Optical circuit switch and communication network system

Abstract

A communication network system 1 comprises a rack group 2 including a plurality of racks for storing a server, a rack group inner hub 3 connected to one rack group, and an inter-rack-group hub 4 connected to the plurality of rack groups. The rack group inner hub 2 is provided with a plurality of interfaces 11 connected to ToR switches of the respective racks included in the rack group of a connection destination by an optical fiber cable. A first interface 11a connected to the ToR switch of a first rack is provided with a plurality of ports connected by an optical fiber cable to interfaces 11b-11h connected to the ToR switch of the racks other than the first rack. The connection destination is switched for each of the plurality of ports.

Description

Optical circuit switch and communication network system

[0001] The present disclosure relates to optical circuit switches and communication network systems.

[0002] In data centers, spine / leaf connections are a method for connecting servers such as computers and storage devices. Multiple servers and leaf switches are installed together in a single rack. Leaf switches house the servers installed in the rack. Leaf switches are also called ToR (Top of Rack) switches. Note that in some literature, the switch directly above the ToR switch is sometimes called a leaf switch. In this disclosure, switches installed in a rack together with servers are called ToR switches or leaf switches, and switches above these are collectively called spine switches.

[0003] Multiple leaf switches are housed in a spine switch. The spine switches may form multiple hierarchical layers. The spine switch is connected to each leaf switch. Multiple servers housed in one leaf switch are connected via the leaf switch. Multiple servers housed in different leaf switches are connected to each leaf switch via the spine switch connected to that leaf switch.

[0004] There is a technology that uses N×N optical circuit switches (OCS) in data centers (Non-Patent Document 1). Non-Patent Document 1 discloses that the use of optical circuit switches reduces the number of spine switches.

[0005] Leon Poutievski, 22 others, "Jupiter Evolving: Transforming Google's Datacenter Network via Optical Circuit Switches and Software-Defined Networking", August 22-26, 2022, SIGCOMM'22

[0006] In spine / leaf topology, connections between servers go through leaf switches and sometimes even spine switches. Bottlenecks can occur at the leaf or spine switches. Frequent upgrades within data centers can require large capital investments. Furthermore, because leaf and spine switches transfer signals (packets) using electrical circuits, power consumption in such data centers can be enormous.

[0007] The method described in Non-Patent Document 1 reduces power consumption by directly connecting racks (leaf switches) using NxN optical circuit switches instead of spine switches that use electrical circuits. However, NxN optical switches have disadvantages such as high switch prices (e.g., high unit price per port), difficulty in control, and the large optical signal loss seen in large-scale optical circuit switches. Compensating for these disadvantages can result in huge costs.

[0008] Therefore, there is a proposal to directly connect racks without using expensive NxN optical circuit switches, thereby reducing capital investment costs and power consumption. A method for connecting racks efficiently and at low cost is required.

[0009] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a technology that enables efficient connection between racks that house servers at low cost.

[0010] An optical circuit switch according to one embodiment of the present disclosure includes a plurality of interfaces connected to a plurality of target devices via optical fiber cables, and a first interface connected to a first target device includes a plurality of ports connected via optical fiber cables to interfaces connected to target devices other than the first target device, and each of the plurality of ports switches its connection destination.

[0011] A communication network system according to one aspect of the present disclosure includes rack groups each including a plurality of racks that accommodate servers, an intra-rack group hub connected to one rack group, and an inter-rack group hub connected to a plurality of rack groups. The intra-rack group hub includes a plurality of interfaces connected by optical fiber cables to ToR switches of each rack included in the connected rack group, a first interface connected to the ToR switch of a first rack includes a plurality of ports connected by optical fiber cables to interfaces connected to ToR switches of racks other than the first rack, and each of the plurality of ports switches its connection destination. The inter-rack group hub includes a plurality of interfaces connected by optical fiber cables to ToR switches of each rack included in the connected rack groups, and a first interface connected to the ToR switch of the first rack group includes a plurality of ports connected by optical fiber cables to interfaces connected to ToR switches of racks other than the first rack group, and each of the plurality of ports switches its connection destination.

[0012] A communication network system according to one aspect of the present disclosure comprises rack groups each including one or more racks that house servers, an intra-rack group hub connected to one rack group, and an inter-rack group hub connected to multiple rack groups, wherein the intra-rack group hub has multiple interfaces connected by optical fiber cables to each of the servers in each rack included in the connected rack group, a first interface connected to the server in a first rack has multiple ports connected by optical fiber cables to interfaces connected to servers in racks other than the first rack, and each of the multiple ports switches its connection destination, and the inter-rack group hub has multiple interfaces connected by optical fiber cables to each of the servers in each rack included in the connected rack groups, and the first interface connected to the server in the first rack group has multiple ports connected by optical fiber cables to interfaces connected to servers in racks other than the first rack group, and each of the multiple ports switches its connection destination.

[0013] According to the present disclosure, it is possible to provide a technology that enables efficient connection between racks that house servers at low cost.

