resolution unit 104, and controls the transmission data frame for data frame transmission rate control. To the unit 106. For example, when the destination communication port is the communication port 11 connected to the core network 10, an Ethernet (registered trademark) header is added to the transmission data frame and output to the data frame transmission rate control unit 106.

  The data frame transmission rate control unit 106 buffers the data frames received from the transmission data frame generation unit 105 and the congestion notification data frame generation unit 108, and transmits the data frames in the buffer to the data frame transmission / reception unit 101. To do.

  At this time, the data frame addressed to the communication port (congestion occurrence communication port) set in the transmission rate setting table 110 is transmitted at the transmission rate set in the transmission rate setting table 110. If the transmission rate is not set in the transmission rate setting table 110, the transmission data frame is extracted from the buffer and transmitted at the predetermined transmission rate stored in the storage unit 140.

  The congestion determination unit (congestion determination unit) 107 for each transmission destination communication port measures the queue length for each transmission destination communication port in the buffer of the data frame transmission rate control unit 106, and sets a threshold for determining the queue length of this communication port. Determine if it has exceeded. Specifically, referring to the queue length for each transmission destination port measured by the congestion determination unit 107 and the congestion determination table 111, whether or not there is a communication port that exceeds the threshold set in the congestion determination table 111. Determine whether. Here, when the congestion determination unit 107 determines that the queue length of the communication port exceeds a predetermined threshold, the congestion notification data frame generation unit 108 is notified of this communication port identification information as congestion occurrence communication port identification information. To do.

Here, the congestion determination table 111 will be described with reference to Table 3. As shown in Table 3, the congestion determination table 111 shows, for each external communication port identification information (destination communication port identification information), a queue length threshold value for determining that the communication port is congested. Is

  For example, when the congestion determination unit 107 determines that the queue length of the communication port of the communication port identification information “a” exceeds “xxx (byte)” based on the congestion determination table 111 of Table 3, the congestion determination unit 107 is congested with the communication port. Is determined to have occurred.

  The congestion notification data frame generation unit 108 sets the value of the data frame type identifier to a value indicating the congestion notification data frame based on the congestion communication port identification information output from the congestion determination unit 107. The data frame is output to the data frame transmission rate control unit 106. This congestion notification data frame is transmitted to all data frame transfer apparatuses that are transmission sources by using a multicast address as a destination address.

Here, the congestion notification data frame generated by the congestion notification data frame generation unit 108 will be described with reference to FIG. FIG. 4 is a diagram illustrating a congestion notification data frame according to the present embodiment.
As shown in FIG. 4, the congestion notification data frame includes a destination MAC address 401, a transmission source MAC address 402, and a type field 403 as a header, and a MAC control command 404, a MAC port 405 of a congestion occurrence communication port, and padding 406 as a payload. including. The value of the data frame type identifier is indicated by a combination of the type field 403 and the MAC control command 404.

  Next, the data frame transfer procedure of the data frame transfer apparatus 1 will be described with reference to FIGS. FIG. 5 is a flowchart showing a data frame transfer procedure of the data frame transfer apparatus of FIG.

  First, a network administrator or the like sets a transmission destination communication port resolution table 109 and a congestion determination table 111 in the storage unit 140 of the data frame transfer apparatus 1 via a PC (Personal Computer) (step S201). For example, a PC is connected to the communication port 11, and setting information is input to the data frame transfer apparatus 1 via the PC and the communication port 11.

  Next, when the data frame transmission / reception unit 101 of the data frame transfer apparatus 1 receives the data frame via the communication port 11 (step S202), the data frame transmission / reception unit 101 outputs the data frame to the congestion notification data frame reception determination unit 102 and receives the congestion notification data frame. The determination unit 102 determines whether the received data frame is a congestion notification data frame (step S203).

  If the congestion notification data frame reception determination unit 102 determines that the received data frame is not a congestion notification data frame (No in step S203), the congestion notification data frame reception determination unit 102 outputs the data frame to the transmission destination communication port resolution unit 104. Then, the transmission destination communication port resolution unit 104 searches the transmission destination communication port resolution table 109 using the destination IP address information included in this data frame as a key, and acquires the transmission destination communication port identification information of this data frame. (Step S204).

