JP4648251B2 - Network relay system, network relay system control method, and management device in network relay system - Google Patents

Description

  The present invention relates to a network relay system, a method for controlling a network relay system, and a management device in the network relay system.

  A technology is known in which a plurality of so-called layer 2 switches that transfer data based on data link layer addresses, for example, MAC addresses, are connected to operate virtually as a single layer 2 switch (for example, patents). Reference 1).

JP 2002-217935 A

  However, a plurality of network relay apparatuses (for example, layer 3 switches and routers) that relay data based on network layer addresses, for example, IP addresses, are connected, so that it can be efficiently used as a single network relay apparatus. The technology to operate has not been established.

  The present invention has been made in order to solve the above-described problem, and connects a plurality of network relay apparatuses that relay data based on addresses in the network layer, so that it is efficient as a single network relay apparatus. The purpose is to make it work.

  In order to solve at least a part of the above problems, a first aspect of the present invention provides a network relay system in which a plurality of network relay devices are connected and operate virtually as one network relay device. A network relay system according to a first aspect of the present invention includes a plurality of ports, a first storage unit, a second storage unit, a reception unit, a first transfer unit, and a second transfer unit. . The plurality of ports are ports for connecting to an external device or a device other than itself among the plurality of network relay devices. The first storage unit stores data link layer information for associating a data link layer address of a transfer destination device with a corresponding port among the plurality of ports. In the data link information, the transfer destination device is adjacent to a device other than the self device, a first external device adjacent to the self device among the external devices, and a device other than the self device among the external devices. A second external device. The second storage unit stores first network layer information that associates a network layer address with the transfer destination device. In the first network layer information, the transfer destination device associated with the assigned address assigned to itself among the addresses of the network layer includes the first external device or the second external device, The transfer destination device associated with a non-assigned address that is not assigned to itself is a device other than the self that is assigned the non-assigned address. The receiving means receives, via any of the plurality of ports, data having a first destination address that is a data link layer address as a destination and a second destination address that is a network layer address as a destination Receive. The first transfer means uses the data link layer information and the first network layer information when the first destination address is an address of its own data link layer. The destination address is changed to the address of the data link layer of the transfer destination device associated with the second destination address, and the destination address is received from the corresponding port associated with the changed first destination address. Transfer the data. The second transfer means is associated with the first destination address using the data link layer information when the first destination address is an address of the data link layer of the transfer destination device. The received data is transferred from the corresponding port.

  According to the network relay system according to the first aspect of the present invention, each network relay device only needs to hold information describing the correspondence with the external device only for the assigned address assigned to itself. The entire relay system can efficiently use the storage resources of each network relay device. Thereby, more routing information can be held in the entire network relay system.

  In the network relay system according to the first aspect of the present invention, each of the plurality of network relay devices further relates to an address of a data link layer of the transfer destination device adjacent to itself among the data link layer information. First learning means for learning first partial information, and the network relay system further includes first collection means for collecting the first partial information from each of the plurality of network relay devices, Based on the collected first partial information, each of the plurality of network relay devices has a first information related to the address of the data link layer of the transfer destination device that is not adjacent to the first information. And first setting means for setting the second partial information. In this way, data link layer information can be easily set for each network relay device.

  In the network relay system according to the first aspect of the present invention, if any of the plurality of network relay devices changes in the adjacency relationship with the first external device, the changed network The first learning unit of the relay device re-learns the first partial information, and the first collection unit re-collects the first partial information from the network relay device that has changed. The first setting unit may reset the second partial information in each of the plurality of network relay devices. In this way, it is possible to automatically reset the data link layer information in response to a change in the adjacency relationship between each network relay device and an adjacent external device.

  In the network relay system according to the first aspect of the present invention, each of the plurality of network relay devices further learns route information possessed by the first external device from the first external device. The network relay system further includes a second collection unit that collects the route information from each of the plurality of network relay devices, and the plurality of the plurality of network relay systems based on the collected route information. Each network relay device may include second setting means for setting the first network layer information. In this way, the first network layer information can be easily set for each network relay device.

  In the network relay system according to the first aspect of the present invention, the second setting means, based on the collected route information, may be a network layer address and the first external device or the second external device. First creating means for creating second network layer information for associating devices, and dividing the network layer address into an address range equal to the number of the plurality of network relay devices, and the addresses included in each of the address ranges Based on the division means for setting the network address as the assigned address of each of the plurality of network relay devices, the second network layer information, and the result of the division, the network address is set to each of the plurality of network relay devices. And second creation means for creating the first network layer information. In such a case, the dividing unit may determine the address range so that the first network layer information corresponding to the capacity of the second storage unit of each of the plurality of network relay devices is created. good. In this way, the first network layer information corresponding to the capacity of the second storage unit of each network relay device is created, so that the second storage unit of each network relay device can be used effectively. .

  In the network relay system according to the first aspect of the present invention, if any of the plurality of network relay devices changes in the adjacency relationship with the first external device, the changed network The second learning unit of the relay device re-learns the route information, the second collection unit re-collects the route information from the changed network relay device, and the second setting unit May reset the first network layer information in each of the plurality of network relay devices. By so doing, it is possible to automatically reset the first network layer information in response to a change in the adjacency relationship between each network relay device and an adjacent external device.

  The network relay system according to the first aspect of the present invention further includes a management device connected to each of the plurality of network relay devices, wherein the management device includes the first collection unit and the first setting. A second collecting unit and a second setting unit. In this way, the management device can manage the data link layer information or the first network layer information of each network relay device.

  The present invention can be realized in various modes. For example, the present invention can be realized as a management apparatus in a network relay system in which a plurality of network relay apparatuses are connected and virtually operate as one network relay apparatus. Can do. In addition to these system and device aspects, a method invention such as a control method for a network relay system in which a plurality of network relay devices each having a plurality of ports are connected and virtually operates as one network relay device. Can be realized. Alternatively, the present invention can be realized in the form of a computer program for constructing such a system, apparatus or method, a recording medium storing the computer program, a data signal including the computer program and embodied in a carrier wave, and the like.

A. Example:
-Network relay system configuration:
Next, embodiments of the present invention will be described based on examples. The configuration of the network relay system according to the embodiment will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a schematic configuration of the network relay system according to the embodiment. FIG. 2 is a block diagram illustrating an internal configuration of the network relay device included in the network relay system according to the embodiment. FIG. 3 is a block diagram illustrating an internal configuration of the management apparatus included in the network relay system according to the embodiment. FIG. 4 is a list of IP addresses assigned to each part of the network relay system in the embodiment.

  As shown in FIG. 1, the network relay system 1000 according to the present embodiment includes three network relay devices, that is, a first relay device 100a, a second relay device 100b, and a third relay device 100c. Yes. In the following, when it is not necessary to distinguish the three network relay devices, the alphabet at the end of the code is omitted and the network relay device 100 is described. Furthermore, the network relay system 1000 includes a management device 200.

  As illustrated in FIG. 2, the network relay device 100 includes a plurality of physical ports 110, a transmission / reception processing circuit 120, a transfer processing circuit 130, and a control unit 140.

  The physical port 110 is an interface for connecting to a network via a line CV such as a coaxial cable or an optical fiber. In this embodiment, the physical port 110 is a port compliant with the Ethernet (registered trademark) standard.

  The transmission / reception processing circuit 120 is connected to each physical port 110, interprets an electrical signal received via the physical port 110, and collects data used in the data link layer (hereinafter referred to as a frame. In this embodiment). , Ethernet (registered trademark) frame). Further, the transmission / reception processing circuit 120 performs transmission processing that receives an Ethernet frame to be transferred from the transfer processing circuit 130, converts the Ethernet frame into an electrical signal, and transmits the electrical signal from a corresponding port described later.

