JP4087319B2 - Bridge device - Google Patents

Description

  The present invention relates to a bridge device, and more particularly to a bridge device that performs frame relay of a data link layer (second layer) in a network using a MAC address.

  Conventionally, a bridge device is used as a relay device constituting a network. When configuring a network using bridge devices, it is necessary to connect a plurality of bridge devices in a tree shape so that no loops are generated. For this purpose, the spanning tree protocol (STP) is generally used. Is.

  FIG. 9 shows a network configured in a tree shape by bridge devices 100 to 106 each having the same configuration.

  Bridge devices 101 and 102 are connected to the bridge device 100, which is a root bridge, by Gigabit Ethernet (GbE) having a communication speed of 1 Gbps, as indicated by a bold line. Further, as indicated by a thin line, bridge devices 103 and 104 and bridge devices 105 and 106 are connected to the ends of the bridge devices 101 and 102 by Fast Ethernet (100ME) having a communication speed of 100 Mbps, respectively.

  Further, hosts 201, 202, and 203 are connected to the bridge devices 106, 105, and 103, respectively.

  Normally, if the spanning tree protocol is operating normally in all the bridge devices 100 to 106, there is no loop connection 300 as shown between the bridge device 104 and the bridge device 106.

  However, if a loop connection 300 is formed between the bridge device 104 and the bridge device 106 as shown in the figure due to erroneous setting, device abnormality, or the like, the bridge devices 101, 100, 102, 106, and 104 form a loop. If the spanning tree protocol is not used, such a situation is caused by a network design / operation error.

  In this loop, there are a route 301 that is a counterclockwise route and a route 302 that is a clockwise route, which is a double route.

  In the figure, paying attention to the bridge device 101, the bridge device 101 has a plurality of ports 10_1 to 10_3, which are connected to the bridge devices 104, 100, and 103, respectively. Each of the ports 10_1 to 10_3 has a frame receiver and a frame transmitter (not shown). For example, the bridge device 101 receives the broadcast frame F10 transmitted from the bridge device 103 by the frame receiver of the port 10_3. In this case, the broadcast frame F10 is copied as broadcast frames F11 and F12 and transmitted from the ports 10_2 and 10_1.

  In the figure, in order to clarify the flow direction of the broadcast frames F11 and F12 and the copied broadcast frames, the broadcast frame F11 flowing along the counterclockwise route 301 and the broadcast copied based on the broadcast frame F11 are copied. The frame is indicated by a solid arrow, and the broadcast frame F12 flowing along the clockwise route 302 and the broadcast frame copied based on the broadcast frame F12 are indicated by a dotted arrow.

  As shown in the figure, the broadcast frames F11 and F12 return to the bridge device 101 again through routes 301 and 302, respectively, and are received by the frame receivers of the ports 10_1 and 10_2.

  Broadcast frames F11 and F12 received at ports 10_1 and 10_2 are copied again and transmitted from ports other than the received ports. In this case, copies of the broadcast frames F11 and F12 are also transmitted from the port 10_3 to the bridge device 103 that has transmitted the broadcast frame F10 first.

  Further, the bridge device 105 receives copies of the broadcast frames F11 and F12 transmitted from the bridge device 102 at the same port.

  In this way, a so-called broadcast storm is caused by duplicate broadcast frames.

  As a conventional technique for dealing with such a broadcast storm, a bridge device having a broadcast storm control function is known.

  An outline of the operation in the conventional example of the bridge device having such a broadcast storm control function will be described below with reference to FIG. 10 showing a configuration example of the bridge device 101 in FIG.

  As shown in the figure, the bridge device 101 has n ports 10_1 to 10_n (n = 3 in the example of FIG. 9), and the ports 10_1 to 10_n are respectively port interface (INF) units 11_1 to 11_n. Frame receiving units 12_1 to 12_n and frame transmitting units 13_1 to 13_n.

  All the frame reception units 12_1 to 12_n and the frame transmission units 13_1 to 13_n are connected to the switch unit 40, the statistical information collection unit 50, the broadcast storm control unit 60, and the loop monitoring unit 70.

  In addition, a MAC learning table management unit 30 that manages the MAC learning table 20 is connected to the frame receiving units 12_1 to 12_n and the switch unit 40.

  Further, the device / route management unit 80 is connected to the MAC learning table management unit 30, the switch unit 40, and the statistical information collection unit 50.

  In the figure, solid arrows indicate the flow of frame data, and dotted arrows indicate the flow of internal control data.

  In operation, the port INF units 11_1 to 11_n perform link establishment and link state (UP / DOWN) management.

  The frame reception units 12_1 to 12_n identify the frame type such as unicast / broadcast for received frames, determine whether to transfer the frame to the device / route management unit 80 for CPU processing, the MAC learning table 20 The frame transfer processing to other ports via the switch unit 40 based on the reference result is performed.

  The frame transmission units 13_1 to 13_n wait for frame transmission based on instructions from the port INF units 11_1 to 11_n.

  For example, when a frame arrives at the port 10_1, the received frame is transferred from the port INF unit 11_1 to the frame receiving unit 12_1, where the frame type is identified.

  When the received frame is a broadcast frame, internal control data is sent to the broadcast storm control unit 60, and it is determined whether or not the broadcast storm control should be activated at the port 10_1.

  When broadcast storm control should be started, the internal control data to that effect is sent from the broadcast storm control unit 60 to the frame receiving unit 12_1, the frame receiving unit 12_1 holds the contents, and thereafter the frame receiving unit 12_1 Broadcast storm control is performed by discarding broadcast frames received in this manner.

  Note that broadcast storm control is canceled after a predetermined time, for example.

  When the broadcast storm control should not be activated, the received broadcast frame is sent from the frame receiving unit 12_1 to the switch unit 40, and all ports other than the receiving port 10_1 are performing transfer processing (in the case of FIG. A copy is sent to ports 10_2 to 10_n).