[0014] FIG. 1 is a diagram illustrating a communication network system according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of a rack. FIG. 3 is a diagram illustrating the configuration of an optical circuit switch. FIG. 4 is a diagram illustrating connections between interfaces of an optical circuit switch. FIG. 5 is table data illustrating an example of connection destinations of each interface of an optical circuit switch. FIG. 6 is a diagram illustrating an example of expanding the scale of a data center and setting an optical circuit switch. FIG. 7 is a diagram illustrating an intra-RG hub. FIG. 8 is a diagram illustrating an inter-RG hub. FIG. 9 is a diagram illustrating connections within an inter-RG hub. FIG. 10 is a diagram illustrating a deviation of a rack to which a connection destination is made in an inter-RG hub. FIG. 11 is a diagram illustrating an example of the relationship between a deviation of a rack to which a connection destination is made in an inter-RG hub and a port number. FIG. 12 is table data illustrating an example of connection destinations of each interface of an inter-RG hub. FIG. 13 is a diagram illustrating an example of an intra-RG hub and an inter-RG hub to which one RG is connected. FIG. 14 is a diagram illustrating an example of expanding a data center. FIG. 15 is a diagram illustrating a communication network system according to a first modified example. Fig. 16 is a diagram illustrating a communication network system according to a second modified example. Fig. 17 is a diagram illustrating an intra-RG hub according to the second modified example. Fig. 18 is table data illustrating an example of connection destinations of each interface of an intra-RG hub according to the second modified example. Fig. 19 is a diagram illustrating a communication network system according to a third modified example. Fig. 20 is table data illustrating an example of connection destinations of each interface of an intra-RG hub according to the third modified example.

[0015] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description will be omitted. In this disclosure, repeated parts may be omitted in the drawings and description. Note that in this disclosure, a case where a ToR switch is provided in a rack will be described, but the ToR switch may also be called a leaf switch.

[0016] (Communication Network System) A communication network system 1 according to the present disclosure connects servers such as computers and storage devices in a data center or the like. Each server is housed in a rack. The communication network system 1 connects the ToR switches in each rack with optical fiber cables, enabling the transmission and reception of optical signals.

[0017] The communication network system 1 efficiently connects racks housing servers at low cost, and can reduce capital investment costs and power consumption required for spine switches.

[0018] The communication network system 1 includes a rack group (RG) 2, an intra-rack group hub (intra-RG hub / Intra-RG Hub) 3, and an inter-rack group hub (inter-RG hub / Inter-RG Hub) 4.

[0019] 1, the communication network system 1 includes a plurality of RGs 2a, 2b, etc., a plurality of intra-RG hubs 3a, 3b, etc., and a plurality of inter-RG hubs 4a, 4b, 4c, and 4d. When the plurality of RGs 2a, 2b, etc. are not particularly distinguished from one another, they may simply be referred to as RG 2. When the plurality of intra-RG hubs 3a, 3b, etc. are not particularly distinguished from one another, they may simply be referred to as inter-RG hub 3. When the plurality of inter-RG hubs 4a, 4b, 4c, and 4d are not particularly distinguished from one another, they may simply be referred to as inter-RG hub 4.

[0020] RG2 includes multiple racks that house servers. As shown in FIG. 2, the racks include a ToR switch and multiple servers. The ToR switch is connected to an intra-RG hub 3 and an inter-RG hub 4, and is also connected to each server in the rack. In this disclosure, a case will be described in which one RG2 is formed by eight racks, but this is not limited to this. One RG2 includes one or more racks. Furthermore, one rack includes one or more servers.

[0021] The intra-RG hub 3 is connected to one RG 2. The intra-RG hub 3 is connected to each of the ToR switches in each rack included in the connected RG via optical fiber cables. In Fig. 1, the first intra-RG hub 3a is connected to each of the ToR switches in the eight racks included in the first RG. The first intra-RG hub 3a enables communication between the servers included in the eight racks included in the first RG 2a.

[0022] The inter-RG hub 4 is connected to multiple rack groups. The inter-RG hub 4 is connected to each of the ToR switches of each rack included in the multiple RGs to which it is connected via optical fiber cables. In Fig. 1, the first inter-RG hub 4a is connected to multiple RGs including the first RG 2a and the second RG 2b. The first inter-RG hub 4a enables communication between the servers housed in each rack included in the first RG 2a and the servers housed in each rack included in the second RG 2b.

[0023] (Optical Circuit Switch) The intra-RG hub 3 and the inter-RG hub 4 shown in FIG. 1 are realized by an optical circuit switch 10 shown in FIG.

[0024] The optical circuit switch 10 has a plurality of interfaces 11 that are connected to a plurality of target devices via optical fiber cables, respectively. The optical circuit switch 10 shown in Fig. 3 has eight interfaces 11a, 11b, ..., 11h.

[0025] Each interface 11 is connected to a different target device. In the example shown in Fig. 4, the first interface 11a is connected to the first target device 7a, and the fifth interface 11e is connected to the fifth target device 7e.

[0026] As shown in Figure 4, each interface 11 has multiple ports P. The first interface 11a, which connects to the first target device, has multiple ports P1-P8. Each of the multiple ports P1-P8 is connected via an optical fiber cable to an interface that connects to a target device other than the first target device. The first interface 11a has eight ports P1-P8. The first interface 11a connects to the other interfaces 11b-11h via the ports P1-P8.

[0027] In the present disclosure, each of the multiple ports P1-P8 in the multiple interfaces 11a-11h is configured to switch its connection destination. In the present disclosure, the connection destination of a port is an interface among the multiple interfaces 11a-11h other than the interface that includes the source port. For example, the connection destination of port P1 of the first interface 11a is any one of the second interface 11b to the eighth interface 11h.