  The Ethernet frame is frame data to which a MAC header including a destination MAC address DM is added. The frame data includes a cluster of data used in the network layer (hereinafter referred to as a packet, which is an IP packet in this embodiment). An IP packet is a packet to which an IP header including a destination IP address DI is added. That is, the Ethernet frame includes a packet, a destination IP address DI, and a destination MAC address DM. The transmission / reception processing circuit 120 sends the Ethernet frame to the transfer processing circuit 130.

  The transfer processing circuit 130 includes a transfer engine 131 and a memory 134. The memory 134 stores a routing table 135 and an ARP table 136. The routing table 135 is a table in which information that associates an IP address with a transfer destination device is described. The ARP table 136 is a table in which information for associating the MAC address of the transfer destination device with the corresponding port is described. The corresponding port means a port connected to the network to which the transfer destination device is connected among the plurality of physical ports 110. The routing table 135 and the ARP table 136 will be further described later. In this embodiment, the information described in the routing table 135 corresponds to the first network layer information in the claims, the information described in the ARP table 136 corresponds to the data link layer information in the claims, and the memory 134 This corresponds to the first and second storage units in the claims.

  The transfer engine 131 is an ASIC (Application Specific Integrated Circuit) designed to realize a function of the circuit described later, and executes the function of the circuit described later by hardware processing. The transfer engine 131 is a circuit that performs a transfer process for transferring the Ethernet frame received from the transmission / reception processing circuit 120. The transfer engine 131 includes a layer 3 transfer unit 132 and a layer 2 transfer unit 133 as functional units.

  The layer 3 transfer unit 132 is included in the Ethernet frame when the destination MAC address DM included in the Ethernet frame received from the transmission / reception processing circuit 120 is the MAC address assigned to the physical port 110 that received the Ethernet frame. Based on the destination IP address DI, the transfer destination device to which the IP packet included in the Ethernet frame is transferred is specified. The transfer destination device is specified with reference to a routing table 135 stored in the memory 134, as will be described later. The layer 3 transfer unit 132 further specifies the MAC address of the specified transfer destination device and specifies the corresponding port for transferring the Ethernet frame to the specified transfer destination device. The identification of the MAC address and the corresponding port is executed with reference to the ARP table 136. The layer 3 transfer unit 132 changes the destination MAC address DM included in the Ethernet frame to the MAC address of the specified transfer destination device, designates the specified corresponding port in the changed Ethernet frame, and the transmission / reception processing circuit 120. Send to. As a result, the Ethernet frame is transferred from the corresponding port to the transfer destination device. In this way, the transfer performed by specifying the corresponding port by the layer 3 transfer unit 132 is performed based on the IP address that is the address of the network layer that is the third layer of the OSI (Open Systems Interconnection) reference model. Hereinafter, it is referred to as layer 3 transfer.

  The layer 2 transfer unit 133 refers to the ARP table 136 when the destination MAC address DM included in the Ethernet frame received from the transmission / reception processing circuit 120 is not the MAC address assigned to the physical port 110 that received the Ethernet frame. Then, it is checked whether the destination MAC address DM is the MAC address of the transfer destination device. When the destination MAC address DM is the MAC address of the transfer destination device, the layer 2 transfer unit 133 refers to the ARP table 136 and specifies a corresponding port for transferring the Ethernet frame to the transfer destination device. The layer 2 transfer unit 133 transmits the Ethernet frame to the transmission / reception processing circuit 120 by designating the identified corresponding port. As a result, the Ethernet frame is transferred from the corresponding port to the transfer destination device. As described above, the transfer performed by specifying the corresponding port by the layer 2 transfer unit 133 is performed based on the MAC address that is the address of the data link layer, which is the second layer of the OSI (Open Systems Interconnection) reference model. Hereinafter, it is referred to as layer 2 transfer.

  The control unit 140 controls the entire network relay device 100. The control unit 140 is a known computer, and includes a central processing unit (CPU) 141 and a memory 142. A control program 143 is stored in the memory 142. The CPU 141 implements a function as a control unit by executing the control program 143. The control program 143 includes various functional units such as a routing protocol such as RIP (Routing Information Protocol) and OSPF (Open Shortest Path First), and a function for communicating with the management apparatus 200. In FIG. 2, the configuration necessary for the description of the present embodiment is selectively illustrated, and the illustrated configuration will be described in this specification. The control program 143 includes an ARP information learning unit 144 and a route information learning unit 145. The ARP information learning unit 144 learns ARP information from adjacent devices (for example, an external router 500, another network relay device 100, and a management device 200 described later) via the physical port 110. The route information learning unit 145 learns route information held by the external router 500 from an external router 500 which will be described later via the physical port 110. The processing of the ARP information learning unit 144 and the route information learning unit 145 will be described later.

  The management device 200 is a computer that manages the entire network relay system 1000. As shown in FIG. 3, the management apparatus 200 is a known computer, such as a personal computer, that includes a CPU 210, a memory 220 such as a ROM or a RAM, and a network interface card (NIC) 270 for connecting to a network. is there. The memory 220 stores an ARP information manager 230 and a path information manager 240, a system routing table 250, and a system ARP table 260, which are programs for managing the entire network relay system 1000. The CPU 210 implements a function as a management device by executing the ARP information manager 230 and the path information manager 240.

  The ARP information manager 230 includes an ARP information collection unit 231 and an ARP information setting unit 232. The ARP information collection unit 231 collects ARP information from each network relay device 100 to be managed, and creates a system ARP table 260. The ARP information setting unit 232 statically sets ARP information in each network relay device 100 based on the system ARP table 260. The route information manager 240 includes a route information collection unit 241 and a route information setting unit 242. The route information collection unit 241 collects route information from each network relay device 100 to be managed. The route information setting unit 242 sets a routing table in each network relay device 100 to be managed based on the collected route information. The route information setting unit 242 includes a system routing table creation unit 243, an address range division unit 244, and a routing table creation unit 245. The system routing table creation unit 243 creates the system routing table 250 based on the collected route information. The address range dividing unit 244 divides the entire IP address range (0.0.0.0 to 255.255.255.255) into the number of address ranges of the number of network relay devices 100 (3 in this embodiment). Then, each divided address range is set as an allocated address range of each network relay device 100. The routing table creation unit 245 creates a routing table to be set for each network relay device 100 based on the system ARP table 260 and the assigned address range of each network relay device 100. The processing executed by the ARP information manager 230 and the route information manager 240 will be described later.

  Returning to FIG. 1, the description will be continued. In FIG. 1, black circles indicate ports provided in each device. For example, the ports O1, M1, I1, and I5 of the network relay device 100 correspond to any of the physical ports 110 in FIG. 2, and the port M4 of the management device 200 corresponds to the port of the NIC 270 in FIG. Yes.

  As shown in FIG. 1, among the three network relay devices 100 included in the network relay system 1000, the port O1 of the first relay device 100a is connected to the port R1 of the external router 500a and the external transfer network ONT1. It is connected. The port O2 of the second relay device 100b is connected to the port R2 of the external router 500b via the external transfer network ONT2. Similarly, the ports O3 and O4 of the third relay device 100c are connected to the port R3 of the external router 500c and the port R4 of the external router 500d via the external transfer networks ONT3 and ONT4, respectively. The external routers 500a to 500d are well-known routers having a plurality of physical ports, and packets are transmitted from one device (for example, the network relay device 100 or another router (not shown)) connected through one physical port. And the packet is transferred to the other device through the other physical port at the layer 3 level. In the following, when it is not necessary to distinguish the four external routers 500a to 500d, the alphabet at the end of the code is omitted and the external router 500 is described.

