JP2008054199A - Data frame relaying apparatus, data frame transmission apparatus and congestion control method in data communication network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control traffic by specifying congestion port information with a set of address information and address mask information when selectively performing traffic control for a data frame to be transmitted to a congestion port. <P>SOLUTION: If a switch card 4 forming a data communication network detects congestion on a transmission port basis, a congestion notice data frame including a communication port identifying address information and address mask information is produced and notified to line cards 1, 2. Using the address mask information written in the congestion notice data frame, the line cards 1, 2 compare the communication port identifying address information with communication port identifying address information added to the frame, and subject the coincident frame to limitation of a sending rate, halt of sending, or change of sending priority of a frame. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a congestion control method and a data frame processing apparatus having a congestion control function in a data communication network.

  As a congestion control method in a data communication network, a method for avoiding frame discard by instructing traffic control to the data frame transmission source data frame processing device when data frame processing congestion occurs in the data frame processing device constituting the data communication network Is conventionally known.

  The PAUSE function disclosed in Non-Patent Document 1 is intended to suppress frame discard when data frame processing is congested in a layer 2 switch or an end station. Using the PAUSE function, when data frame processing congestion is detected at a traffic reception side switch, the reception side switch transmits a PAUSE frame to the traffic transmission side switch or end station, and the PAUSE frame is transmitted. The received data frame transmitting side apparatus stops transmission of the data frame. Thereby, since the transmission rate of the transmission side apparatus is limited according to the congestion status of the reception side apparatus, it is possible to avoid a data frame processing congestion state in the reception side switch.

  The congestion control function using the Source Quench message shown in Non-Patent Document 2 selectively controls the traffic of a data frame addressed to a specific IP address contributing to the congestion when the data frame transmission processing is congested in the IP router. With the goal. Using this function, an IP router that has detected data frame processing congestion is a congestion that includes destination IP address information that contributes to congestion, called a Source Quench message, to the source device based on the source IP address. The transmission source device that transmits the notification message and receives the message limits the transmission rate of the data frame addressed to the destination IP address in the message. As a result, when the data frame transmission processing is congested in the IP router, it is possible to prevent the discard of the data frame addressed to the IP address that does not contribute to the congestion.

The congestion control function using an explicit con- nection notification (ECN) message shown in Non-Patent Document 3 is a method for transmitting data frames belonging to a TCP (Transmission Control Protocol) connection that contributes to congestion at the time of data frame transmission processing congestion in the IP router. The purpose is to selectively control traffic. If this function is used, the IP router that has detected the data frame processing congestion adds an ECN bit to the data of the TCP connection contributing to the congestion, and the receiving end point of the TCP connection that received the data is the transmitting side Similarly, the ECN bit is added to the transmission data to the endpoint, and the transmission rate of the data belonging to the TCP connection is limited at the transmission-side endpoint of the TCP connection that has received the data. As a result, when the data frame transmission processing is congested in the IP router, it is possible to prevent the data frame belonging to the TCP connection not contributing to the congestion from being discarded.
IEEE802.3, "IEEE Standard for information technology - Telecommunications and information exchange between systems - Local and metropolitan are a networks - Specific requirements - Part3: Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications "(Annex 31B" MAC Control PAUSE operation ") (http: // standards. p.763~772 of eee.org/getieee802/download/802.3-2005_section2.pdf) IETF RFC 792, “INTERNET CONTROL MESSAGE PROTOCOL DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION”, J. Postel, (1981.9), http: // www. ietf. org / rfc / rfc792. txt? number = 792 IETF RFC3168, “The Addition of Explict Notification Notification (ECN) to IP”, K.C. Ramakrishnan, (2001. 9), http: // www. ietf. org / rfc / rfc3168. txt? number = 3168

  In a situation where transmission congestion occurs only at some communication ports of the data frame relay device that constitutes the data communication network and transmission congestion does not occur at other communication ports, congestion occurs in the data communication network. It is desirable to prevent frame discard of data frame transfer destined to no communication port.