  The transmission data frame generation unit 105 then determines the type of transmission destination communication port (for example, whether it is a communication port connected to the core network 10) based on the transmission destination communication port identification information specified by the transmission destination communication port resolution unit 104. Judging. Then, the transmission data frame generation unit 105 generates a transmission data frame according to the type of the transmission destination communication port determined by the transmission destination communication port resolution unit 104 based on the transmission destination communication port identification information (step S205).

  Subsequently, the data frame transmission rate control unit 106 buffers the transmission data frame generated by the transmission data frame generation unit 105 (step S206). At this time, the congestion determination unit 107 measures the queue length for each transmission destination communication port in this buffer, and determines whether or not there is a communication port having a queue length exceeding a predetermined threshold (step S207). Specifically, the congestion determination unit 107 refers to the congestion determination table 111 and determines whether each of the communication ports 11 to 13 exceeds the queue length defined in the congestion determination table 111.

  Here, when there is a communication port exceeding the predetermined threshold (Yes in Step S207), the congestion notification data frame generation unit 108 generates a congestion notification data frame including the congestion occurrence communication port identification information (Step S207). S221), the process proceeds to step S222. On the other hand, when there is no communication port exceeding the predetermined threshold (No in step S207), the process proceeds to step S222 as it is.

  In step S222, the data frame transmission rate control unit 106 controls the data frame transmission / reception unit 101 to set the data frame addressed to the congestion occurrence communication port set in the transmission rate setting table 110 in the transmission rate setting table. The transmission data frame is extracted from the buffer at the transmission rate that has been set, or at the determined transmission rate otherwise. Then, based on the destination communication port identification information, the transmission data frame is transmitted to the corresponding communication port (step S223), and the process returns to step S202.

  Here, if the data frame received in step S203 is a congestion notification data frame (Yes in step S203), that is, the data frame transfer device 1 is connected to another data frame transfer device (for example, the data frame transfer devices 2 and 3). A processing procedure when a congestion notification data frame is received will be described.

  When receiving the congestion notification data frame, the data frame transfer apparatus 1 analyzes the received congestion notification data frame and acquires congestion occurrence communication port identification information (step S210). Specifically, the congestion notification data frame analysis unit 103 reads the congestion occurrence communication port identification information included in the received congestion notification data frame. Then, a set of the congestion occurrence communication port identification information and the transmission rate is set in the transmission rate setting table 110 so as to limit the transmission rate of the data frame addressed to the communication port (step S211), and the process returns to step S202.

  For example, the congestion notification data frame analysis unit 103 of the data frame transfer apparatus 2 in FIG. 1 has received a notification that congestion has occurred in the communication port 12 of the communication port identification information “a” of the data frame transfer apparatus 2. At this time, as in the transmission rate setting table 110 shown in Table 1, communication destination port identification information “a” and the transmission rate “500 Mbps” of this communication port are set. The data frame transmission rate control unit 106 of the data frame transfer apparatus 2 controls the data frame transmission rate based on the transmission rate setting table 110. In this way, the traffic addressed to the communication port 13 of the data frame transfer apparatus 1 can be transmitted regardless of the congestion occurring at the communication port 12 of the data frame transfer apparatus 1 (the communication port corresponding to the communication port identification information “a”). Can be transferred without data loss.

  Next, the operation of the data frame transfer apparatuses 1 to 3 according to the present embodiment will be described in detail with reference to FIGS. 1 to 5 and FIG. Here, a plurality of MAC addresses (Media Access Control addresses) are assigned to the communication ports 11, 21 and 31 to the core network 10 of the data frame transfer apparatuses 1 to 3 as transmission destination communication port identification information, and the MAC addresses are assigned to the MAC addresses. The case where this MAC address is used when the external communication port of the data frame transfer apparatus 1 is uniquely determined based on this will be described. FIG. 6 is a diagram for explaining the operation of the data frame transfer apparatus of FIG.

  Here, two addresses of MAC addresses “a” and “b” are assigned to the communication port 11 to the core network 10 of the data frame transfer apparatus 1.

  When the data frame transfer apparatus 1 receives the data frame of the MAC address “a” from the core network 10, the data frame transfer apparatus 1 sends out the data frame from the communication port 12. When the data frame transfer apparatus 1 receives the data frame of the MAC address “b”, this data frame The frame is transmitted from the communication port 13. Such communication port assignment is performed by the transmission destination communication port resolution unit 104 based on the transmission destination communication port resolution table 109 (see Table 2).