  Also, the port I1 of the first relay device 100a and the port I2 of the second relay device 100b, the port I3 of the second relay device 100b, the port I4 of the third relay device 100c, and the port of the first relay device 100a I5 and the port I6 of the third relay device 100c are connected via internal transfer networks INT1, INT2, and INT3, respectively. The port M1 of the first relay device 100a, the port M2 of the second relay device 100b, and the port M3 of the third relay device 100c are connected to the port M4 of the management device 200 via the management network MNT. Yes.

  Assume that the IP addresses shown in FIG. 4 are assigned to the above-described ports and networks, respectively. In the following, a code in which IP_ is added before the code of the port is used as a code representing the IP address assigned to the port. For example, the IP address (192.168.1.2) assigned to the port M1 is represented using the code IP_M1, and the IP address (192.168.1.0/28) assigned to the network MNT is And IP_MNT. The management apparatus 200 has an IP address assigned inside the network relay system 1000, that is, an IP address assigned to a port of each network relay apparatus 100, external transfer networks ONT1 to ONT3, and internal transfer networks. Assume that INT1 to INT3 and the IP address (network address) assigned to the management network MNT are recognized.

ARP Table Setting Process Next, an ARP table setting process for setting the ARP table 136 in each of the first to third relay apparatuses 100a to 100c will be described with reference to FIGS. FIG. 5 is a sequence diagram showing a processing sequence of the ARP table setting process. FIG. 6 is a diagram illustrating a learning result of ARP information in each network relay device. FIG. 7 is a schematic diagram showing a system ARP table. FIG. 8 is a diagram showing static ARP information set in each network relay device. FIG. 9 is a diagram showing an ARP table set in each network relay device.

  The ARP information learning unit 144 of the control unit 140 of each network relay device 100 learns the ARP information of the device adjacent to itself (FIG. 5: Steps S110a, S110b, and S110c). The ARP information is notified, for example, when a device adjacent to the ARP information is turned on or periodically. The ARP information learning unit 144 dynamically learns the ARP information of the device adjacent to itself by acquiring the notification. The ARP information is a combination of an IP address and a MAC address assigned to a port for communicating with itself in a device adjacent to the ARP information. For example, as shown at the top of FIG. 6, one of the ARP information learned by the ARP information learning unit 144 in the first relay device 100a is adjacent to the first relay device 100a via the external transfer network ONT1. This is a combination of the IP address IP_R1 of the port R1 and the MAC address MAC_R1 of the port R1 for communicating with the first relay device 100a in the external router 500a. Here, the MAC address is actually a 48-bit identification code, but in FIG. 6, a code with MAC_ added before the port code is used as a code representing the MAC address assigned to the port. . For example, as described above, the MAC address assigned to the port R1 is represented as MAC_R1.

  As can be seen from FIG. 6, for example, the ARP information that the first relay device 100a learns in this step includes the ARP information of the port R1 of the external router 500a described above and the management device 200 adjacent via the management network MNT. The ARP information of the port M1, the ARP information of the port I2 of the second relay device 100b adjacent via the internal transfer network INT1, and the port I6 of the third relay device 100c adjacent via the internal transfer network INT3 ARP information.

  Further, the ARP information learning unit 144 of each network relay device 100 learns the ARP information in association with its own port (learning port) that has received the notification of the ARP information. For example, as can be seen from FIG. 6, the ARP information learning unit 144 of the first relay device 100a uses the ARP information of the port R1 of the external router 500a as the port O1 of the first relay device 100a that has received the ARP information. Learning in association (in the example of FIG. 6, the IP address IP_O1 is associated with the ARP information of the port R1 as the identifier of the port O1).

  The ARP information learning unit 144 of each network relay device 100 notifies the learned ARP information to the management device 200 via the management network MNT (steps S120a, S120b, and S120c).

  The ARP information collection unit 231 of the ARP information manager 230 of the management device 200 collects the ARP information notified from each network relay device 100 and creates the system ARP table 260 (step S130). FIG. 7 shows the created system ARP table 260. As shown in FIG. 7, in the system ARP table 260, the ARP information collected from each network relay device 100 is recorded in association with the transmission port (its IP address) and the learning source device. The sending port is a port that sends out data when sending data to a port to which an IP address and a MAC address as ARP information are assigned. The learning source device is the network relay device 100 that has notified the ARP information. In the system ARP table 260, the upper part SO is ARP information of an external device of the network relay system 1000, that is, ARP information of four external routers 500a to 500b in this embodiment. On the other hand, in the system ARP table 260, the lower part SI is ARP information inside the network relay system 1000, that is, ARP information of the three network relay devices 100 in this embodiment. The external device APR information SO includes ARP information of all external devices adjacent to any one of the network relay devices 100 included in the network relay system 1000.

  When the system ARP table 260 is created, the ARP information setting unit 232 of the ARP information manager 230 of the management device 200 sets the ARP information (statically set) to each network relay device 100 based on the system ARP table 260. ARP information). FIG. 8 shows the created static ARP information for each network relay device 100 in which the static ARP information is set. The static ARP information set in one network relay device 100 is ARP information of an external device that is not adjacent to the network relay device 100, that is, an external device that is adjacent to another network relay device 100. The static ARP information is a transmission port that sends out data when the network relay device 100 in which the static ARP information is set sends data to a port to which an IP address and a MAC address are assigned as static ARP information. Is associated. For example, as shown in FIG. 8, the static ARP information set in the first relay device 100a includes the ARP information of the port R4 of the external router 500d adjacent to the third relay device 100c. When the first relay device 100a wants to send data to the port R4 of the external router 500d, the data is sent via the third relay device 100c. Accordingly, the ARP information of the port R4 set in the first relay device 100a is associated with the port I5 for sending data to the third relay device 100c as the transmission port. Note that the static ARP information set for each network relay device 100 includes all external devices that are not adjacent to the network relay device 100 and that are adjacent to one of the other network relay devices 100. Contains static ARP information.

  Next, the ARP information setting unit 232 notifies the corresponding network relay device 100 of the static ARP information created for each network relay device 100 (steps S150a to 150c).

  Each network relay device 100 notified of the static ARP information creates an ARP table 136 using the notified static ARP information and the previously dynamically learned ARP information (steps S160a to S160c). ). FIG. 8 shows an ARP table 136 created in each network relay device 100. In order to distinguish the ARP table 136 created in each of the three network relay apparatuses 100a to 100c, the alphabet of the end of the code of the relay apparatus is added to the end of each code, which is expressed as the ARP tables 136a to 136c. The ARP information stored in each of the ARP tables 136a to 136c is divided into two types. One type is ARP information acquired by dynamic learning in steps S110a to S110c described above, and the other type is statically set (created) by the management apparatus 200 in step S140 described above. Static ARP information. For example, as shown in FIG. 9, among the ARP information stored in the ARP table 136a of the first relay device 100a, the ARP information of the ports R1, M4, I2, and I6 of the devices adjacent to the first relay device 100a. Is the former type, and the ARP information of the ports R2, R3, and R4 of the external router 500 not adjacent to the first relay device 100a is the latter type. When the ARP table 136 is created in each network relay device 100, the ARP table setting process is terminated.