  In this case, the frame transmitting units 13_2 to 13_n of the ports 10_2 to 10_n that have received the broadcast frame from the switch unit 40 transmit the broadcast frame if transmission is possible according to the instructions of the port INF units 11_2 to 11_n.

  If the received frame is a unicast frame, the frame receiving unit 12_1 extracts the destination / source MAC address of the frame and sends it to the MAC learning table management unit 30 as internal control data. The MAC learning table management unit 30 searches the MAC learning table 20 using the destination MAC address as a key, and if there is an entry, notifies the port identifier described in the entry to the frame reception unit 12_1. The receiving unit 12_1 is instructed to perform flooding.

  Flooding means transmission to all ports performing transfer processing other than the reception port.

  In addition, the MAC learning table management unit 30 searches the MAC learning table 20 using the transmission source MAC address of the received frame as a key, and if there is no entry, the transmission source MAC address of the received frame and the identifier of the port that received it Is recorded in the MAC learning table 20 to learn.

  Here, when the frame is received at a port different from the port indicated by the port identifier in the entry, the MAC learning table 20 To re-learn the entry contents.

  The frame receiving unit 12_1 that has received the port identifier notification or flooding instruction from the MAC learning table management unit 30 described above adds the information required by the switch unit 40 based on the content of the notification or instruction, and then receives the received frame. The frame data is transmitted to the switch unit 40.

  When a port identifier is specified, the switch unit 40 transmits frame data to the frame transmitters 13_2 to 13_n of any port specified by the specified port identifier, and flooding is instructed. In the same manner as in the case of the broadcast frame, copy transmission is performed to all ports other than the reception port 10_1 (ports 10_2 to 10_n in the case shown in the figure).

  In addition, the frame receiving units 12_1 to 12_n and the frame transmitting units 13_1 to 13_n send identification signals to the statistical information collecting unit 50 according to the type of frame to be processed, and perform statistical information counting.

  For example, the number of broadcast frames received per unit time by each of the ports 10_1 to 10_n collected by the statistical information collection unit 50 is referred to by the broadcast storm control unit 60, and broadcast storms when a predetermined threshold for each port is exceeded. This is basic data for determining that the control should be activated.

  Instead of releasing the broadcast storm control after a predetermined time has passed as described above, the broadcast storm control may be released when the number of broadcast frames falls below another threshold value for each port.

  If the loop frame detection / removal control is set for the port 10_1 that received the frame, the frame receiving unit 12_1 extracts predetermined information in the received frame and sends it to the loop monitoring unit 70. The loop monitoring unit 70 searches whether or not there is the same information as the information in the database recorded and held in its own unit, and if not, records the information, and if there is, increments a counter that counts the number of loops. To do.

  When this counter reaches a certain threshold value, it is determined that the same frame is circulating around the loop, and the frame receiving unit 12_1 is instructed to discard the received frame.

  As a conventional example of a bridge device having a broadcast storm control function other than that shown in FIG. 10 above, a bridge circuit that connects a plurality of LANs and relays frames between the LANs is connected to each LAN. A broadcast storm detector that detects when a broadcast storm has occurred in any of the segments based on the amount of information transmitted by the normal frame of each segment and the amount of information transmitted by the broadcast frame of each segment. Some are provided (see, for example, Patent Document 1).

  Also, in a bridge that is connected to two networks and performs a relay operation to relay broadcast frames from one network to the other network, the number of broadcast frames per certain time is counted, and the count value is larger than a predetermined value. Some increase the relay operation when it becomes larger (for example, see Patent Document 2).

  In addition, even when the amount of broadcast frames received exceeds a predetermined threshold, the priority determined by the priority determination unit according to the type of the received broadcast frame, rather than stopping all broadcast frames uniformly. On the basis of the above, there is a technique in which the relay is stopped in order from the broadcast frame with the lowest priority to keep the broadcast frame with the higher priority as much as possible (see, for example, Patent Document 3).

  Furthermore, there is one that deals with broadcast storms on a VLAN basis (see, for example, Patent Document 4).

  Also, the source address in the received packet received from each of two or more ports is monitored, and when a packet with the same source address is received at the above-mentioned multiple ports within a predetermined time, other than BPDU There is also one that stops the relay operation of the packet (for example, see Patent Document 5).

  A feature of broadcast storm control common to the above conventional examples is that it is implemented in units of reception ports (in the case of VLANs, in units of logical reception ports).

  For this reason, for example, as in the bidirectional routes 301 and 302 shown in FIG. 9, only one direction can be blocked with respect to one reception port in the double path generated by the loop.

  Even if the routes 301 and 302 in both directions can be individually blocked, this is only a blocking at the receiving port, and only the broadcast frame is discarded at the end points of the routes 301 and 302. Is not removed.

  That is, paying attention to the bridge device 101 in the figure, as shown by reference numeral # 1, even if the broadcast storm control is activated on the port 10_1, it only discards the broadcast frame received by the port 10_1 as the end point of the route 301, The broadcast frame is continuously transmitted toward the route 302.

  Also, as shown by reference # 2 in the figure, even if broadcast storm control is activated at port 10_2 next to port 10_1, only the broadcast frame received by port 10_2 as the end point of route 302 is discarded, and route 301 Continue to send broadcast frames.

  As a result, the double paths of the routes 301 and 302 are still not removed, and the number of broadcast frames in the loop path cannot be reduced. Therefore, the traffic in the network becomes high, compresses the traffic band of communication between hosts, and causes deterioration in response / throughput.

  In addition, when a spanning tree protocol is used, a BPDU frame that is a control frame is lost, and a topology change due to the spanning tree protocol is induced. As a result, a network transfer service is interrupted. there is a possibility.