  In congestion control using the PAUSE function shown in Non-Patent Document 1, congestion occurs because the card that has received PAUSE stops all transmission of frames to be transferred to the data frame relay apparatus that accommodates the congestion occurrence communication port. Data frame transfer frames addressed to communication ports that have not been used are also discarded.

  In the congestion control using the Source Quench message shown in Non-Patent Document 2, the card that has received the Source Quench message identifies a frame to be traffic controlled using the destination IP address. In general, even if there is only one congestion occurrence communication port, a data frame transmitted to the communication port includes a large number of destination IP addresses. Therefore, it is necessary to notify a plurality of IP addresses to be traffic-controlled, and traffic control is complicated. Become.

  In the congestion control using the ECN message shown in Non-Patent Document 3, since congestion control is performed only on data using a TCP connection, congestion control on other traffic such as UDP (User Datagram Protocol) cannot be performed.

  The object of the present invention is to discard a data frame transmitted from a communication port in which congestion has not occurred in some external communication ports and congestion has not occurred in other external communication ports. In a situation where there are a large number of final destinations of data frames to be transmitted to a communication port where congestion has occurred and a large number of flow identifiers need to be specified, one set per congestion-occurring communication port It is an object of the present invention to provide a congestion control method and a data frame processing apparatus having a congestion control function capable of specifying the data frame using the address information and address mask information.

  In the data frame processing device according to the present invention, a data frame relay device (line card) having a communication port (external communication port) provided at the edge of a data communication network to be subjected to congestion control and connected to an external data communication network. There are two types of data frame transmission devices (switch cards) installed to transfer data frames between the line cards.

  The line card and the switch card according to the present invention are written in one or more communication ports, means for determining the occurrence of transmission congestion for each communication port, and a frame transmitted to the congestion occurrence communication port when transmission congestion occurs. Means for generating a congestion notification data frame including destination communication port identification address information and address mask information set in advance in the own device and notifying the line card.

  The line card according to the present invention includes one or more ports, a means for adding the destination communication port identification address information corresponding to the destination communication port of the line card as the final destination to the frame, and transmitting the frame. The destination communication port identification address information acquired using the means for acquiring the destination communication port identification address information and the address mask information written in the congestion notification data frame when the notification data frame is received, and the acquired address mask information And a destination communication port identification address information added to the frame, and a means for performing frame transmission rate limitation, transmission stoppage, or transmission priority change for a matching frame.

  In the congestion control method according to the present invention, in the line card, in the line card or the switch card, a procedure for adding the destination communication port identification address information corresponding to the destination external communication port of the destination line card to the frame, The procedure for detecting the occurrence of transmission congestion on a port basis, the line card or switch card, the transmission destination communication port identification address information written in the frame transmitted to the congestion occurrence port when transmission congestion occurs, A procedure for generating a congestion notification data frame including the set address mask information and notifying the line card, and a transmission destination communication port written in the congestion notification data frame when the congestion notification data frame is received in the line card Identification address information and address mask information In the line card, using the acquired address mask information, the acquired transmission destination communication port identification address information is compared with the port identification address information added to the frame, and for the matching frame, A frame transmission rate limit, a transmission stop, or a transmission priority change procedure.

  When transmission congestion occurs in a line card or a switch card, address information and address mask information for identifying a congestion occurrence port are notified to a traffic transmission source line card. Here, when an address corresponding to the topology of the data communication network is assigned to the external communication port in advance, and when the address information and the address mask information are combined, all traffic transmitted from the congestion occurrence port is set to one set. The line card which can be specified by the address information and the address mask information and receives the congestion notification data frame selectively controls only the traffic transmitted from the congestion occurrence communication port. As a result, it is possible to prevent frame discard of traffic transmitted from a communication port in which congestion has not occurred.