Routing Table Setting Processing Routing table setting processing for setting the routing table 135 in each of the first to third relay devices 100a to 100c will be described with reference to FIGS. FIG. 10 is a sequence diagram showing a processing sequence of the routing table setting process. FIG. 11 is a diagram illustrating route information held by the network relay system. FIG. 12 is a diagram showing route information advertised by each external router. FIG. 13 is a schematic diagram showing a system routing table. FIG. 14 is a diagram illustrating a routing table set in each network relay device.

  The route information learning unit 145 of the control unit 140 of each network relay device 100 learns the route information advertised by the external router by exchanging the route information advertised with each other by the adjacent external router. (FIG. 10: Steps S210a, S210b, S210c). Such exchange of route information is performed according to a routing protocol. The route information to be exchanged differs depending on the routing protocol supported by the network relay device 100 and the external router 500. For example, the routing information is the routing table for RIP and the link state for OSPF. FIG. 11 shows an example of route information of the entire network relay system 1000. The management apparatus 200 grasps the route information of the entire network relay system 1000. Of the route information in the entire network relay system 1000, the route information advertised to the external router 500 is a part related to the outside of the network relay system 1000, for example, an external transfer network adjacent to the network relay system 1000 as shown in FIG. Only the part related to ONT1 to ONT3. Of the route information of the entire network relay system 1000, a part related to the inside of the network relay system 1000, for example, a part related to the internal transfer networks INT1 to INT3 and a part related to the management network MNT are not advertised to the external router 500. This is because the network relay system 1000 is virtually shown as one network relay device to the external router 500. The route information advertised to the external router 500 is notified to each network relay device 100 by the management device 200.

  FIG. 12 shows route information advertised by each external router 500. The route information advertised by the external router 500a is learned by the first relay device 100a adjacent to the external router 500a. Similarly, the route information advertised by the external router 500b is the second relay device 100b, the route information advertised by the external router 500c and the route information advertised by the external router 500d is the third relay device. 100c learns each.

  The route information learning unit 145 of each network relay device 100 notifies the learned route information to the management device 200 via the management network MNT (steps S220a, S220b, and S220c).

  The route information collection unit 241 of the route information manager 240 collects the route information notified from each network relay device 100, and the system routing table creation unit 243 of the route information setting unit 242 of the route information manager 240 displays the system routing table 250. Is created (step S230). FIG. 13 shows the created system routing table 250. As shown in FIG. 13, the system routing table 250 is a routing table when the entire network relay system 1000 is considered as one relay device. The system routing table creation unit 243 creates the system routing table 250 by calculating the optimum route based on the collected route information according to the rules defined in the routing protocol.

  Subsequently, the address range dividing unit 244 of the route information setting unit 242 calculates the entire network address range (0.0.0.0 to 255.255.255.255) to the number of network relay devices 100 (this embodiment). Then, it is divided into the address range of 3), and the allocated address range assigned to each network relay device 100 is determined (step S240). As shown in FIG. 13, in this embodiment, the assigned address range assigned to the first relay device 100a is 0/2 (0.0.0.0 to 63.255.255.255), and the second The assigned address range assigned to the relay device 100b is 64/2 (64.0.0.0 to 127.255.255.255), and the assigned address range assigned to the third relay device 100c is 128/1 (128 0.0.0 to 255.255.255.255), respectively.

  The allocation address range is determined such that the size of the routing table 135 of each network relay device 100 generated in a later step is substantially the same.

  Next, the routing table creation unit 245 of the route information setting unit 242 creates a routing table 135 to be assigned (set) to each network relay device 100 (step S250). In FIG. 14, the created routing table 135 is shown for each network relay device 100 in which the routing table 135 is set. In order to distinguish the routing tables 135 set in the three network relay apparatuses 100a to 100c, the same alphabets as the relay apparatus codes are added to the end of the respective codes to represent the routing tables 135a to 135c.

  As shown in FIG. 14, each routing table 135 is a table for associating a range of IP addresses described by path information and mask length with a transfer destination device. In FIG. 14, the IP address of the port of the transfer destination device is used as the identifier of the transfer destination device. By referring to this, the layer 3 transfer unit 132 of the network relay device 100 can determine the transfer destination device of the Ethernet frame. That is, the layer 3 transfer unit 132 searches the routing table 135 for the range of IP addresses that include the destination IP address included in the Ethernet frame. Then, the layer 3 transfer unit 132 specifies the device corresponding to the IP address associated with the searched IP address range as the transfer destination device of the frame.

  Here, in each routing table 135, when an IP address included in the assigned address range assigned to the network relay device 100 in which the routing table 135 is set is to be transferred to the external router 500, the external router Regardless of whether or not 500 is adjacent to the network relay device 100, the external router 500 is associated as a transfer destination device. For example, an Ethernet frame whose destination IP address is an IP address included in the range of 50.0.0.0/8 should be transferred to the external router 500b that is not adjacent to the first relay device 100a. And In this case, as shown in FIG. 14, in the routing table 135a set in the first relay device 100a to which the range of 50.0.0.0/8 is assigned, 50.0.0.0/8 In the range of IP addresses, the port R2 of the external router 500b is associated as the transfer destination device, not the port I2 of the second relay device 100b between the first relay device 100a and the external router 500b.

  On the other hand, in each routing table 135, another network relay device 100 to which the unassigned address is assigned to an IP address included in the non-assigned address range that is not assigned to the network relay device 100 in which the routing table 135 is set. Corresponding as a transfer destination device. For example, in the routing table 135a set in the first relay device 100a, the allocation address range of the second relay device 100b is 64/2 (64.0.0.0 to 127.255.255.255). Is associated with the port I2 of the second relay device 100b.

  Here, in each routing table 135, an IP address associated with (local) is an Ethernet frame whose destination IP address is the IP address, and is addressed to the network relay device 100 storing the routing table 135. It shows that there is.

  Next, the route information setting unit 242 sets the routing tables 135a to 135c created for each network relay device 100 in the corresponding network relay device 100 (steps S260a to S260c). That is, the routing tables 135a to 135c are transmitted to the control unit 140 of the corresponding network relay device 100 via the management network MNT, and stored in the memory 134 of the transfer processing circuit 130 by the control unit 140 of each network relay device 100. Is done. When the routing tables 135a to 135c are set in the corresponding network relay device 100, the routing table setting process ends.

-Operation of Network Relay System 1000 When the ARP table setting process and the routing table setting process described above are executed, the network relay system 1000 is in a state where it can virtually operate as one network relay device.

  The operation of the network relay system 1000 will be described with reference to FIGS. FIG. 15 is an explanatory diagram illustrating the operation of the network relay system according to the embodiment. FIG. 16 is an explanatory diagram illustrating the operation of the network relay system according to the comparative example.

  The operation of the network relay system 1000 according to the embodiment will be described by taking as an example a case where the Ethernet frame P having the destination IP address DI of 50.2.3.1 is transferred from the external router 500d. In such a case, the external router 500d designates the MAC address MAC_O4 of the port O4 of the third relay device 100c as the destination MAC address DM, and transfers the Ethernet frame to the third relay device 100c (FIG. 15). . When the third relay device 100c receives the Ethernet frame P, since the destination MAC address DM of the Ethernet frame P is the MAC address MAC_O4 of the third relay device 100c itself, the layer 3 transfer unit 132 of the third relay device 100c. Determines the transfer destination with reference to the routing table 135c based on the destination IP address DI. Since the destination IP address DI = 50.2.3.1 is an assigned address of the first relay device 100a, the layer 3 transfer unit 132 of the third relay device 100c transfers the first relay device 100a to the transfer destination. Determine as a device. That is, the layer 3 transfer unit 132 of the first relay device 100a specifies the IP address IP_I5 of the port I5 of the first relay device 100a as the transfer destination (FIG. 14: entry in the second row from the bottom of the routing table 135c). See). The layer 3 transfer unit 132 of the third relay device 100c identifies the MAC address MAC_I5 corresponding to the IP address IP_I5 and the transmission port I6 of the Ethernet frame P with reference to the ARP table 136c (FIG. 9: ARP table 136c). (See entry at the bottom of.) As a result, the third relay device 100c changes the destination MAC address DM of the Ethernet frame P to MAC_I5, and transfers the Ethernet frame P from the port I6 to the first relay device 100a by Layer 3 (FIG. 15).