The communication speed of the line to which the data frame transfer apparatus 1 is connected (the maximum communication amount per predetermined time permitted to be transferred by the line) is 1.6 Gbps for the line connected to the communication port 11, and the communication port 12 and the communication port The line connected to 13 is 1 Gbps.
The lines connected to the communication ports 22 and 23 of the data frame transfer apparatus 2 and the communication ports 32 and 33 of the data frame transfer apparatus 3 are 1 Gbps, respectively, and the communication port 21 of the data frame transfer apparatus 2 and the data frame transfer apparatus 3 are connected. Each of the lines connected to the communication port 31 is 2 Gbps.

Here, the data frame transfer device 2 transfers the traffic (data frame) of the destination MAC address “a” via the core network 10 at a transmission rate of 700 Mbps and the traffic of the destination MAC address “b” at a transmission rate of 300 Mbps. It shall be transferred with.
Further, the data frame transfer apparatus 3 transfers the traffic of the destination MAC address “a” at a transmission rate of 700 Mbps and transfers the traffic of the destination MAC address “b” at a transmission rate of 300 Mbps via the core network 10. To do.

  Each of the data frame transfer apparatuses 2 and 3 holds a destination communication port resolution table 109 (see Table 2), and data frames (traffic) received from the communication ports 22 and 23 and the communication ports 32 and 33, respectively. The destination communication port (destination data frame transfer device) of this data frame is specified from the destination IP address of the destination.

Here, since the communication speed of the line of the communication port 11 on the core network 10 side of the data frame transfer apparatus 1 is 1.6 Gbps, the data frame transfer apparatus 1 transmits all the traffic transferred by the data frame transfer apparatuses 2 and 3. Data frame cannot be received.
Here, assuming that traffic is randomly discarded, the data frame transfer apparatus 1 sends traffic to be transmitted from the communication port 12 to the communication port 11 from 700 Mbps × 1.6 / 2 + 700 Mbps × 1.6 / 2 = 1.12 Gbps. The traffic to be transmitted from the communication port 13 is received from the communication port 11 at a traffic rate of 300 Mbps × 1.6 / 2 + 300 Mbps × 1.6 / 2 = 480 Mbps. That is, before the transmission rate control, the data frame transfer apparatuses 2 and 3 transmit the traffic to be transmitted from the communication port 13 of the data frame transfer apparatus 1 to 1 Gbps which is the communication speed of the line connected to the communication port 13. Despite sending at a low total of 600 Mbps, the traffic rate transmitted from the communication port 13 by the data frame transfer apparatus 1 is 480 Mbps, and packet discard occurs. Here, since the communication speed of the line connected to the communication port 12 is 1 Gbps, the communication port 12 is congested and the transmission rate is controlled. Accordingly, the data frame transfer apparatus 1 can transmit all traffic (600 Mbps) transferred by the data frame transfer apparatuses 2 and 3 for the traffic to be transmitted from the communication port 13.
That is, when the congestion determination unit 107 detects the occurrence of congestion, the congestion notification data frame generation unit 108 generates a congestion notification data frame using the MAC address “a” as the congestion occurrence communication port identification information. Then, a congestion notification data frame is transmitted to the data frame transfer apparatuses 2 and 3 via the data frame transmission / reception unit 101 and the communication port 11. The data frame transfer apparatuses 2 and 3 that have received the congestion notification data frame limit the traffic transmission rate addressed to the MAC address “a” to, for example, 500 Mbps.
That is, when the congestion notification data frame reception determination unit 102 of the data frame transfer apparatuses 2 and 3 detects that the congestion notification data frame has been received, the congestion notification data frame analysis unit 103 analyzes and transmits the congestion notification data frame. In the rate setting table 110, the value of the transmission rate addressed to the MAC address “a” is set.

  For example, the congestion notification data frame analysis unit 103 writes information for setting the transmission rate addressed to the MAC address “a” to 500 Mbps. Alternatively, the transmission rate value may be rewritten to 0 Mbps, and the data frame transmission addressed to the MAC address “a” from the data frame transfer apparatuses 2 and 3 may be stopped.

  As a result, when congestion occurs in the data frame transfer apparatus 1, it is possible to prevent traffic interference from occurring between the destination communication ports. In other words, the data frame transfer apparatus 1 controls the transmission rate of traffic (data frame) addressed to the communication port 12 where congestion has occurred with respect to the other data frame transfer apparatuses 2 and 3. It is possible to prevent the discard of traffic (data frame) addressed to the communication port 13 where no occurrence occurs.

