JP5566967B2 - Frame transfer system, frame transfer apparatus, and frame transfer method - Google Patents

Description

  The present invention relates to a frame transfer system including a plurality of frame transfer apparatuses having an address table, a frame transfer apparatus, and a frame transfer method.

  In recent years, with the growing demand for cloud computing, the importance of data centers that support network virtualization has increased, and there is a need for large-scale data center networks that can connect hundreds of thousands of servers. It has been.

  In order to realize such a large-scale data center network, methods for constructing a data center network with a large number of general-purpose transfer devices are disclosed in Non-Patent Documents 1 to 3, for example. In particular, a method using an L (Layer) 2 switch that is a frame transfer device (see, for example, Non-Patent Documents 4 and 5) is regarded as promising as realizing reduction in operation cost and ease of management.

  The L2 switch has a plurality of ports that transmit and receive frames. The L2 switch associates the MAC address information indicating the source MAC (Media Access Control) address of the received frame with the port information indicating the port that received the frame among a plurality of ports, and stores it as an address table entry. To do. The source MAC address is included in the header of the frame.

  Then, when the L2 switch receives the frame, it confirms the transmission destination address of the received frame. The transmission destination MAC address is included in the header of the frame. If the confirmed destination MAC address matches one of the MAC addresses indicated by the MAC address information stored in the address table, the L2 switch indicates the port information corresponding to the MAC address information indicating the matching MAC address. The received frame is transmitted from the port.

  On the other hand, if the confirmed destination MAC address does not match any of the MAC addresses indicated by the MAC address information stored in the address table, the received frame is sent to all of the ports other than the port that received the frame. Send (flood) from the port.

M. Al-Fares, A. Loukissas, and A. Vahdat, "A Scalable, Commodity Data Center Network Architecture," Proc. Of the ACM SIGCOMM 2008, pp. 63-74. C. Guo, H. Wu, K. Tan, L. Shiy, Y. Zhang, S. Luz, "Dcell: a scalable and fault-tolerant network structure for data centers," Proc. Of the ACM SIGCOMM 2008, pp. 75-86. C. Guo, G. Lu, D. Li, H. Wu, X. Zhang, Y. Shi, C. Tian, Y. Zhang, and S. Lu, "Bcube: a high performance, server-centric network architecture for modular data centers, "Proc. of the ACM SIGCOMM 2009, pp. 63-74. RN Mysore, A. Pam Boris, N. Farrington, N. Huang, P. Miry, S. Radhakrishnan, V. Subramanya, and A. Vahdat, "PortLand: A Scalable Fault-Tolerant Layer 2 Data Center Network Fabric," Proc of the ACM SIGCOMM 2009, pp. 39-50. R. Perlman, "Challenges and Opportunities in the Design of TRILL: a Routed layer 2 Technology," Proc. Of IEEE GLOBECOM Workshop, pp. 1-6, 2009.

  A MAC address having a long bit length of 48 bits is not configured to indicate position information hierarchically like an IP (Internet Protocol) address. Therefore, it is necessary to store all the MAC address information indicating the source MAC address of the received frame in the address table in association with each of the plurality of ports.

  Therefore, when a network composed of a plurality of frame transfer devices is widened, the amount of information stored in the address table increases. In this case, each of the plurality of frame transfer apparatuses needs to have a large capacity memory. In addition, power consumption is increased by using a frame transfer apparatus having a large-capacity memory. That is, there is a problem in that the cost for constructing and operating a network constituted by frame transfer devices increases.

    Conversely, if the amount of information stored in the address table is limited when the network configured by the frame transfer device is wide-area, flooding frequently occurs because frames with destination addresses not listed in the address table are flooded. Therefore, there is a problem that the bandwidth of the network becomes narrow.

  As a technique for solving the above-described problems, a server is provided separately from a network constituted by a plurality of frame transfer apparatuses, and each address table of the plurality of frame transfer apparatuses is centrally managed by the server. A centralized entry control method is being studied.

  However, in this entry centralized control method, it takes time to exchange information between the frame transfer apparatus and the server, and to update information on the server. Also, in this entry centralized control system, it is difficult to scale out as the network becomes wider.

  In other words, the above-described entry centralized control method has many adverse effects caused by providing a server that centrally manages the address table.

  The present invention can suppress an increase in cost due to a wide area of a network constituted by a plurality of frame transfer apparatuses and a reduction in bandwidth without providing a server that centrally manages an address table. It is an object to provide a frame transfer system, a frame transfer apparatus, and a frame transfer method.

In order to achieve the above object, a frame transfer system of the present invention has a plurality of frame transfer apparatuses, and each of the plurality of frame transfer apparatuses transmits / receives a frame to / from each of a plurality of hosts. A frame transfer system comprising one port and an address table,
Each of the plurality of frame transfer devices includes:
A second port for transmitting / receiving a frame to / from a frame transfer apparatus other than the frame transfer apparatus among the plurality of frame transfer apparatuses;
When a frame received at each of the plurality of first ports is a first type frame, MAC address information indicating a source MAC address of the first type frame, and the plurality of first types An address table generating unit that associates and stores in the address table port information indicating the first port that has received the first type of frame of the first port;
A first transfer unit that receives frames received at the plurality of first ports;
A second transfer unit for receiving a frame received at the second port,
When each of the first and second transfer units matches the destination MAC address of the received frame with one of the MAC addresses indicated by the MAC address information stored in the address table, the plurality of first addresses The frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and the frame is transmitted from the second port if they do not match.