  When the first relay device 100a receives the Ethernet frame P, since the destination MAC address DM of the Ethernet frame P is the MAC address MAC_I5 of the first relay device 100a itself, the layer 3 transfer unit 132 of the first relay device 100a. Determines a transfer destination by referring to the routing table 135a based on the destination IP address DI. Since the destination IP address DI = 50.2.3.1 is an assigned address of the first relay device 100a, the layer 3 transfer unit 132 of the first relay device 100a determines the external router 500b as the transfer destination device. To do. That is, the layer 3 transfer unit 132 of the first relay device 100a specifies the IP address IP_R2 of the port R2 of the external router 500b as the transfer destination (see the fourth entry from the top of the routing table 135a). . The layer 3 transfer unit 132 of the first relay device 100a identifies the MAC address MAC_R2 corresponding to the IP address IP_R2 and the transmission port I1 of the Ethernet frame P with reference to the ARP table 136a (FIG. 9: ARP table 136a). (See entry in the third row from the top). As a result, the first relay device 100a changes the destination MAC address DM of the Ethernet frame P to MAC_R2, and transfers the Ethernet frame P from the port I1 to the second relay device 100b by Layer 3 (FIG. 15).

  When the second relay device 100b receives the Ethernet frame P, since the destination MAC address DM of the Ethernet frame P is not the MAC address of the second relay device 100b itself, the layer 2 transfer unit 133 of the second relay device 100b Based on the destination MAC address DM, the transfer destination is determined by referring to the ARP table 136b. That is, the layer 2 transfer unit 133 specifies the transmission port IP_O2 associated with the destination MAC address DM = MAC_R2. As a result, the second relay device 100b transfers the Ethernet frame P as it is to the external router 500b by Layer 2 (FIG. 15). In FIG. 14, white arrows indicate layer 3 transfer, and black arrows indicate layer 2 transfer.

  Through the operation described above, the Ethernet frame P transferred from the external router 500d is transferred to the external router 500b via the network relay system 1000.

  Next, consider the case where the above-described Ethernet frame P is transferred from the external router 500a. In such a case, the external router 500a designates the MAC address MAC_O1 of the port O1 of the first relay device 100a as the destination MAC address DM, and transfers the Ethernet frame to the first relay device 100a.

  When the first relay device 100a receives the Ethernet frame P, the destination MAC address DM of the Ethernet frame P is the MAC address MAC_O1 of the first relay device 100a itself, and the destination IP address DI is within its assigned address range. Therefore, the same processing as when the Ethernet frame P is received from the third relay device 100c described above is performed. That is, the first relay device 100a changes the destination MAC address DM of the Ethernet frame P to MAC_R2, and transfers the Ethernet frame P from the port I1 to the second relay device 100b by Layer 3 transfer.

  When the second relay device 100b receives the Ethernet frame P, the second relay device 100b transfers the Ethernet frame P as it is to the external router 500b in a layer 2 manner as described above.

  Here, for easy understanding, a network relay system according to a comparative example will be described with reference to FIG. The network relay system 20000 according to the comparative example is a system in which three network relay devices (first to third relay devices 2000a to 2000c), which are conventional routers, are connected in the same manner as in the embodiment. In order to avoid complications, the same reference numerals as those in FIG.

  Similar to the description of the operation of the network relay system 1000 according to the embodiment, the case where the Ethernet frame P having the destination IP address DI of 50.2.3.1 is transferred from the external router 500d is taken as an example for comparison. The operation of the network relay system 20000 according to FIG. In this case, as described above, the external router 500d designates the MAC address MAC_O4 of the port O4 of the third relay device 2000c as the destination MAC address DM, and transfers the Ethernet frame to the third relay device 2000c. come. When the third relay device 2000c receives the Ethernet frame P, the third relay device 2000c refers to the destination IP address DI and identifies the port I3 of the second relay device 2000b that is the next transfer destination. Therefore, as shown in FIG. 16, in the routing table 1350c of the third relay device 2000c, the transfer destination of the destination IP address DI = 50.2.3.1 is the port I3 of the second relay device 2000b. Must be described. The third relay device 2000c changes the destination MAC address DM of the Ethernet frame P to MAC_I3, and transfers the Ethernet frame P from the port I4 to the second relay device 2000b by Layer 3 (FIG. 16).

  When the second relay apparatus 2000b receives the Ethernet frame P, the second relay apparatus 2000b refers to the destination IP address DI and identifies the port R2 of the external router 500b that is the next transfer destination. Therefore, as shown in FIG. 16, the routing table 1350b of the second relay device 2000b describes that the transfer destination of the destination IP address DI = 50.2.3.1 is the port R2 of the external router 500b. Need to be. The second relay device 2000b changes the destination MAC address DM of the Ethernet frame P to MAC_R2, and transfers the Ethernet frame P from the port O2 to the external router 500b by Layer 3 (FIG. 16).

  Next, similarly to the description of the operation of the network relay system 1000 according to the embodiment, consider the case where the Ethernet frame P described above is transferred from the external router 500a in the network relay system 20000 according to the comparative example. In this case, as described above, the external router 500a designates the MAC address MAC_O1 of the port O1 of the first to third relay devices 2000a as the destination MAC address DM, and sends the Ethernet frame to the first relay device 2000a. Come forward. When the first relay device 2000a receives the Ethernet frame P, the first relay device 2000a refers to the destination IP address DI and identifies the port I2 of the second relay device 2000b that is the next transfer destination. Therefore, as shown in FIG. 16, in the routing table 1350a of the first relay device 2000a, the transfer destination of the destination IP address DI = 50.2.3.1 is the port I2 of the second relay device 2000b. Must be described. The first relay device 2000a changes the destination MAC address DM of the Ethernet frame P to MAC_I2, and transfers the Ethernet frame P from the port I1 to the second relay device 2000b by Layer 3 transfer.

  When the second relay device 2000b receives the Ethernet frame P, the second relay device 2000b changes the destination MAC address DM of the Ethernet frame P to MAC_R2 and the Ethernet frame P from the port O2 as described above. Layer 3 transfer to the router 500b.

  As can be understood from the above description, in the network relay system 20000 according to the comparative example, each of the first to third relay apparatuses 2000a to 2000c has the destination IP address DI = 50.2.3.1 in the routing table. It is necessary to describe the forwarding destination. Similarly, it can be understood that the first to third relay apparatuses 2000a to 2000c need to have detailed transfer destinations for all ranges of IP addresses.

