Patent Publication Number: US-2015078253-A1

Title: Information processing device, information processing system, communication method, and computer-readable storage medium storing communication program

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2013-190802, filed on Sep. 13, 2013, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to an information processing device, an information processing system, a communication method, and a computer-readable storage medium storing a communication program. 
     BACKGROUND 
     In recent years, highly integrated servers including a large number of nodes mounted in a rack thereof have been utilized as a server for cloud computing or a data center. Herein, a node means an information processing device including a central processing unit (CPU), a memory, a storage, a crossbar switch, and the like. 
     For example, several tens to hundreds of nodes are mounted in the rack. The nodes are connected to each other through a cable or a backplane.  FIG. 21  is a diagram illustrating an example of a cable connection, and  FIGS. 22A and 22B  are diagrams illustrating an example of a backplane connection.  FIG. 22A  illustrates a front surface and a back surface of a housing utilizing the backplane connection, and  FIG. 22B  illustrates an example of a backplane wiring pattern. 
     In  FIG. 21 , thirty nodes  91  are connected to each other through cables via two switching nodes  92 . In  FIG. 22A , forty nodes  93  are connected to each other via four switching nodes  94  and a backplane  95 . In  FIG. 22A , the front surface of the housing is illustrated in the upper row, and the back surface of the housing is illustrated in the lower row. 
     As illustrated in  FIG. 21 , the number of cables is significantly increased as the number of nodes becomes large in the cable connection. Accordingly, when the cable connection is used, cable cost increases, maintenance by inserting or removing the cable is burdensome, and a space occupied by the cables increases. 
     On the other hand, as illustrated in  FIG. 22B , a wiring pattern  96  becomes large scale as the number of nodes increases in the backplane connection. Accordingly, when the backplane connection is used, the wiring in the backplane is difficult, the number of layers in the backplane increases, and production cost increases. In addition, when the backplane connection is used, a risk caused by a failure in the backplane increases, and the entire system should be stopped to maintain the backplane. 
     Accordingly, a technique has been developed for performing data transfer between modules in the housing in a wireless manner without using the cable connection or the backplane connection (for example, refer to Japanese Laid-open Patent Publication No. 2005-6329). There is also related art in which a tray part connecting a server device and a console part of the server device communicates with the console part in a wireless manner (for example, refer to Japanese Laid-open Patent Publication No. 2006-185419). 
     Unfortunately, communication speed of wireless communication is lower than that of wired communication. Although some wireless communication techniques of which speed is substantially the same as that of the wired communication have been developed, high-speed wireless communication is not suitable for communication at a distance because radio waves are easily attenuated. Accordingly, in a case of connecting a large number of information processing devices with each other by high-speed wireless communication, communication is performed via a plurality of information processing devices, so that delay time is increased and the communication speed is reduced. 
     SUMMARY 
     According to an aspect of an embodiment, an information processing device includes a first communication unit that communicates with another information processing device using a first communication scheme; a second communication unit that communicates with another information processing device using a second communication scheme; and a control unit that determines a communication scheme for transmitting data to a destination based on information about a distance to an information processing device as the destination of the data, causes the first communication unit to transmit the data when the determined communication scheme is the first communication scheme, and causes the second communication unit to transmit the data when the determined communication scheme is the second communication scheme. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating a configuration of an information processing system according to a first embodiment; 
         FIG. 2  is a diagram for explaining wireless local area network (WLAN) communication using an AP; 
         FIG. 3A  is a diagram illustrating a configuration of an XB; 
         FIG. 3B  is a diagram illustrating a configuration of another XB; 
         FIG. 4  is a diagram illustrating an arrangement of nodes; 
         FIG. 5A  is a first diagram illustrating an example of a routing table according to the first embodiment; 
         FIG. 5B  is a second diagram illustrating an example of the routing table according to the first embodiment; 
         FIG. 6  is a flowchart illustrating the procedure of transmission processing by the node according to the first embodiment; 
         FIG. 7  is a flowchart illustrating the procedure of reception processing by a node according to the first embodiment; 
         FIG. 8A  is a first diagram illustrating an example of a routing table according to a second embodiment; 
         FIG. 8B  is a second diagram illustrating an example of the routing table according to the second embodiment; 
         FIG. 9  is a flowchart illustrating the procedure of transmission processing by the node according to the second embodiment; 
         FIG. 10  is a flowchart illustrating the procedure of reception processing by the node according to the second embodiment; 
         FIG. 11  is a diagram illustrating an example of grouping the nodes; 
         FIG. 12A  is a first diagram illustrating an example of a routing table according to a third embodiment; 
         FIG. 12B  is a second diagram illustrating an example of the routing table according to the third embodiment; 
         FIG. 12C  is a third diagram illustrating an example of the routing table according to the third embodiment; 
         FIG. 12D  is a fourth diagram illustrating an example of the routing table according to the third embodiment; 
         FIG. 13  is a flowchart illustrating the procedure of transmission processing by a node according to the third embodiment; 
         FIG. 14  is a flowchart illustrating the procedure of reception processing by a node according to the third embodiment; 
         FIG. 15A  is a diagram illustrating a configuration of an XB according to a fourth embodiment; 
         FIG. 15B  is a diagram illustrating another configuration of the XB according to the fourth embodiment; 
         FIG. 16A  is a first diagram illustrating an example of a routing table according to the fourth embodiment; 
         FIG. 16B  is a second diagram illustrating an example of the routing table according to the fourth embodiment; 
         FIG. 17  is a flowchart illustrating the procedure of transmission processing by the node according to the fourth embodiment; 
         FIG. 18  is a flowchart illustrating the procedure of transmission processing by a node according to a fifth embodiment; 
         FIG. 19  is a diagram illustrating a configuration of an information processing system according to a sixth embodiment; 
         FIG. 20  is a diagram illustrating a hardware configuration of the XB that executes a communication program; 
         FIG. 21  is a diagram illustrating an example of a cable connection; 
         FIG. 22A  is a diagram illustrating a front surface and a back surface of a housing a backplane connection; and 
         FIG. 22B  is a diagram illustrating an example of a backplane wiring pattern. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preferred embodiments of the present invention will be explained with reference to accompanying drawings. A technique disclosed herein is not limited to the embodiments described below. 