In order to achieve the above object, the frame transfer system of the present invention includes a plurality of hierarchical frame transfer device groups each including an uppermost frame transfer device and a plurality of lower layer frame transfer devices. Each of the upper layer frame transfer apparatuses includes a plurality of first ports for transmitting / receiving frames to / from a plurality of lower layer frame transfer apparatuses, and a top layer address table, and the plurality of lower layer frame transfers Each of the devices transmits / receives a frame to / from a plurality of hosts or a plurality of lower layer frame transfer devices in the lower layer, and to / from the uppermost layer frame transfer device or the lower layer frame transfer device in the upper layer A frame transfer system comprising a second port and a lower layer address table,
Each of the plurality of uppermost frame transfer devices includes:
A third port for transmitting / receiving a frame to / from an uppermost frame transfer device other than the uppermost frame transfer device among the plurality of uppermost frame transfer devices;
When a frame received at each of the plurality of first ports is a first type frame, MAC address information indicating a source MAC address of the first type frame, and the plurality of first types A first address table generation unit that associates port information indicating the first port that has received the first type of frame and stores it in the uppermost layer address table;
A first transfer unit that receives frames received at the plurality of first ports;
A second transfer unit for receiving a frame received at the third port;
When the destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the first transfer unit is configured to output the plurality of first ports. Among these, the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and if the two do not match, the frame is transmitted from the third port,
The second transfer unit, when a destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the plurality of first ports Out of the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address is transmitted by adding predetermined information to the frame. Send a frame,
Each of the plurality of lower layer frame transfer devices,
If the predetermined information is not added to a frame received at each of the plurality of second ports, MAC address information indicating a source MAC address of the frame, and the plurality of second ports A second address table generation unit that associates and stores the port information indicating the second port that has received the frame in the lower layer address table;
A third transfer unit that receives frames received at the plurality of second ports,
When the destination MAC address of the accepted frame matches one of the MAC addresses indicated by the MAC address information stored in the lower layer address table, the third transfer unit is configured to receive the plurality of second ports. If the frame is transmitted from the second port indicated by the port information corresponding to the MAC address information indicating the matching MAC address and does not match, a predetermined second of the plurality of second ports is transmitted. The frame is transmitted from the port.

In order to achieve the above object, a frame transfer apparatus of the present invention is a frame transfer apparatus including a plurality of first ports that transmit and receive frames to and from a plurality of hosts, and an address table. And
A second port for transmitting and receiving frames to and from other frame transfer devices;
When a frame received at each of the plurality of first ports is a first type frame, MAC address information indicating a source MAC address of the first type frame, and the plurality of first types An address table generating unit that associates and stores in the address table port information indicating the first port that has received the first type of frame of the first port;
A first transfer unit that receives frames received at the plurality of first ports;
A second transfer unit for receiving a frame received at the second port,
When each of the first and second transfer units matches the destination MAC address of the received frame with one of the MAC addresses indicated by the MAC address information stored in the address table, the plurality of first addresses The frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and the frame is transmitted from the second port if they do not match.

In order to achieve the above object, a frame transfer method of the present invention includes a plurality of frame transfer apparatuses, and each of the plurality of frame transfer apparatuses transmits / receives a frame to / from each of a plurality of hosts. A frame in a frame transfer system comprising: a first port; a second port for transmitting / receiving a frame to / from a frame transfer device other than the frame transfer device among the plurality of frame transfer devices; and an address table A transfer method,
Each of the plurality of frame transfer devices indicates a source MAC address of the first type frame when the frame received at each of the plurality of first ports is a first type frame. A process of associating MAC address information with port information indicating a first port that has received the first type of frame among the plurality of first ports and storing the information in the address table;
In each of the plurality of frame transfer apparatuses, a MAC address indicated by the MAC address information stored in the address table is a transmission destination MAC address of a frame received at the plurality of first ports and the second port. Of the plurality of first ports, the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address. Processing to transmit the frame from the second port.

  Since the present invention is configured as described above, the amount of information stored in the address table of each of the plurality of frame transfer apparatuses does not increase. That is, it is not necessary for each of the plurality of frame transfer apparatuses to include a large capacity memory. Moreover, the occurrence of flooding is suppressed.

  Therefore, it is possible to suppress an increase in cost due to a wide area of a network constituted by a plurality of frame transfer apparatuses and a reduction in bandwidth without providing a server that centrally manages the address table.

It is a block diagram which shows one structural example of 1st Embodiment of the frame transfer system of this invention. It is a block diagram which shows the example of 1 structure of the frame transfer apparatus shown in FIG. FIG. 3 is a diagram illustrating a configuration example of an address table provided in the address table storage unit illustrated in FIG. 2. It is a block diagram which shows the other structural example of 1st Embodiment of the frame transmission system of this invention. It is a block diagram which shows one structure of 2nd Embodiment of the frame transmission system of this invention. FIG. 6 is a block diagram illustrating a configuration example of an uppermost frame transfer apparatus illustrated in FIG. 5. FIG. 6 is a block diagram illustrating a configuration example of a lower frame transfer apparatus illustrated in FIG. 5. It is a figure which shows one structural example of the address table with which the address table memory | storage part shown in FIG. 7 is provided. It is a block diagram which shows the other structural example of 2nd Embodiment of the frame transmission system of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a configuration example of the first embodiment of the frame transfer system of the present invention.

  As shown in FIG. 1, the frame transfer system 1 of this embodiment includes frame transfer apparatuses 10, 20, and 30 connected to each other in a ring configuration.

  Note that Ethernet (registered trademark) and IP are used as communication protocols in the frame transfer system of the present embodiment.

  In the present embodiment, the number of frame transfer apparatuses is three, but the number of frame transfer apparatuses is not limited to three.

  FIG. 2 is a block diagram illustrating a configuration example of the frame transfer apparatus 10 illustrated in FIG. The frame transfer apparatuses 20 and 30 have the same configuration as the frame transfer apparatus 10.

  As shown in FIG. 2, the frame transfer apparatus 10 shown in FIG. 1 includes ports 11-1 to 11-3 that are first ports, ports 12-1 and 12-2 that are second ports, and addresses. A table storage unit 13, a frame transmission unit 14, an address table generation unit 15, a transfer unit 16 as a first transfer unit, and a transfer unit 17 as a second transfer unit are provided.

  Each of the ports 11-1 to 11-3 is a port for connecting to a host. Each of the ports 11-1 to 11-3 receives a frame transmitted from the connected host. Each of the ports 11-1 to 11-3 transmits a frame to the connected host. In the present embodiment, the number of ports for connecting to the host is three, but the number of ports for connecting to the host is not limited to three.