  In addition, due to the existence of the dual paths of the remaining routes 301 and 302 that have not been removed, the duplicate frame of the broadcast frame continues to arrive at the bridge device 105 located in the tree-branching path from the path on the loop. become.

  In general, the closer to the end of the tree, the narrower the bandwidth of the link. In addition, the threshold value that is a trigger for starting broadcast storm control is set in proportion to the bandwidth of the link in order to consider broadcast congestion when it is not a loop.

  Therefore, in the bridge device at the end of the tree in which duplicate broadcast frames flow, like the bridge device 105, a low threshold is set because the bandwidth of the link is narrow, so that broadcast storm control is activated relatively easily. .

  As a result, the broadcast storm is surely calmed down. However, for example, when the broadcast storm control is activated in the bridge 105 as shown by reference numeral # 3 in the figure, the bridge device 105 needs to use the broadcast frame. ARP (Address Resolution Protocol) cannot be resolved.

Accordingly, when ARP resolution is required in the host-to-host communication 400 from the host 201 to the host 202, the communication is interrupted.
Japanese Patent Laid-Open No. 04-81145 JP 07-336373 A JP 2003-124963 A Japanese Patent Laid-Open No. 11-112544 JP-A-11-205367

  The problem common to each of the above conventional examples is that broadcast storm control is performed in units of receiving ports (in the case of VLANs, in units of logical receiving ports), so the double path caused by the loop cannot be removed. It is.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bridge device that can eliminate a double path caused by a loop, thereby suppressing instability of the network, and further preventing deterioration of transfer service of the network. To do.

  In order to achieve the above object, a bridge device according to the present invention monitors a plurality of ports each including a frame reception unit and a frame transmission unit, and a reception amount of a broadcast frame per unit time at a frame reception unit of each port. When the received amount of one port exceeds the first threshold corresponding to the one port, the frame receiving unit of the one port is instructed to discard the broadcast frame received thereafter. Further, when the difference between the received amount of any one port other than the one port and the received amount of the one port is equal to or less than a first predetermined value, the one port And a broadcast storm control unit that instructs the frame transmission unit to discard a broadcast frame to be transmitted thereafter.

  That is, the broadcast storm control unit monitors the reception amount of broadcast frames per unit time in the frame reception unit for each of the plurality of ports of the bridge device, and the reception amount of one port corresponds to the one port. When the first threshold value is exceeded, first, as in the conventional case, the frame receiving unit of the one port is instructed to discard the broadcast frame received thereafter.

  Further, the broadcast storm control unit, when the difference between the received amount of any one port other than the one port and the received amount of the one port is equal to or less than a first predetermined value, An instruction is given to the frame transmission unit of one port to discard the broadcast frame to be transmitted thereafter.

  With reference to FIG. 1 showing the principle (1) of the present invention, the manner in which the broadcast storm due to the duplicate broadcast frame caused by the loop generated in the network is eliminated by the operation of the broadcast storm control unit will be described below.

  FIG. 1A shows a network constituted by bridge devices 100 to 106 each having the same configuration. The bridge device 100 is a root bridge, and the bridge devices 103 and 104 and the bridge devices 105 and 106 are further connected to the ends of the bridge devices 101 and 102 connected to the bridge device 100 to form a tree-structured network. is doing.

  However, as shown in the figure, when there is a loop connection 300 caused by an incorrect setting, equipment abnormality, or the like between the bridge device 104 and the bridge device 106, the bridge devices 101, 100, 102, 106, and 104 other than the bridge devices 103 and 105 constitute a loop. . In this loop, there are a counterclockwise route 301 and a clockwise route 302, which form a double route.

  In the figure, paying attention to the bridge device 101, the bridge device 101 has a plurality of ports 10_1 to 10_3, which are connected to the bridge devices 104, 100, and 103, respectively. Each of the ports 10_1 to 10_3 has a frame receiving unit and a frame transmitting unit (not shown). For example, the bridge device 101 receives a broadcast frame transmitted from the bridge device 103 by the frame receiving unit of the port 10_3. In this case, the broadcast frame is copied and transmitted from the ports 10_1 and 10_2, returns to the bridge device 101 again through the routes 302 and 301, and is received by the frame receivers of the ports 10_2 and 10_1.

  Since the frames received at the ports 10_2 and 10_1 are broadcast frames, they are copied again and transmitted from ports other than the received ports. In this case, the broadcast frame copied from the port 10_3 is also transmitted to the bridge device 103 that transmitted the first broadcast frame.

  In this way, a so-called broadcast storm is caused by overlapping broadcast frames traveling around routes 301 and 302. In this case, it is expected that the amount of broadcast frames traveling around the routes 301 and 302 will be substantially the same.

  When the received amount exceeds the first threshold corresponding to the port 10_1 when the port 10_1 corresponding to the one port in the state of FIG. 11 receives the broadcast frame F1, the broadcast storm control unit of the bridge device 101 (Not shown) instructs the frame receiver of the port 10_1 to discard the broadcast frame received thereafter, as indicated by reference numeral # 1 in FIG.

  At this time, if the difference between the received amount of the port 10_2 and the received amount of the port 10_1 is equal to or less than the first predetermined value, it indicates that the received amount of the port 10_2 is as large as the port 10_1. Since the amount of broadcast frames traveling around each of the routes 301 and 302 is almost the same, the broadcast frame to be transmitted thereafter is discarded to the frame transmitting unit of the port 10_1 as indicated by reference numeral # 2 in FIG. To instruct.

  That is, since the broadcast frame transmitted from the port 10_1 to the route 302 is blocked, there is no double path. As a result, it is possible to eliminate the adverse effects of broadcast storms caused by duplicate broadcast frames, so that it is possible to suppress instability of the network and further prevent deterioration of the network transfer service.