  On the other hand, in the network relay system 1000 according to the embodiment, each network relay device 100 describes a detailed transfer destination only for the IP address within the allocated address range allocated to itself in the routing table 135 (see FIG. 14). For the IP address in the non-allocation address range, another network relay device 100 having the non-allocation address range as the allocation address range is described as the transfer destination. This is as follows. 1. In the routing table 135, for the IP address within the allocated address range, the external router 500 that is not adjacent to itself is described as a direct transfer destination; This is realized by setting the MAC address of the external router 500 not adjacent to the ARP table 136 as static ARP information. Therefore, the size of the routing table 135 in each network relay device 100 can be made smaller than before. As a result, the entire network relay system 1000 can hold a larger amount of routing information. Therefore, the network relay system 1000 as a whole can establish adjacency relationships with more external devices (in this embodiment, the external router 500). Further, according to the number of network relay devices 100 included in the network relay system 1000, the number of routes that can be handled by the network relay system 1000 as a whole and the number of external devices that can establish an adjacency relationship increase. Therefore, by adding the network relay device 100 to the network relay system 1000, the processing capability of the network relay system 1000 can be easily increased.

  In particular, in the network relay device 100, in order to speed up the routing process, the entry of the routing table 135 is registered in the high-speed search memory (CAM), and the high-speed routing process is performed by the hardware process. The required capacity of the search memory can be suppressed, or more paths can be handled with a limited capacity of the high-speed search memory.

Processing when there is a change in the adjacency relationship of the network relay system A process when there is a change in the adjacency relationship of the network relay system 1000 will be described with reference to FIGS. FIG. 17 is a sequence diagram showing a processing sequence of the ARP table update processing. FIG. 18 is a sequence diagram showing a processing sequence of the routing table update process.

  When there is a change in the adjacency relationship of the network relay system 1000, when there is a change in the ARP information that one network relay device 100 learns dynamically, an ART table update process is performed. Changes in the ARP information learned dynamically include, for example, disappearance of ARP information that occurs when one network relay device 100 becomes unable to communicate with an adjacent external router 500 due to a line failure or the like, or one network relay This includes the addition of ARP information that occurs when an external router 500 adjacent to the device 100 is newly added. Hereinafter, the ARP table update process will be described by taking as an example a case where the ARP information dynamically learned by the first relay device 100a has changed.

  When there is a change in the ARP information that the first relay device 100a learns dynamically, the ARP information learning unit 144 of the control unit 140 of the first relay device 100a recognizes the change and stores it in its own ARP table 136. The recorded ARP information is updated (step S310c). The change in the ARP information is because, for example, the newly connected external router 500 is notified of the ARP information of the external router 500 or there is no notification of the known ARP information from the external router 500 over a predetermined period. When the ARP information is aged out, it is recognized by the ARP information learning unit 144.

  The ARP information learning unit 144 notifies the update content of the ARP information to the management apparatus 200 (step S320). The ARP information collection unit 231 of the ARP information manager 230 of the management apparatus 200 updates the system ARP table 260 based on the notified update contents of the ARP information (step S330). The ARP information setting unit 232 of the ARP information manager 230 statically sets other network relay devices 100, that is, the second relay device 100b and the third relay device 100c, based on the updated system ARP table 260. Each piece of static ARP information is updated (step S340). The ARP information setting unit 232 notifies the contents of the updated static ARP information to the second relay device 100b and the third relay device 100c, respectively (steps S350b and S350c). The second relay device 100b and the third relay device 100c notified of the update contents of the static ARP information update their ARP tables 136 based on the notified contents (steps S360b and S360c). When each ARP table 136 is updated, the ARP table update process is terminated.

  When there is a change in the adjacency relationship of the network relay system 1000, a routing table update process is performed when there is a change in the route information dynamically learned by one network relay device 100. Changes in the dynamically learned route information include, for example, disappearance of route information that occurs when one network relay device 100 cannot communicate with the adjacent external router 500 due to a line failure or the like, or one network relay This includes the acquisition of new route information that occurs when a newly adjacent external router 500 is added to the device 100, the case of acquiring updated route information from the adjacent external router 500, and the like.

  Hereinafter, the routing table update process will be described by taking as an example a case where the route information dynamically learned by the first relay device 100a has changed. When there is a change in the route information dynamically learned by the first relay device 100a, the route information learning unit 145 of the control unit 140 of the first relay device 100a recognizes the change (step S410). The change in the route information is, for example, the learning of the route information advertised by the newly connected external router 500 or the disappearance of the adjacency relationship with the adjacent external router 500 by periodic communication interruption. By being recognized, the route information learning unit 145 recognizes it.

  The route information learning unit 145 notifies the management device 200 of a change in route information (step S420). Specifically, the management apparatus 200 is notified of newly learned route information, or notification that the adjacency relationship with the adjacent external router 500 has disappeared. When the management device 200 receives the notification of the change of the route information, the system routing table creation unit 243 of the route information setting unit 242 of the route information manager 240 updates the system ARP table 260 based on the notification content (step S430). . For example, when new route information is notified, the system routing table creation unit 243 adds the new route information to the known route information, and recalculates the optimal transfer route according to the routing protocol. The system ARP table 260 is updated. In addition, when the disappearance of the adjacent relationship is notified, the system routing table creation unit 243 deletes the route information advertised by the external router 500 in which the adjacent relationship has disappeared, and optimizes based on the remaining route information. The system ARP table 260 is updated by recalculating the correct transfer path according to the routing protocol.

  Subsequently, the address range dividing unit 244 of the route information setting unit 242 re-divides the entire range of network addresses, and re-decides the assigned address range to be assigned to each network relay device 100 (step S440). The routing table creation unit 245 of the route information setting unit 242 updates the routing tables 135a to 135c assigned to each network relay device 100 according to the result of the re-determination of the allocation range (step S450). The path information setting unit 242 sets the updated routing tables 135a to 135c for each network relay device 100 in the corresponding network relay device 100 (steps S460a to S460c). In this way, when the updated routing tables 135a to 135c are set in the corresponding network relay devices 100, the routing table update processing is ended.

  The ARP table update process and the routing table update process described above are executed as needed according to the change in the adjacent relationship of the network relay system 1000, so that the network relay system 1000 can correctly perform the above-described Ethernet frame transfer operation. The state can be maintained.

B. Modifications-First modification:
In the above embodiment, an example is shown in which three network relay devices 100 are connected to each other. However, the number of network relay devices 100 included in the network relay system can be arbitrarily changed. The 100 connection modes can be arbitrarily changed. For example, the four network relay devices 100 may be connected in a straight line, may be connected in a ring shape, or may be connected in a star shape.

  FIG. 19 is an explanatory diagram showing a network relay system according to a first modification. Referring to FIG. 19, a network relay system 1000a in which five network relay devices 100 (first to fifth relay devices 100a to 100e) are connected in a ring shape will be described as a first modification. As in the embodiment, the network relay system 1000a according to the modification includes the management device 200 connected to each of the network relay devices 100a to 100e via the management network MNT. In FIG. In order to avoid this, the management device 200 is not shown.

  Similarly to the above-described embodiment, the ARP table 136 of each network relay device 100 in the first modified example includes the ARP information (dynamically learned) of the external router 500 and other network relay devices 100 that are adjacent to each other. In addition, static ARP information of the external router 500 and other network relay devices 100 that are not adjacent to each other is recorded.

  As in the above embodiment, in the routing table 135 of the network relay device 100 according to the first modification, only the external router 500 adjacent to itself is used as the forwarding destination device for the IP address in the assigned address range assigned to itself. The external router 500 adjacent to the other network relay device 100 is also directly associated. On the other hand, as in the above-described embodiment, in the routing table 135 of the network relay device 100 in the first modification, the unassigned address range is assigned to the IP address of the unassigned address range that is not assigned to itself. A device other than itself is associated as a transfer destination device.