     [a] First Embodiment 
     First, the following describes a configuration of an information processing system according to a first embodiment.  FIG. 1  is a diagram illustrating the configuration of the information processing system according to the first embodiment. As illustrated in FIG.  1 , the information processing system is a highly integrated server including an NW switch  2 , an AP  3 , and the ninety-nine nodes  10  mounted in a rack  1 . Although one NW switch  2  and ninety-nine nodes  10  are mounted in the rack  1  herein, more NW switches  2 , more nodes  10 , or less nodes  10  may be mounted in one rack. 
     The NW switch  2  is a switch for connecting with an external network such as the Internet. The AP  3  is an access point of a wireless local area network (WLAN) using a frequency of 2.4 GHz band and 5 GHz band.  FIG. 2  is a diagram for explaining WLAN communication using the AP  3 .  FIG. 2  is a wireless system including the AP  3  and three stations (STAs)  4 . 
     As illustrated in  FIG. 2 , when transferring data to the other STA  4 , the STA  4  transfers the data via the AP  3 . Accordingly, when the number of STAs  4  is large, the data concentrates on the AP  3  and congestion occurs. Communication speed of WLAN is about 600 Mbits/second (Mbps) and wired communication speed is higher than 1.0 Gbit/second (Gbps), so that the communication speed of WLAN is lower than the wired communication speed. 
     A communication mode illustrated in  FIG. 2  is called an infrastructure mode, and communication between devices is performed via the AP  3 . On the other hand, a mode in which the devices directly communicate with each other without using the AP  3  is called an ad hoc mode. The infrastructure mode is suitable for a case in which a large number of devices communicate with each other, and the ad hoc mode is suitable for a case in which a small number of devices communicate with each other. 
     The node  10  is an information processing device including a CPU  11 , a memory  12 , a storage  13 , and an XB  14 . The node  10  also includes an upper antenna for 60 G wireless  15   a , a lower antenna for 60 G wireless  15   b , a left antenna for 60 G wireless  15   c , a right antenna for 60 G wireless  15   d , and an antenna for WLAN  15   e . The nodes  10  are housed in a housing. The upper antenna for 60 G wireless  15   a , the lower antenna for 60 G wireless  15   b , the left antenna for 60 G wireless  15   c , the right antenna for 60 G wireless  15   d , and the antenna for WLAN  15   e  are connected to the XB  14 . 
     The CPU  11  is a central processing unit that reads and executes a computer program from the memory  12 . The memory  12  is a random access memory (RAM) that stores therein the computer program or results in the midway obtained in the execution of the computer program. The storage  13  is a nonvolatile memory that stores therein data, for example, a NAND flash memory. The storage  13  also stores therein the computer program installed in the node  10 . 
     The XB  14  is a crossbar switch for communicating with an other node  10 . The XB  14  is one LSI. The upper antenna for 60 G wireless  15   a  is an antenna for 60 G wireless that uses a frequency of 60 GHz band, installed facing upward, and used for communicating with the node  10  adjacent above in the rack  1 . Similarly, the lower antenna for 60 G wireless  15   b  is the antenna for 60 G wireless, installed facing downward, and used for communicating with the node  10  adjacent below in the rack  1 . 
     The left antenna for 60 G wireless  15   c  is the antenna for 60 G wireless, installed facing leftward, and used for communicating with the node  10  adjacent on the left in the rack  1 . The right antenna for 60 G wireless  15   d  is the antenna for 60 G wireless, installed facing rightward, and used for communicating with the node  10  adjacent on the right in the rack  1 . 
     Communication speed of the 60 G wireless can be about several Gbps, which is higher than that of the WLAN. However, radio waves hardly reach in the 60 G wireless and the housing blocks the radio waves, so that it is difficult to communicate with the adjacent upper, lower, left, and right nodes  10  using one 60 G wireless module. Accordingly, the node  10  includes four 60 G wireless modules that communicate with the adjacent upper, lower, left, and right nodes  10 , respectively. The antenna for WLAN  15   e  is a WLAN antenna. 
     The node  10  communicates with other nodes  10  having a distance therefrom equal to or smaller than a predetermined threshold using the 60 G wireless, and communicates with other nodes  10  having a distance therefrom larger than the predetermined threshold using the WLAN. For example, in  FIG. 1 , in a case of communicating with an other node  10  positioned at D 1 , a node  10  positioned at S in the rack  1  performs communication via a node positioned below in the rack  1  using the 60 G wireless because the distance therebetween is short. In a case of communicating with an other node  10  positioned at D 2 , the node  10  positioned at S in the rack  1  performs communication using the WLAN via the AP  3  because the distance therebetween is long. 
     In this way, the node  10  communicates with the other nodes  10  having the distance therefrom smaller than the predetermined threshold using the 60 G wireless, and communicates with the other nodes  10  having the distance therefrom equal to or larger than the predetermined threshold using the WLAN. Accordingly, the node  10  can perform wireless communication at high speed with a large number of nodes  10  without causing congestion at the AP  3 . 
     The following describes a configuration of the XB  14 .  FIG. 3A  is a diagram illustrating the configuration of the XB  14 . As illustrated in  FIG. 3A , the XB  14  includes a host interface (I/F)  141 , two routing tables  142 , a routing unit  143 , five packet analysis units  144 , and five I/Fs  145 . The XB  14  also includes an upper unit for 60 G wireless  146   a , a lower unit for 60 G wireless  146   b , a left unit for 60 G wireless  146   c , a right unit for 60 G wireless  146   d , a WLAN unit  147 , and an NI register  148 . 
     The host I/F  141  is an interface with the CPU  11  of its own node. The host I/F  141  passes a packet received from the CPU  11  to the routing unit  143 , and passes a packet received from the routing unit  143  to the CPU  11  of the own node. The host I/F  141  also passes a destination of the packet received from the CPU  11  of the own node to the routing table  142 . 