  Each of the ports 12-1 and 12-2 is a port for connecting to another frame transfer apparatus constituting the frame transfer system 1 shown in FIG. 1. Each of the ports 12-1 and 12-2 receives a frame transmitted from a connected frame transfer apparatus. Each of the ports 12-1 and 12-2 transmits a frame to the connected frame transfer device.

  The address table storage unit 13 includes an address table.

  FIG. 3 is a diagram illustrating a configuration example of an address table provided in the address table storage unit 13 illustrated in FIG.

  The address table provided in the address table storage unit 13 shown in FIG. 2 includes, as shown in FIG. 3, port information indicating each of a plurality of ports, MAC address information indicating a MAC address, and an IP address indicating an IP address. Information is associated.

  In FIG. 3, port information indicating each of the plurality of ports is represented as 1 to 3. In FIG. 3, the MAC address is represented as AAA and the IP address is represented as aaa, but actually, the MAC address is 48 bits and the IP address is 32 bits (in the case of IPv4). It is.

  Also, the number of entries in the address table shown in FIG. 3 is three because it is assumed that the number of hosts directly connected to the frame transfer apparatus 10 is three.

  Referring to FIG. 2 again, the frame transmission unit 14 is a Reverse ARP (Address Resolution) which is one of the second type frames having the MAC address indicated by the MAC address information stored in the address table as the transmission destination MAC address. Protocol) frame is transmitted at a predetermined time interval from the port indicated by the port information corresponding to the MAC address information among the ports 11-1 to 11-3. Note that Reverse ARP is a protocol used to retrieve an IP address from a MAC address.

  The address table generation unit 15 acquires frames received at the ports 11-1 to 11-3 and the ports 12-1 and 12-2. Then, the address table generation unit 15 confirms whether the port that has received the acquired frame is any of the ports 11-1 to 11-3 or any of the ports 12-1 and 12-2. As a result of the confirmation, if the port that has received the acquired frame is one of the ports 11-1 to 11-3, the address table generating unit 15 checks the type of the acquired frame. As a result of the confirmation, when the acquired frame is the first type of frame transmitted from the host when the host is newly connected to the network, the address table generation unit 15 transmits the source MAC of the acquired frame. The MAC address information indicating the address and the port information indicating the port that received the frame among the ports 11-1 to 11-3 are associated with each other and stored in the address table. The first type of frame is, for example, a DHCP (Dynamic Host Configuration Protocol) Request or Gratuitous ARP frame. The DHCP Request is transmitted to a DHCP server (not shown) that manages the IP address in order to request assignment of the IP address. Gratuitous ARP is sent to check whether the IP address of the local host is the same as that of other hosts. When the host is configured with a virtual machine, when a part of the host moves to another virtual machine by live migration or the like, Gratuitous ARP is transmitted from the destination virtual machine. Then, when the frame transfer device connected to the virtual machine receives this gratuitous ARP, the information stored in the address table is updated. Live migration is a technique for moving an OS or software running in a virtual machine to another virtual machine while operating. As a result of confirming the type of the acquired frame, when the acquired frame is a RARP response frame that is a response frame to the Reverse ARP frame, the address table generation unit 15 includes the MAC address information stored in the address table. The MAC address information indicating the MAC address that matches the source MAC address of the acquired RARP response frame and the IP address information indicating the source IP address of the acquired RARP response frame are stored in the address table in association with each other. As described above, the Reverse ARP frame is transmitted from the frame transmission unit 14 at a predetermined time interval. Therefore, the IP address information stored in the address table is periodically updated to the latest information. Then, the address table generation unit 15 outputs the acquired frame to the transfer unit 16. On the other hand, as a result of confirming whether the port that received the acquired frame is any of the ports 11-1 to 11-3 or any of the ports 12-1 and 12-2, the acquired frame is received. When the port is any of the ports 12-1 and 12-2, the address table generation unit 15 outputs the acquired frame to the transfer unit 17.

  The transfer unit 16 receives the frame output from the address table generation unit 15. Then, the transfer unit 16 confirms whether or not the transmission source MAC address of the received frame matches any of the MAC addresses indicated by the MAC address information stored in the address table. If they do not match as a result of the confirmation, the transfer unit 16 discards the accepted frame. As a result, it is possible to prevent outflow of a frame in which the MAC address is camouflaged onto the network. On the other hand, if they match as a result of the confirmation, the transfer unit 16 confirms whether or not the destination MAC address of the accepted frame matches any of the MAC addresses indicated by the MAC address information stored in the address table. If they match as a result of the confirmation, the transfer unit 16 transmits the received frame from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address among the ports 11-1 to 11-3. On the other hand, if they do not match as a result of the confirmation, the transfer unit 16 transmits the accepted frame from the ports 12-1 and 12-2. In addition, when transmitting the received frame from the ports 12-1 and 12-2, the transfer unit 16 may add a first tag, which is identification information indicating its own device, to the frame. This makes it possible to easily realize a function for preventing an infinite loop of frames in the transfer unit 17 described later. The transfer unit 16 may transmit the received frame from only one of the ports 12-1 and 12-2. However, in this case, for example, the transmission direction of the frame in the ring configuration needs to be determined in advance so that the received frame reaches all of the other frame transfer apparatuses.

