JP4483335B2 - Ring network device - Google Patents

Description

  The present invention relates to a ring network device connected to a bidirectional ring network, and more particularly to a ring network device that performs packet communication while performing link aggregation processing.

  2. Description of the Related Art A ring network device that is connected to a bidirectional ring network and transmits / receives a packet to / from another ring network device via the ring network is known.

  Some ring network devices have a link aggregation function that enables high-speed packet communication by theoretically treating a plurality of links (channels) constituting the ring network as one link (for example, (See Patent Document 1).

  A ring network device having a link aggregation function divides transmission data to be transmitted to another ring network device into a plurality of data flows using a predetermined link aggregation algorithm, and data packets included in each data flow are It is configured to send to a link (sending direction) determined for each flow.

Further, in the ring network device disclosed in Patent Literature 1, when a failure occurs in any of the links constituting the ring network, the failure occurrence point is bypassed by forcibly switching the port of the link aggregate control unit. A packet path is secured.
According to such a configuration, when no failure occurs, high-speed packet communication can be performed by the link aggregation function, and when a failure occurs, the link aggregate control unit is used, A packet path can be secured.
JP 2002-359628 A

  By the way, in a ring network, transmission of data packets by a plurality of ring network devices is concentrated, and congestion may partially occur. In such a situation, the transmission of the data packet may not only partially stagnate, but the data packet may be discarded.

Therefore, it is proposed that when the ring network is partially congested, the data packet transmission direction is switched by the method disclosed in Patent Document 1 to secure a packet path that bypasses the congestion occurrence point.
However, in the method disclosed in Patent Document 1, since the transmission direction is forcibly switched so as to avoid the transmission of all data packets toward the failure occurrence location, when this method is applied to avoid the congestion occurrence location, the link There is a problem that the aggregation function is disabled and the communication efficiency is significantly reduced.

  In addition, if the transmission direction is switched during transmission of a data flow divided by link aggregation, the order of the data packets may be disturbed in the ring network device on the reception side, so that the order of the data packets is required. The application has a problem that the transmission direction cannot be switched.

  The present invention has been considered in view of the above circumstances, and when the ring network is partially congested, the transmission of data packets toward the congestion occurrence point is suppressed without invalidating the link aggregation function. As a result, an object of the present invention is to provide a ring network device capable of preventing partial stagnation of packet transmission and discarding of data packets while maintaining high-speed packet communication by link aggregation.

  In order to achieve the above object, a ring network device of the present invention is a ring network device that is connected to a bidirectional ring network and transmits / receives a packet to / from another ring network device via the ring network. A link aggregation unit that divides transmission data to be sent to the ring network device into a plurality of data flows using a predetermined link aggregation algorithm, and data packets included in the plurality of data flows are determined for each data flow. A packet transmission / reception unit for transmitting to the ring network in the transmission direction, and congestion for detecting congestion of the ring network and partially switching the transmission direction of the data packet in units of the data flow according to the detection result Equipped with a detector That it is constituted.

In this way, when congestion occurs in the ring network, transmission of the data packet toward the congestion occurrence point is suppressed, so that the transmission of the data packet partially stagnates or the data packet is discarded. Can be eliminated.
In addition, since the data packet transmission direction is partially switched in units of data flows according to the congestion of the ring network, the link aggregation function is not invalidated, and high-speed packet communication by link aggregation can be maintained.

In the ring network device of the present invention, the link aggregation unit divides the transmission data into a plurality of the data flows using a link aggregation algorithm defined by IEEE 802.3ad.
In this way, not only can the link aggregation unit be easily configured, but also the compatibility of the ring network device can be improved.

Further, in the ring network device of the present invention, the congestion detection unit detects congestion of the ring network based on a transmission waiting packet amount of each data flow, and the transmission waiting packet amount exceeds a predetermined amount. The data flow packet transmission direction is switched to the reverse direction.
In this way, it is possible not only to easily detect the occurrence of congestion in the ring network, but also to switch the transmission direction only for data flows where data packet transmission is stagnant, and to maximize the link aggregation function even when congestion occurs You can save it.

In the ring network device of the present invention, the congestion detection unit returns the packet sending direction of the data flow switched to the reverse direction to the normal direction based on a predetermined condition.
In this way, the degradation of the link aggregation function due to switching of the packet transmission direction can be minimized.

The ring network apparatus of the present invention is configured to switch the packet transmission direction after transmitting a switching request packet to the ring network and receiving a response packet when switching the packet transmission direction of the data flow. .
In this way, even when a data flow divided by link aggregation is being transmitted, it is possible to switch the transmission direction without disturbing the packet order on the receiving side. As a result, even in an application that requires guarantee of the order of data packets, the transmission direction can be switched according to the occurrence of congestion.