The present invention has the following effects.
-It is possible to prevent the discarding of data frames transmitted from communication ports that are not congested when congestion occurs only in some external communication ports and no congestion occurs in other external communication ports. .
-In the situation where there are a large number of final destinations of data frames transmitted to the communication port where congestion has occurred, and it is necessary to specify many flow identifiers to identify them, one set of address information and address mask for each communication port where congestion occurs The data frame can be identified using information.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram of a data frame processing apparatus according to an embodiment of the present invention.

  Referring to FIG. 1, the data frame processing apparatus according to this embodiment includes line cards 1, 2, and 3 and a switch card 4. The line cards 1, 2, and 3 are connected to the communication ports 41, 42, and 43 of the switch card 4 through the communication ports 11, 21, and 31, respectively. The line card 1 is connected to the IP network N1 via the communication port 12, and is connected to the IP network N2 via the communication port 13. The line card 2 is connected to the IP network N3 via the communication port 22, and is connected to the IP network N4 via the communication port 23. The line card 3 is connected to the IP network N5 via the communication port 32 and is connected to the IP network N6 via the communication port 33.

  FIG. 2 shows a configuration example of the switch card 4. The switch card 4 includes communication ports 41, 42, 43, a data frame transmission / reception unit 101, a destination communication port congestion determination unit 102, a congestion notification data frame generation unit 103, and an address mask information setting table 104. ing.

  The communication ports 41, 42, and 43 transfer data frames received from the line cards 1, 2, and 3 to the data frame transmission / reception unit 101, and receive data frames received from the data frame transmission / reception unit 101, respectively. 3 is transferred.

  The data frame transmission / reception unit 101 determines a transmission destination communication port of the data frame received from the communication ports 41, 42, and 43, and transmits the data frame to the communication ports 41, 42, and 43 based thereon.

  The congestion determination unit 102 for each transmission destination communication port periodically measures the queue length for each transmission destination communication port in the transmission buffer of the data frame transmission / reception unit 101 (for example, every T seconds), and the queue length is determined. Determine whether the threshold is exceeded. When there is a communication port exceeding the threshold, the congestion notification data frame generation unit 103 is notified of the destination communication port identification address information described in the frame in the queue corresponding to the communication port.

  The congestion notification data frame generation unit 103 is configured to generate congestion notification data based on the destination communication port identification address information received from the destination communication port congestion determination unit 102 and the address mask information set in the address mask information setting table 104. A frame is generated, and the data frame is transferred to the data frame transmitting / receiving unit 101.

  Here, the congestion notification data frame generated by the congestion notification data frame generation unit 103 will be described with reference to FIG. FIG. 6 is a diagram illustrating a congestion notification data frame according to the present embodiment. As shown in FIG. 6, the congestion notification data frame includes a preamble 301, a frame start delimiter 302, a destination MAC (Media Access Control) address 303, a source MAC address 304, a type field 305, a MAC control instruction 306, and port identification address information. 307, address mask information 308, traffic control duration 309, padding 310, and frame check sequence 311 are included. As a value set in the traffic control duration 309, a queue length measurement period (T seconds) can be used.

  Here, the address mask information setting table 104 will be described with reference to Table 1. As shown in Table 1, the address mask information setting table 104 stores one piece of address mask information. This information is used as a value set in the address mask information 308.

  FIG. 3 shows a configuration example of the line card 1. The line card 1 includes communication ports 11, 12, and 13, a data frame transmission / reception unit 101, a destination communication port congestion determination unit 102, a congestion notification data frame generation unit 103, an address mask information setting table 104, a congestion A notification data frame reception determination unit 105, a congestion notification data frame analysis unit 106, a transmission destination communication port identification address adding unit 107, a transmission destination communication port identification address resolution table 108, and a traffic control setting table 109 are configured. .

  The communication ports 11, 12, and 13 transfer the frames received from the switch card 4, the IP network N 1, and the IP network N 2 to the data frame transmission / reception unit 101, and the frames received from the data frame transmission / reception unit 101 respectively , Forward to IP network N1 and IP network N2.