  The transfer unit 17 receives the frame output from the address table generation unit 15. Then, the transfer unit 17 confirms whether the received frame is a broadcast frame. As a result of confirmation, when the received frame is a broadcast frame, the transfer unit 17 determines that the transmission destination of the received broadcast frame is based on the information included in the received broadcast frame and the information stored in the address table. Check if the host is directly connected to the device. Specifically, for example, when the received broadcast frame is an ARP request frame, the IP address included in the ARP field of the received ARP request frame is one of the IP addresses indicated by the IP address information stored in the address table. To see if they match. As a result of the confirmation, the transfer unit 17 transmits the received broadcast frame from the ports 11-1 to 11-3 only when they match. The transfer unit 17 may transmit the received broadcast frame only from the ports indicated by the port information corresponding to the IP address information indicating the matching IP address among the ports 11-1 to 11-3. If the received frame is not a broadcast frame, the transfer unit 17 checks whether the source MAC address of the received frame matches any of the MAC addresses indicated by the MAC address information stored in the address table. . That is, the transfer unit 17 confirms whether or not the transmission source of the received frame is a host directly connected to the own device. If they match as a result of the confirmation, the transfer unit 17 discards the accepted frame. Thereby, an infinite loop of frames between the frame transfer apparatuses 10, 20, and 30 can be prevented. Since the frame transfer apparatuses 10, 20, and 30 are connected in a ring configuration, if they do not have a function for preventing an infinite loop, a frame with an unknown destination address continues to circulate on the ring. This is because the network bandwidth is occupied. When the transfer unit 16 described above adds the first tag to the frame, the transfer unit 17 checks whether the first tag added to the received frame indicates the own device, and If the device is indicated, the received frame is discarded. Thereby, an infinite loop can be prevented like the case mentioned above. On the other hand, as a result of the confirmation, when the transmission source MAC address of the received frame does not match any of the MAC addresses indicated by the MAC address information stored in the address table, the transfer unit 17 transmits the transmission included in the header of the received frame. It is confirmed whether or not the destination MAC address matches any of the MAC addresses indicated by the MAC address information stored in the address table. As a result of the confirmation, if they match, the transfer unit 17 transmits the accepted frame from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address among the ports 11-1 to 11-3. On the other hand, if they do not match as a result of the confirmation, the transfer unit 17 transmits the received frame from the ports 12-1 and 12-2. The transfer unit 17 may transmit the received frame from only one of the ports 12-1 and 12-2. However, in this case, for example, the transmission direction of the frame in the ring configuration needs to be determined in advance so that the received frame reaches all of the frame transfer apparatuses 10, 20, and 30.

  As described above, in the present embodiment, each of the frame transfer apparatuses 10, 20, and 30 receives the first type frame when the frame received at each of the ports 11-1 to 11-3 is the first type frame. The MAC address information indicating the source MAC address of the type of frame and the port information indicating the port that has received the first type of frame among the ports 11-1 to 11-3 are associated with each other and stored in the address table. An address table generation unit 15 is included.

  Each of the frame transfer apparatuses 10, 20, and 30 receives a frame received at the ports 12-1 and 12-2 and a transfer unit 16 that receives frames received at the ports 11-1 to 11-3. And a transfer unit 17 for receiving.

  When the transmission destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the address table, the transfer units 16 and 17 include the ports 11-1 to 11-3. The frame is transmitted from the port indicated by the port information corresponding to the MAC address information indicating the coincident MAC address, and if not coincident, the frame is transmitted from the ports 12-1 and 12-2.

  As a result, the amount of information stored in the address table included in each of the plurality of frame transfer apparatuses does not increase. That is, it is not necessary for each of the plurality of frame transfer apparatuses to include a large capacity memory. Moreover, the occurrence of flooding is suppressed.

  Therefore, it is possible to suppress an increase in cost due to a wide area of a network constituted by a plurality of frame transfer apparatuses and a reduction in bandwidth without providing a server that centrally manages the address table.

  In addition, the number of flooding frames and broadcast frames such as ARP Request is reduced. Therefore, it is possible to reduce the processing load on the host while maintaining communication reachability.

  In this embodiment, the case where a plurality of frame transfer apparatuses are connected in a ring configuration has been described as an example. However, the connection method of the plurality of frame transfer apparatuses is not limited to the ring configuration.

  FIG. 4 is a block diagram showing another configuration example of the first embodiment of the frame transfer system of the present invention.

  In the frame transfer system 1-1 shown in FIG. 4, the frame transfer apparatuses 10, 20, and 30 are connected in a star configuration via a relay frame transfer apparatus 40 as shown in FIG.

  The relay frame transfer device 40 includes a plurality of ports (not shown), and is connected to the frame transfer devices 10, 20, and 30 via each of the plurality of ports. The relay frame transfer device 40 does not generate and update the address table, and transmits the received frame from a port other than the port that received the frame among the plurality of ports.

(Second Embodiment)
FIG. 5 is a block diagram showing a configuration of the second embodiment of the frame transfer system of the present invention.

  As shown in FIG. 5, the frame transfer system 2 of the present embodiment includes frame transfer device groups 5 to 7 including a plurality of layered frame transfer devices.

  The frame transfer device group 5 includes an uppermost frame transfer device 50 that is the uppermost frame transfer device, and lower layer frame transfer devices 50 a and 50 b that are lower layer frame transfer devices connected to the uppermost frame transfer device 50. Yes.

  The frame transfer device group 6 includes an uppermost frame transfer device 60 and lower frame transfer devices 60 a and 60 b connected to the uppermost frame transfer device 60.

  The frame transfer device group 7 includes an uppermost frame transfer device 70 and lower layer frame transfer devices 70 a and 70 b connected to the uppermost frame transfer device 70.

  The uppermost frame transfer devices 50, 60, and 70 are connected to each other in a ring configuration as shown in FIG.

  It is assumed that Ethernet (registered trademark) and IP are used as communication protocols in the frame transfer system of the present embodiment, as in the first embodiment described above.

  In the present embodiment, the number of frame transfer device groups is three, but the number of frame transfer device groups is not limited to three.

  In the present embodiment, the frame transfer apparatuses are divided into two hierarchies in each of the frame transfer apparatus groups 5 to 7, but the number of hierarchies is not limited to two. That is, the lower frame transfer apparatus can be further hierarchized into a plurality of hierarchies.

  FIG. 6 is a block diagram showing a configuration example of the uppermost frame transfer apparatus 50 shown in FIG. The uppermost frame transfer devices 60 and 70 have the same configuration as the uppermost frame transfer device 50.