[0028] Specifically, each of the ports P1-P8 is a 1xN switch. Port P connects to one of N destinations. In the present disclosure, the number of destinations is equal to or less than the N of the 1xN switch. This 1xN switch, like the NxN switch of Non-Patent Document 1, does not use electrical circuits and therefore consumes less power. Furthermore, the 1xN switch has a lower port cost than the NxN switch. Therefore, the 1xN switch can reduce both power consumption and capital investment costs. Note that while an NxN switch is assumed to have N≈100, the 1xN switch in the present disclosure is assumed to have N≈4.

[0029] 4, each port P is provided with a terminal T for each connection destination. When a connection destination is specified for the first port P1 of the first interface 11a, the optical circuit switch 10 connects the terminal of the first port P1 of the first interface 11a on the side of the first target device 7a to the terminal corresponding to the specified connection destination.

[0030] 4 illustrates a case where N=3 and each port P is formed by a 1×3 switch. Port P1 includes terminals T1a, T1b, and T1c, and the optical circuit switch 10 switches the connection destination by connecting a terminal (not shown) on the side of the first target device 7a to one of the terminals T1a, T1b, and T1c. The first interface 11a connects the terminal on the side of the first target device 7a to the terminal T1c in the first port P1, thereby connecting to the fifth interface 11e. In this disclosure, the identifier of the terminal T of the port P that is the connection destination of the terminal on the target device 7 is sometimes referred to as the “selector position.” In port P1 of the first interface 11a illustrated in FIG. 4, the selector position is the identifier of the terminal T, among the terminals T1a, T1b, and T1c, that is the connection destination of the terminal on the target device 7.

[0031] The connection destination is specified by an operator or externally. In the present disclosure, when the connection destination is specified along with the interface identifier and port number, a control unit (not shown) of the optical circuit switch 10 connects an input from the outside to a terminal corresponding to the specified connection destination at the specified interface 11 and port P. The control unit may be a processing unit implemented by a computer or may be a circuit. In the present disclosure, the connection destination of each interface 11 is specified as the identifier of the terminal T connected to the connection destination or as a selector position.

[0032] In the example shown in FIG. 4 , the terminal T1c of the first port P1 of the first interface 11a is connected in advance to the terminal T1c of the first port P1 of the fifth interface 11e via an optical fiber cable. For the first port P1 of the first interface 11a, the terminals T1a and T1b are each connected to one of the second interface 11b to the eighth interface 11h. When the terminal T1c is designated as the selector position for the first port P1 of the first interface 11a, the terminal on the first target device 7a side of the first port P1 of the first interface 11a is connected to the terminal T1c. When the terminal (not shown) on the fifth target device 7e side of the port P1 of the fifth interface 11e is connected to the terminal T1c, the first target device 7a and the fifth target device 7e are connected via the terminals T1c-T1c. In this disclosure, the direction of the signal flowing through the optical fiber cable is not specified. The signal can be transmitted in either one direction or both directions. When transmitting signals in only one direction, it is common to set up an optical circuit switch that pairs two optical fiber cables to enable bidirectional communication.

[0033] Similarly, terminal T5c of fifth port P5 of first interface 11a is connected in advance to terminal T5c of fifth port P5 of fifth interface 11e via an optical fiber cable. For fifth port P5 of first interface 11a, terminals T5a and T5b are each connected to any of second interface 11b to eighth interface 11h. When terminal T5c is designated as the selector position for fifth port P5 of first interface 11a, the terminal on the side of first target device 7a at fifth port P5 of first interface 11a is connected to terminal T5c. When the terminal on the side of fifth target device 7e at port P5 of fifth interface 11e is connected to terminal T5c, first target device 7a and fifth target device 7e are connected via terminals T5c-T5c.

[0034] Although Figure 4 illustrates a case where the identifiers of the two port numbers and two terminals that are pre-connected within the optical circuit switch 10 are the same, the identifiers of the two port numbers and two terminals that are pre-connected may be different.

[0035] In the optical circuit switch 10, each terminal T of a port P is connected to a different interface, so that the network can be dynamically changed by specifying the selector position.

[0036] Fig. 5 shows the connection destination of each port P of each interface 11 for each selector position. In Fig. 5, the selector position is indicated by three identifiers: A, B, and C. The interface 11 to which the connection is made is identified using the interface 11 identifier, selector position, and port number as keys.

[0037] In the present disclosure, each port P of each interface 11 of the optical circuit switch 10 is connected to a destination designated by a predetermined selector position. Each of the multiple ports P of a given interface 11 may be connected to a different set of interfaces. For example, seven of the ports P1-P8 of the first interface 11a may be connected to each of the ports of the second interface 11b-the eighth interface 11h. This allows a target device connected to the first interface 11a to communicate with each of the other target devices.

[0038] Furthermore, two or more of the multiple ports included in the first interface 11a may be connected to ports of one interface 11 other than the first interface 11a. For example, ports P2 and P3 of the first interface 11a are connected to two ports P of the third interface 11c, respectively. In this case, the connection target device connected to the first interface 11a and the connection target device connected to the third interface 11c are connected by two optical fiber cables, and therefore communication can be performed using the bandwidth of two cables.