  The data frame transmitting / receiving unit 101 transfers the frames received from the communication ports 11, 12, and 13 to the congestion notification data frame reception determining unit 105, and the frame received from the transmission destination communication port identification address adding unit 107 is used as the received frame. Based on the destination communication port identification information included, the data is transferred to any one of the communication ports 11, 12, and 13. Further, based on the contents of the traffic control setting table 109, the rate limit is executed for the traffic to be controlled.

  The congestion determination unit 102 for each transmission destination communication port periodically measures the queue length for each transmission destination communication port in the transmission buffer of the data frame transmission / reception unit 101 (for example, every T seconds), and the threshold value for which the queue length is determined It is determined whether or not. When there is a communication port exceeding the threshold, the congestion notification data frame generation unit 103 is notified of the port identification address information described in the frame in the queue corresponding to the port.

  The congestion notification data frame generation unit 103 is configured to generate congestion notification data based on the destination communication port identification address information received from the destination communication port congestion determination unit 102 and the address mask information set in the address mask information setting table 104. A frame is generated, and the data frame is transferred to the data frame transmitting / receiving unit 101.

  The congestion notification data frame reception determination unit 105 determines whether the data frame received from the data frame transmission / reception unit 101 is a congestion notification data frame. If the data frame is a congestion notification data frame, the congestion notification data frame analysis unit 106 If it is not a congestion notification data frame, the received frame is transferred to the destination communication port identification address adding unit 107.

  The congestion notification data frame analysis unit 106 analyzes the congestion notification data frame received from the congestion notification data frame reception determination unit 105 and acquires transmission destination communication port identification address information, address mask information, and traffic control duration information. Using the address mask information, the acquired transmission destination communication port identification address information is compared with the transmission destination communication port identification address information added by the transmission destination communication port identification address adding unit 107, and a matching data frame is transmitted. A set of a destination communication port identification address, address mask information, and traffic control end time information is set in the traffic control setting table 109 so that the traffic is controlled only for the traffic control duration. Among the entries set in the traffic control setting table 109, entries whose traffic control end time is earlier than the current time are excluded.

  The destination communication port identification address adding unit 107 receives the destination IP address information included in the received data frame as a key for the data frame received from the congestion notification data frame reception determination unit 105, and transmits the destination communication port identification address resolution table 108. To obtain the destination communication port identification address and add the address to the received data frame. In addition, a transmission data frame is generated according to the type of the destination communication port included in the received packet, and the transmission data frame is transferred to the data frame transmission / reception unit 101. For example, when the destination communication port is an Ethernet port, a correct Ethernet header is added.

  Here, the destination communication port identification address resolution table 108 will be described with reference to Table 2. As shown in Table 2, the transmission destination communication port identification address resolution table 108 shows the communication port identification address of the transmission destination data frame processing device when transmitting the data frame addressed to the IP address as the destination IP address of the data frame. It is shown. For example, when a data frame having a destination IP address “192.168.1.0/24” is received, “1000B” is added to the transmission frame as a destination communication port identification address.

  Here, the traffic control setting table 109 will be described with reference to Table 3. As shown in Table 3, the traffic control setting table 109 shows destination communication port identification address information, an address mask, and an end time at which traffic control is performed for traffic matching the address. For example, when a congestion notification data frame having destination communication port identification address information “1000B”, address mask “1100B”, and traffic control duration information “T” is received, the destination communication port is sent to the traffic control setting table 109. An entry of identification address information “1000B”, address mask “1100B”, and traffic control end time information “a” is added. Here, the traffic control end time information “a” can be a value obtained by adding the traffic control end time information “T” to the time when the entry addition process is performed.

  The destination communication port identification address adding unit 107 can add the destination communication port identification address to the received data frame by using a label field of a MPLS protocol (Multi Protocol Label Switching) Shim header. Further, it can be added to a received data frame using an Ethernet VLAN tag field.