  The operation of the network relay system 1000a according to the first modification will be described by taking as an example the case where the Ethernet frame P having the destination IP address DI of 50.2.3.1 is transferred from the external router 500d. In such a case, the external router 500d designates the MAC address MAC_O4 of the port O4 of the fourth relay device 100d as the destination MAC address DM, and transfers the Ethernet frame to the fourth relay device 100d. When the fourth relay device 100d receives the Ethernet frame P, the destination IP address DI = 50.3.2.3.1 is the assigned address of the first relay device 100a, and therefore the layer 3 of the fourth relay device 100d. The transfer unit 132 determines the first relay device 100a as the transfer destination device. The fourth relay device 100d changes the destination MAC address DM of the Ethernet frame P to the MAC address MAC_I10 of the first relay device 100a, and transfers the Ethernet frame P from the port I7 to the fifth relay device 100e by Layer 3 transfer. (FIG. 19).

  When the fifth relay device 100e receives the Ethernet frame P, since the destination MAC address DM of the Ethernet frame P is not the MAC address of the fifth relay device 100e itself, the layer 2 transfer unit 133 of the fifth relay device 100e Based on the destination MAC address DM, the transfer destination is determined by referring to the ARP table. As a result, the fifth relay device 100e transfers the Ethernet frame P as it is to the first relay device 100a by Layer 2 (FIG. 19).

  When the first relay device 100a receives the Ethernet frame P, since the destination MAC address DM of the Ethernet frame P is the MAC address MAC_I10 of the first relay device 100a itself, the layer 3 transfer unit 132 of the first relay device 100a. Determines the transfer destination with reference to the routing table based on the destination IP address DI. As a result, the first relay device 100a changes the destination MAC address DM of the Ethernet frame P to the MAC address MAC_R3 of the external router 500c, and transfers the Ethernet frame P to the second relay device 100b by Layer 3 (FIG. 19). ).

  When the second relay device 100b receives the Ethernet frame P, since the destination MAC address DM of the Ethernet frame P is not the MAC address of the second relay device 100b itself, the layer 2 transfer unit 133 of the second relay device 100b Based on the destination MAC address DM, the transfer destination is determined by referring to the ARP table. As a result, the second relay device 100b transfers the Ethernet frame P as it is to the third relay device 100c by Layer 2 (FIG. 19). When the third relay device 100c receives the Ethernet frame P, the destination MAC address DM of the Ethernet frame P is not the MAC address of the third relay device 100c itself, so the layer 2 transfer unit of the third relay device 100c 133 determines a transfer destination by referring to the ARP table based on the destination MAC address DM. As a result, the third relay device 100c transfers the Ethernet frame P as it is to the external router 500c by Layer 2 (FIG. 19). In this way, the Ethernet frame P is transferred to the external router 500c.

  As can be understood from the above description, the network relay system 1000a can operate as one virtual network relay device even in a form in which the five network relay devices 100 are connected in a ring shape. Further, the above-described Ethernet frame P is transferred to the external router 500c via all the five network relay devices 100. However, among these transfers, the layer 3 transfer (outlined arrow) is performed from the fourth relay device 100d to the fifth relay device 100e and from the first relay device 100a. Only the transfer to the second relay device 100b, the remaining transfer, that is, the transfer from the fifth relay device 100e to the first relay device 100a, and from the second relay device 100b to the third relay device 100c. And the transfer from the third relay device 100c to the external router 500c are layer 2 transfers. Therefore, it is understood that the number of hops when the Ethernet frame P passes through the network relay system 1000a is 2.

  As can be understood from the above description, the maximum number of hops through the network relay system is two no matter how many network relay devices 100 are used to configure the network relay system. As described above, the network relay system shown in the present embodiment and the modification can suppress an increase in the number of hops to 2 or less even when many network relay devices 100 are connected.

・ Second modification:
In the above embodiment, the MAC address is used as the address of the data link layer, and the IP address is used as the address of the network layer. This is because the network connecting each device in this embodiment is the data link layer. This is because Ethernet (registered trademark) is used as the protocol, and IP (internet protocol) is used as the network layer protocol. Of course, when other protocols are used for the data link layer and network layer protocols, the addresses used in those protocols may be used.

・ Third modification:
In the above embodiment, the correspondence between the MAC address of the transfer destination device and the port to which the Ethernet frame having the MAC address as the destination MAC address DM is to be sent is described in the ARP table 136 as shown in FIG. Although the correspondence between the address and the transfer destination device is described in the routing table 135 as shown in FIG. 14, the information describing the correspondence is not limited to the embodiment. These one or more types of information are transferred based on the destination IP address DI when the destination MAC address DM of the Ethernet frame received by the network relay device 100 is the MAC address of the network relay device 100 itself. It is information that can properly determine the destination device, and can recognize the MAC address of the determined destination device and the port to which an Ethernet frame having the MAC address as the destination MAC address DM should be transmitted, and network relay When the destination MAC address DM of the Ethernet frame received by the device 100 is the MAC address of the transfer destination device other than the network relay device 100 itself, the Ethernet frame having the MAC address as the destination MAC address DM is transmitted. Rubeki port may be any information that can be recognized.

-Fourth modification:
In the above embodiment, the allocation address range is determined so that the size of the routing table 135 of each network relay device 100 is substantially the same, but this is a memory area for storing the routing table 135. Is assumed to be the same in each network relay device 100. The allocation address range is determined by determining the memory area for storing the routing table 135 of each network relay apparatus 100 so that the routing table 135 of each network relay apparatus 100 can be accommodated in the memory area for storing the routing table 135. Depending on the size, it is preferably performed. In this way, it is possible to effectively use the memory capacity of each network relay device 100 and hold more routing information as the entire network relay system 1000.

・ Other variations:
In the above embodiment, the management apparatus 200 is configured as an apparatus independent of the network relay apparatus 100, but is not limited thereto. For example, the control unit 140 of any of the plurality of network relay devices 100 included in the network relay system 1000 includes the functions of the management device 200 (functions realized by the ARP information manager 230 and the path information manager 240). May be. In this way, the configuration of the network relay system 1000 can be simplified.

  In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware.

  As mentioned above, although this invention was demonstrated based on the Example and the modification, Embodiment mentioned above is for making an understanding of this invention easy, and does not limit this invention. The present invention can be changed and improved without departing from the spirit and scope of the claims, and equivalents thereof are included in the present invention.

The block diagram which shows schematic structure of the network relay system which concerns on an Example. The block diagram which shows the internal structure of the network relay apparatus contained in the network relay system which concerns on an Example. The block diagram which shows the internal structure of the management apparatus contained in the network relay system which concerns on an Example. The table of the IP address allocated to each part of the network relay system in the embodiment. The sequence diagram which shows the process sequence of an ARP table setting process. The figure which shows the learning result of the ARP information in each network relay apparatus. Schematic which shows a system ARP table. The figure which shows the static ARP information set to each network relay apparatus. The figure which shows the ARP table set to each network relay apparatus. The sequence diagram which shows the process sequence of a routing table setting process. The figure which shows the routing information which a network relay system holds. The figure which shows the routing information which each external router advertised. Schematic which shows a system routing table. The figure which shows the routing table set to each network relay apparatus. Explanatory drawing which shows operation | movement of the network relay system which concerns on an Example. Explanatory drawing which shows operation | movement of the network relay system which concerns on a comparative example. The sequence diagram which shows the process sequence of an ARP table update process. The sequence diagram which shows the process sequence of a routing table update process. Explanatory drawing which shows the network relay system which concerns on a 1st modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100a-100e ... Network relay apparatus 110 ... Physical port 120 ... Transmission / reception processing circuit 130 ... Transfer processing circuit 131 ... Transfer engine 132 ... Layer 3 transfer part 133 ... Layer 2 transfer part 134 ... Memory 135a-135c ... Routing table 136a-136c ... ARP table 140 ... control unit 141 ... CPU
DESCRIPTION OF SYMBOLS 142 ... Memory 143 ... Control program 144 ... ARP information learning part 145 ... Path information learning part 200 ... Management apparatus 210 ... CPU
DESCRIPTION OF SYMBOLS 220 ... Memory 230 ... ARP information manager 231 ... ARP information collection part 232 ... ARP information setting part 240 ... Path information manager 241 ... Path information collection part 242 ... Path information setting part 243 ... System routing table creation part 244 ... Address range division part 245 ... Routing table creation unit 250 ... System routing table 260 ... System ARP table 500a to 500d ... External router 1000, 1000a ... Network relay system ONT1-ONT3 ... External transfer network INT1-INT3 ... Internal transfer network CV ... Line MNT ... Management network