  The broadcast storm control unit further monitors the discard amount of the broadcast frame in each frame receiving unit discarding the received broadcast frame, and the discard amount in the frame receiving unit of the one port is the one of the discard amounts. When the second threshold value corresponding to the one port is exceeded, the difference between the discard amount in any one port other than the one port and the discard amount in the one port is equal to or less than a second predetermined value. In this case, the frame transmission unit of the one port may be instructed to discard the broadcast frame to be transmitted thereafter.

  The principle (2) of the present invention will be described below with reference to FIGS.

  The network shown in FIGS. 2 and 3 is configured by the bridge devices 100 to 106 as in the case shown in FIG. 1, and the loop connection 300 exists between the bridge device 104 and the bridge device 106. Devices 101, 100, 102, 106 and 104 constitute a loop.

  First, FIG. 2 (1) shows a state similar to FIG. 1 (1), and shows a broadcast storm state in which routes 301 and 302 are generated by the loop connection 300. FIG.

  At this time, paying attention to the bridge device 101 in FIG. 2 (1), when the port 10_1 corresponding to one port when focusing on the above “reception amount” receives the broadcast frame F2, the reception amount becomes the port 10_1. Since the first threshold value corresponding to is exceeded, the broadcast storm control unit discards the broadcast frame received thereafter to the frame receiving unit of the port 10_1 as indicated by reference numeral # 1 in FIG. Instruct.

  Here, unlike the case of FIG. 1 (2), in the state of FIG. 2 (2), it is assumed that the difference between the reception amount of the port 10_2 and the reception amount of the port 10_1 is not less than the first predetermined value. To do. That is, it is assumed that the reception amount of the port 10_2 is not as large as the reception amount of the port 10_1.

  In such a state, for example, depending on the timing at which the broadcast frame transmitted from the bridge device 103 or 105 flows through the routes 301 and 302, the flow rate of the broadcast frame of the routes 301 and 302 is not necessarily even if the loop connection 300 exists. It occurs because it is not uniform.

  Therefore, in the same figure, unlike the case of FIG. 1 (2), the broadcast storm control unit does not instruct the frame transmission unit of the port 10_1 to discard the broadcast frame, and passes through the route 301. Although the broadcast frame is discarded at port 10_1, since the broadcast frame is transmitted from port 10_1, the route 302 is not blocked, and a double path still exists as shown by the solid routes 301 and 302. Yes.

  Following the port 10_1, as shown in FIG. 2 (3), the port 10_2 is assumed to correspond to one port when paying attention to the “reception amount” in the same manner as the port 10_1. When the received amount exceeds the first threshold corresponding to the port 10_2, the broadcast storm control unit receives the broadcast frame received thereafter from the frame receiving unit of the port 10_2 as indicated by reference numeral # 2 in FIG. To discard.

  Also in this case, if the difference between the received amount of the port 10_2 and the received amount of the port 10_1 is not less than the first predetermined value, the broadcast storm control unit discards the broadcast frame to the frame transmitting unit of the port 10_2 You are not instructed to do so. Therefore, although broadcast frames that have passed through routes 301 and 302 are discarded at ports 10_1 and 10_2, respectively, there are still double paths as indicated by solid routes 301 and 302.

  Here, since the broadcast storm control unit monitors the discard amount of the broadcast frame in each frame reception unit discarding the received broadcast frame, in the same figure, each frame reception unit of the ports 10_1 and 10_2 The amount of discard of the broadcast frame is monitored.

  In this case, the “discard amount” corresponds to the amount of broadcast frames that travel around the routes 301 and 302.

  In this state, as shown in the figure, when the frame receiving unit of the port 10_1 receives the broadcast frame F4, the frame receiving unit of the port 10_1 discards the broadcast frame F4 as indicated by reference numeral # 1.

  Assuming that the discard amount exceeds the second threshold corresponding to the port 10_1 due to discarding of the broadcast frame F4 in the frame receiving unit of the port 10_1 corresponding to one port when attention is paid to the “discard amount” To do.

  In this case, if the difference between the discard amount at any one port other than the port 10_1 (port 10_2 in the example in the figure) and the discard amount at the port 10_1 is equal to or smaller than the second predetermined value, the port 10_2 Therefore, the broadcast storm control unit should transmit to the frame 10 transmission unit of the port 10_1 after that, as indicated by reference numeral # 3 in FIG. 3 (2). Instructs to discard the broadcast frame.

  That is, as in the case of FIG. 1 (2), the route 302 is blocked as shown by the dotted line in FIG. 3 (2) for the broadcast frame, and the double path is removed.

  As a result, it is possible to detect and remove a double path that cannot be detected by monitoring only the reception amount as described above based on the discard amount.

  Therefore, the adverse effects of broadcast storms caused by duplicate broadcast frames can be eliminated, network instability can be suppressed, and network transfer service deterioration can be prevented.

  In order to achieve the above object, the bridge device according to the present invention includes a plurality of ports each including a frame reception unit and a frame transmission unit, a MAC learning table that holds a correspondence relationship between MAC addresses and ports, A MAC learning table that monitors the number of times another port is received for each reception port such that the correspondence between the MAC address of the transmission source of the received frame and the reception port differs from the correspondence held in the MAC learning table in unit time When the number of times another port is received by the management unit and the two receiving ports exceeds the third predetermined value, the frame receiving unit and the frame transmitting unit of any one of the ports receive broadcasts thereafter. A broadcast storm control unit that instructs to discard a frame and a broadcast frame to be transmitted It may be used as the butterflies.

  The principle (3) of the present invention will be described below with reference to FIG.

  The network shown in FIG. 4 is configured by bridge devices 100 to 106 similar to those shown in FIGS. 1 to 3, and a loop connection 300 exists between the bridge device 104 and the bridge device 106. Devices 101, 100, 102, 106 and 104 constitute a loop.