  As shown in FIG. 6, the uppermost frame transfer apparatus 50 shown in FIG. 5 includes ports 51-1 and 51-2, ports 52-1 and 52-2 as third ports, and an address table storage unit 53. A frame transmission unit 54, an address table generation unit 55 as a first address table generation unit, and transfer units 56 and 57.

  In the present embodiment, the ports 51-1 and 51-2 are the first ports. In the present embodiment, the transfer unit 56 is a first transfer unit, and the transfer unit 57 is a second transfer unit.

  Each of the ports 51-1 and 51-2 is a port for connecting to a lower frame transfer apparatus. Each of the ports 51-1 and 51-2 receives a frame transmitted from the connected lower frame transfer device. Each of the ports 51-1 and 51-2 transmits a frame to the connected lower frame transfer device. In this embodiment, the number of ports for connecting to the lower layer frame transfer apparatus is two, but the number of ports for connecting to the lower layer frame transfer apparatus is not limited to two.

  Each of the ports 52-1 and 52-2 is a port for connecting to the uppermost frame transfer device of the other frame transfer device group constituting the frame transfer system 2 shown in FIG. Each of the ports 52-1 and 52-2 receives a frame transmitted from the uppermost frame transfer device of another connected frame transfer device group. Each of the ports 52-1 and 52-2 transmits a frame to the uppermost frame transfer device of another frame transfer device group.

  The address table storage unit 53 includes an uppermost address table. The configuration of the top-layer address table is the same as that shown in FIG. 3, and thus detailed description thereof is omitted here.

  The frame transmission unit 54 transmits a Reverse ARP frame, which is one of the second types of frames with the MAC address indicated by the MAC address information stored in the uppermost address table, as the transmission destination MAC address, Among 51-2, it transmits at a predetermined time interval from the port indicated by the port information corresponding to the MAC address information.

  The address table generation unit 55 acquires frames received at the ports 51-1 and 51-2 and the ports 52-1 and 52-2, respectively. Then, the address table generation unit 55 confirms whether the port that has received the acquired frame is either the port 51-1 or 51-2, or the port 52-1 or 52-2. As a result of the confirmation, if the port that received the acquired frame is one of the ports 51-1 and 51-2, the address table generation unit 55 confirms the type of the acquired frame. As a result of the confirmation, if the acquired frame is the first type frame described above, the address table generating unit 55 includes the MAC address information indicating the source MAC address of the acquired frame, and the ports 51-1 and 51-. 2 is stored in the top layer address table in association with port information indicating the port that received the frame. Also, as a result of confirming the type of the acquired frame, if the acquired frame is a RARP response frame, the address table generating unit 55 includes the acquired RARP response frame among the MAC address information stored in the uppermost layer address table. The MAC address information indicating the MAC address that matches the source MAC address and the IP address information indicating the source IP address of the acquired RARP response frame are associated with each other and stored in the uppermost layer address table. As described above, the Reverse ARP frame is transmitted from the frame transmission unit 54 at a predetermined time interval. Accordingly, the IP address information stored in the top layer address table is periodically updated to the latest information. Then, the address table generation unit 55 outputs the acquired frame to the transfer unit 56. On the other hand, as a result of confirming whether the port that received the acquired frame is any of the ports 51-1 and 51-2 or any of the ports 52-1 and 52-2, the ports 52-1 and 52-2 are confirmed. In the case of -2, the address table generation unit 55 outputs the acquired frame to the transfer unit 57.

  The transfer unit 56 receives the frame output from the address table generation unit 55. Then, the transfer unit 56 checks whether or not the source MAC address of the received frame matches any of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table. If they do not match as a result of the confirmation, the transfer unit 56 discards the accepted frame. On the other hand, if they match as a result of the confirmation, the transfer unit 56 matches the destination MAC address included in the header of the received frame with one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table. Check whether or not. As a result of the confirmation, if they match, the transfer unit 56 transmits the received frame from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address among the ports 51-1 and 51-2. On the other hand, if they do not match as a result of the confirmation, the transfer unit 56 transmits the accepted frame from the ports 52-1 and 52-2. In addition, the transfer part 56 may add the 1st tag which is the identification information which shows an own apparatus to a flame | frame, when transmitting the received flame | frame from port 52-1, 52-2. This makes it possible to easily realize a function for preventing an infinite loop of frames in the transfer unit 57 described later.

  The transfer unit 57 receives the frame output from the address table generation unit 55. Then, the transfer unit 57 confirms whether or not the accepted frame is a broadcast frame. When the received frame is a broadcast frame as a result of the confirmation, the transfer unit 57 transmits the received broadcast frame based on the information included in the received broadcast frame and the information stored in the uppermost address table. Is a host connected to the lower frame transfer device of the frame transfer device group including its own device. Specifically, for example, when the received broadcast frame is an ARP request frame, the IP address included in the ARP field of the received ARP request frame indicates the IP address information stored in the uppermost address table. Check if it matches any of the addresses. As a result of the confirmation, the transfer unit 57 transmits the received broadcast frame from the ports 51-1 and 51-2 only when they match. The transfer unit 57 may transmit the received broadcast frame from only the port indicated by the port information corresponding to the IP address information indicating the matching IP address among the ports 51-1 and 51-2. Here, as a result of checking whether or not the received frame is a broadcast frame, if the received frame is not a broadcast frame, the transfer unit 57 stores the MAC address information in which the transmission source MAC address of the received frame is stored in the uppermost layer address table. Check if it matches any of the MAC addresses indicated by. That is, the transfer unit 57 confirms whether or not the transmission source of the received frame is a host connected to the lower frame transfer device of the frame transfer device group including the own device. If they match as a result of the confirmation, the transfer unit 57 discards the accepted frame. Thereby, an infinite loop of frames between the uppermost frame transfer devices 50, 60, 70 can be prevented. When the transfer unit 56 described above adds a first tag to the frame, the transfer unit 57 checks whether the first tag added to the received frame indicates its own device. If the device is indicated, the received frame is discarded. Thereby, an infinite loop can be prevented like the case mentioned above. On the other hand, as a result of confirmation, when the source MAC address included in the header of the received frame does not match any of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the transfer unit 57 has received It is confirmed whether or not the destination MAC address included in the header of the frame matches one of the MAC addresses indicated by the MAC address information stored in the top layer address table. As a result of the confirmation, if they match, the transfer unit 57 transmits the received frame from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address among the ports 51-1 and 51-2. At this time, the transfer unit 57 adds a second tag, which is predetermined information that instructs not to store the transmission source address of the frame in a later-described lower-layer address table, and transmits the frame. This tag is, for example, a VLAN (Virtual LAN) tag. On the other hand, if they do not match as a result of the confirmation, the transfer unit 57 transmits the received frame from the ports 52-1 and 52-2.