     The routing table  142  is a retrieval table for retrieving routing information that indicates a routing destination from the destination of the packet. The routing unit  143  receives the packet from the host I/F  141 , and passes the packet to any of the I/Fs  145  based on the routing information received from the routing table  142  and information of the NI register  148 . The routing unit  143  also receives the packet from any of the packet analysis units  144 , and passes the packet to the host I/F  141  or any of the I/Fs  145  based on the routing information received from the routing table  142  and the information of the NI register  148 . 
     The packet analysis unit  144  receives the packet from the I/F  145 , analyzes the packet based on the information of the NI register  148 , and extracts a destination. The packet analysis unit  144  passes the extracted destination to the routing table  142  and passes the packet to the routing unit  143 . 
     The I/F  145  converts a signal received from the 60 G wireless module or the WLAN unit  147  into a packet, and passes the packet to the corresponding packet analysis unit  144 . The I/F  145  receives the packet routed by the routing unit  143 , and instructs the corresponding 60 G wireless module or the corresponding WLAN module to transmit the packet. The upper unit for 60 G wireless  146   a , the lower unit for 60 G wireless  146   b , the left unit for 60 G wireless  146   c , and the right unit for 60 G wireless  146   d  are 60 G wireless modules that perform wireless communication using a frequency of 60 GHz band. 
     The upper unit for 60 G wireless  146   a  performs wireless communication with the node  10  adjacent above in the rack  1  using the upper antenna for 60 G wireless  15   a  illustrated in  FIG. 1 . The lower unit for 60 G wireless  146   b  performs wireless communication with the node  10  adjacent below in the rack  1  using the lower antenna for 60 G wireless  15   b  illustrated in  FIG. 1 . The left unit for 60 G wireless  146   c  performs wireless communication with the node  10  adjacent on the left in the rack  1  using the left antenna for 60 G wireless  15   c  illustrated in  FIG. 1 . The right unit for 60 G wireless  146   d  performs wireless communication with the node  10  adjacent on the right in the rack  1  using the right antenna for 60 G wireless  15   d  illustrated in  FIG. 1 . 
     The WLAN unit  147  has a function of the STA  4 , and communicates with the WLAN unit  147  in an other node  10  via the AP  3  using the WLAN. The NI register  148  is a register that stores therein information about the own node such as a node identifier (ID), an Internet Protocol (IP) address, and a media access control (MAC) address. 
     Although the XB  14  illustrated in  FIG. 3A  includes the 60 G wireless modules and the WLAN unit  147 , the 60 G wireless modules and the WLAN unit  147  may be provided outside the XB. The  FIG. 3B  is a diagram illustrating another configuration of the XB of which the 60 G wireless modules and the WLAN unit  147  are provided outside. 
     As illustrated in  FIG. 3B , an XB  14   a  does not include the upper unit for 60 G wireless  146   a , the lower unit for 60 G wireless  146   b , the left unit for 60 G wireless  146   c , the right unit for 60 G wireless  146   d , and the WLAN unit  147 . The XB  14   a  performs wireless communication using an upper unit for 60 G wireless  10   a , a lower unit for 60 G wireless  10   b , a left unit for 60 G wireless  10   c , a right unit for 60 G wireless  10   d , and a WLAN unit  10   e  provided outside. 
     The following describes details about the routing table  142  with reference to  FIGS. 4 ,  5 A, and  5 B.  FIG. 4  is a diagram illustrating an arrangement of the nodes  10 , and  FIGS. 5A and 5B  are diagrams illustrating an example of the routing table  142  according to the first embodiment. In  FIG. 4 , “1, 2, . . . , and 18” represent the numbers for identifying each node  10 . That is,  FIG. 4  illustrates an arrangement such that a node 1 , a node 2 , . . . , a node 9  are arranged from the upper left toward the right in the rack  1 , and a node 10 , a node 11 , . . . , a node 18  are arranged in the next row. 
       FIG. 5A  illustrates the routing table  142  set to the node in a case of the node arrangement illustrated in  FIG. 4 , and  FIG. 5B  illustrates the routing table  142  set to the node 2  in a case of the node arrangement illustrated in  FIG. 4 . 
     As illustrated in  FIG. 5A , the routing destination is associated with the destination of the packet in the routing table  142  of the node 1 . In  FIG. 5A , the routing destination “60 G wireless right” indicates that the routing destination is the right unit for 60 G wireless  146   d , and the routing destination “60 G wireless lower” indicates that the routing destination is the lower unit for 60 G wireless  146   b . Similarly, the routing destination “60 G wireless left” indicates that the routing destination is the left unit for 60 G wireless  146   c , and the routing destination “60 G wireless upper” indicates that the routing destination is the upper unit for 60 G wireless  146   a . The routing destination “WLAN” indicates that the routing destination is the WLAN unit  147 . 
     For example, when the destination of the packet is the node 1 , that is, the own node, the routing destination is the CPU  11  of the host, that is, the own node. When the destination of the packet is the node 2 , the routing destination is the right unit for 60 G wireless  146   d  because the node 2  is arranged on the right. 
     When the destination of the packet is the node 3 , the routing destination is the right unit for 60 G wireless  146   d  because the node 3  is arranged in the right direction. When the destination of the packet is the node 10 , the routing destination is the lower unit for 60 G wireless  146   b  because the node 10  is arranged below. When the destination of the packet is the node 18 , a distance to the node 18  is 9 assuming that the distance is the number of nodes  10  through which the packet passes. For example, assuming that a threshold of the distance is 4, the node 18  is at a distance, so that the routing destination is the WLAN unit  147 . 
     In the routing table  142  of the node 2  illustrated in  FIG. 5B , when the destination of the packet is the node 1 , the routing destination is the left unit for 60 G wireless  146   c  because the node 1  is arranged on the left. When the destination of the packet is the node 2 , the routing destination is the CPU  11  of the host, that is, the own node. 