  Also, a set of the MAC address assigned to the communication port 11 of the core network 10 of the data frame transfer apparatus 1 and the communication port identification information uniquely determined in the data frame transfer apparatus 1 as the congestion occurrence communication port identification information May be used.

  That is, for example, the MAC address assigned to the communication port 11 is “a”, the communication port identification information uniquely determined in the data frame transfer apparatus 1 is “BB” for the communication port 12, and the communication port 13 is In the case of “CC”, when congestion occurs in the communication port 12, the congestion occurrence communication port identification information included in the congestion notification data frame may be “a, BB” that is a combination of these information. Good.

In this case, the MAC address assigned to the communication port of the transmission destination data frame transfer apparatus and the communication uniquely determined in the data frame transfer apparatus 1 are also included in the transmission destination communication port identification information of the transmission rate setting table 110 described above. A combination with the port identification information is described (see Table 4).

  The destination communication port identification information in the destination communication port resolution table 109 also includes the MAC address assigned to the communication port of the destination data frame transfer device and the communication port identification uniquely determined in the data frame transfer device 1. A combination with information is described.

  In the above-described embodiment, the case where the core network 10 is an Ethernet (registered trademark) network has been described as an example. However, the core network 10 may be an MPLS (Multi-Protocol Label Switching) network or a GMPLS (Generalized Multi-Network). A Protocol Label Switching (ATM) network or an ATM (Asynchronous Transfer Mode) network may be used. When the core network 10 is an MPLS network or a GMPLS network, an MPLS label is used as communication port identification information, and, for example, an edge node having an MPLS router function or a GMPLS router function is used as the data frame transfer apparatuses 1 to 3. Further, when the core network 10 is an ATM network, VP (Virtual Path) or VC (Virtual Circuit) is used as communication port identification information, and the data frame transfer devices 1 to 3 are, for example, edges having an ATM switch function. Use nodes.

  The present invention is not limited to the above-described embodiment and can be modified. For example, the congestion notification data frame to the other data frame transfer apparatuses 2 and 3 created by the congestion notification data frame generation unit 108 described above includes the other data frame transfer apparatuses 2 and 3 in addition to the congestion occurrence communication port identification information. It may include request information on the transmission rate.

  That is, the congestion determination unit 107 calculates the transmission rate of the data frame requested from the data frame transfer apparatuses 2 and 3 from the queue length of the transmission data frame, and the data frame transmission / reception unit 101 includes the congestion including this transmission rate. The notification data frame is transmitted to the data frame transfer apparatuses 2 and 3. That is, it instructs the data frame transfer apparatuses 2 and 3 that are transmission sources to what extent the data frame transmission rate is to be reduced.

In response, the congestion notification data frame analysis unit 103 of the data frame transfer apparatuses 2 and 3
Sets (updates) the transmission rate setting table 110 based on the congestion occurrence communication port identification information included in the received congestion notification data frame and the transmission rate of the data frame to this communication port. The data frame transmission rate control unit 106 determines the transmission rate of the data frame addressed to the communication port based on the information in the transmission rate setting table 110 and transmits the data frame via the data frame transmission / reception unit 101.

  In this way, the data frame transfer apparatus 1 can also cause the data frame transfer apparatuses 2 and 3 to suppress the data frame transmission rate. In addition, by specifying the transmission rate in the congestion notification data frame, it becomes possible to assign the traffic amount addressed to the communication port where the congestion occurs to the transmission side data frame transfer apparatus fairly.

  Further, the congestion notification data frame to the other data frame transfer apparatuses 2 and 3 created by the congestion notification data frame generation unit 108 described above includes the other data frame transfer apparatuses 2 and 3 in addition to the congestion occurrence communication port identification information. The request information of the transmission rate control time may be included.

  That is, the congestion determination unit 107 transmits a congestion notification data frame including a transmission rate control duration requested to the data frame transfer apparatuses 2 and 3 to the data frame transfer apparatuses 2 and 3 based on the queue length of the transmission data frames. To do. That is, it instructs the data frame transfer apparatuses 2 and 3 that are the transmission sources the time from when the transmission rate of the data frame transmitted to the congestion occurrence communication port is updated to the initial value after being updated low.