  FIG. 7 is a block diagram showing a configuration example of the lower frame transfer apparatus 50a shown in FIG. The lower frame transfer apparatuses 50b, 60a, 60b, 70a, and 70b have the same configuration as the lower frame transfer apparatus 50a.

  As shown in FIG. 7, the lower frame transfer apparatus 50a shown in FIG. 5 includes ports 51a-1 to 51a-4, an address table storage unit 52a, and an address table generation unit 53a that is a second address table generation unit. And a transfer unit 54a which is a third transfer unit.

  In the present embodiment, the ports 51a-1 to 51a-4 are the second ports.

  Each of the ports 51a-1 to 51a-4 is a port for connecting the uppermost frame transfer device constituting the frame transfer system 2 shown in FIG. 5 and a plurality of hosts. Each of the ports 51a-1 to 51a-4 receives a frame transmitted from each of the connected uppermost frame transfer apparatus or the plurality of hosts. Each of the ports 51a-1 to 51a-4 transmits a frame to each of the connected uppermost frame transfer apparatus or a plurality of hosts. In the present embodiment, the number of ports provided in the lower frame transfer apparatus is four, but the number of ports provided in the lower frame transfer apparatus is not limited to four.

  The address table storage unit 52a includes a lower layer address table.

  FIG. 8 is a diagram illustrating a configuration example of an address table provided in the address table storage unit 52a illustrated in FIG.

  As shown in FIG. 8, the lower layer address table provided in the address table storage unit 52a shown in FIG. 7 associates each of a plurality of port information indicating each of a plurality of ports with MAC address information indicating a MAC address. It has been.

  In FIG. 8, port information indicating each of the plurality of ports is represented as 1 to 3. In FIG. 8, the MAC address is represented as DDD, but actually, the MAC address is 48-bit information.

  Further, the number of entries in the address table shown in FIG. 8 is three because it is assumed that the number of hosts directly connected to the lower frame transfer apparatus 50a is three.

  Referring to FIG. 7 again, the address table generation unit 53a acquires frames received at the ports 51a-1 to 51a-4. Then, the address table generating unit 53a checks whether or not the second tag is added to the acquired frame. As a result of the confirmation, when the second tag is added, the address table generation unit 53a outputs the acquired frame to the transfer unit 54a. On the other hand, when the second tag is not added to the acquired frame as a result of the confirmation, it is confirmed whether or not the MAC address information indicating the transmission source MAC address of the acquired frame is stored in the lower layer address table. As a result of the confirmation, when the MAC address information indicating the transmission source MAC address of the acquired frame is stored in the lower layer address table, the address table generation unit 53a outputs the acquired frame to the transfer unit 54a. On the other hand, if the MAC address information indicating the source MAC address of the acquired frame is not stored in the lower layer address table as a result of the confirmation, the address table generating unit 53a displays the MAC address indicating the source MAC address of the acquired frame. The information and the port information indicating the port that received the frame among the ports 51a-1 to 51a-4 are stored in the lower layer address table in association with each other. Then, the address table generation unit 53a outputs the acquired frame to the transfer unit 54a.

  The transfer unit 54a receives the frame output from the address table generation unit 53a. Then, the transfer unit 54a checks whether the transmission destination MAC address of the received frame matches any of the MAC addresses indicated by the MAC address information stored in the lower layer address table. As a result of the confirmation, if they match, the transfer unit 54a transmits the accepted frame from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address among the ports 51a-1 to 51a-4. On the other hand, if they do not match as a result of the confirmation, the transfer unit 54a transmits the received frame from a predetermined port among the ports 51a-1 to 51a-4. This predetermined port is a port connected to the uppermost frame transfer device among the ports 51a-1 to 51a-4.

  As described above, in the present embodiment, when the frames received at the ports 51-1 and 51-2 are the first type frames, the uppermost frame transfer devices 50, 60, and 70 respectively MAC address information indicating the source MAC address of one type of frame and the top layer address in association with port information indicating the port that received the first type frame among the ports 51-1 and 51-2 An address table generation unit 55 that stores the table is included.

  Each of the uppermost frame transfer apparatuses 50, 60, and 70 receives the frame received at the ports 51-1 and 51-2 and the ports 52-1 and 52-2. And a transfer unit 57 for receiving a frame.

  Then, when the destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the transfer unit 56 selects one of the ports 51-1 and 51-2. Then, the frame is transmitted from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and if not matched, the frame is transmitted from the ports 52-1 and 52-2.

  In addition, when the transmission destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the transfer unit 57 selects one of the ports 51-1 and 51-2. The frame indicated by the port information corresponding to the MAC address information indicating the matching MAC address is transmitted with the second tag added to the frame, and if they do not match, the frame is transmitted from the ports 52-1 and 52-2. Send.

  Each of the lower frame transfer devices 50a, 50b, 60a, 60b, 70a, and 70b, when the second tag is not added to the frame received at each of the ports 51a-1 to 51a-4, The address table generating unit 53a stores the MAC address information indicating the source MAC address and the port information indicating the port that received the frame among the ports 51a-1 to 51a-4 in association with the lower layer address table.

  Each of the lower frame transfer devices 50a, 50b, 60a, 60b, 70a, and 70b has a transfer unit 54a that receives frames received at the ports 51a-1 to 51a-4.