[0039] In the example shown in FIG. 5 , when each of ports P1-P8 of the first interface 11a is set to selector position A, the first interface 11a connects to the second interface 11b. When the connection destination of each port P1-8 of the first interface 11a is set to each of ports P1-8 of the second interface 11b, and the connection destination of each port P1-8 of the second interface 11b is set to each of ports P1-8 of the first interface 11a, eight optical fibers are connected between the first interface 11a and the second interface 11b. Similarly, when each of ports P1-P8 of the first interface 11a is set to selector position B, four optical fiber cables are connected to each of the third interface 11c and the fourth interface 11d. When each of ports P1-P8 of the first interface 11a is set to selector position C, two optical fiber cables are connected to each of the fifth interface 11e through the eighth interface 11h.

[0040] The selector position is independent for each interface and port. For example, port P1 of the first interface 11a can be set to selector position A and connected to the second interface 11b. Port P2 of the first interface 11a can also be set to selector position B and connected to the fourth interface 11d. The port numbers and selector positions of the connection source and destination can be the same or different. For example, if the connection source is port P1 and selector position A, the connection destination can be port P1 and selector position A, just like the connection source, or port P8 and selector position C.

[0041] In another embodiment, when a selector position is specified in the optical circuit switch 10, all interfaces 11 and all ports P may be specified as the applicable range of the selector position. The applicable range of the specified selector position may be set arbitrarily, such as specifying all ports P of one interface 11 or specifying ports P with a predetermined number of all interfaces 11.

[0042] In this way, the optical circuit switch 10 can dynamically switch connection destinations and bandwidths by switching the connection destinations of each port provided in each interface. Within the optical circuit switch 10, the terminals connecting two interfaces 11 are pre-connected. When the optical circuit switch 10 is installed, each interface 11 of the optical circuit switch 10 and the target device are simply connected with an optical fiber cable. This reduces the labor and errors associated with cable connections, enabling efficient realization of diverse connections. In the examples shown in FIGS. 3-5, each interface has eight ports, so cabling between the interfaces and the target device can be reduced by using an eight-core optical fiber cable.

[0043] An example of use of the optical circuit switch 10 according to the present disclosure will be described with reference to Fig. 6. Fig. 6 shows an example in which the settings of the optical circuit switch 10 are changed over time, from the first day to the fifth day, when the scale of the data center expands and the number of devices to be connected increases. Note that the notation using dates such as the first day and the second day is a metaphor for each stage in the construction of a data center and does not necessarily represent the actual number of days.

[0044] On day 1, three connection target devices are reconfigurably mesh-connected. The optical circuit switch 10 can assign four of the eight ports of one interface 11 to each of the other two interfaces 11, ensuring four bandwidths for one communication pair.

[0045] On the second day, the four connection target devices are reconfigurably mesh-connected. The optical circuit switch 10 can assign two of the eight ports of one interface 11 to each of the other three interfaces 11, ensuring two bandwidths for one communication pair.

[0046] On the third day, five devices are reconfigurably connected in a mesh configuration. The optical circuit switch 10 can assign two of the eight ports of one interface 11 to each of the other four interfaces 11, ensuring two bandwidths for one communication pair.

[0047] Also, on the third day, it is possible to divide the devices into two groups, one with three target devices and the other with two target devices, and connect them. As with the first day, four bandwidths can be secured for one communication pair between the three target devices. Between the two target devices, eight ports can be assigned to one interface, so eight bandwidths can be secured for one communication pair. Furthermore, whether to connect five target devices in a mesh or in two groups can be selected appropriately depending on the connection destination settings of each port P.

[0048] On the fourth day, six target devices are reconfigurably mesh-connected. The optical circuit switch 10 can assign one of the eight ports of one interface to each of the five interfaces, ensuring one bandwidth for each communication pair. It is also possible to divide the six target devices into two groups of three and connect them with four bandwidths.

[0049] On the fifth day, the eight connection target devices are reconfigurably mesh-connected. The optical circuit switch 10 may appropriately switch between various connection configurations, such as two groups of 4+4, two groups of 5+3, or three groups of 3+3+2, by setting the connection destination of each port P.

[0050] In this way, the optical circuit switch 10 according to the present disclosure can appropriately set the interface to be connected and the number of ports to be connected. Because the optical circuit switch 10 realizes a wide variety of connection configurations, it can provide an optimal communication environment depending on the scale of the data center, the amount of data traffic, etc.

[0051] (Intra-RG Hub) The intra-RG hub 3 will be described with reference to Fig. 7. The intra-RG hub 3 is one embodiment of the optical circuit switch 10, and is connected to one RG 2. When the optical circuit switch 10 is an intra-RG hub 3, the connection target devices are the ToR switches of each rack included in the rack group 2 to which the optical circuit switch 10 is connected.

[0052] The RG intra-hub 3 has multiple interfaces 11a-11h that connect via optical fiber cables to the ToR switches of each rack included in the connected RG. The first interface 11a that connects to the ToR switch of rack 1 has multiple ports that connect via optical fiber cables to interfaces 11b-11h that connect to the ToR switches of racks 2-8 other than rack 1. Each of the multiple ports switches its connection destination.