     When the destination of the packet is the node 3 , the routing destination is the right unit for 60 G wireless  146   d  because the node 3  is arranged on the right. When the destination of the packet is the node 10 , the routing destination is the lower unit for 60 G wireless  146   b  because the node 10  is arranged at the lower left. In this case, the routing destination may be the left unit for 60 G wireless  146   c . When the destination of the packet is the node 18 , a distance to the node 18  is 8 assuming that the distance is the number of nodes  10  through which the packet passes. For example, assuming that the threshold of the distance is 4, the node 18  is at a distance, so that the routing destination is the WLAN unit  147 . 
     In this way, the routing table  142  is set such that the routing is performed to the 60 G wireless module for a close node  10 , and the routing is performed to the WLAN module for a distant node  10 . Accordingly, the node  10  can transmit the data to the close node  10  at high speed using the 60 G wireless module, and can transmit the data to the distant node  10  by one hop using the WLAN module. Due to this, the node  10  can transmit the data to the distant node  10  with efficiency. 
     The following describes the procedure of transmission processing by the node  10  according to the first embodiment.  FIG. 6  is a flowchart illustrating the procedure of the transmission processing by the node  10  according to the first embodiment. As illustrated in  FIG. 6 , the node  10  performs table retrieval for a destination using the routing table  142  (Step S 1 ), and routes the packet to the corresponding wireless module (Step S 2 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 3 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 4 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 5 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 6 ). If the routing destination is the WLAN unit  147 , the WLAN unit  147  transmits the packet using the WLAN (Step S 7 ). 
     The following describes the procedure of reception processing by the node  10  according to the first embodiment.  FIG. 7  is a flowchart illustrating the procedure of the reception processing by the node  10  according to the first embodiment. As illustrated in  FIG. 7 , when receiving the packet (Step S 11 ), the node  10  determines whether the destination of the packet is the own node (Step S 12 ). If the destination of the packet is the own node, the packet is transmitted to the host (Step S 20 ), and the node  10  transmits ACK to a transmission source (Step S 21 ). 
     On the other hand, if the destination of the packet is not the own node, the node  10  performs table retrieval for the destination using the routing table  142  (Step S 13 ), and routes the packet to the corresponding wireless module (Step S 14 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 15 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 16 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 17 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 18 ). If the routing destination is the WLAN unit  147 , the WLAN unit  147  transmits the packet using the WLAN (Step S 19 ). 
     In this way, the node  10  determines the routing destination of the packet using the routing table  142 , so that the node  10  can properly use the 60 G wireless and the WLAN by setting the routing destination based on the distance from the node  10  in the routing table  142 . 
     As described above, in the first embodiment, the routing table  142  stores therein whether the routing destination is the 60 G wireless or the WLAN based on the distance between the own node and the destination node  10 . Accordingly, the node  10  can properly use the 60 G wireless and the WLAN by retrieving the routing table  142 , so that the information processing system can connect a large number of nodes  10  with each other at high speed in a wireless manner. 
     In the first embodiment, the node  10  performs 60 G wireless communication with adjacent upper, lower, left, and right nodes  10  using four 60 G wireless antennas arranged in the upper, lower, left, and right directions. Accordingly, the node  10  can prevent the housing from interfering with radio waves and perform wireless communication with the adjacent node  10  with high reliability. 
     [b] Second Embodiment 
     In the first embodiment, the routing table  142  has been described in which the routing destination is set to either the 60 G wireless or the WLAN based on the distance between the own node and the destination node  10 . Alternatively, the node  10  may determine the routing destination to be the WLAN or the 60 G wireless using the routing table  142  in which the distance between the own node and the destination node  10  is set. In the second embodiment, the following describes a case in which the node  10  determines the routing destination to be the WLAN or the 60 G wireless using the routing table  142  in which the distance between the own node and the destination node  10  is set. 
       FIGS. 8A and 8B  are diagrams illustrating an example of the routing table  142  according to the second embodiment.  FIG. 8A  illustrates an example of the routing table  142  set to the node in a case of the node arrangement illustrated in  FIG. 4 , and  FIG. 8B  illustrates an example of the routing table  142  set to the node 2  in a case of the node arrangement illustrated in  FIG. 4 . 
     As illustrated in  FIG. 8A , in the routing table  142  of the node 1 , the destination of the packet is associated with the routing destination and a distance D. Herein, the distance D is the number of hops of the node  10  to the destination. For example, if the destination of the packet is the node 1 , that is, the own node, the routing destination is the host and there is no distance D. If the destination of the packet is the node 2 , the node 2  is arranged on the right, so that the routing destination is the right unit for 60 G wireless  146   d  and the distance D is 1. 
     If the destination of the packet is the node 3 , the node 3  is arranged on the right of the node 2 , so that the routing destination is the right unit for 60 G wireless  146   d  and the distance D is 2. If the destination of the packet is the node 9 , the node 9  is arranged at the right end, so that the routing destination is the right unit for 60 G wireless  146   d  and the distance is 8. If the destination of the packet is the node 10 , the node 10  is arranged below, so that the routing destination is the lower unit for 60 G wireless  146   b  and the distance is 1. 
     In the routing table  142  of the node 2  as illustrated in  FIG. 8B , if the destination of the packet is the node 1 , the node 1  is arranged on the left, so that the routing destination is the left unit for 60 G wireless  146   c  and the distance D is 1. If the destination of the packet is the node 2 , the routing destination is the CPU  11  of the host, that is, the own node, and there is no distance D. 
     If the destination of the packet is the node 3 , the node 3  is arranged on the right, so that the routing destination is the right unit for 60 G wireless  146   d  and the distance D is 1. If the destination of the packet is the node 9 , the node 9  is arranged at the right end, so that the routing destination is the right unit for 60 G wireless  146   d  and the distance D is 7. If the destination of the packet is the node 10 , the node 10  is arranged on the lower left, so that the routing destination is the lower unit for 60 G wireless  146   b  and the distance D is 2. In this case, the routing destination may be the left unit for 60 G wireless  146   c.    