  Then, when the transmission destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the lower layer address table, the transfer unit 54a includes the ports 51a-1 to 51a-4. The frame is transmitted from the port indicated by the port information corresponding to the MAC address information indicating the matching MAC address. If the frames do not match, the frame is transmitted from a predetermined port among the ports 51a-1 to 51a-4. .

  As a result, the same effects as those in the first embodiment described above can be obtained, and more hosts can be connected as compared to the first embodiment. In other words, it is possible to flexibly cope with the widening of the network composed of a plurality of frame transfer apparatuses.

  In the present embodiment, the case where the number of the uppermost frame transfer devices in each of the plurality of frame transfer device groups is one has been described. In this case, the uppermost frame transfer apparatus may become a performance bottleneck. In order to avoid this, the number of uppermost frame transfer devices in each of the plurality of frame transfer device groups may be plural.

  FIG. 9 is a block diagram showing another configuration example of the second embodiment of the frame transfer system of the present invention.

  In the frame transfer system 2-1, as shown in FIG. 9, each of the frame transfer device groups 5-1 to 7-1 has two uppermost frame transfer devices. Two is an example, and the number of uppermost frame transfer apparatuses is not limited to two. Each of the two uppermost frame transfer apparatuses is connected to one uppermost frame transfer apparatus of another frame transfer apparatus group in a ring configuration. That is, there are two networks having a ring configuration.

  In each of the frame transfer device groups 5-1 to 7-1, each of the lower layer frame transfer devices 50a, 50b, 60a, 60b, 70a, and 70c, which is one layer lower than the uppermost frame transfer device, has two uppermost frame transfer devices. Connected to each of the upper frame transfer apparatuses. Accordingly, each of the lower layer frame transfer devices 50a, 50b, 60a, 60b, 70a, and 70c includes the above-described two predetermined ports.

  In the frame transfer system 2-1 shown in FIG. 9, each transfer unit 54 a of the lower frame transfer devices 50 a, 50 b, 60 a, 60 b, 70 a, 70 c stores the destination MAC address of the accepted frame in the address table. As a result of checking whether or not it matches any of the MAC addresses indicated by the MAC address information, if they do not match, first, one of the two predetermined ports is selected according to a predetermined rule. The predetermined rule may be round robin or priority given to each of two predetermined ports. Then, the transfer unit 54a transmits the received frame from the selected port.

  Thereby, it is possible to avoid that the frame is distributed to each of the two uppermost frame transfer apparatuses and the uppermost frame transfer apparatus becomes a bottleneck in performance.

  In the case of the configuration shown in FIG. 9, it is necessary to synchronize the information stored in the address table between the two uppermost frame transfer devices of each of the plurality of frame transfer device groups.

  In this embodiment, the case where a plurality of uppermost frame transfer apparatuses are connected in a ring configuration has been described as an example. However, the connection method of the plurality of frame transfer apparatuses is not limited to the ring configuration. A plurality of uppermost frame transfer apparatuses may be connected in a star configuration by a relay frame transfer apparatus as shown in FIG.

1,1-1,2,2-1 Frame transfer system 5,6,7,5-1,6-1,7-1 Frame transfer device group 10, 20, 30 Frame transfer device 11-1 to 11-3 , 12-1, 12-2, 51-1, 51-2, 52-1, 52-2, 51 a-1 to 51 a-4 port 13, 53, 52 a Address table storage unit 14, 54 Frame transmission unit 15, 55, 53a Address table generation unit 16, 17, 54a, 56, 57, transfer unit 40 Relay frame transfer device 50, 60, 70 Uppermost frame transfer device 50a, 50b, 60a, 60b, 70a, 70b Lower layer frame transfer device

Claims (9)

