JP2009171401A - Node management apparatus, node, node management method, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accomplish a specification, in simple configuration, allowing only a device connected to a predetermined port of a predetermined hub to perform particular operation. <P>SOLUTION: A USB-compliant [number-of-steps] data field DF1 for storing the number of steps stores the number of steps to be stored originally and port numbers indicating ports connected to nodes in a route hub. Namely, in the [number-of-steps] data field DF1 of (n) bits, the number of steps indicating the depth of layers connected for a node is stored in low-order (k) bits ((k) is an integer of <(n)) and the port numbers of ports connected to the relevant node in the route hub are stored in a portion other than the low-order (k) bits. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for managing a node hierarchically connected to a root hub, and a technique for the node.

  One interface for connecting peripheral devices to a personal computer is the USB (Universal Serial Bus) standard. According to USB, it is possible to add a maximum of 127 devices in a tree shape, that is, hierarchically, by providing a hub to the host controller.

  Hubs and equipment are called “nodes”. The host controller manages the topology (connection form) of the nodes by providing management information therein. As a specific example, as shown in Patent Document 1, the management is performed by grasping the number of stages indicating the depth of the hierarchy in addition to the address assigned when the node is connected. The host controller notifies the node of the address and notifies the number of stages as necessary.

Japanese Patent Laid-Open No. 2002-7307

  The root hub of the host controller is provided with two or more ports. In recent years, depending on the peripheral device, there is a case in which a special operation is performed when connected to a predetermined specific port among the two or more ports. Since it is not possible to easily recognize to which port of the root hub the peripheral device is connected only by managing the number of stages and addresses, a great deal of design changes are required to achieve a configuration that satisfies the above specifications. There is a problem that the configuration is complicated. The design change may be a circuit change such as providing a dedicated endpoint for the node, or a software change such as a review of internal management information and a new notification of internal management information. The configuration is complicated.

  The present invention has been made in order to solve at least a part of the above-described conventional problems, and has a simple configuration with a specification in which only a device connected to a predetermined port of a predetermined hub performs a special operation. It aims to be realized.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A node management device comprising a root hub of a predetermined interface and managing nodes hierarchically connected to the root hub,
A memory for storing management information;
In the first data field of n bits (n is an integer) included in the management information, information indicating the depth of the connection hierarchy for the node is stored in the lower k bits (k is an integer smaller than n). First information storage means for
Second information for storing information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node in at least a part of the first data field excluding the lower k bits. A node management device comprising storage means.

  According to the node management device of the application example 1, the first data field for storing information indicating the depth of the connection hierarchy for the node, together with the information indicating the depth of the hierarchy to be originally stored, Information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node can be stored. For this reason, it is possible to manage information indicating a port connected to the node in a predetermined hub, which is a connection source of the node, in a form compliant with a predetermined interface standard.

  Therefore, according to the node management apparatus of the application example 1, since it is possible to easily recognize which port of a predetermined hub located in a hierarchy higher than the node, the predetermined hub is connected to the predetermined hub. It is possible to realize a specification in which only a node connected to a predetermined port provided has a special operation with a simple configuration.

[Application Example 2]
The node management apparatus according to Application Example 1, wherein the predetermined hub is the root hub. According to this configuration, a specification in which only a node connected to a predetermined port provided in the root hub performs a special operation can be realized with a simple configuration.

[Application Example 3]
The node management apparatus according to Application Example 1 or 2, further comprising a third information storage unit that stores an assigned address for the node in a second data field included in the management information. According to this configuration, an address assigned to each node can also be obtained as one piece of management information.

[Application Example 4]
4. The node management apparatus according to any one of application examples 1 to 3, further comprising a notification unit that collectively notifies the node of information stored in the first data field. According to this configuration, it is possible to notify the node of information stored in the first data field in conformity with USB.

[Application Example 5]
A node that receives information notified from a node management device that manages nodes hierarchically connected to a root hub of a predetermined interface,
Of the first data field of n bits (n is an integer) for storing information indicating the depth of the connection hierarchy for the node that constitutes the information, the lower k bits (k is smaller than n) Information extracting means for extracting information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node from at least a part of a portion excluding the integer);
A node comprising operation restriction means for restricting the operation of the node based on the information extracted by the information extraction means.

  According to the node of the application example 5, it is possible to easily limit the operation of a node connected to a predetermined port provided in a predetermined hub located in a hierarchy higher than the node.