In the ring network device of the present invention, the switching request packet is composed of a control packet.
In this way, it is possible to make a switching request to another ring network device using the control packet.

In the ring network device of the present invention, the switching request packet is a data packet to which switching request information is added.
In this way, it is possible to make a switching request to another ring network device using the data packet.

As described above, according to the present invention, the data directed to the congestion occurrence point is utilized while utilizing the link aggregation function by partially switching the transmission direction of the data packet in units of data flow according to the congestion of the ring network. Packet transmission can be suppressed.
As a result, it is possible to prevent partial stagnation of packet transmission and discard of data packets while maintaining high-speed packet communication by link aggregation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the overall configuration of the ring network system, and FIG. 2 is a block diagram showing a specific configuration example of the ring network.
As shown in FIG. 1, the ring network system includes a bidirectional ring network 10 and a plurality of ring network devices 20 connected thereto.

Specifically, as shown in FIG. 2, a ring network 10 is configured by connecting a plurality of ring network devices 20 in a ring shape via a plurality of links 0-1 to 5 and 1-1 to 5. Is done.
The ring network 10 shown in FIG. 2 has a clockwise ringlet 0 composed of links 0-1 to 5 and a counterclockwise ringlet 1 composed of links 1-1 to 5, and a ring network device 20 The packet transmission direction can be switched by selecting ringlets 0 and 1.

FIG. 3 is a block diagram showing the configuration of the ring network apparatus, FIG. 4 is a block diagram showing an example of a packet buffer unit, and FIG. 5 is an explanatory diagram showing an example of a packet direction table.
As illustrated in FIG. 3, the ring network device 20 transmits and receives packets via the ring network 10, and includes a link aggregation unit 21, a packet buffer unit 22, a packet direction table 23, a packet direction determination unit 24, and packet transmission / reception. Unit 25, congestion detection unit 26, and control packet transmission / reception unit 27.

The link aggregation unit 21 is a part that enables high-speed packet communication by treating a plurality of links theoretically as one link.
For example, when sending the transmission data to another ring network device 20, link aggregation unit 21, using a predetermined link aggregation algorithm, it divides the transmission data into a plurality of data flows. At this time, the packet transmission direction of each data flow is also determined.

The link aggregation algorithm used by the link aggregation unit 21 may be unique, but it is preferable to use a link aggregation algorithm defined by IEEE 802.3ad.
In this way, not only the link aggregation unit 21 can be easily configured, but also the compatibility of the ring network device 20 is improved.

  The packet buffer unit 22 is configured with a plurality of packet queues for storing packets, and data packets included in the data flow divided by the link aggregation unit 21 are stored in the corresponding packet queues.

FIG. 4 shows the packet buffer unit 22 when there are four data flows divided by the link aggregation unit 21. The packet buffer unit 22 further distributes the data packets belonging to each data flow to two packet queues depending on whether they are sent in the normal ringlet 0 direction or in the ringlet 1 direction.
For example, among data packets belonging to data flow A, those normally sent in the direction of ringlet 0 are stored in packet queue A-0, and those normally sent in the direction of ringlet 1 are stored in packet queue A-1. is doing.

The packet direction table 23 stores information for determining the data packet sending direction for each data flow.
For example, the packet direction table 23 shown in FIG. 5 includes a data flow name storage area for storing the name of each data flow, a packet transmission direction storage area for storing a normal packet transmission direction of each data flow, and a data flow name storage area. It consists of an inverted bit storage area for storing whether or not to reverse the packet transmission direction.

The packet direction determination unit 24 has a function of finally determining the transmission direction of the data packet belonging to each data flow according to the stored information of the packet direction table 23.
The packet transmitting / receiving unit 25 multiplexes and transmits a data packet flowing through the ring network 10 and a data packet newly added from the own device 20 toward the ring network 10, and a data packet addressed to the own device 20. It has a function to receive.
When a data packet included in the data flow is transmitted, the data packet is transmitted to the ringlet in the transmission direction determined for each data flow.

The congestion detection unit 26 detects the occurrence of congestion in the ring network 10 and generates a command for switching the packet transmission direction and the packet transmission direction of the data flow switched to the reverse direction according to a predetermined condition. And a function to return to the normal direction based on the above.
For example, the congestion of the ring network 10 is detected based on the amount of packets waiting to be sent for each data flow in the packet buffer unit 22, and the packet sending direction of the data flow in which the amount of packets waiting to be sent exceeds a predetermined amount is switched to the reverse direction. Configured as follows.

  The control packet transmission / reception unit 27 has a function of transmitting / receiving a switching request control packet to confirm with other ring network devices 20 whether or not the packet transmission direction can be switched when switching the packet transmission direction of each data flow. I have. This function is used when the ring network device 20 needs to guarantee the packet order on the receiving side.