  In the data frame transmission / reception unit 101, as traffic control based on the contents of the traffic control setting table 109, for traffic that matches the communication port identification address and address mask set in the traffic control setting table 109, until the traffic control end time. Any one of stopping the traffic transmission, limiting the traffic transmission rate, and changing the transmission priority may be performed.

  FIG. 4 is a flowchart showing an example of a congestion control processing procedure in the line cards 1 to 3 according to the present embodiment.

  An address mask information setting table 104, a destination communication port identification address resolution table 108, and a traffic control setting table 109 are set in the line cards 1 to 3 (step 201), and reception processing and transmission processing are performed in parallel.

  In the reception processing, it is determined whether there is a reception data frame waiting for processing (step 202). If there is no reception data frame waiting for processing, the processing after step 207 is repeated and there is a reception data frame waiting for processing. It is determined whether or not the received data frame is a congestion notification data frame (step 203). If the received data frame is not a congestion notification data frame, the destination communication port identification address is set using destination IP address information included in the data frame as a key. Search the resolution table 108 to obtain the destination communication port identification address, add the address to the data frame (step 204), generate a transmission data frame according to the type of the destination communication port (step 205), Determine the destination communication port of the data frame, Whether data frames are buffered for the queue for each destination communication port (step 206), the queue length for each destination communication port is measured every T seconds, and the measured value exceeds a predetermined threshold value. (Step 207), if the threshold value is exceeded, congestion notification based on the destination communication port identification address information described in the data frame and the address mask information set in the address mask information setting table 104 A data frame is generated (step 208), and the processing of the generated congestion notification data frame is repeated from step 205. If the threshold is not exceeded in step 207, the processing is repeated from step 202. If the received data frame is a congestion notification data frame in step 203, the congestion notification data frame is analyzed to acquire transmission destination communication port identification address information, address mask information, and traffic control time information (step 209), and the acquired address Using the mask information, the destination communication port identification address information and the destination communication port identification address information added by the destination communication port identification address adding unit 107 are compared and the traffic control of the matching data frame is performed. A set of a communication port identification address, an address mask, and traffic control end time information is set in the traffic control setting table 109 so as to limit only the time (step 210), and the processing from step 202 is repeated.

  In the transmission process, based on the contents of the traffic control setting table 109, traffic control is executed for the transmission traffic to be set for traffic control (step 211), and it is determined whether there is a transmission data frame waiting for transmission (step 211). 212) Based on the destination communication port information, the data frame is transmitted to the corresponding communication port (step 213), and the processing from step 211 is repeated.

  FIG. 5 is a flowchart showing an example of a congestion control processing procedure in the switch card 4 according to the present embodiment. This procedure is a part of the procedure of the congestion control processing of the line card. In step 201, only the setting of the address mask information setting table 104 is performed. Thereafter, only steps 202, 206 to 208, and 212 to 213 are performed.

  Next, operations of the switch card 4 and the line cards 1 to 3 when transmission congestion occurs in the port 43 of the switch card 4 will be described with reference to FIG.

  The switch card 4 that has detected that the port 43 is congested acquires the destination communication port identification address information 1000B to 1001B described in the data frame transmitted from the port 43, and stores it in the address mask information setting table 104. Since 1100B (compare only the upper 2 bits) is set, a congestion notification data frame is created by setting communication port identification address information = 1000B to 1001B, address mask information = 1100B, and traffic control duration = T. , Transmitted from ports 41 and 42.

  The line card 1 that has received the congestion notification data frame stops transmission for T seconds with respect to the traffic in which the upper 2 bits of the destination communication port identification address information is 10B according to the content of the received congestion notification data frame. Similarly, the line card 2 that has received the congestion notification data frame stops transmission only for T seconds with respect to the traffic whose upper 2 bits of the communication port identification address information is 10B according to the content of the received congestion notification data frame. As a result, discarding of data frames transmitted from the ports 41 and 42 of the switch card 4 can be suppressed.