[0053] In the intra-RG hub 3, one interface 11 is provided for one rack included in the connected RG 2. The eight ToR ports of rack 1 in RG 2 are connected to eight ports of the first interface 11a of the intra-RG hub 3. The ToR switches of racks 2-8 in RG 2 are connected to eight ports of the second to eighth interfaces of the intra-RG hub, respectively.

[0054] (Inter-RG Hub) The inter-RG hub 4 will be described with reference to Fig. 8. The inter-RG hub 4 is one embodiment of the optical circuit switch 10, and is connected to multiple RGs 2. When the optical circuit switch 10 is the inter-RG hub 4, the connection target devices are the ToR switches of each rack included in the multiple rack groups RG to which the optical circuit switch 10 is connected. Note that the inter-RG hub 4 shown in Fig. 8 depicts a connection between the first RG 2a and the second RG 2b, but in reality it is connected to eight RGs, from the third RG 2c to the eighth RG 2h.

[0055] The inter-RG hub 4 has a plurality of interfaces 11a-11h that connect via optical fiber cables to the ToR switches of each rack included in the plurality of connected RGs. The first interface 11a that connects to the ToR switch of the first RG 2a has a plurality of ports that connect via optical fiber cables to interfaces 11b-11h that connect to the ToR switches of RGs 2b-2h other than the first RG 2a. Each of the plurality of ports switches its connection destination.

[0056] In the inter-RG hub 4, one interface 11 is provided for one RG 2 out of the multiple connection destination RGs 2. The ToR ports of each of the eight racks of the first RG 2a are connected to the ports of the first interface 11a of the inter-RG hub 4. Here, the ToR switch of one rack uses eight ports for connection to each inter-RG hub 4, so each interface 11 of the inter-RG hub 4 has 64 ports. The ToR switches of each rack of the first RG 2a and the first interface 11a are connected by a 64-core optical fiber cable.

[0057] The connections within the inter-RG hub 4 will be described with reference to Fig. 9. Fig. 9 describes the connections between the first interface 11a and the second interface 11b, and between the first interface 11a and the third interface 11c. In Fig. 9, in the first RG 2a, each rack has eight ports, which are referred to as the first port, second port, etc. from the left. The same applies to the second RG 2b and the third RG 2c.

[0058] The first interface 11a has a 1×3 optical circuit switch as each port of each rack of the first RG 2a to which it is connected. In Fig. 9, the first interface 11a has, from the left, eight switches connected to eight terminals connected to port 1 of each rack, eight switches connected to eight terminals connected to port 2 of each rack, eight switches connected to eight terminals connected to port 3 of each rack, and eight switches connected to eight terminals connected to port 4 of each rack.

[0059] The second interface 11b has a 1x3 optical circuit switch as each port of each rack in the second RG2b to which it is connected. In Fig. 9, switches connected to ports 1 and 2 of each rack in the second RG2b to which it is connected are drawn within the second interface 11b. The third interface 11c has a 1x3 optical circuit switch as each port of each rack in the third RG2c to which it is connected. In Fig. 9, switches connected to port 1 of each rack in the second RG2b to which it is connected are drawn within the third interface 11c.

[0060] 9, selector position A indicates a state in which the terminal connected to RG in each interface 11 is connected to the leftmost terminal of the three terminals of each switch. Selector position B indicates a state in which the terminal connected to RG in each interface 11 is connected to the center terminal of the three terminals of each switch. Selector position C indicates a state in which the terminal connected to RG in each interface 11 is connected to the rightmost terminal of the three terminals of each switch.

[0061] In the first interface 11a, the eight switches connected to ports P1 of each rack of the first RG 2a are respectively at selector position A and are connected to eight switches connected to ports P1 of each rack of the second RG 2b to which the second interface 11b is connected. The eight switches connected to ports P1 of each rack of the first RG 2a are respectively at selector position B and are connected to eight switches connected to ports P1 of each rack of the third RG 2c to which the third interface 11c is connected.

[0062] In the first interface 11a, the eight switches connected to ports P2 of each rack of the first RG2a are each at selector position A and are connected to eight switches connected to ports P2 of each rack of the second RG2b to which the second interface 11b is connected.

[0063] Here, the inter-RG hub 4 comprehensively connects any RGs to be connected and also comprehensively connects any racks within the RGs to be connected. The inter-RG hub 4 is provided with an interface 11 for each RG 2 to be connected, and each interface 11 connects to another interface 11, thereby comprehensively connecting any RGs. In this case, the inter-RG hub 4 connects the ports of any two racks selected from two different RGs. Through such connections, the inter-RG hub 4 enables a mesh connection between the two RGs to be connected and a mesh connection between the racks included in the two RGs to be connected. For example, the inter-RG hub 4 connects a first rack included in a first RG 2a to a first rack included in a second RG 2b, and connects a first rack included in the first RG 2a to a second rack included in the second RG 2b.

[0064] In the example shown in FIG. 9, a case where selector position A is designated for each port will be described.

[0065] The inter-RG hub 4 connects a port of the inter-RG hub 4 that is connected to a port with a first port number in a rack with a first rack number included in the first RG 2a to a port within the inter-RG hub 4 that is connected to a port with a first port number in a rack with a first rack number included in the second RG 2b. The inter-RG hub 4 also connects a port within the inter-RG hub 4 that is connected to a port with a second port number in a rack with a second rack number included in the first RG 2a to each port within the inter-RG hub 4 that is connected to a port with a second port number in a rack with a rack number that is shifted by a predetermined number from the second rack number and included in the second RG 2b.