[Application Example 6]
A node management method for storing management information in a memory and managing nodes hierarchically connected to a root hub of a predetermined interface,
In the first data field of n bits (n is an integer) included in the management information, information indicating the depth of the connection hierarchy for the node is stored in the lower k bits (k is an integer smaller than n). A first step of:
A second step of storing information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node in at least a part of the first data field excluding the lower k bits; A node management method comprising:

[Application Example 7]
In a computer comprising a root hub of a predetermined interface and a memory, a computer program for managing nodes hierarchically connected to the root hub,
In the first data field of n bits (n is an integer) included in the management information, information indicating the depth of the connection hierarchy for the node is stored in the lower k bits (k is an integer smaller than n). A first function to
A second function of storing information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node in at least a part of the first data field excluding the lower k bits. And a computer program for causing the computer to realize the above.

  According to the node management method of the application example 6 and the computer program of the application example 7, as in the node management apparatus of the application example 1, the node is connected to any port of a predetermined hub located in the hierarchy above the node. Therefore, it is possible to realize a specification in which only a node connected to a predetermined port provided in the predetermined hub performs a special operation with a simple configuration.

[Application Example 8]
The computer program according to Application Example 7, wherein the computer program further realizes a third function of collectively notifying the node of information stored in the first data field.

[Application Example 9]
A computer program for executing in a node that receives information notified from a node management device that manages nodes hierarchically connected to a root hub of a predetermined interface,
Of the first data field of n bits (n is an integer) for storing information indicating the depth of the connection hierarchy for the node that constitutes the information, the lower k bits (k is smaller than n) A function of extracting information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node from at least a part of a portion excluding the integer);
A computer program that causes the node to realize a function of restricting an operation in the node based on the extracted information.

  According to the computer program for the node of application example 9, as with the node of application example 5, the operation for the node connected to the predetermined port provided in the predetermined hub located above the node is performed. Can be easily limited.

  The present invention can be realized in various application examples or forms other than those described above. For example, various types of apparatuses (for example, a node management apparatus and a system including a node that are application examples, and various apparatuses (for example, a node management apparatus that is an application example) It can be realized in the form of a projector.

  Hereinafter, a node management device, a node, a node management method, and a computer program according to the present invention will be described based on embodiments with reference to the drawings.

1. Hardware configuration:
FIG. 1 is an explanatory diagram showing a schematic configuration of a projector system as an embodiment of the present invention. As shown in the figure, a projector system 1 includes a projector 10 and five peripheral devices connected to the projector 10, that is, a first peripheral device (hereinafter referred to as “device A”) 21, a second peripheral device. A device (hereinafter referred to as “device B”) 22, a third peripheral device (hereinafter referred to as “device C”) 23, a fourth peripheral device (hereinafter referred to as “device D”) 24, and a fifth Peripheral device (hereinafter referred to as “device E”) 25. The projector 10 and the devices A21 to E25 are connected using a USB interface. Specifically, by providing the hub (concentrator) 30, the devices A21 to E25 are connected to the projector 10 in a tree shape, that is, hierarchically.

  The projector 10 is a device that displays an image or video by projecting it on a large screen or the like. The projector 10 corresponds to a node management device according to the present invention. The devices A21 to E25 are a keyboard, a mouse, a monitor, a storage device, and a communication device. The devices A21 to E25 may be devices other than these, that is, devices equipped with USB. The devices A21 to E25 correspond to nodes according to the present invention.

  FIG. 2 is a block diagram showing an electrical configuration of the projector system. The projector 10 includes a CPU 11, a memory 12, a host controller 14, a root hub 16 and the like inside. The CPU 11 is a central processing unit. The memory 12 stores various data, various programs, and the like, and serves as a work area for the CPU 11. The host controller 14 is a USB interface unit. The root hub 16 is a connection portion of the first USB hub and is integrated with the host controller 14. In the present embodiment, the root hub 16 includes three ports 16a, 16b, and 16c. The CPU 11, the memory 12 and the host controller 14 are mutually connected by a bus 17.

  In addition, two USB connectors 18 a and 18 b are provided on the rear surface of the projector 10, and one USB connector 18 c is provided on the side surface of the projector 10. The first port 16a of the root hub 16 is connected to the USB connector 18a, the second port 16b of the root hub 16 is connected to the USB connector 18b, and the third port 16c of the root hub 16 is connected to the USB connector 18c. The first port 16a has a port number of 1, the second port 16b has a port number of 2, and the third port 16c has a port number of 3.

  A hub 30 is connected to one USB connector 18 a provided on the rear surface of the projector 10. Specifically, the USB cable 18 is connected between the USB connector 18 a and the up port (input-side USB connector) 32 of the hub 30.