  In response to this, the congestion notification data frame analysis unit 103 of the data frame transfer apparatuses 2 and 3 sets (updates) the transmission rate setting table 110 based on the congestion occurrence communication port identification information included in the received congestion notification data frame. Then, after the time based on the transmission rate control duration included in the received congestion notification data frame has elapsed, the transmission rate setting table 110 is set (updated) based on the congestion communication port identification information. In the first setting in the transmission rate setting table 110, a value lower than the initial value is set as the value of the transmission rate, and in the subsequent settings, the initial value is set as the value of the transmission rate. The data frame transmission rate control unit 106 determines the transmission rate of the data frame addressed to the communication port based on the information in the transmission rate setting table 110 and transmits the data frame via the data frame transmission / reception unit 101.

  Incidentally, when the transmission rate control duration included in the congestion notification data frame is set to 0, the received data frame transfer apparatus sets the transmission rate setting table 110 only once, and at this time the value of the transmission rate is set. Set the initial value as. Even in this way, the data frame transfer device 1 can cause the data frame transfer devices 2 and 3 to suppress the data frame transmission rate. Also, by specifying the transmission rate control duration in the congestion notification data frame, the traffic volume addressed to the congestion communication port is sent to the transmission side data frame transfer device according to the buffer amount held by the reception side data frame transfer device. It becomes possible to instruct.

  The data frame transfer apparatuses 1 to 3 according to the present embodiment can be realized by the data frame transfer program 120 for executing the processing as described above, and the program can be read by a computer-readable storage medium (CD-ROM or the like). ) Can be stored and provided. It is also possible to provide the program through a network.

It is a block diagram which shows the whole structure of the system by which the data frame transfer apparatus of this Embodiment is connected (accommodated). It is a block diagram which shows the structure of the data frame transfer apparatus of FIG. FIG. 3 is a diagram illustrating functions of the data frame transfer apparatus in FIG. It is the figure which illustrated the congestion notification data frame of this Embodiment. It is a flowchart which shows the data frame transfer procedure of the data frame transfer apparatus of FIG. It is a figure explaining operation | movement of the data frame transfer apparatus of FIG.

Explanation of symbols

1, 2, 3 Data frame transfer device 4-9 IP network (external data communication network)
10 Core network 11, 21, 31 Communication port (core network communication port)
12, 13, 22, 23, 32, 33 Communication port (external communication port)
14 CPU
16 Main memory 101 Data frame transmission / reception unit 102 Congestion notification data frame reception determination unit 103 Congestion notification data frame analysis unit 104 Destination communication port resolution unit 105 Transmission data frame generation unit 106 Data frame transmission rate control unit 107 Congestion for each destination communication port Judgment unit (congestion judgment unit)
108 Congestion Notification Data Frame Generation Unit 109 Destination Communication Port Resolution Table 110 Transmission Rate Setting Table 111 Congestion Determination Table 120 Data Frame Transfer Program 130 Control Unit 140 Storage Unit

Claims (12)

