JP4914733B2 - Network connection device - Google Patents

Description

  The present invention relates to a network connection apparatus, and more particularly to a network connection apparatus with a shortened connection configuration rebuilding time.

  The Spanning Tree Protocol is defined by IEEE802.1 and is prioritized by sending and receiving BPDU (Bridge Protocol Data Unit: Spanning Tree Protocol Control Frame) for a network with a connection configuration that physically forms a loop. It is a protocol for avoiding a physical loop by judging the degree and finding the path with the lowest priority and cutting it.

  In the spanning tree protocol, each designated bridge receives the root bridge information, designated bridge information, path cost, designated port information of the received BPDU, and the root bridge information, designated bridge information, path cost, designated information stored in the cache memory. The port information is compared with each other, and the information having the smaller value is stored again in the cache memory as information having a higher priority. Here, the root bridge information and the designated bridge information are composed of a bridge priority and a MAC address. The designated port information includes a port priority and a port number.

  The operation of the designated bridge in the spanning tree protocol will be described with reference to FIGS. Here, FIG. 1 is a flowchart of the operation of the spanning tree process. FIG. 2 is a flowchart of the timer processing operation. FIG. 3 is a flowchart of the operation of the BPDU reception process.

  In FIG. 1, when the designated bridge starts the spanning tree process, it determines whether the process start is activated by a timer (S302). If YES, the designated bridge performs timer processing (S303), and proceeds to step 304. The timer process will be described in detail with reference to FIG. If NO in step 302, the designated bridge skips step 303 and transitions to step 304. The designated bridge determines whether the BPDU from the root bridge has been received (S304). If YES, the designated bridge performs BPDU reception processing (S305), and proceeds to step 306. The BPDU reception process will be described in detail with reference to FIG. If NO in step 304, the designated bridge skips step 305 and transitions to step 306. The designated bridge determines whether the reconstruction flag is set (S306). If YES, the designated bridge rebuilds the network connection configuration (S307) and ends. If NO in step 306, the designated bridge ends the spanning tree process. Although step 307 is briefly described, it is not an operation of the designated bridge alone. Details of step 307 are well known to those skilled in the art.

  In FIG. 2, the designated bridge counts the BPDU transmission interval when the timer process is started (S402). Next, the designated bridge counts the holding period of the received BPDU information (S403). The designated bridge determines whether the BPDU transmission interval is over (S404). If YES, the designated bridge transmits a BPDU (S405), and the process proceeds to step 406. When step 404 is NO, the designated bridge skips step 405 and transitions to step 406. The designated bridge determines whether the retention period of the received BPDU information has expired (S406). When the answer is YES, the designated bridge sets a rebuild flag (S407), clears the cache memory, stores default BPDU information (S408), and ends. When NO in step 406, the designated bridge ends the timer process.

  In FIG. 3, when the designated bridge starts the BPDU reception process, the designated bridge checks the usefulness of the received BPDU (S702), and determines the priority of the BPDU (S703). The designated bridge determines whether the priority of the received BPDU is higher than the priority recorded in the cache memory (S704). If YES, the designated bridge sets a reconfiguration flag (S705), holds the received BPDU information in the cache memory (S706), and ends. If NO in step 704, the designated bridge determines whether the priority of the received BPDU is the same as the priority recorded in the cache memory (S707). If YES, the designated bridge resets the holding period of the received BPDU information (S708) and ends. When NO in step 707, the designated bridge discards the received BPDU (S709) and ends the BPDU reception process.

  That is, the BPDU information determined to have a high priority in FIG. 3 is held in the cache memory until the BPDU holding period has passed. On the other hand, BPDUs determined to have low priority are discarded.

  When the network administrator or the maintenance person intentionally changes the priority of the root bridge to change the root bridge, the BPDU information before the priority change is high in priority. For this reason, the designated bridge discards the received BPDU. For this reason, in the designated bridge, the connection configuration cannot be reconstructed until the retention period of the BPDU determined to have a high priority expires.

IEEE802.1D IEEE802.1w IEEE802.1s

  When there is no change in the connection configuration configured by the spanning tree protocol, there is provided a network connection device that triggers network reconstruction even for a low-priority BPDU.

  In the present invention, when there is no change in the network connection configuration, that is, when there is no change in the MAC address of the root bridge information, the MAC address of the designated bridge information, and the port number of the designated port information, the received BPDU information is stored in the cache memory. Even if the information is lower than the high-priority BPDU information held in step 1, the reconstruction flag is set, and the received BPDU information is held in the cache memory. The network connection configuration is reconfigured by setting the reconfiguration flag.

  The problem described above is that the first network and the second network are connected, the loop avoidance protocol is implemented, the received protocol control frame priority determination means, and the connection configuration confirmation means, and the priority determination means Can be achieved by the network connection device that triggers the reconstruction of the connection configuration when it is determined that the priority of the protocol control frame is low and the connection configuration confirmation means determines that there is no change in the connection configuration.

  According to the present invention, the communication interruption time can be shortened even when the priority of the route network connection device is lowered.

  Embodiments of the present invention will be described below with reference to FIGS. Note that the same reference numerals are assigned to the same parts, and description thereof is not repeated. Here, FIG. 4 is a block diagram illustrating a network configuration using a spanning tree. FIG. 5 is a block diagram of the bridge. FIG. 6 is a flowchart of the operation of the BPDU reception process. FIG. 7 is a flowchart for explaining the rebuild flag setting determination process when the BPDU priority is low.