  The hub 30 includes four down ports (output-side USB connectors) 34a, 34b, 34c, and 34d. The device A21 is connected to the first down port 34a via the USB cable 42, the device B22 is connected to the second down port 34b via the USB cable 43, and the USB cable is connected to the third down port 34c. The device C23 is connected via the terminal 44. The fourth down port 34d is in an empty state.

  On the other hand, the device D24 is connected to the other USB connector 18b provided on the rear surface of the projector 10 via the USB cable 45. The device E25 is connected to the USB connector 18c provided on the side surface of the projector 10 via the USB cable 46.

  As a result of the connection described above, the root hub is provided in the 0th stage where the number of stages indicating the depth of the hierarchy is 0, and the hub 30, the device D24, and the equipment E25 are provided in the 1st stage where the number of stages is 1. Thus, the topology in which the device A21, the device B22, and the device C23 are provided in the second stage having two stages is constructed. The constructed topology is merely an example, and is appropriately designed according to the contents of the system to be realized. The hub 30 and the devices A21 to E25 are hereinafter referred to as “nodes” as necessary. Further, the projector 10 is referred to as “host” or “computer” as necessary.

2. Configuration of internal management information:
The memory 12 provided in the projector 10 stores internal management information MN indicating the topology (see FIG. 2).

  FIG. 3 is an explanatory diagram conceptually showing the internal management information MN. The internal management information MN is tabular data, and includes a unit of data set (hereinafter referred to as “record”) for each node. Each record R1 to R6 has a [number of stages] data field DF1 for storing the number of stages indicating the depth of the connection hierarchy for the corresponding node, and an [address] data field DF2 for storing the address of the corresponding node. Etc.

  [Number of stages] The data field DF1 has a size of 8 bits, the number of stages is stored in the lower 4 bits, and the upper 4 bits are connected to the corresponding node in the root hub 16 (here, “connected” is directly connected) Port number indicating the port) including the case where the connection is made and the case where the connection is made indirectly through the hub. It should be noted that the division between the part storing the number of stages and the part storing the port number need not be limited to the above, and any classification is possible as long as the number of stages and the port number can be stored respectively. Good. In USB, since the hub subordinate connection is limited to 5 stages, the number of stages may be 3 bits in binary notation. For this reason, a configuration in which the number of stages is stored in the lower 3 bits and the port number is stored in the upper 5 bits can be taken as an example. Further, it is not always necessary to use the entire 8 bits, and the number of stages may be stored in the lower 3 bits, and the port number may be stored in the 4 bits from the second to the fifth from the top. Note that the part where the number of stages is stored needs to be right-justified. The data structure of the internal management information MN including the [Stage] data field DF1 is originally compliant with the USB standard, and in this embodiment, the [Stage] data field DF1 defined by the standard is used. This is because of

  In other words, the [stage number] data field DF1 is, in other words, n (n is an integer) = 8 and k (k is an integer smaller than n) = 4, and the lower k bits of the n-stage [stage number] data field DF1. The number of stages is stored, and the port number is stored in at least a part of the portion excluding the lower k bits. N and k can be any values as long as the number of stages and the port number can be stored.

  [Address] data field DF2 has a size of 7 bits and stores the address of the node. The address is unique in the system assigned when the node is connected.

  The internal management information MN configured as described above is updated to contents representing the topology after the connection every time a new node is connected to the projector 10. The processing at the time of new node connection including the update of the internal management information MN will be described in detail below.

3. Processing by the host driver:
FIG. 4 is a flowchart showing enumeration processing executed when a node is connected. This enumeration process is a process executed by the CPU 11 in accordance with the host driver HD (see FIG. 2) stored in the memory 12 in advance. When a new device (equipment) is connected to the hub port by the operator, the hub detects the connection of the device and waits for communication from the host controller 14. When the process is started, the CPU 11 infiltrates the device by instructing the hub to open the port to which the device is connected (step S10).

  Next, the CPU 11 requests a device descriptor from the device and acquires the device descriptor (step S20). Subsequently, a unique address is assigned to the device in the projector system 1 (step S30), and related class drivers and others are relied on based on information of the address device descriptor (class code, VID / PID, etc.). The client driver is loaded (step S40). Thereafter, the internal management information MN is updated based on the address assigned in step S30 (step S50), and the enumeration process is temporarily terminated. As a result, the new device can be used.