  First, FIG. 4 (1) shows a state similar to FIG. 1 (1), and shows a broadcast storm state in which routes 301 and 302 are generated by the loop connection 300. FIG.

  Here, the bridge device 101 shown in FIG. 4 (1) has a MAC learning table 20. This MAC learning table 20 holds the correspondence between MAC addresses and ports as in the conventional case. For example, ports 10_3 and 10_2 are associated with MAC addresses “MAC_s” and “MAC_d”, respectively. Yes.

  Here, when the port 10_1 of the bridge device 101 receives a broadcast frame F5 whose source MAC address is “MAC_s” as shown in the figure, the port 10_1 receives the MAC address “MAC_s” registered in the MAC learning table 20. Since it is different from the port 10_3 corresponding to “,” the MAC learning table management unit (not shown) counts up every unit time as the number of reception of another port of the port 10_1.

  As shown in the figure, when the routes 301 and 302 are generated by the loop connection 300, the broadcast frame F5 reaches the port 10_1 through the route 301, but conversely, through the route 302. There should be a similar broadcast frame (not shown) that reaches port 10_2.

  When the source MAC address of the broadcast frame passing through the routes 301 and 302 is “MAC_s”, both are received at ports 10_1 and 10_2 different from the port 10_3 registered in the MAC address “MAC_s” of the MAC learning table 20 Therefore, the number of receptions of the different ports at ports 10_1 and 10_2 will eventually exceed the third predetermined value.

  Note that some conventional MAC learning tables 20 have entries rewritten according to the correspondence between the MAC address and port indicated by the received frame, but the results are the same with such a MAC learning table 20. It is.

  In other words, in the case of the figure, for example, a broadcast frame whose source MAC address is “MAC_s” circulates around the routes 301 and 302, so the port associated with “MAC_s” in the MAC learning table 20 is First, after the port 10_3 is rewritten to, for example, the port 10_1, rewriting of the ports 10_1 and 10_2 occurs frequently.

  Therefore, a broadcast frame is often received at port 10_2 when port 10_1 is associated with “MAC_s”, and a broadcast frame is often received at port 10_1 when port 10_2 is associated. Therefore, the number of receptions of the different ports at the ports 10_1 and 10_2 also exceeds the third predetermined value.

  When the number of reception of different ports at each of the two ports 10_1 and 10_2 exceeds the third predetermined value, the broadcast storm control unit, as shown by reference numerals # 1 and # 2 in FIG. The frame receiving unit and the frame transmitting unit (port 10_1 in the example in the figure) are each instructed to discard the broadcast frame to be received thereafter and the broadcast frame to be transmitted.

  In this case, the two ports such as the ports 10_1 and 10_2 are detected based on the number of receptions of different ports that accurately support the existence of the double path such as the routes 301 and 302 by the loop connection 300.

  Therefore, by removing the double path connecting the ports 10_1 and 10_2, the harmful effects of broadcast storms caused by duplicate broadcast frames are eliminated, as in the case of monitoring the reception amount and discard amount of broadcast frames for each port as described above. It is possible to suppress instability of the network and to prevent deterioration of the network transfer service.

  In addition, with respect to the unicast frame received by the frame receiving unit, only the port where the frame transmitting unit discards the broadcast frame is monitored, and it is confirmed whether the same unicast frame is circulating. When the circuit is circulated, it may further comprise a loop monitoring unit that instructs the frame receiving unit to discard the unicast frame.

  That is, the loop detection operation by the loop monitoring unit and the discard instruction of the circulating unicast frame itself (hereinafter also referred to as loop frame detection / removal control) are the same as those in the past, but the loop is detected. The ports to be monitored are limited to the ports for which the frame transmission unit discards the broadcast frame.

  Note that, in a port where the frame transmitting unit to be monitored discards the broadcast frame, the frame receiving unit normally discards the blade cast frame.

  The principle (4) of the present invention will be described below with reference to FIG.

  This figure corresponds to FIG. 1 (2), FIG. 3 (2), and FIG. 4 (2), and in the network constituted by the bridge devices 100 to 106, the loop connection is made between the bridge device 104 and the bridge device 106. Since 300 exists, when the bridge devices 101, 100, 102, 106, and 104 form a loop, the route 302 is blocked.

  That is, as indicated by reference numerals # 1 and # 2 in FIG. 5, the frame receiving unit and the frame transmitting unit of the port 10_1 of the bridge device 101 discard the received broadcast frame and the broadcast frame to be transmitted, respectively.

  Accordingly, the loop monitoring unit (not shown) of the present invention checks whether or not the unicast frame UF received by, for example, the bridge device 101 circulates only for the port 10_1.

  Conventionally, all the ports 10_1 to 10_3 of the bridge device 101 are monitored, and loop frame detection and removal control with a large processing load is performed. Therefore, especially when the number of ports is large, the processing load of the bridge device becomes enormous. However, in the present invention, since the monitoring target ports are limited, it is possible to reduce the processing load of the bridge device.

  In addition, since there is a high probability that the port from which the frame transmitting unit discards the broadcast frame is the starting point of the loop, the loop frame detection and removal can be controlled more efficiently.

  The loop monitoring unit monitors only the unicast frame destined for the port that caused the frame transmission unit to discard the broadcast frame from the received unicast frames. It may be confirmed whether or not the frame is circulating.

  That is, the monitoring target of the loop frame detection / removal control is limited to, for example, only the unicast frame directed to the port that caused the frame transmission unit of the port 10_1 in FIG. 5 to discard the broadcast frame.

  In this case, the cause of the frame transmitter of the port 10_1 discarding the broadcast frame is that the port 10_2 in any of the principles (1) to (3) of the present invention shown in FIGS. Therefore, the loop frame detection and removal control described above is performed only for unicast frames received by the frame receiver of the port 10_1 toward the port 10_2.

  As a result, the processing load on the bridge device can be further reduced.