Data is provided with at least one core network communication port connected to a core network for communication between data frame transfer apparatuses and one or more external communication ports for communication with an external data communication network different from the core network. A data frame transfer device that performs frame transfer,
The external communication port;
The core network communication port;
According to the routing information written in the header of the data frame received from the external communication port, the identification information of the transmission destination external communication port of the transmission destination data frame transfer device of the data frame is specified, and the transmission destination external communication port is resolved. A destination communication port resolution unit;
A storage unit for storing a transmission rate setting table indicating a transmission rate of a data frame to the communication port for each identification information of a transmission destination external communication port of the transmission destination data frame transfer device;
Measure the queue length for each destination external communication port in the data frame buffer of its own data frame transfer device , and when there is a communication port whose queue length exceeds a predetermined threshold, there is congestion in the communication port . is judged to have occurred, the initial and congestion communication port identification information is identification information of the communication port to which the congestion has occurred in the other data frame transfer device delivery rate of the data frame to be transmitted to the congestion communication port A congestion notification data frame generation unit that generates a congestion notification data frame including a transmission rate control duration that is a time from when the value is lower than the value until the initial value is restored ;
A congestion notification data frame the generating, via the core network communication ports, a data frame transmission and reception unit which transmits to said another data frame transfer device,
When the congestion notification data frame is received from another data frame transfer device via the core network communication port, the congestion occurrence communication port identification information of the congestion notification data frame is read, and the congestion occurrence communication is read in the transmission rate setting table. A congestion notification data frame analysis unit for writing the transmission rate of the data frame to the port;
A data frame transmission rate control unit for controlling a transmission rate of a data frame to be transmitted to the congestion occurrence communication port based on the transmission rate setting table;
I have a,
The congestion notification data frame analysis unit writes a value lower than the initial value as the transmission rate when writing the transmission rate of the data frame to the congestion occurrence communication port in the transmission rate setting table, and the congestion notification data A data frame transfer apparatus , wherein after the transmission rate control duration included in a frame elapses, the initial value is restored .   The congestion notification data frame generator measures the queue length of each destination external communication port in the data frame buffer of its own data frame transfer device, and there is a communication port whose queue length exceeds a predetermined threshold. The communication port determines that congestion has occurred, calculates how much to reduce the data frame transmission rate based on the queue length, and calculates the calculated transmission rate and the communication in which the congestion occurs. Generate a congestion notification data frame that includes congestion occurrence communication port identification information that is port identification information,
  When the congestion notification data frame analysis unit receives the congestion notification data frame from another data frame transfer device via the core network communication port, the congestion notification data frame analysis unit sets the congestion occurrence communication port identification information and the transmission rate of the congestion notification data frame. 2. The data frame transfer apparatus according to claim 1, wherein the read transmission rate is written as a data frame transmission rate to the congestion occurrence communication port in the reading and transmission rate setting table. The core network is a network using Ethernet (registered trademark), and the core network communication port of the data frame transfer device is connected to the core of the data frame transfer device based on the MAC address assigned to the core network communication port. A plurality of MAC addresses are assigned so that the external communication port is uniquely determined, the MAC address is used as identification information of the destination external communication port specified in the destination communication port resolution, and the congestion occurrence communication port The data frame transfer apparatus according to claim 1 or 2 , wherein the MAC address is used as identification information. When Ethernet (registered trademark) is used for the core network, as the identification information of the transmission destination communication port specified in the transmission destination communication port resolution, and as the congestion occurrence communication port identification information, the data frame transfer device The data according to claim 1 or 2 , wherein a set of a MAC address assigned to the core network communication port and external communication port identification information uniquely determined by the data frame transfer device is used. Frame transfer device. A data frame transfer apparatus including at least one core network communication port connected to a core network for performing communication between data frame transfer apparatuses and one or more external communication ports connected to an external data communication network different from the core network. A data frame transfer method for performing data frame transfer,
The data frame transfer device comprises:
Measure the queue length for each destination external communication port in the data frame buffer of its own data frame transfer device, and when there is a communication port whose queue length exceeds a predetermined threshold, there is congestion in the communication port . is judged to have occurred, the initial and congestion communication port identification information is identification information of the communication port to which the congestion has occurred in the other data frame transfer device delivery rate of the data frame to be transmitted to the congestion communication port Generating a congestion notification data frame including a transmission rate control duration that is a time from lower than a value to returning to the initial value ;
Transmitting the generated congestion notification data frame to another data frame transfer device;
When receiving a congestion notification data frame from another data frame transfer device via the core network communication port, reading the congestion occurrence communication port identification information in the congestion notification data frame;
Based on the read congestion occurrence communication port identification information, for each identification information of the transmission destination external communication port of the transmission destination data frame transfer device, this congestion is displayed in a transmission rate setting table indicating the transmission rate of the data frame to this communication port. Writing the data frame transmission rate to the originating communication port;
Performing a step of controlling a transmission rate of a data frame to be transmitted to the congestion occurrence communication port based on the transmission rate setting table ;
In the step of writing the transmission rate of the data frame to the congestion occurrence communication port in the transmission rate setting table, a value lower than the initial value is written as the transmission rate, and the transmission rate control included in the congestion notification data frame A data frame transfer method characterized by returning to the initial value after a lapse of duration .   The data frame transfer device comprises:
  In the step of generating the congestion notification data frame, a queue length for each destination external communication port in the data frame buffer of its own data frame transfer device is measured, and the communication port whose queue length exceeds a predetermined threshold When there is, it is determined that congestion has occurred in the communication port, and how much the data frame transmission rate is to be reduced is calculated based on the queue length, and the calculated transmission rate and the congestion occur A congestion notification data frame including congestion occurrence communication port identification information that is identification information of the communication port being
  When the congestion notification data frame is received from another data frame transfer device via the core network communication port in the step of writing the transmission rate of the data frame to the congestion occurrence communication port in the transmission rate setting table, The congestion occurrence communication port identification information and the transmission rate of the congestion notification data frame are read, and the read transmission rate is written in the transmission rate setting table as the transmission rate of the data frame to the congestion occurrence communication port. Item 6. The data frame transfer method according to Item 5. The core network is a network using Ethernet (registered trademark), and the core network communication port of the data frame transfer device is connected to the core of the data frame transfer device based on the MAC address assigned to the core network communication port. A plurality of MAC addresses are assigned so that the external communication port is uniquely determined, the MAC address is used as identification information of the destination communication port specified in the destination communication port port resolution, and the congestion occurrence communication port 7. The data frame transfer method according to claim 5 , wherein the MAC address is used as identification information. When Ethernet (registered trademark) is used for the core network, as the identification information of the transmission destination communication port specified in the transmission destination communication port resolution, and as the congestion occurrence communication port identification information, the data frame transfer device 7. The data according to claim 5 , wherein a set of a MAC address assigned to the core network communication port and external communication port identification information uniquely determined by the data frame transfer device is used. Frame transfer method. When congestion occurs in the receiving data frame transfer device that receives the data frame in the data frame transferring device that transmits and receives data frames between the devices via the core network, the transmitting data frame transfer device of the data frame A data frame transfer method for transmitting a congestion notification data frame to control a transmission rate of the data frame from the transmission-side data frame transfer device,
The transmitting side data frame transfer device is
The congestion data communication port identification information which is the identification information of the communication port in which the congestion occurs and the transmission rate of the data frame transmitted to the congestion occurrence communication port are lower than the initial value from the reception side data frame transfer device. Receiving a congestion notification data frame including a transmission rate control duration that is a time until returning to the initial value ;
Based on the congestion occurrence communication port identification information in the received congestion notification data frame, for each transmission destination communication port identification information of the transmission destination data frame transfer device in the transmission side data frame transfer device, to this communication port Setting a data frame transmission rate to the congestion occurrence communication port in a transmission rate setting table indicating the transmission rate of the data frame;
Performing a step of controlling a transmission rate of a data frame to be transmitted to the congestion occurrence communication port of the receiving side data frame transfer device based on the transmission rate setting table ;
In the step of writing the data frame transmission rate to the congestion occurrence communication port in the transmission rate setting table, a value lower than the initial value is written as the transmission rate, and the transmission rate control duration included in the congestion notification data frame A data frame transfer method characterized by returning to the initial value after elapse . In a data frame transfer device that transmits and receives data frames between devices via a core network, when congestion occurs in the receiving data frame transfer device that receives the data frame, the transmitting data frame transfer of the data frame A data frame transfer method for transmitting a congestion notification data frame to a device and controlling a transmission rate of the data frame from the transmitting data frame transfer device,
The receiving side data frame transfer device is
Measure the queue length for each destination external communication port in the data frame buffer, and when there is a communication port whose queue length exceeds a predetermined threshold, it is determined that congestion has occurred in the communication port, The congestion generation communication port identification information, which is the identification information of the communication port in which congestion has occurred, and the data frame transmission rate to be transmitted to the congestion generation communication port in another data frame transfer apparatus after being lower than the initial value A congestion notification data frame including a transmission rate control duration that is a time until the initial value is restored, and transmits the created congestion notification data frame to the transmission-side data frame transfer device,
The transmitting side data frame transfer device is
Receiving the congestion notification data frame from the receiving side data frame transfer device;
Based on the congestion occurrence communication port identification information in the received congestion notification data frame, for each transmission destination communication port identification information of the transmission destination data frame transfer device in the transmission side data frame transfer device, to this communication port Setting a data frame transmission rate to the congestion occurrence communication port in a transmission rate setting table indicating the transmission rate of the data frame;
Performing a step of controlling a transmission rate of a data frame to be transmitted to the congestion occurrence communication port of the receiving side data frame transfer device based on the transmission rate setting table ;
In the step of writing the transmission rate of the data frame to the congestion occurrence communication port in the transmission rate setting table, a value lower than the initial value is written as the transmission rate, and the transmission rate control included in the congestion notification data frame A data frame transfer method characterized by returning to the initial value after a lapse of duration . The congestion occurrence communication port identification information is a combination of identification information of the receiving side data frame transfer apparatus and external communication port identification information uniquely determined by the receiving side data frame transfer apparatus. The data frame transfer method according to claim 9 or claim 10 . The control of the delivery rate of the data frame, the data frame according to any one of claims 5 to 11, wherein the a drop and stop of transmission of the data frame transmission rate of the data frame Transfer method.

Images