  FIG. 5 is a flowchart showing details of the internal management information update process executed in step S50. When the processing shifts to this update processing, the CPU 11 first performs processing for obtaining the port number and the number of stages of the port connected to the newly connected node in the root hub 16 (step S52). Since the above enumeration process is repeated every time a new node including a hub is connected, the projector (host) 10 is connected to which port of which node the new node is already connected to. I understand. This form of connection is stored in accordance with the USB and in accordance with parameters included in the internal management information MN. In step S52, the port number and the number of stages are obtained based on this parameter.

  Next, the CPU 11 adds one record to the internal management information MN (step S53). Subsequently, the CPU 11 writes (stores) the port number obtained in step S52 in the upper 4 bits of the [stage number] data field DF1 provided in the one record (step S56), and [stage number] data. The number of stages obtained in step S52 is written (stored) in the lower 4 bits of field DF1 (step S58).

  After executing step S58, the CPU 11 advances the process to step S59, and writes (stores) the address assigned in step S30 in the [address] data field DF2 provided in one record added in step S53. Thereafter, the process returns to “Return” to end the internal management information update process.

  The process in step S58 corresponds to “first information storage unit” included in the node management apparatus of the present invention. The process of step S56 corresponds to a “second information storage unit” included in the node management apparatus of the present invention. Note that the execution order of step S56 and step S58 need not be limited to this order, and may be executed in the reverse order. Further, the process of step S59 may be executed at any timing as long as it is after step S54.

  Note that enumeration is executed not only when the node is connected, but also when the node is removed. In the enumeration at the time of node removal, the internal management information is updated so as to delete information about the node and information about a node located downstream of the node.

  The value of each [number of stages] data field DF2 illustrated in FIG. 3 corresponds to the topology shown in FIG. That is, since the hub 30 is the first-stage node connected to the port having the port number 1 in the root hub 16, the value of the [stage number] data field DF2 included in the record R1 corresponding to the hub 30 is a binary number. The notation is “00010001” and the hexadecimal notation is “11”. Since the device A is the second-stage node connected to the port having the port number 1 in the root hub 16, the value of the [Stage] data field DF2 included in the record R2 corresponding to the device A is expressed in binary notation. “00010010” and “12” in hexadecimal notation. Similarly, in the devices B and C, the value of the [Stage] data field DF2 included in the records R3 and R4 corresponding to the hub 30 is “00010010” in binary notation and “12” in hexadecimal notation.

  Since the device D is the first-stage node connected to the port having the port number 2 in the root hub 16, the value of the [Stage] data field DF2 included in the record R5 corresponding to the device D24 is expressed in binary notation. “00100001” and “21” in hexadecimal notation. Since the device E25 is a first-stage node connected to the port having the port number 3 in the root hub 16, the value of the [Stage] data field DF2 included in the record R6 corresponding to the device E25 is expressed in binary notation. “00110001” and “31” in hexadecimal notation.

  The value of the [stage number] data field DF2 constituting at least a part of the internal management information MN is notified from the host 10 to the corresponding node at an appropriate time in a form compliant with USB. This notification is transmitted in units of packets.

  FIG. 6 is an explanatory diagram showing an example of a packet notified from the host 10 to the node. The first packet PK1 is for specifying an end point in a destination node, and includes an [address] data field DF11 and an [end point] data field DF12. [Address] data field DF11 stores the value of [Address] data field DF2 of internal management information MN. [Endpoint] data field DF12 stores an endpoint number.

  The second packet PK2 includes a [number of stages] data field DF13 and the like. The value of the [stage number] data field DF1 of the internal management information MN is stored in the [stage number] data field DF13. A plurality of packets including the first and second packets PK2 are reduced by one in the value of the [SYNC] data field DF10. In the form of this set of kets, the host controller 14 of the projector 10 transmits the value of the [stage number] data field DF2 of the internal management information MN.

4). Processing by device driver:
The hub 30 and the devices A21 to A25 as nodes described above include a microcomputer having a CPU and a memory. A program for controlling the operation of the node (hereinafter referred to as “device driver”) is stored in advance in the memory, and the CPU executes control processing according to the device driver.

  FIG. 7 is a flowchart showing a control process according to the device driver. As shown in the figure, when the process is started, the CPU of the node receives the above-described set of packets sent from the host controller 14 (step S100). The host controller 14 issues a packet by broadcast, and the node selectively receives the data by determining that it is addressed to the node by the value of the [address] data field DF11 included in the first packet PK1.