  In addition, the loop monitoring unit extends the period and discards the broadcast frame to the frame receiving unit and the frame transmitting unit of the port that has detected that the same unicast frame is circulating. The broadcast storm control unit may instruct.

  That is, for example, as the port 10_1 in FIG. 5, the port that the loop monitoring unit has detected that the same unicast frame is circulating is surely the starting point of the loop. The broadcast storm control unit instructs extension of the period so that the broadcast frame discarding process performed by the unit and the frame transmission unit is not canceled due to a timeout condition or other conditions.

  This enables more efficient broadcast storm control without interrupting broadcast storm control for a port where a loop exists.

  The above ports may be logical ports that support VLANs.

  That is, even in a VLAN environment, it is possible to perform control of removal of a double path related to a broadcast frame and efficient loop frame detection removal related to a unicast frame.

  In this case, the received amount to be compared with the first threshold and the discarded amount to be compared with the second threshold are the sum of the received amount and the discarded amount of all logical ports belonging to the same physical port, respectively. It may be a value.

  That is, the determination for instructing the frame reception unit and the frame transmission unit of each logical port to discard the broadcast frame is performed for each physical port to which the logical port belongs.

  As a result, the processing load of the bridge device can be reduced as compared with the case where the above determination is made for all logical ports.

  As described above, according to the bridge device of the present invention, it is possible to remove a double path caused by a loop, thereby suppressing instability of the network and further preventing deterioration of the transfer service of the network. It becomes possible.

  An operation embodiment of the present invention will be described below with reference to FIGS.

  It should be noted that the bridge devices for realizing each operation embodiment are similar to the conventional example shown in FIG. N ports 10_1 to 10_n including ~ 13_n, MAC learning table 20, MAC learning table management unit 30, switch unit 40, statistical information collection unit 50, broadcast storm control unit 60, loop monitoring unit 70, and device / route management What is necessary is just to be comprised by the part 80. FIG.

  In this case, the ports 10_1 to 10_n may be logical ports in the VLAN.

  FIG. 6 shows a processing flow when a frame is received at any port of the bridge device as an overall processing flow of the embodiment of the present invention.

  First, broadcast storm control based on a storm control counter value C1 provided for each port (hereinafter, sometimes referred to as “storm control” for short) will be described with reference to FIG.

  The storm control counter value C1 is a counter provided for each port, and indicates the number of broadcast frames received by the frame reception unit of the port per unit time.

  Unless otherwise specified, the processing in each step in the figure is for the port that received the frame in step S101.

  Further, steps S109, S110, S200, S300, and S401 to S406 indicated by dotted lines in the figure are processes related to Examples 2 to 4 described later, and thus description thereof is omitted here.

  First, when a frame is received at any port in step S101, frame identification is performed (step S103), and it is determined whether the frame is a unicast frame (S103).

  If it is determined in step S103 that the frame is a unicast frame, the frame is transmitted to a predetermined port according to the search result of the MAC learning table (S116), and the process ends (S999).

  If it is determined in step S103 that the frame is not a unicast frame (that is, it is a broadcast frame), the storm control counter value C1 of the reception port is incremented (S104).

  Next, it is confirmed whether or not the receiving port is under storm control (S105). If the storm control is underway, the received frame is discarded (S115), and the process is terminated (S999).

  If it is determined in step S105 that storm control is not being performed, storm control counter value C1 of the reception port and storm control in the frame reception unit of the reception port (hereinafter also referred to as reception-side storm control) should be activated. Is compared with the threshold value T1 for determining whether or not the image is received (step S106), and only when it is determined that C1 <T1, the frame is transmitted to the other port (S112), and the process is terminated (same as above). S999).

  The process in step S112 is a normal broadcast process, and the “other ports” referred to here are all ports other than the reception port.

  If it is determined in step S106 that C1 <T1 is not satisfied, the reception side storm control is activated as in the conventional case (S107), and the storm control counter value C1 of the other port and the storm control counter value of the reception port The difference between C1 and the predetermined value K1 are compared (at step S108).

  This predetermined value K1 is a first predetermined value for determining whether or not to activate storm control (hereinafter also referred to as transmission-side storm control) in the frame transmission unit of the reception port.

  If it is determined in step S108 that the difference is greater than K1, it is determined whether there are other ports that have not been confirmed in step S108 (S113). Reads the storm control counter value of the port (S114), repeats the process of returning to step S108, and if it is determined in step S113 that there is no other unconfirmed port, transmits a frame to the other port. (S112), and the process ends (S999).

  If it is determined in step S108 that the difference is equal to or less than K1, the transmission side storm control of the receiving port is activated (S111), the frame is transmitted to the other port (S112), and the process is terminated (S11). S999).

  In other words, the broadcast frame received thereafter is discarded at the port where the reception-side storm control is activated in step S107, and if the transmission-side storm control is also activated in step S111, the transmission is performed thereafter. The broadcast frame that should be discarded.

  Control based on the discard counter C2 for supplementing control based on the storm control counter value C1 in the first embodiment will be described below with reference to FIGS.

  The discard counter C2 is a counter provided for each port, and indicates the number of broadcast frames to be discarded per unit time by the frame receiving unit of the port performing the reception-side storm control.

  The basic processing flow in the second embodiment is the same as that in the first embodiment. However, when it is determined in step S105 in FIG. 6 that storm control is being performed, step S200 is inserted before step S115. Is the difference.

  FIG. 7 shows a detailed processing flow of step S200 in FIG.

  If it is determined in step S105 in FIG. 6 that storm control is being performed, in step S200, as shown in FIG. 7, first, in step S201, the discard counter C2 of the reception port is incremented.

  Next, the reception port discard counter value C2 is compared with the threshold value T2 for determining whether or not the transmission side storm control of the reception port should be started (step S202), and when it is determined that C2 <T2 is not satisfied Determines whether the receiving-side storm control has been activated on the other port (S203).