  In FIG. 4, the spanning tree network 300 includes a bridge 100R that is a root bridge and two bridges 100D that are designated bridges. Each port 100 of the root bridge 100R is a port closest to the root bridge on each segment (cable), and thus becomes a designated port (Designated Port) 101D. The port closest to the root bridge 100R of the designated bridges 100D-1 and 100D-2 is the root port 101R. In the case of FIG. 4, since the cost of the segment between the root bridge 100R and the designated bridge 100D-1 is lower than the cost of the segment between the root bridge 100R and the designated bridge 100D-2, the designated bridge 100D-1 is designated. In the segment between the bridge 100D-2, the port of the designated bridge 100D-1 becomes the designated port 101D. On the other hand, the port of the designated bridge 100D-2 becomes a non-designated port 101ND and enters a blocking state.

  In the state shown in FIG. 4, the root bridge 100R periodically transmits BPDUs from the designated port 101D. The designated bridge 100D-1 that has received the BPDU floods the BPDU from the designated port 101D. On the other hand, the designated bridge 100D-2 that has received the BPDU does not have the designated port 101D, and the non-designated port 101ND is in the blocking state, and therefore does not flood the BPDU. The BPDU includes root bridge information, designated bridge information, path cost, and designated port information that is a transmission port of the root bridge. In addition, the cache memory of the designated bridge 100D holds root bridge information, designated bridge information, path cost, and designated port information that is a transmission port of the root bridge of the received BPDU.

  In FIG. 5, the bridge 100 includes a plurality of ports 101, a processor 110, a cache memory 102, and a timer 103. In FIG. 5, the timer 103 is configured by hardware, but may be configured by a program executed by the processor 110. The bridge 100 may include an HDD, a RAM, and the like (not shown). The processor 110 determines the priority of the BPDU by executing the program. The processor 110 determines a change in the connection configuration by executing a program. The processor 110 also reconstructs the connection configuration by executing a program.

  In FIG. 6, the BPDU reception process of the present embodiment only replaces step 709 of the background art BPDU reception process described with reference to FIG. 3 with the determination process of the reconstruction flag setting when the BPDU priority is low shown in step 710. It is. In this way, even if there is no change in the connection configuration, the received BPDU is discarded if it is determined that the priority is low, so that the high-priority BPDU information is retained. Therefore, a useless processing period occurs in which the connection configuration cannot be reconstructed until the period to complete is completed. Therefore, if this useless processing period can be omitted, the processing period can be used for communication.

  In this embodiment, paying attention to this point and considering the case where there is no change in the connection configuration, the connection configuration is reconstructed without discarding the received BPDU. The inventors considered that it is possible to effectively use the period until the retention period of BPDU information with high priority expires.

  In FIG. 7, in the determination processing of the reconfiguration flag setting when the BPDU priority is low in Step 710, the designated bridge 100 </ b> D receives the MAC address of the root bridge information stored in the cache memory as the MAC address of the root bridge information of the received BPDU. It is determined whether it matches the address (S602). When YES, the designated bridge 100D determines whether the MAC address of the designated bridge information of the received BPDU matches the MAC address of the designated bridge information stored in the cache memory (S603). If YES, the designated bridge 100D determines whether the port number of the designated port information of the received BPDU matches the port number of the designated port information stored in the cache memory (S604). In the case of YES, the designated bridge 100D sets a rebuild flag (S606), holds it in the cache memory (S607), and ends. When any of step 602, step 603, and step 604 is NO, the received BPDU is discarded (S605), and the determination process of the reconstruction flag setting when the BPDU priority is low ends.

  According to the present embodiment, it is determined that there is no change in the connection configuration by performing the determinations in steps 602 to 604, and the retention period of BPDU information having a high priority is achieved by performing steps 606 and 607. Rebuild the connection configuration without waiting for it to expire.

  According to the present embodiment, as shown in Table 1, when a designated bridge receives a low-priority BPDU, the connection is made without waiting for the expiration of the retention period of the high-priority BPDU information necessary for reconfiguration of the connection configuration. It was confirmed that a reconfiguration of the configuration could be performed.

Table 1 Application results
--------------------------------------------------
Rebuild time
Applicable standard ----------------------------
After applying default
--------------------------------------------------
IEEE802.1D 50 seconds 30 seconds IEEE802.1w 6 seconds 1 second IEEE802.1s 6 seconds 1 second
--------------------------------------------------

It is a flowchart of operation | movement of a spanning tree process. It is a flowchart of the operation | movement of a timer process. It is a flowchart of operation | movement of a BPDU reception process. It is a block diagram explaining the network structure using a spanning tree. It is a block diagram of a bridge. It is a flowchart of operation | movement of a BPDU reception process. It is a flowchart explaining the reconstruction flag setting determination process at the time of BPDU priority low.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Bridge, 101 ... Port, 102 ... Cache memory, 103 ... Timer, 200 ... BPDU, 300 ... Spanning tree network.

Claims (4)

In a network connection device that connects a first network and a second network and implements a loop avoidance protocol,
A priority determination unit for the received protocol control frame, and a connection configuration confirmation unit;
When the priority determination unit determines that the priority of the protocol control frame is low and the connection configuration confirmation unit determines that there is no change in the connection configuration, the connection configuration reconstruction is triggered. Network connection device to be used. The network connection device according to claim 1,
The network connection device, wherein the connection configuration confirmation unit determines whether the address of the route device of the protocol control frame is the same as the held address. The network connection device according to claim 1,
The network connection device, wherein the connection configuration confirmation unit determines whether the address of the designated device of the protocol control frame is the same as the address held. The network connection device according to claim 1,
The network connection apparatus, wherein the connection configuration confirmation unit determines whether a port number of a designated port of the protocol control frame is the same as a held port number.

Images