Next, the operation of the ring network device 20 will be described with reference to FIGS.
For example, when transmitting a data packet belonging to a predetermined data flow from the ring network apparatus 20A to the ring network apparatus 20B in FIG. 2, the ring network apparatus 20A transmits data to the ring network apparatus 20B via the ringlet 0. Assuming that a packet is transmitted, when congestion occurs in the link 0-1 or the link 0-2, it becomes difficult for the ring network device 20A to transmit a data packet to the ring network device 20B. In such a case, the congestion detection unit 26 of the ring network device 20A detects congestion and reverses the packet transmission direction of the corresponding data flow. As a result, a packet path that bypasses the congestion point is secured, and a data packet can be transmitted to the ring network device 20B.

More specifically, the congestion detection unit 26 of the present embodiment monitors the amount of packets waiting to be sent for each data flow (packet queue) in the packet buffer unit 22, and the data for which the amount of packets waiting to be sent exceeds a predetermined amount. The packet transmission direction is reversed preferentially from the flow.
In the example shown in FIG. 4, since the amount of packets waiting to be transmitted accumulated in the packet queue B-0 in the ringlet 0 direction of the data flow B exceeds the threshold value, the data flow B belonging to the packet queue B-0. In order to reverse the packet transmission direction of −0, the inverted bit storage area related to the data flow B-0 in the packet direction table 23 is rewritten.

That is, the ring network device 20 normally transmits the data packet transmitted from each packet queue in the packet transmission direction associated with the corresponding data flow name in the packet direction table 23, but the packet direction table 23 is rewritten as described above. When the inversion bit of “” is “inversion”, the packet data is transmitted in the direction opposite to the normal packet transmission direction as much as possible.
For example, in the example shown in FIG. 5, since the inversion bit of the data flow B-0 is in the inversion state, the ring network device 20A can transmit data packets belonging to the data flow B-0 to the ringlet 0 instead of the ringlet 0 as much as possible. It is transmitted in one direction.

This procedure is repeated, and the packet transmission direction of each data flow is reversed until the congestion detection unit 26 detects no congestion.
According to such an operation, the transmission direction of the data packet is partially switched in units of data flow according to the congestion of the ring network 10, and therefore the link aggregation function is disabled when the ring network 10 is partially congested. Therefore, it is possible to suppress the transmission of the data packet toward the congestion occurrence point. Thus, it is possible to prevent partial packet transmission stagnation and discard of data packets while maintaining high-speed packet communication by link aggregation.

If the congestion detection unit 26 no longer detects congestion, the data transmission direction of the inverted data flow is returned to the original direction in the reverse procedure, and the normal direction is set. For example, a method of preferentially returning the packet transmission direction to a normal state from a data flow with a large amount of transmission waiting packets can be used.
According to such an operation, it is possible to minimize the deterioration of the link aggregation function due to switching of the packet transmission direction.

FIG. 6 is a flowchart showing a processing procedure of the control packet transmission / reception unit.
When the ring network device 20A needs to guarantee the packet order on the receiving side, the processing shown in FIG. 6 is used in addition to the above processing.
As shown in FIG. 6, when the congestion detection unit 26 switches the packet transmission direction of each data flow from the inverted state to the normal state, or when switching from the normal state to the inverted state (S1), as shown in FIG. The switching request control packet is transmitted to the adjacent ring network device 20 in the same procedure as the corresponding data flow (S2), and the transmission of the data of the corresponding data flow is stopped (S3). When the adjacent ring network device 20 receives the switching request control packet, the adjacent ring network device 20 transfers the packet to the next ring network device 20.

When this procedure is repeated and the switching request control packet goes around the ring network 10 and is received by the original ring network device 20 (S4), the control packet transmitting / receiving unit 27 determines that all the transmitted data packets of the corresponding data flow have been transmitted. It is determined that the packet has been received by another ring network device 20, and the transmission of the data packet is resumed after switching the packet transmission direction of the corresponding data flow (S5).
On the other hand, when the original ring network device 20 cannot receive the switching request control packet within a predetermined time, the transmission of the data packet is resumed without switching the packet transmission direction of the corresponding data flow.

According to such an operation, the ring network device 20 confirms that all the transmitted data packets of the corresponding data flow have been received by other ring network devices 20 when switching the packet transmission direction. The packet transmission direction can be switched.
Thus, overtaking of data packets caused by switching of communication paths can be surely prevented, and the packet order on the receiving side can be guaranteed.