     In this way, the distance D to the destination node  10  is set in the routing table  142 . Accordingly, the node  10  compares the distance D with a threshold Dth. If D&gt;Dth, the node  10  uses the WLAN module. If D≦Dth, the node  10  uses the 60 G wireless module. Due to this, the node  10  can transmit the data to the distant node  10  with efficiency. The threshold Dth is stored in the NI register  148 . 
     The following describes the procedure of transmission processing by the node  10  according to the second embodiment.  FIG. 9  is a flowchart illustrating the procedure of the transmission processing by the node  10  according to the second embodiment. As illustrated in  FIG. 9 , the node  10  performs table retrieval for the destination using the routing table  142  (Step S 31 ), and acquires the routing destination and the distance D. The node  10  then determines whether D is larger than Dth (Step S 32 ). If D is not larger than Dth, the node  10  routes the packet to the corresponding wireless module (Step S 33 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 34 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 35 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 36 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 37 ). 
     On the other hand, if D is larger than Dth, the node  10  routes the packet to the WLAN module (Step S 38 ), and the WLAN unit  147  transmits the packet using the WLAN (Step S 39 ). 
     The following describes the procedure of reception processing by the node  10  according to the second embodiment.  FIG. 10  is a flowchart illustrating the procedure of the reception processing by the node  10  according to the second embodiment. As illustrated in  FIG. 10 , when receiving the packet (Step S 41 ), the node  10  determines whether the destination of the packet is the own node (Step S 42 ). If the destination of the packet is the own node, the packet is transmitted to the host (Step S 52 ), and the node  10  transmits the ACK to the transmission source (Step S 53 ). 
     On the other hand, if the destination of the packet is not the own node, the node  10  performs table retrieval for the destination using the routing table  142  (Step S 43 ), and acquires the routing destination and the distance D. The node  10  then determines whether D is larger than Dth (Step S 44 ). If D is not larger than Dth, the node  10  routes the packet to the corresponding wireless module (Step S 45 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 46 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 47 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 48 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 49 ). 
     On the other hand, if D is larger than Dth, the node  10  routes the packet to the WLAN module (Step S 50 ), and the WLAN unit  147  transmits the packet using the WLAN (Step S 51 ). 
     In this way, the node  10  compares the threshold Dth with the distance D acquired from the routing table  142  to determine the routing destination of the packet. Accordingly, the node  10  can properly use the 60 G wireless and the WLAN by setting the distance D from the node  10  in the routing table  142 . 
     As described above, in the second embodiment, the distance D from the own node to the destination node  10  is set in the routing table  142 . Accordingly, the node  10  can properly use the 60 G wireless and the WLAN by retrieving the distance D from the routing table  142  to compare the distance D with the threshold Dth, so that the information processing system can connect a large number of nodes  10  with each other at high speed in a wireless manner. 
     [c] Third Embodiment 
     In the first and the second embodiments, described is the case in which each node  10  has the STA function of the WLAN. Alternatively, the node  10  having the STA function can be limited. The following describes a case of limiting the node  10  having the STA function. 
     First, grouping of the nodes  10  will be described.  FIG. 11  is a diagram illustrating an example of grouping the nodes  10 . As illustrated in  FIG. 11 , every twelve nodes  10  close to each other are grouped. For example, a group 1  includes the node 1  to the node 3 , the node 10  to the node 12 , the node 19  to the node 21 , and the node 28  to the node 30 , and a group 2  includes the node 4  to the node 6 , the node 13  to the node 15 , the node 22  to the node 24 , and the node 31  to the node 33 . A group 3  includes the node 7  to the node 9 , the node 16  to the node 18 , the node 25  to the node 27 , and the node 34  to the node 36 . 
     In each group, only one node  10  has the STA function of the WLAN. For example, in the group 1 , only the node has the STA function. Each node  10  uses the 60 G wireless to communicate with an other node  10  in the group, and uses the WLAN to communicate with a node  10  outside the group. 
     For example, the node 1  uses the 60 G wireless to transmit the packet to the node 3  in the group. On the other hand, to transmit the packet to the node 15  outside the group, the node 1  transmits the packet to the node 15  using the WLAN via the node 11  having the STA function. The node 1  transmits the packet to the node 11  using the 60 G wireless. 
     In this way, by grouping the nodes  10  and limiting the node  10  having the STA function of the WLAN to be only one in the group, the information processing system can reduce the number of nodes connected to the AP  3  and prevent congestion at the AP  3 . 
       FIGS. 12A to 12D  are diagrams illustrating an example of the routing table  142  according to the third embodiment. Corresponding to the grouping illustrated in  FIG. 11 ,  FIG. 12A  illustrates the routing table  142  of the node and  FIG. 12B  illustrates the routing table  142  of the node 2 . Corresponding to the grouping illustrated in  FIG. 11 ,  FIG. 12C  illustrates the routing table  142  of the node 10  and  FIG. 12D  illustrates the routing table  142  of the node 11 . 
     As illustrated in  FIGS. 12A to 12D , the routing table  142  stores therein a destination, a routing destination, a group ID, and a WSTA in association with each other. The group ID represents an identifier for identifying a group to which the destination node  10  belongs. The WSTA represents whether the destination node  10  has the STA function of the WLAN, in which “0” indicates that the destination node  10  does not have the STA function and “1” indicates that the destination node  10  has the STA function. 
     For example, in the routing table  142  of the node as illustrated in  FIG. 12A , if the destination of the packet is the node 1 , that is, the own node, the routing destination is the host, the group ID is 1, and the WSTA is 0. If the destination of the packet is the node 2 , the node 2  is arranged on the right, so that the routing destination is the right unit for 60 G wireless  146   d , the group ID is 1, and the WSTA is 0. 
     If the destination of the packet is the node 11 , the node 11  is arranged on the lower right of the node 1 , so that the routing destination is the lower unit for 60 G wireless  146   b , the group ID is 1, and the WSTA is 1 because the node 11  has the STA function. If the destination of the packet is the node 14 , the node 14  belongs to an other group and the node 11  having the STA function within the group is arranged on the lower right, so that the routing destination is the lower unit for 60 G wireless  146   b , the group ID is 2, and the WSTA is 1 because the node 14  has the STA function. 