[0066] 9, the "port with the first port number of the rack with the first rack number" is the "second port of rack 2." Specifically, the inter-RG hub 4 connects the port of the inter-RG hub 4 that connects to the second port of rack 2 included in the first RG 2a to each port within the inter-RG hub 4 that connects to the second port of rack 2 included in the second RG 2b. Here, the inter-RG hub 4 connects racks with the same number in the first RG 2a and the second RG 2b.

[0067] 9 , the "port with the second port number of the rack with the second rack number" is the "first port of rack 1." The "port with the second port number of the rack with a rack number shifted a predetermined number from the second rack number" is the "first port of rack 8." Here, the predetermined number is "7." Specifically, the inter-RG hub 4 connects a port in the inter-RG hub 4 that connects to the first port of rack 1 included in the first RG 2a to a port in the inter-RG hub 4 that connects to the first port of rack 8 included in the second RG 2b. Similarly, the inter-RG hub 4 connects a port in the inter-RG hub 4 that connects to the first port of rack 2 included in the first RG 2a to each port in the inter-RG hub 4 that connects to the first port of rack 1 included in the second RG 2b. Here, the inter-RG hub 4 connects a rack with a certain rack number in the first RG 2a to a rack with a number shifted by seven from that rack number in the second RG 2b. Moreover, by changing the degree of deviation, the number of connection combinations can be increased.

[0068] In this way, by comprehensively connecting racks in a connection between two RG2s, it becomes possible to realize various connections between racks.

[0069] The deviation of the connected racks in the inter-RG hub 4 will be described with reference to Fig. 10. (a) to (d) of Fig. 10 show an example in which each rack in the first RG 2a on the left column is comprehensively connected to each rack in the second RG 2b on the right column. In the deviation degree in Fig. 10, the numerator indicates the difference in rack numbers between the connected racks, and the denominator indicates the number of racks in one RG.

[0070] Figure 10(a) shows racks with the same rack number being connected. Figure 10(b) shows an example where there is a difference of 1 between the rack number of the first RG 2a and the rack number of the second RG 2b. Figure 10(c) shows an example where there is a difference of 4 between the rack number of the first RG 2a and the rack number of the second RG 2b. Figure 10(d) shows an example where there is a difference of 5 between the rack number of the first RG 2a and the rack number of the second RG 2b. In this way, the eight ports of each rack are used to shift the rack numbers of the connected racks.

[0071] Referring to Figure 11, an example of the relationship between the offset of the connected racks and the port number in the inter-RG hub 4 will be described. The same port number is used for connection between the first RG 2a and the second RG 2b. Port number 1 of each rack in the first RG 2a is connected to port number 2 of each rack in the second RG 2b, and there is no offset in this case. In contrast, when port numbers 2 are connected together, there is an offset of one between the rack numbers of each rack in the first RG 2a and the rack numbers of each rack in the second RG 2b. In the example shown in Figure 11, although the same port number is used for connection, there is an offset of a predetermined number between the rack numbers of the two connected racks.

[0072] Referring to FIG. 12, the destination interfaces and racks in the inter-RG hub 4 will be described. In the data table shown in FIG. 12, as in FIG. 5, the destination interface 11 is identified using the interface 11 identifier, selector position, and port number as keys. However, for the destination, FIG. 12 identifies not only the interface 11 identifier but also the rack offset. For example, the destination of the first interface 11a, selector position A, and port 1 is identified as "2 (+7 / 8)." This indicates that the destination interface is the second interface 11b, and the rack number is offset by seven. The three connection topologies enclosed by dashed lines in FIG. 12 are depicted in FIG. 9.

[0073] (Hub connected to one RG) The optical circuit switch 10 to which one RG is connected will be described with reference to Fig. 13. Fig. 13 shows a connection between one intra-RG hub 3 and three inter-RG hubs 4. One RG is connected to multiple inter-RG hubs 4. This allows communication via the inter-RG hubs 4 even between racks in different RGs.

[0074] One RG has eight racks. The ToR switch of one rack needs to be connected with eight ports to one inter-RG hub 4 and each of three inter-RG hubs 4. Therefore, the ToR switch of one rack needs 32 ports for connection to those hubs.

[0075] 13, optical fiber cables are collected from eight ports in each of eight racks in one RG, and a total of 64 optical fiber cables are input to one intra-RG hub 3. Similarly, the 64 optical fiber cables collected from eight ports in each of eight racks in one RG are input to three inter-RG hubs 4. Note that each inter-RG hub 4 also receives input of 64 optical fiber cables per RG 2 from other RGs 2 not shown in FIG.

[0076] (Data Center Expansion Example) An example of data center expansion in the present disclosure will be described with reference to Fig. 14. In the example shown in Fig. 14, one room has 40 RG2. A patch panel is provided in each room.

[0077] First, we will explain the case where a data center is operated using only Room 1. Each RG 2 in Room 1 is connected to a patch panel installed in Room 1 with 64 optical fiber cables. When Room 1 is first opened, the data center connects the patch panel in Room 1 to several inter-RG hubs 4, as shown by the solid lines. Later, with the opening of Room 2, the patch panel in Room 2 is connected to the existing inter-RG hub 4, as shown by the thick lines. Furthermore, a new inter-RG hub 4 is installed, and the newly installed inter-RG hub 4 is connected to the patch panel in Room 2, as shown by the dashed lines.