A plurality of frame transfer apparatuses connected to each other in a ring configuration, each of the plurality of frame transfer apparatuses transmitting and receiving a frame to and from each of a plurality of hosts; and an address table A frame transfer system comprising:
Each of the plurality of frame transfer devices includes:
And two second ports for transmitting and receiving frames each with the frame transfer apparatus adjacent at the ring structure other than the frame transfer apparatus of the plurality of frame transfer apparatus,
When a frame received at each of the plurality of first ports is a first type frame, MAC address information indicating a source MAC address of the first type frame, and the plurality of first types An address table generating unit that associates and stores in the address table port information indicating the first port that has received the first type of frame of the first port;
A first transfer unit that receives frames received at the plurality of first ports;
A second transfer unit for receiving a frame received at the second port,
The first transfer unit , when the destination MAC address of the accepted frame matches any of the MAC addresses indicated by the MAC address information stored in the address table, among the plurality of first ports, Transmitting the frame from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and if not matching, transmitting the frame from the second port ;
The second transfer unit, when the destination MAC address of the accepted frame matches any of the MAC addresses indicated by the MAC address information stored in the address table, among the plurality of first ports, If the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address and does not match, the second port is different from the second port that received the frame. A frame transfer system that transmits frames. The frame transfer system according to claim 1,
The frame transfer system, wherein the first transfer unit discards the frame when the source MAC address of the accepted frame does not match any of the MAC addresses indicated by the MAC address information stored in the address table. The frame transfer system according to claim 1 or 2,
Each of the plurality of frame transfer apparatuses transmits a second type of frame having a MAC address indicated by the MAC address information stored in the address table as a destination MAC address, out of the plurality of first ports. A frame transmission unit configured to transmit at a predetermined time interval from the first port indicated by the port information corresponding to the address information;
The address table generation unit, when a frame received at each of the plurality of first ports is a response frame to the second type frame, an IP address indicating an IP address included in the response frame Information is stored in the address table in association with the MAC address information,
When the received frame is a broadcast frame, the second transfer unit matches an IP address included in the broadcast frame with any of the IP addresses indicated by the IP address information stored in the address table. And a frame transfer system for transmitting the broadcast frame from the plurality of first ports. The frame transfer system according to any one of claims 1 to 3,
The frame transfer system in which the second transfer unit discards the frame when the source MAC address of the received frame matches any of the MAC addresses indicated by the MAC address information stored in the address table. The frame transfer system according to any one of claims 1 to 3,
When the first transfer unit transmits the received frame from the second port, the first transfer unit adds identification information for identifying the frame transfer device to the frame,
The frame transfer system, in which the second transfer unit discards the frame when identification information for identifying the frame transfer apparatus is added to the received frame. A plurality of hierarchized frame transfer device groups each including an uppermost frame transfer device and a plurality of lower layer frame transfer devices, wherein the plurality of uppermost frame transfer devices are connected to each other in a ring configuration; Each of the upper layer frame transfer apparatuses includes a plurality of first ports for transmitting / receiving frames to / from a plurality of lower layer frame transfer apparatuses, and a top layer address table, and the plurality of lower layer frame transfers Each of the devices transmits / receives a frame to / from a plurality of hosts or a plurality of lower layer frame transfer devices in the lower layer, and to / from the uppermost layer frame transfer device or the lower layer frame transfer device in the upper layer A frame transfer system comprising a second port and a lower layer address table,
Each of the plurality of uppermost frame transfer devices includes:
Two third ports for transmitting and receiving frames to and from the uppermost frame transfer devices adjacent to each other in the ring configuration other than the uppermost frame transfer device among the plurality of uppermost frame transfer devices;
When a frame received at each of the plurality of first ports is a first type frame, MAC address information indicating a source MAC address of the first type frame, and the plurality of first types A first address table generation unit that associates port information indicating the first port that has received the first type of frame and stores it in the uppermost layer address table;
A first transfer unit that receives frames received at the plurality of first ports;
A second transfer unit for receiving a frame received at the third port;
When the destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the first transfer unit is configured to output the plurality of first ports. Among these, the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and if the two do not match, the frame is transmitted from the third port,
The second transfer unit, when a destination MAC address of the received frame matches one of the MAC addresses indicated by the MAC address information stored in the uppermost layer address table, the plurality of first ports Among these, the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address is transmitted with the predetermined information added to the frame. Send the frame from a third port different from the other port,
Each of the plurality of lower layer frame transfer devices,
If the predetermined information is not added to a frame received at each of the plurality of second ports, MAC address information indicating a source MAC address of the frame, and the plurality of second ports A second address table generation unit that associates and stores the port information indicating the second port that has received the frame in the lower layer address table;
A third transfer unit that receives frames received at the plurality of second ports,
When the destination MAC address of the accepted frame matches one of the MAC addresses indicated by the MAC address information stored in the lower layer address table, the third transfer unit is configured to receive the plurality of second ports. If the frame is transmitted from the second port indicated by the port information corresponding to the MAC address information indicating the matching MAC address and does not match, a predetermined second of the plurality of second ports is transmitted. A frame transfer system that transmits the frame from a port. The frame transfer system according to claim 6, wherein
Each of the plurality of frame transfer device groups includes a plurality of the uppermost frame transfer devices, and each of the uppermost frame transfer devices includes two adjacent frame transfer device groups including the uppermost frame transfer device. Each of the plurality of frame transfer device groups is connected to one uppermost frame transfer device in the adjacent frame transfer device group,
Among the plurality of lower layer frame transfer devices, a plurality of lower layer frame transfer devices that are one layer lower than the plurality of uppermost layer frame transfer devices are provided with a plurality of the predetermined second ports,
When the lower layer frame transfer apparatus is a lower layer frame transfer apparatus that is one layer lower than the uppermost frame transfer apparatus, the third transfer unit is configured such that the destination MAC address of the received frame is the lower layer address table. If any of the MAC addresses indicated by the MAC address information stored in is not matched with one of the plurality of predetermined second ports, the frame is selected from the selected second port. Send frame transfer system. A frame transfer apparatus comprising a plurality of first ports for transmitting and receiving frames to and from each of a plurality of hosts, and an address table,
And two second ports for transmitting and receiving frames to and from another frame transfer device adjacent in the ring structure,
When a frame received at each of the plurality of first ports is a first type frame, MAC address information indicating a source MAC address of the first type frame, and the plurality of first types An address table generating unit that associates and stores in the address table port information indicating the first port that has received the first type of frame of the first port;
A first transfer unit that receives frames received at the plurality of first ports;
A second transfer unit for receiving a frame received at the second port,
The first transfer unit , when the destination MAC address of the accepted frame matches any of the MAC addresses indicated by the MAC address information stored in the address table, among the plurality of first ports, Transmitting the frame from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and if not matching, transmitting the frame from the second port ;
The second transfer unit, when the destination MAC address of the accepted frame matches any of the MAC addresses indicated by the MAC address information stored in the address table, among the plurality of first ports, If the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address and does not match, the second port is different from the second port that received the frame. A frame transfer device that transmits frames. A plurality of frame transfer devices connected in a ring configuration, each of the plurality of frame transfer devices transmitting and receiving a frame to and from each of a plurality of hosts; and the plurality of frames and two second ports for transmitting and receiving, respectively frames between the neighboring frame transfer device in the ring structure other than the frame transfer device of the transfer device, a frame transfer in the frame transfer system comprising an address table, the A method,
Each of the plurality of frame transfer devices indicates a source MAC address of the first type frame when the frame received at each of the plurality of first ports is a first type frame. A process of associating MAC address information with port information indicating a first port that has received the first type of frame among the plurality of first ports and storing the information in the address table;
Each of the plurality of frame transfer device, the plurality of transmission destination MAC address of the first frame which is manually received port matches one of the MAC address MAC address information stored in the address table shown In this case, the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address among the plurality of first ports. Processing to transmit the frame;
When each of the plurality of frame transfer devices matches a destination MAC address of a frame received at the second port with any of the MAC addresses indicated by the MAC address information stored in the address table, Among the plurality of first ports, the frame is transmitted from the first port indicated by the port information corresponding to the MAC address information indicating the matching MAC address, and if the two do not match, the second port that has received the frame A process of transmitting the frame from a second port different from
A frame transfer method comprising:

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