     In the routing table  142  of the node 2  as illustrated in  FIG. 12B , for example, if the destination of the packet is the node 1 , the node 1  is arranged on the left, so that the routing destination is the left unit for 60 G wireless  146   c , the group ID is 1, and the WSTA is 0. If the destination of the packet is the node 2 , the routing destination is the CPU  11  of the host, that is, the own node, the group ID is 1, and the WSTA is 0. 
     In the routing table  142  of the node 10  as illustrated in  FIG. 12C , for example, if the destination of the packet is the node 1 , the node is arranged above, so that the routing destination is the upper unit for 60 G wireless  146   a , the group ID is 1, and the WSTA is 0. If the destination of the packet is the node 10 , the routing destination is the CPU  11  of the host, that is, the own node, the group ID is 1, and the WSTA is 0. 
     In the routing table  142  of the node 11  as illustrated in  FIG. 12D , for example, if the destination of the packet is the node 1 , the node is arranged on the upper left, so that the routing destination is the upper unit for 60 G wireless  146   a , the group ID is 1, and the WSTA is 0. If the destination of the packet is the node 11 , the routing destination is the CPU  11  of the host, that is, the own node, the group ID is 1, and the WSTA is 1 because the node 11  has the STA function. 
     The following describes the procedure of transmission processing by the node  10  according to the third embodiment.  FIG. 13  is a flowchart illustrating the procedure of the transmission processing by the node  10  according to the third embodiment. As illustrated in  FIG. 13 , the node  10  performs table retrieval for the destination using the routing table  142  (Step S 61 ), and acquires the routing destination and the group ID. The node  10  then determines whether the GID is the same as its own GID, that is, whether the group ID is the same as the group ID of the own node (Step S 62 ). If the GID is the same as the own GID, the node  10  routes the packet to the corresponding wireless module (Step S 63 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 64 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 65 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 66 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 67 ). 
     On the other hand, if the GID is not the same as the own GID (No at Step S 62 ), which is a case in which the packet is transmitted to an other group, the node  10  determines whether the WSTA of the own node is 1 (Step S 68 ). If the WSTA of the own node is not 1, the node  10  routes the packet to the wireless module used in a case of transmitting the packet to the node  10  of which WSTA is 1 in the group (Step S 69 ), and the process proceeds to any of Steps S 64  to S 67 . 
     On the other hand, if the WSTA of the own node is 1, the node  10  routes the packet to the WLAN module (Step S 70 ), and the WLAN unit  147  transmits the packet using the WLAN (Step S 71 ). 
     The following describes the procedure of reception processing by the node  10  according to the third embodiment.  FIG. 14  is a flowchart illustrating the procedure of the reception processing by the node  10  according to the third embodiment. As illustrated in  FIG. 14 , when receiving the packet (Step S 81 ), the node  10  determines whether the destination of the packet is the own node (Step S 82 ). If the destination of the packet is the own node, the packet is transmitted to the host (Step S 94 ), and the node  10  transmits the ACK to the transmission source (Step S 95 ). 
     On the other hand, if the destination of the packet is not the own node, the node  10  performs table retrieval for the destination using the routing table  142  (Step S 83 ), and acquires the routing destination and the group ID. The node  10  then determines whether the GID is the same as the own GID (Step S 84 ). If the GID is the same as the own GID, the node  10  routes the packet to the corresponding wireless module (Step S 85 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 86 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 87 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 88 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 89 ). 
     On the other hand, if the GID is not the same as the own GID (No at Step S 84 ), which is a case in which the packet is transmitted to an other group, the node  10  determines whether the WSTA of the own node is 1 (Step S 90 ). If the WSTA of the own node is not 1, the node  10  routes the packet to the wireless module used in a case of transmitting the packet to the node  10  of which WSTA is 1 in the group (Step S 91 ), and the process proceeds to any of Steps S 86  to S 89 . 
     On the other hand, if the WSTA of the own node is 1, the node  10  routes the packet to the WLAN module (Step S 92 ), and the WLAN unit  147  transmits the packet using the WLAN (Step S 93 ). 
     In this way, to transmit the packet to the outside of the group, the node  10  transmits the packet to the other node  10  having the STA function in the group, and the node  10  having the STA function transmits the packet using the WLAN. Accordingly, the information processing system can reduce the congestion at the AP  3 . 
     As described above, in the third embodiment, the nodes  10  close to each other are grouped, and the node  10  transmits the packet using the 60 G wireless within the same group and transmits the packet using the WLAN to an other group. Accordingly, the node  10  can properly use the 60 G wireless and the WLAN using the group ID, and the information processing system can connect a large number of nodes  10  with each other at high speed in a wireless manner. Herein, twelve nodes  10  close to each other are grouped. Alternatively, the information processing system can group an arbitrary number of nodes  10 . 
     [d] Fourth Embodiment 
     In the first to the third embodiments, it is fixed that which of the 60 G wireless and the WLAN is to be used between the two nodes. However, the wireless module used between the two nodes may be preferably changed to perform communication with efficiency depending on a communication state. In the fourth embodiment, the following describes a case of changing the wireless module used between the two nodes depending on the communication state. 
     First, the following describes a configuration of an XB according to the fourth embodiment.  FIG. 15A  is a diagram illustrating the configuration of the XB according to the fourth embodiment. For convenience of explanation, functional parts same as those illustrated in  FIG. 3A  are denoted by the same reference numerals, and detailed description thereof will not be repeated here. 
     As illustrated in  FIG. 15A , an XB  14   b  includes the host I/F  141 , two routing tables  142   b , a routing unit  143   b , five packet analysis units  144   b , and the five I/Fs  145 . The XB  14   b  also includes the upper unit for 60 G wireless  146   a , the lower unit for 60 G wireless  146   b , the left unit for 60 G wireless  146   c , the right unit for 60 G wireless  146   d , the WLAN unit  147 , the NI register  148 , a timer  149 , and a switching unit  150 . 