[0078] In this way, each time a new room is created, the data center can be easily expanded by connecting the patch panel of the newly created room to the inter-RG hub connected to the existing room and installing a new inter-RG hub connected to the newly created room. Also, by connecting the RGs and patch panels, and between the patch panels and the inter-RG hub 4 with a single cable consisting of 64 optical fiber cables, human errors such as connection errors can be reduced and expansion can be easily achieved.

[0079] In the present disclosure, the communication network system 1 can flexibly respond to expansion or contraction of the data center by using an intra-RG hub 3 that connects within the RG and an inter-RG hub 4 that connects between RGs.

[0080] In addition, the intra-RG hub 3 and inter-RG hub 4 can predefine different connection target device pairs for multiple selector positions, so the connection destination can be changed by switching the selector position without manual rewiring. This reduces the costs and human errors associated with cable connections and makes connections easier.

[0081] In this manner, the communication network system 1 according to the present disclosure can efficiently connect racks housing servers at low cost.

[0082] (First Modification) A communication network system 1a according to a first modification will be described with reference to FIG.

[0083] Generally, in one room of a data center, multiple RG2s are defined as rows. In the example shown in FIG. 15, five RG2s are defined as one row, and 40 RG2s are grouped into five rows. An intra-RG hub is provided within each RG2. An inter-RG hub 4 connecting RGs in one row is called an intra-row connection hub. Here, RGs across rows are connected via two inter-RG hubs of the intra-row connection hub. For example, the first RG2a in the first row and the sixth RG2f in the second row are connected via the inter-RG hub 4 connecting the RGs in the first row and the inter-RG hub 4 connecting the RGs in the second row.

[0084] The communication network system 1a according to the first modification proposes an inter-RG hub 4 as an inter-row connection hub, connecting multiple RGs across rows. For example, the inter-row connection hub can connect the first RG 2a in the first row to the sixth RG 2f in the second row. Also, five RGs in each row are connected by an intra-row connection hub. Then, by combining an intra-row hub and an inter-row hub, any pair of RGs can be connected. However, any pair of RGs must go through another RG. For example, when connecting RG1 and RG40, RG1 can be connected to RG5 via an intra-row connection hub, and then RG5 can be connected to RG40 via an inter-row connection hub. As another example, RG36 can be used instead of RG5.

[0085] (Second Modification) A communication network system 1b according to a second modification will be described with reference to FIG.

[0086] The communication network system 1 b according to the second modification further includes a spine switch 6 connected to a plurality of intra-RG hubs 5 , as compared with the communication network system 1 shown in FIG.

[0087] As shown in Fig. 17 , in an intra-RG hub 5 according to the second modification, some of the multiple interfaces 11 are spine connection units S1 that connect to spine switches. In the example shown in Fig. 17 , the intra-RG hub 5 includes four spine connection units S1-S4. Each spine connection unit S is connected to multiple racks in the RG to which the intra-RG hub 5 is connected, enabling connection to the spine switch 6. The spine switch 6 is connected to multiple intra-RG hubs 5, enabling communication between different RGs.

[0088] The connection destination of the selector position of each interface of the intra-RG hub 5 according to the second modification will be described with reference to Fig. 18. In the data table shown in Fig. 18, the identifier of the interface connected to the rack is set for some port numbers, and the identifier of the spine connection section S connected to the spine switch is set for some port numbers. At selector position A, the first interface 11a connects port P1 to spine connection section S1.

[0089] In the communication network system 1b according to the second modification, the spine switch 6 is connected to a plurality of intra-RG hubs 5, thereby enabling communication between different RGs.

[0090] (Third Modification) A communication network system 1c according to a third modification will be described in which one RG has 16 racks. The intra-RG hub 30 according to the third modification is connected to the 16 racks. The inter-RG hub 40 enables connection between multiple RGs 2 using 256 optical fiber cables.

[0091] In the third modification, each ToR switch has twice the number of ports compared to the case shown in FIG. 1. To avoid doubling the number of ports, one ToR switch with double the capacity may be provided in one rack, rather than two ToR switches. For example, one rack may have one 12.8 Tbps (terabits per second) switch instead of two 6.4 Tbps switches.

[0092] (Fourth Modification) In a communication network system according to a fourth modification, the intra-RG hub 3 and the inter-RG hub 4 each connect servers housed in racks as connection target devices, rather than ToR switches. The number of servers grouped as an RG is expected to be less than eight, and the number of ports used for connection is expected to be less than 32. In the fourth modification, each server is connected in the same manner as each communication network according to the present disclosure described above. Note that in the fourth modification, the servers do not have to be housed in racks, and the term "rack" may be used to refer to a collection of multiple servers. Furthermore, the term "rack group" may be used to refer to a collection of racks, each of which is a collection of multiple servers.

[0093] In the fourth modified example, the connection target devices of the RG intra-hub 3 are servers in each rack included in the rack group to which the RG intra-hub 3 is connected. The RG intra-hub 3 has multiple interfaces 11 that connect via optical fiber cables to each of the servers in each rack included in the RG to which it is connected. A first interface 11a that connects to a server in a first rack has multiple ports that connect via optical fiber cables to interfaces 11 that connect to servers in racks other than the first rack. Each of the multiple ports switches its connection destination.