When switching the packet transmission direction of the data flow, instead of the control packet transmitting / receiving unit 27 newly generating a switching request control packet, switching request information (identifier) is added to the data packet immediately before the packet transmission is stopped. May be treated as a substitute for the switching request control packet.
In that case, for example, a method of rewriting the header portion of the data packet flowing through the ring network 10, a method of rewriting the payload portion of the data packet flowing through the ring network 10, a method of adding data to the data packet flowing through the ring network 10, etc. Can be used.

  According to the ring network device 20 of the present embodiment configured as described above, a link aggregation unit that divides transmission data to be transmitted to another ring network device 20 into a plurality of data flows using a predetermined link aggregation algorithm. 21 and the packet transmission / reception unit 25 for sending data packets included in a plurality of data flows to the ring network 10 in the sending direction determined for each data flow, and the congestion of the ring network 10 is detected, and the detection result Accordingly, the congestion detection unit 26 that partially switches the transmission direction of the data packet in units of data flow is provided, so that the transmission of the data packet toward the congestion occurrence point is suppressed. Thereby, it is possible to solve the problem that the transmission of the data packet is partially stagnated or the data packet is discarded.

  In addition, since the data packet transmission direction is partially switched in units of data flows in accordance with the congestion of the ring network 10, the link aggregation function is not disabled, and high-speed packet communication by link aggregation can be maintained.

  Further, since the link aggregation unit 21 divides transmission data into a plurality of data flows using a link aggregation algorithm defined in IEEE 802.3ad, not only can the link aggregation unit 21 be easily configured, but also the ring network device 20 Can improve compatibility.

  Further, the congestion detection unit 26 detects congestion of the ring network 10 based on the amount of packets waiting to be sent for each data flow, and reverses the packet sending direction of the data flow in which the amount of packets waiting to be sent exceeds a predetermined amount. Since switching is performed, not only the occurrence of congestion in the ring network 10 can be easily detected, but also the transmission direction can be switched only for data flows in which the transmission of data packets is stagnant. As a result, the link aggregation function can be utilized to the maximum even when congestion occurs.

  In addition, the congestion detection unit 26 returns the packet transmission direction of the data flow switched to the reverse direction to the normal direction based on a predetermined condition, so that the degradation of the link aggregation function due to switching of the packet transmission direction is minimized. Can do.

  In addition, when switching the packet transmission direction of the data flow, the switching request packet is transmitted to the ring network 10 and the packet transmission direction is switched after receiving the response packet. Therefore, the data flow divided by link aggregation is transmitted. Even in the middle, it is possible to switch the transmission direction without disturbing the packet order on the receiving side. As a result, even in an application that requires guarantee of the order of data packets, the transmission direction can be switched according to the occurrence of congestion.

  The present invention is applied to a ring network device connected to a bidirectional ring network. In particular, it is suitable for a ring network device that performs packet communication while performing link aggregation processing.

It is a block diagram which shows the whole structure of a ring network system. It is a block diagram which shows the specific structural example of a ring network. It is a block diagram which shows the structure of a ring network apparatus. It is a block diagram which shows the example of a packet buffer part. It is explanatory drawing which shows the example of a packet direction table. It is a flowchart which shows the process sequence of a control packet transmission / reception part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ring network 20 Ring network apparatus 21 Link aggregation part 22 Packet buffer part 23 Packet direction table 24 Packet direction determination part 25 Packet transmission / reception part 26 Congestion detection part 27 Control packet transmission / reception part

Claims (6)

A ring network device that is connected to a bi-directional ring network and transmits / receives a packet to / from another ring network device via the ring network,
A link aggregation unit that divides transmission data to be transmitted to the other ring network device into a plurality of data flows using a predetermined link aggregation algorithm;
A packet transmission / reception unit that transmits data packets included in the plurality of data flows to the ring network in a transmission direction determined for each data flow;
A congestion detection unit that detects congestion of the ring network and switches a transmission direction of the data packet in units of the data flow according to the detection result ;
When switching the packet sending direction of the data flow, a switching request packet is sent to the ring network, the response packet is received, the packet sending direction is switched, and if the response packet cannot be received, the packet sending direction A ring network device characterized in that no switching is performed .   The ring network apparatus according to claim 1, wherein the link aggregation unit divides the transmission data into a plurality of the data flows using a link aggregation algorithm defined in IEEE 802.3ad.   The congestion detection unit detects congestion of the ring network based on a transmission waiting packet amount of each data flow, and reverses the packet transmission direction of the data flow in which the transmission waiting packet amount exceeds a predetermined amount. 3. The ring network device according to claim 1, wherein the ring network device is switched.   The ring network device according to claim 1, wherein the congestion detection unit returns the packet transmission direction of the data flow switched to the reverse direction to a normal direction based on a predetermined condition. The switching request packet, ring network system according to claim 1, characterized in that a control packet. The switching request packet, ring network system according to claim 1, characterized in that a data packet added with the change request information.

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