  If it is determined in step S202 that C2 <T2, and if it is determined in step S203 that the reception-side storm control has not been activated for another port, the process of step S200 is terminated. That is, the process proceeds to step S115 in FIG. 6, and after discarding the frame, the process ends (S999).

  If it is determined in step S203 that reception-side storm control has been activated for the other port, the difference between the discard counter value C2 of the other port and the discard counter value C2 of the reception port is compared with a predetermined value K2 (S204). ).

  This predetermined value K2 is a second predetermined value for determining whether or not the transmission side storm control of the reception port should be activated.

  If it is determined in step S204 that the difference is greater than K2, it is checked whether there are other ports that have not been confirmed in step S204 (S208). Reads the discard counter value C2 of the port (S209), repeats the process of returning to step S204, and if it is determined in step S208 that there is no other unconfirmed port, the process of step S200 is terminated. .

  If it is determined in step S204 that the difference is equal to or smaller than K2, the transmission port storm control of the reception port is activated (S207), and the process of step S200 is terminated.

  Note that steps S205 and S206 in FIG. 7 correspond to steps S109 and S110 in FIG. 6, and a description thereof will be omitted here.

  Control based on the source MAC address of the received frame, which can be implemented in addition to the first and second embodiments, will be described below with reference to FIGS.

  FIG. 8 shows the detailed processing flow of step S300 in FIG.

  After performing frame identification in step S102 in FIG. 6, in step S300, as shown in FIG. 8, first, in step S301, it is confirmed whether or not the number of reception of another port of the reception port is a predetermined number or more.

  Here, the other port reception count is obtained by counting the number of times that the reception port is different from the port associated with the MAC learning table for the transmission source MAC address of the received frame per unit time.

  If it is determined in step S301 that the number of reception times of the reception port is less than the predetermined number, the processing in step S300 is terminated as it is. That is, the process proceeds to step 103 in FIG. 6, and thereafter, the same process as in the first and second embodiments is performed.

  If it is determined in step S301 that the number of receptions at the other port is greater than or equal to the predetermined number, it is determined whether or not the number of receptions at the other port is greater than or equal to the predetermined number (S302). If it is less than, it is confirmed whether there is another port whose contents in step S302 have not been confirmed (S303 in the same), and when there is an unconfirmed other port, the number of times another port has been received is read ( In step S304, after the process of returning to step S302 is repeated, if it is determined in step S303 that there is no other unconfirmed port, the process of step S300 ends.

  In step S302, if the number of times other ports receive another port is greater than or equal to the predetermined number, the reception side and transmission side storm control of the reception port is activated (S307), and the processing in step S300 is terminated.

  Note that steps S305 and S306 in FIG. 8 correspond to steps S109 and S110 in FIG. 6 and steps S205 and S206 in FIG. 7, and a description thereof will be omitted here.

  In the above description, the third embodiment is shown as a flow processed in combination with the first and second embodiments. However, the present embodiment can be independent of the first and second embodiments. is there.

  As a fourth embodiment, a process when the loop frame detection and removal control is effectively performed while reducing the processing load of the bridge device will be described below with reference to FIGS.

  As a premise of the fourth embodiment, in each of the first to third embodiments described above, it is necessary to activate the loop frame detection / removal control only at the port where the transmission side storm control is activated. In this case, it is assumed that the loop detection removal control is activated in steps S110, S206, and S306 in FIGS.

  In order to further reduce the processing load of the bridge device, in order to limit the frames subject to loop frame detection and removal control to the frames transferred to the port that caused the transmission side storm control to be activated, In steps S109, S205, and S305 of 6 to 8, the identifiers of other ports that have been determined in the immediately preceding steps S108, S204, and S302 are recorded.

  Based on the above assumption, when it is determined in step S103 in FIG. 6 that the received frame is a unicast frame, it is determined whether the received port is a loop frame detection removal control target port (step S401). .

  In the reception port, if the loop frame detection removal control has already been activated by the process of any of steps S110, S206, and S306 in FIGS. 6 to 8, this reception port is a loop frame detection removal control target port. It is confirmed whether or not the transmission destination port of the received frame is the port recorded in any of steps S109, S205, and S305 in FIGS. 6 to 8 (step S402).

  If it is determined in step S402 that the transmission destination port of the received frame is the recorded port, loop frame detection removal control is executed (S403), and it is confirmed whether a loop is detected (same as above). S404).

  If it is determined in step S404 that a loop has been detected, an instruction to continue bidirectional storm control is given (S405), the frame is discarded (S406), and the process ends (S999).

  If it is determined in step S401 that it is not a loop frame detection removal control target port, if it is determined in step S402 that the transmission destination port of the received frame is not the recorded port, and a loop is detected in step S404. If it is determined that it is not, the frame is transmitted to a predetermined port according to the search result of the MAC learning table (S116), and the process is terminated (S999).

  Note that the above flow minimizes the processing load due to the loop frame detection and removal control of the bridge device, but for example, steps S109, S205, and S305 of FIGS. 6 to 8 are omitted, and further, FIG. A modification in which step S402 is omitted is also possible.