     The routing table  142   b  is a retrieval table for retrieving the routing information that indicates the routing destination from the destination of the packet. Unlike the routing table  142 , the routing table  142   b  includes two routing destinations. 
     The routing unit  143   b  receives the packet from the host I/F  141  or the packet analysis unit  144   b , and passes the packet to the host I/F  141  or the I/F  145  based on the information of the NI register  148  and the routing information received from the routing table  142   b . Unlike the routing unit  143 , the routing unit  143   b  starts the timer  149  in routing to measure a packet transfer time. 
     The packet analysis unit  144   b  receives the packet from the I/F  145 , analyzes the packet based on the information of the NI register  148 , and extracts the destination. The packet analysis unit  144   b  passes the extracted destination to the routing table  142   b  and passes the packet to the routing unit  143   b . The packet analysis unit  144   b  stops the timer  149  if the packet is ACK. 
     The timer  149  is a device for measuring the packet transfer time. The timer  149  is started by the routing unit  143   b  to transmit the packet, and stopped by the packet analysis unit  144   b  when the ACK is received. 
     The switching unit  150  compares a timer value with a threshold Tth with reference to the timer  149 . If the timer value is larger than the threshold Tth, the switching unit  150  switches the routing destination to the other wireless module. In this way, the switching unit  150  switches the routing destination to the other wireless module based on the packet transfer time, so that a node  10   f  can properly use the wireless modules depending on the communication state. Herein, the “node  10   f ” represents a node according to the fourth embodiment. 
     Although the XB  14   b  illustrated in  FIG. 15A  includes the 60 G wireless modules and the WLAN unit  147 , the 60 G wireless modules and the WLAN unit  147  may be provided outside the XB. The  FIG. 15B  is a diagram illustrating another configuration of the XB of which the 60 G wireless modules and the WLAN unit  147  are provided outside. 
     As illustrated in  FIG. 15B , an XB  14   c  does not include the upper unit for 60 G wireless  146   a , the lower unit for 60 G wireless  146   b , the left unit for 60 G wireless  146   c , the right unit for 60 G wireless  146   d , and the WLAN unit  147 . The XB  14   c  performs wireless communication using the upper unit for 60 G wireless  10   a , the lower unit for 60 G wireless  10   b , the left unit for 60 G wireless  10   c , the right unit for 60 G wireless  10   d , and the WLAN unit  10   e  provided outside. 
       FIGS. 16A and 16B  are diagrams illustrating an example of the routing table  142   b  according to the fourth embodiment.  FIG. 16A  illustrates the routing table  142   b  of the node in a case of the node arrangement illustrated in  FIG. 4 , and  FIG. 16B  illustrates the routing table  142   b  of the node 2  in a case of the node arrangement illustrated in  FIG. 4 . 
     As illustrated in  FIGS. 16A and 16B , the routing table  142   b  stores therein the destination, two routing destinations, and the routing destination to be used in association with each other. The routing destination to be used indicates that which of the routing destination 1  and the routing destination 2  is to be used, and a value thereof is 1 or 2. 
     For example, as illustrated in  FIG. 16A , the routing destination corresponding to the destination node 2  is the right unit for 60 G wireless  146   d  because the node 2  is arranged on the right of the node 1 , and the routing destination 2  corresponding to the destination node 2  is the WLAN unit  147 . The routing destination to be used is the routing destination 1 . The routing destination corresponding to the destination node 3  is the right unit for 60 G wireless  146   d  because the node 3  is arranged in the right direction of the node 1 , and the routing destination 2  corresponding to the destination node 3  is the WLAN unit  147 . The routing destination to be used is the routing destination 2 . 
     As illustrated in  FIG. 16B , the routing destination and the routing destination 2  corresponding to the destination node 2  are the host, and the routing destination to be used is the routing destination 1 . The routing destination corresponding to the destination node 3  is the right unit for 60 G wireless  146   d  because the node 3  is arranged on the right of the node 2 , and the routing destination 2  corresponding to the destination node 3  is the WLAN unit  147 . The routing destination to be used is the routing destination 1 . 
     In this way, two routing destinations are provided to the routing table  142   b , so that the node  10   f  can transmit the packet with efficiency by properly using the two routing destinations. 
     The following describes the procedure of transmission processing by the node  10   f  according to the fourth embodiment.  FIG. 17  is a flowchart illustrating the procedure of the transmission processing by the node  10   f  according to the fourth embodiment. As illustrated in  FIG. 17 , the node  10   f  performs table retrieval for the destination using the routing table  142   b  (Step S 101 ), and routes the packet to the corresponding wireless module (Step S 102 ). At the same time, the node  10   f  starts the timer  149  (Step S 103 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 104 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 105 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 106 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 107 ). If the routing destination is the WLAN unit  147 , the WLAN unit  147  transmits the packet using the WLAN (Step S 108 ). 
     When receiving the ACK from the node  10   f  as the transmission destination of the packet (Step S 109 ), the node  10   f  stops the timer  149  (Step S 110 ). The node  10   f  then determines whether the timer value is larger than the threshold Tth (Step S 111 ). If the timer value is larger than the threshold Tth, the node  10   f  switches the routing destination of the routing table  142   b  (Step S 112 ). 
     The procedure of the reception processing by the node  10   f  is the same as the procedure of the reception processing by the node  10  illustrated in  FIG. 7 . 
     As described above, in the fourth embodiment, the routing table  142   b  stores therein two routing destinations, and the node  10   f  switches the routing destination if the packet transfer time is larger than the predetermined threshold Tth. Accordingly, the node  10   f  can transmit the packet while avoiding a busy wireless module, so that transmission speed of the packet can be increased. 
     [e] Fifth Embodiment 
     In the second embodiment, described is a case in which the threshold Dth is a fixed value, the threshold Dth being for determining which of the 60 G wireless module and the WLAN wireless module is to be used. However, the threshold Dth may be changed depending on a communication state. In the fifth embodiment, the following describes a case in which the threshold Dth is changed depending on a communication state. The configurations of the rack  1 , the node  10 , and the routing table  142 , and the procedure of the reception processing are the same as those in the second embodiment. The configuration of the XB is the same as that in the fourth embodiment. Herein, the following describes the procedure of the transmission processing by the node  10   f . Note that the NI register  148  stores therein two thresholds Tth1 and Tth2 as thresholds of the timer value. 