Claims (11)

A network relay system in which a plurality of network relay devices are connected and operate virtually as one network relay device,
Each of the plurality of network relay devices is
A plurality of ports for connecting to an external device or a device other than one of the plurality of network relay devices;
Data link layer information for associating a data link layer address of a transfer destination device with a corresponding port of the plurality of ports, wherein the transfer destination device is assigned to a device other than the self device and a self of the external device. A first storage unit for storing the data link layer information, including a first external device adjacent to the second external device adjacent to a device other than the self device among the external devices;
1st network layer information which matches the address of a network layer, and the said transfer destination apparatus, Comprising: The said transfer destination apparatus matched with the allocation address allocated to self among the addresses of the said network layer is said 1st The transfer destination device that includes an external device or the second external device and is associated with a non-assigned address that is not assigned to itself is a device other than the self that is assigned the non-assigned address. A second storage unit for storing one network layer information;
Receiving means for receiving data having a first destination address that is a data link layer address as a destination and a second destination address that is a network layer address as a destination via any of the plurality of ports When,
When the first destination address is an address of its own data link layer, the first destination address is changed to the second address using the data link layer information and the first network layer information. Change to the data link layer address of the transfer destination device associated with the destination address, and transfer the received data from the corresponding port associated with the changed first destination address Transfer means;
When the first destination address is an address of the data link layer of the transfer destination device, the data is received from the corresponding port associated with the first destination address using the data link layer information. A second transfer means for transferring the received data;
A network relay system comprising: The network relay system according to claim 1,
Each of the plurality of network relay devices further includes:
Of the data link layer information, comprising: first learning means for learning first partial information related to an address of a data link layer of the transfer destination device adjacent to the data link layer information;
The network relay system further includes:
First collection means for collecting the first partial information from each of the plurality of network relay devices;
Based on the collected first partial information, each of the plurality of network relay devices has a first information related to the address of the data link layer of the transfer destination device that is not adjacent to the first information. First setting means for setting the partial information of 2;
A network relay system comprising: The network relay system according to claim 2,
In any one of the plurality of network relay devices, when there is a change in the adjacency relationship with the first external device, the first learning means of the network relay device having the change is the first The first collection unit re-collects the first partial information from the changed network relay device, and the first setting unit includes the plurality of network relay devices. The network relay device resets the second partial information to each of the network relay devices. In the network relay system according to any one of claims 1 to 3,
Each of the plurality of network relay devices further includes:
Comprising second learning means for learning route information owned by the first external device from the first external device;
The network relay system further includes:
Second collection means for collecting the route information from each of the plurality of network relay devices;
Second setting means for setting the first network layer information in each of the plurality of network relay devices based on the collected route information;
A network relay system comprising: The network relay system according to claim 4,
The second setting means includes
First creation means for creating second network layer information for associating a network layer address with the first external device or the second external device based on the collected path information;
Dividing the network layer address into an address range equal to the number of the plurality of network relay devices, and using the network address included in each of the address ranges as the assigned address of each of the plurality of network relay devices Means,
Second creation means for creating the first network layer information set in each of the plurality of network relay devices based on the second network layer information and the result of the division;
A network relay system. The network relay system according to claim 5,
The network relay system, wherein the dividing unit determines the address range so that the first network layer information corresponding to the capacity of the second storage unit of each of the plurality of network relay devices is created. The network relay system according to any one of claims 4 to 6,
In any one of the plurality of network relay devices, when there is a change in the adjacency relationship with the first external device, the second learning unit of the network relay device that has changed the route information The second collection unit re-collects the route information from the changed network relay device, and the second setting unit transmits the first information to each of the plurality of network relay devices. A network relay system that reconfigures network layer information. The network system according to claim 2 or 3, further comprises:
A management device connected to each of the plurality of network relay devices;
The network management system, wherein the management device includes the first collection unit and the first setting unit. The network relay system according to any one of claims 4 to 7, further comprising:
A management device connected to each of the plurality of network relay devices;
The network management system, wherein the management device includes the second collection unit and the second setting unit. A network relay system control method in which a plurality of network relay devices each having a plurality of ports are connected and operate virtually as one network relay device,
Data link layer information for associating each of the plurality of network relay devices with a data link layer address of the transfer destination device to a corresponding port of the plurality of ports, wherein the transfer destination device is the plurality of network relay devices. Storing the data link layer information including a device other than itself among the devices, a first external device adjacent to the device, and a second external device adjacent to the device other than the device;
First network layer information that associates a network layer address and the transfer destination device with each of the plurality of network relay devices, and is associated with an assigned address assigned to itself among the network layer addresses. The transfer destination device includes the first external device or the second external device, and the transfer destination device associated with a non-assignment address not assigned to itself is assigned the non-assignment address. Storing the first network layer information that is a device other than the device;
Among the plurality of network relay devices, a device that has received data having a first destination address that is a data link layer address as a destination and a second destination address that is a network layer address as a destination.
When the first destination address is an address of its own data link layer, the first destination address is changed to the second address using the data link layer information and the first network layer information. Change to the address of the data link layer of the transfer destination device associated with the destination address, transfer the received data from the corresponding port associated with the first destination address after the change,
When the first destination address is an address of the data link layer of the transfer destination device, the data is received from the corresponding port associated with the first destination address using the data link layer information. Control method to transfer the data. A management device in a network relay system that connects a plurality of network relay devices and operates virtually as one network relay device,
Each of the plurality of network relay devices is
A plurality of ports for connecting to an external device or a device other than one of the plurality of network relay devices;
Data link layer information for associating the address of the data link layer of the transfer destination device with the corresponding port of the plurality of ports;
First network layer information associating a network layer address with the transfer destination device;
Receiving means for receiving data having a first destination address that is a data link layer address as a destination and a second destination address that is a network layer address as a destination via any of the plurality of ports When,
When the first destination address is an address of its own data link layer, the first destination address is changed to the second address using the data link layer information and the first network layer information. Change to the data link layer address of the transfer destination device associated with the destination address, and transfer the received data from the corresponding port associated with the changed first destination address Transfer means;
When the first destination address is an address of the data link layer of the transfer destination device, the data is received from the corresponding port associated with the first destination address using the data link layer information. A second transfer means for transferring the received data;
Have
The management device
The data link layer information of each of the plurality of network relay devices is associated with the corresponding port of the data link layer address of a device adjacent to the device other than the device other than the device other than the device itself and the external device. A first setting unit for setting information;
Each of the plurality of network relay devices includes the external device, and the transfer destination device associated with the assigned address assigned to the network relay device among the addresses of the network layer is assigned to the network relay device. A second setting unit configured to set the first network layer information which is another network relay device to which the unassigned address is assigned;
A management device comprising:

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