In this case, if it is determined in step S401 in FIG. 5 that the port is a loop frame detection / removal control target port, the process may be advanced to step S403.
(Appendix 1)
A plurality of ports each including a frame receiver and a frame transmitter;
The amount of broadcast frames received per unit time in the frame receiver of each port is monitored, and when the amount of reception of one port exceeds a first threshold corresponding to the one port, the amount of the one port The frame receiving unit is instructed to discard the broadcast frame received thereafter, and the difference between the received amount of any one port other than the one port and the received amount of the one port is A broadcast storm control unit for instructing the frame transmission unit of the one port to discard a broadcast frame to be transmitted thereafter, if the first predetermined value or less;
A bridge device comprising:
(Appendix 2) In Appendix 1,
The broadcast storm control unit further monitors the discard amount of the broadcast frame at each frame receiving unit discarding the received broadcast frame, and the discard amount at the frame receiving unit of the one port is the one of the ones. When the second threshold corresponding to the port is exceeded, the difference between the discard amount in any one port other than the one port and the discard amount in the one port is equal to or less than a second predetermined value A bridge device characterized by instructing the frame transmission unit of the one port to discard a broadcast frame to be transmitted thereafter.
(Appendix 3)
A plurality of ports each including a frame receiver and a frame transmitter;
A MAC learning table that holds the correspondence between MAC addresses and ports;
A MAC learning table that monitors the number of times another port is received for each reception port such that the correspondence between the MAC address of the transmission source of the received frame and the reception port differs from the correspondence held in the MAC learning table in unit time The management department,
When the reception count of the different port at the two reception ports exceeds the third predetermined value, the broadcast frame and transmission received thereafter are transmitted to the frame reception unit and the frame transmission unit of one of the ports, respectively. A broadcast storm control unit instructing to discard a broadcast frame to be transmitted;
A bridge device comprising:
(Appendix 4) In any one of Appendices 1 to 3,
For the unicast frame received by the frame receiver, only the port where the frame transmitter discards the broadcast frame is monitored, and it is checked whether the same unicast frame is circulating. And a loop monitoring unit that instructs the frame receiving unit to discard the unicast frame.
(Appendix 5) In Appendix 4,
The loop monitoring unit circulates the same unicast frame only for the unicast frame that goes to the port that caused the frame transmission unit to discard the broadcast frame among the received unicast frames. It is confirmed whether or not the bridge device.
(Appendix 6) In Appendix 4 or 5,
The broadcast monitoring unit extends the period and discards the broadcast frame to the frame reception unit and the frame transmission unit of the port where the loop monitoring unit detects that the same unicast frame is circulating. A bridge device, characterized by a storm control unit.
(Appendix 7) In any one of Appendices 1 to 6,
A bridge device, wherein the port is a logical port supporting VLAN.
(Appendix 8) In Appendix 7,
The reception amount to be compared with the first threshold and the discard amount to be compared with the second threshold are the total values of the reception amount and the discard amount of all logical ports belonging to the same physical port, respectively. A bridge device.

It is a block diagram for demonstrating the principle (1) of this invention. It is a block diagram for demonstrating the principle (2) of this invention. It is a block diagram for demonstrating the principle (2) of this invention with FIG. It is a block diagram for demonstrating the principle (3) of this invention. It is a block diagram for demonstrating the principle (4) of this invention. It is the flowchart figure which showed the whole processing flow in the Example of the bridge | bridging apparatus which concerns on this invention. It is the flowchart figure which showed the detailed processing flow in step S200 of FIG. It is the flowchart figure which showed the detailed processing flow in step S300 of FIG. It is a block diagram for demonstrating the outline | summary of the broadcast storm control by the conventional bridge | bridging apparatus. It is the block diagram which showed the structural example of the bridge | bridging apparatus common to this invention and a prior art example.

Explanation of symbols

F1 to F5, F10 to F12 broadcast frames
UF unicast frame
10_1-10_n ports
11_1 to 11_n Port interface (INF) part
12_1 to 12_n frame receiver
13_1 to 13_n frame transmitter
20 MAC learning table
30 MAC learning table manager
40 Switch section
50 Statistics information collection
60 Broadcast Storm Control Unit
70 Loop monitor
80 Device / Route Management Department
100 to 106 bridge device
300 loop connection
301, 302 route In the figure, the same reference numerals indicate the same or corresponding parts.

Claims (5)

A plurality of ports each including a frame receiver and a frame transmitter;
The amount of broadcast frames received per unit time in the frame receiver of each port is monitored, and when the amount of reception of one port exceeds a first threshold corresponding to the one port, the amount of the one port The frame receiving unit is instructed to discard the broadcast frame received thereafter, and the difference between the received amount of any one port other than the one port and the received amount of the one port is A broadcast storm control unit for instructing the frame transmission unit of the one port to discard a broadcast frame to be transmitted thereafter, if the first predetermined value or less;
A bridge device comprising: In claim 1,
The broadcast storm control unit further monitors the discard amount of the broadcast frame at each frame reception unit discarding the received broadcast frame, and the discard amount at the frame reception unit of the one port is the one of the ones. When the second threshold corresponding to the port is exceeded, the difference between the discard amount in any one port other than the one port and the discard amount in the one port is equal to or less than a second predetermined value A bridge device characterized by instructing the frame transmission unit of the one port to discard a broadcast frame to be transmitted thereafter. A plurality of ports each including a frame receiver and a frame transmitter;
A MAC learning table that holds the correspondence between MAC addresses and ports;
A MAC learning table that monitors the number of times another port is received for each reception port such that the correspondence between the MAC address of the transmission source of the received frame and the reception port differs from the correspondence held in the MAC learning table in unit time The management department,
When the reception count of the different port at the two reception ports exceeds the third predetermined value, the broadcast frame and transmission received thereafter are transmitted to the frame reception unit and the frame transmission unit of one of the ports, respectively. A broadcast storm control unit instructing to discard a broadcast frame to be transmitted;
A bridge device comprising: In any one of Claim 1 to 3,
For the unicast frame received by the frame receiver, only the port where the frame transmitter discards the broadcast frame is monitored, and it is checked whether the same unicast frame is circulating. And a loop monitoring unit that instructs the frame receiving unit to discard the unicast frame. In claim 4,
The loop monitoring unit circulates the same unicast frame only for the unicast frame that goes to the port that caused the frame transmission unit to discard the broadcast frame among the received unicast frames. It is confirmed whether or not the bridge device.

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