[0094] The connection target devices of the inter-RG hub 4 are the servers of each rack included in the multiple rack groups to which the inter-RG hub 4 is connected. The inter-RG hub 4 has multiple interfaces 11 that connect via optical fiber cables to each of the servers of each rack included in the multiple RGs to which it is connected. The first interface 11a that connects to the server of the first RG 2a has multiple ports that connect via optical fiber cables to interfaces 11 that connect to servers of RGs 2 other than the first RG 2a. Each of the multiple ports switches its connection destination.

[0095] Although the communication network systems according to the present disclosure have been described as connecting servers within a data center, the present disclosure is not limited to this and may be applied to connecting any number of servers, such as servers used for machine learning, in addition to servers within a data center.

[0096] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0097] REFERENCE SIGNS LIST 1 Communication network system 2 Rack group (RG) 3, 5, 30 Intra-rack group hub (intra-RG hub) 4, 40 Inter-rack group hub (inter-RG hub) 6 Spine switch 7 Device to be connected 10 Optical circuit switch 11 Interface P Port S Spine connection part T Terminal

Claims

1. It includes a plurality of interfaces each connected to a respective one of a plurality of devices to be connected by an optical fiber cable. The first interface connected to the first device to be connected has a plurality of ports connected by an optical fiber cable to interfaces connected to devices to be connected other than the first device to be connected. Each of the plurality of ports is an optical circuit switch for switching the connection destination.

2. Each port is provided with a terminal for each connection destination. When a connection destination is specified for the first port of the first interface, the optical circuit switch according to claim 1, wherein at the first port of the first interface, the terminal on the side of the first device to be connected is connected to the terminal corresponding to the specified connection destination.

3. The optical circuit switch according to claim 1, wherein each of the plurality of ports included in the first interface is connected to a respective one of a plurality of different interfaces.

4. The optical circuit switch according to claim 1, wherein each of two or more ports among the plurality of ports included in the first interface is connected to each port of one interface other than the first interface.

5. The optical circuit switch is an in-rack-group hub connected to one rack group. The rack group includes one or more racks for housing servers. The device to be connected is a ToR switch of each rack included in the rack group that is the connection destination of the optical circuit switch according to claim 1.

6. The interface is a spine connection part connected to a spine switch. The optical circuit switch according to claim 5.

7. The optical circuit switch is an inter-rack-group hub connected to a plurality of rack groups. The rack group includes one or more racks for housing servers. The device to be connected is a ToR switch of each rack included in the plurality of rack groups that are the connection destinations of the optical circuit switch according to claim 1.

8. The optical circuit switch according to claim 7, which connects the first rack included in the first rack group and the first rack included in the second rack group, and connects the first rack included in the first rack group and the second rack included in the second rack group.

9. The optical circuit switch is an in-rack-group hub connected to one rack group, the rack group includes one or more racks that house servers, and the device to be connected is a server in each rack included in the rack group that is the connection destination of the optical circuit switch. The optical circuit switch according to claim 1.

10. The optical circuit switch is an inter-rack-group hub connected to a plurality of rack groups, the rack group includes one or more racks that house servers, and the device to be connected is a server in each rack included in the plurality of rack groups that are the connection destinations of the optical circuit switch. The optical circuit switch according to claim 1.

11. A communication network system comprising: a rack group including a plurality of racks that house servers; an in-rack-group hub connected to one rack group; and an inter-rack-group hub connected to a plurality of rack groups. The in-rack-group hub includes a plurality of interfaces connected to respective ToR switches of each rack included in the connection destination rack group by optical fiber cables. The first interface connected to the ToR switch of the first rack includes a plurality of ports connected by optical fiber cables to interfaces connected to ToR switches of racks other than the first rack, and each of the plurality of ports switches the connection destination. The inter-rack-group hub includes a plurality of interfaces connected to respective ToR switches of each rack included in the plurality of connection destination rack groups by optical fiber cables. The first interface connected to the ToR switch of the first rack group includes a plurality of ports connected by optical fiber cables to interfaces connected to ToR switches of rack groups other than the first rack group, and each of the plurality of ports switches the connection destination.

12. One rack group is connected to an inter-rack-group hub. The communication network system according to claim 11.

13. Further comprising a spine switch, and the interface of the in-rack-group hub is connected to the spine switch. The communication network system according to claim 11.

14. A rack group including one or more racks for housing servers, a within-rack-group hub connected to one rack group, and an inter-rack-group hub connected to a plurality of rack groups. The within-rack-group hub includes a plurality of interfaces for connecting to each server in each rack included in the destination rack group with optical fiber cables. The first interface for connecting to the server in the first rack includes a plurality of ports for connecting to the interfaces for connecting to the servers in the racks other than the first rack with optical fiber cables. Each of the plurality of ports switches the connection destination. The inter-rack-group hub includes a plurality of interfaces for connecting to each server in each rack included in the plurality of destination rack groups with optical fiber cables. The first interface for connecting to the server in the first rack group includes a plurality of ports for connecting to the interfaces for connecting to the servers in the rack groups other than the first rack group with optical fiber cables. Each of the plurality of ports switches the connection destination. A communication network system.

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