       FIG. 18  is a flowchart illustrating the procedure of transmission processing by the node  10   f  according to the fifth embodiment. As illustrated in  FIG. 18 , the node  10   f  performs table retrieval for the destination using the routing table  142  (Step S 121 ), and acquires the routing destination and the distance D. The node  10   f  then determines whether D is larger than Dth (Step S 122 ). If D is not larger than Dth, the node  10   f  determines whether D is equal to Dth (Step S 123 ). If D is equal to Dth, the node  10   f  routes the packet to the corresponding wireless module (Step S 124 ), and starts the timer  149  (Step S 125 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 126 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 127 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 128 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 129 ). 
     When receiving ACK from the node  10   f  as the transmission destination of the packet (Step S 130 ), the node  10   f  stops the timer  149  (Step S 131 ). The node  10   f  then determines whether the timer value is larger than the threshold Tth1 (Step S 132 ). If the timer value is larger than the threshold Tth1, which is a case in which the 60 G wireless communication is busy, the node  10   f  decrements the threshold Dth by 1 (Step S 133 ). On the other hand, if the timer value is not larger than the threshold Tth1, the node  10   f  determines whether the timer value is smaller than the threshold Tth2 (Step S 134 ). If the timer value is smaller than the threshold Tth2, which is a case in which the 60 G wireless communication is not busy, the node  10   f  increments the threshold Dth by 1 (Step S 135 ). 
     On the other hand, if D is not equal to Dth (No at Step S 123 ), the node  10   f  routes the packet to the corresponding wireless module (Step S 136 ). 
     If the routing destination is the upper unit for 60 G wireless  146   a , the upper unit for 60 G wireless  146   a  transmits the packet using the 60 G wireless (Step S 137 ). If the routing destination is the lower unit for 60 G wireless  146   b , the lower unit for 60 G wireless  146   b  transmits the packet using the 60 G wireless (Step S 138 ). 
     If the routing destination is the left unit for 60 G wireless  146   c , the left unit for 60 G wireless  146   c  transmits the packet using the 60 G wireless (Step S 139 ). If the routing destination is the right unit for 60 G wireless  146   d , the right unit for 60 G wireless  146   d  transmits the packet using the 60 G wireless (Step S 140 ). The node  10   f  then ends the transmission processing. 
     On the other hand, if the D is larger than Dth, the node  10   f  routes the packet to the WLAN module (Step S 141 ), and the WLAN unit  147  transmits the packet using the WLAN (Step S 142 ). 
     As described above, in the fifth embodiment, the node  10   f  changes the threshold Dth based on the packet transfer time. Accordingly, the node  10   f  can properly use the 60 G wireless and the WLAN depending on a change in the communication state. 
     [f] Sixth Embodiment 
     In the first to the fifth embodiments, described is a case of using four 60 G wireless modules. Alternatively, only one 60 G wireless module may be used to communicate with the upper, lower, left, and right nodes. The following describes a case of communicating with the upper, lower, left, and right nodes by using only one 60 G wireless module. 
       FIG. 19  is a diagram illustrating the configuration of the information processing system according to a sixth embodiment. For convenience of explanation, functional parts same as those illustrated in  FIG. 1  are denoted by the same reference numerals, and detailed description thereof will not be repeated here. As illustrated in  FIG. 19 , the information processing system is a highly integrated server including the NW switch  2 , the AP  3 , and ninety-nine nodes  20  mounted in a rack  5 . Unlike the node  10 , the node  20  includes a 60 G wireless module  6  outside the housing. 
     The 60 G wireless module  6  transmits radio waves to any one of the upper, lower, left, and right nodes  20  by using beam-forming. Herein, the beam-forming means that radio waves are narrowly emitted only in a specified direction. 
     In this way, the information processing system according to the sixth embodiment can reduce the number of 60 G wireless modules by including the 60 G wireless module  6  outside the housing and using the beam-forming. 
     In the first to the sixth embodiments, described is the case in which the XB is implemented in hardware. Alternatively, by implementing a routing function of the XB with software, a communication program having the same function can be obtained. The following describes a hardware configuration of the XB that executes the communication program. 
       FIG. 20  is a diagram illustrating the hardware configuration of the XB that executes the communication program. As illustrated in  FIG. 20 , an XB  14   d  includes the host I/F  141 , the five I/Fs  145 , a micro processing unit (MPU)  151 , a flash memory  152 , and a random access memory (RAM)  153 . 
     The host I/F  141  is an interface with the CPU  11  of its own node. The host I/F  141  passes the packet received from the CPU  11  to the MPU  151 , and passes the packet received from the MPU  151  to the CPU  11  of the own node. The I/F  145  converts a signal received from the 60 G wireless module or the WLAN module into a packet, and passes the packet to the MPU  151 . The I/F  145  also converts the packet received from the MPU  151  into a signal and passes the signal to the 60 G wireless module or the WLAN module connected thereto. 
     The MPU  151  is a processing unit that reads and executes the communication program from the flash memory  152 . The flash memory  152  is a nonvolatile memory that stores therein the communication program. The flash memory  152  also stores therein information in the routing table  142  and information in the NI register  148 . The RAM  153  is a memory that stores therein a table or a result in the midway obtained in the execution of the computer program. The information in the routing table  142  and the information in the NI register  148  are read out from the flash memory  152  to be written to the RAM  153  when the communication program is executed. 
     In the first to sixth embodiments, described is a case of using the WLAN and the 60 G wireless that uses the frequency of 60 GHz band. However, the present invention is not limited to the 60 G wireless and the WLAN, and may also be applied to a case of appropriately combining two types of wireless module or wired communication of which the communication speed and range where radio waves reach are different. 
     According to an aspect of an embodiment, a large number of information processing devices can be connected with each other at high speed in a wireless manner. 
     All examples and conditional language recited herein are intended for pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.