  The functions of the line card and the switch are those in which a program for realizing the function is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the computer and executed. May be. The computer-readable recording medium refers to a recording medium such as a flexible disk, a magneto-optical disk, and a CD-ROM, and a storage device such as a hard disk device built in a computer system. Further, the computer-readable recording medium is a medium that dynamically holds the program for a short time (transmission medium or transmission wave) as in the case of transmitting the program via the Internet, and in the computer serving as a server in that case Such as a volatile memory that holds a program for a certain period of time.

It is a block diagram of the data frame processing apparatus of one Embodiment of this invention. FIG. 2 is a block diagram illustrating a configuration example of a switch card in FIG. It is a block diagram which shows one structural example of the line card in FIG. It is a flowchart which shows an example of the congestion control processing procedure in the line card in FIG. It is a flowchart which shows an example of the congestion control processing procedure in the line card in FIG. It is a figure which shows the example of the structure of a congestion notification data frame. It is a figure which shows operation | movement of a switch card and a line card at the time of congestion generating.

Explanation of symbols

1, 2, 3 Line card 4 Switch card 11-13, 21-23, 31-33, 41-43 Communication port N1-N6 IP network 101 Data frame transmission / reception unit 102 Congestion judgment unit for each destination communication port 103 Congestion notification data Frame generation unit 104 Address mask information setting table 105 Congestion notification data frame reception determination unit 106 Congestion notification data frame analysis unit 107 Destination communication port identification address addition unit 108 Destination communication port identification address resolution table 109 Traffic control setting tables 201 to 213 Step

Claims (5)

A data frame relay device constituting a data communication network,
One or more communication ports;
Means for determining the occurrence of transmission congestion for each communication port;
When transmission congestion occurs, a congestion notification data frame is generated that includes destination communication port identification address information written in a frame transmitted to the congestion communication port and address mask information set in advance in the data frame relay device. Means for notifying a data frame transmitting device in the data communication network;
A data frame relay device. A data frame transmitting apparatus constituting a data communication network,
One or more communication ports;
Means for adding the destination communication port identification address information corresponding to the destination communication port of the data frame relay device which is the final transmission destination to the frame and transmitting the frame;
Means for acquiring destination communication port identification address information and address mask information written in the congestion notification data frame when receiving the congestion notification data frame generated by the data frame relay device according to claim 1;
Using the acquired address mask information, the acquired transmission destination communication port identification address information is compared with the transmission destination communication port identification address information added to the frame, and the frame transmission rate limit or Means for stopping transmission or changing transmission priority;
A data frame transmitting apparatus having:   The data frame transmitting device according to claim 2, wherein the communication port identification address information is added to the frame using a label field of a Shim header of MPLS (Multi Protocol Label and Switching).   3. The data frame transmitting apparatus according to claim 2, wherein the communication port identification address information is added to the frame using an Ethernet VLAN tag field. A data communication network subject to congestion control, a plurality of line cards provided at the edge of the data communication network and having an external communication port connected to an external data communication network, and data frame transfer between the line cards Congestion control method in a data communication network having a switch card installed to perform
In the line card, adding a destination communication port identification address information corresponding to a destination external communication port of the destination line card to the frame and transmitting the frame
In the line card or the switch card, determining the occurrence of transmission congestion on a port basis;
In the line card or the switch card, when transmission congestion occurs, transmission destination communication port identification address information written in a frame transmitted to the congestion occurrence port, and address mask information set in advance in the line card or the switch card Generating a congestion notification data frame including: and notifying the line card;
In the line card, acquiring the destination communication port identification address information and the address mask information written in the congestion notification data frame when the congestion notification data frame is received;
In the line card, using the acquired address mask information, the acquired transmission destination communication port identification address information is compared with the transmission destination communication port identification address information added to the frame. A method for controlling congestion in a data communication network, comprising the steps of: limiting transmission rate, stopping transmission, or changing transmission priority.

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