  Next, the CPU of the node determines whether or not the value of the [stage number] data field DF1 included in the packet received in step S100 is “30” or more in hexadecimal notation and “3F” or less in hexadecimal notation. Determination is made (step S110). This condition is satisfied when the node is connected to the port having the port number 3 of the root hub 16, that is, directly to the USB connector 18 c provided on the side surface of the projector 10 or indirectly through the hub. Is connected to. In other words, in step S110, the node determines whether the port number of the root hub 16 is connected to the port of 3. If it is determined that the value of the [Stage] data field DF1 is “30” or more and “3F” or less, the process proceeds to step S120 to execute a predetermined process to be performed by the node. To do. When the execution of the process is finished, the process returns to “RETURN” to end this routine.

  On the other hand, if the value of the [number of stages] data field DF1 is less than “30” or greater than “3F” in step S110, the predetermined process is executed assuming that the value is “NG”. Without (step S130), the process returns to “RETURN” and the routine is terminated.

5. Example effect:
As described above, according to the projector system 1 of the present embodiment, the port connected to the node in the root hub 16 together with the number of stages to be originally stored in the [stage number] data field DF1 for storing the number of stages conforming to USB. Can be stored. For this reason, the port number of the port connected to the node in the root hub which is the connection source of the node can be managed by the internal management information MN in a form compliant with USB.

  Therefore, according to the projector system 1, it is easy to determine which port the node is connected to in the root hub 16 in a USB-compliant manner, that is, without making a circuit change such as providing a dedicated end point. Can be recognized. In particular, in this embodiment, since the device E25 connected to the USB connector 18c on the side surface of the projector 10 connected to the third port (port number = 3) 16c of the root hub 16 can be recognized, only this device E25 is recognized. Thus, it is possible to realize a specification that allows the operation to be performed with a simple configuration.

6). Variations of the embodiment:
In the above-described embodiment, the configuration is such that the node connected to the root hub 16 is managed by the [stage] data field DF1, but instead the node is a predetermined hub, that is, a hierarchy above the node. It is good also as a structure which manages which port of the predetermined | prescribed hub located in is connected. That is, in the topology described in the above embodiment (see FIG. 2), it may be configured to manage which device A, device B, or device C is connected to 34a, 34b, 34c, or 34d of the hub 30.

  Specifically, in the [number of stages] data field DF1 described in the first embodiment, the number of stages is stored in the lower 4 bits, and the port number indicating the port connected to the node in the hub 30 is stored in the upper 4 bits. The configuration is stored. That is, the [number of stages] data field has a size of n (n is an integer) bits, and the number of stages is stored in the lower k bits (k is an integer smaller than n) in the [stage number] data field, and the lower k bits are A port number connected to the node in the hub 30 located in a hierarchy above the node is stored in at least a part of the excluded portion.

  According to this modification, nodes connected directly to a predetermined hub other than the root hub or indirectly through the hub can be easily recognized in a form compliant with USB. Therefore, when a node is connected to a predetermined port provided in a predetermined hub other than the root hub, a configuration in which only the node performs a special operation can be easily realized.

7). Other embodiments:
(1) In the above embodiment and modification, when a node is connected to a specific port of the root hub or a predetermined hub, only that node executes a predetermined operation and the node is connected to another port. In some cases, the operation is configured not to be executed. However, it is not always necessary to select between execution and non-execution, and when connected to the specific port, the first operation is executed. The configuration may be such that the second operation is executed when connected to another port. The relationship between the first operation and the second operation may be a completely different operation, or a part of the functions may be limited. The function restriction may be applied to either the first operation or the second operation.

(2) In the above-described embodiments and modifications, the interface between the host and the node is USB, but it can be applied to HDMI (High-Definition Multimedia Interface) or the like instead. In short, it can be applied to any interface that can construct a hierarchical topology. For example, it can be replaced with a star-type interface such as 10BASE-T or 100BASE-TX.

(3) In the above embodiments and modifications, the host including the root hub is configured as a projector. However, instead of the projector, the host may be configured as various devices such as a printer, a personal computer, a display device, and a video device.

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

It is explanatory drawing which shows schematic structure of the projector system as one Example of this invention. It is a block diagram which shows the electrical structure of a projector system. It is explanatory drawing which shows the internal management information MN notionally. It is a flowchart which shows the process of enumeration performed at the time of node connection. It is a flowchart which shows the detail of the update process of internal management information. It is explanatory drawing which shows an example of the packet notified with respect to a node from a host. It is a flowchart which shows the control processing according to a device driver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector system 10 ... Projector 11 ... CPU
DESCRIPTION OF SYMBOLS 12 ... Memory 14 ... Host controller 16 ... Root hub 16a ... 1st port 16b ... 2nd port 16c ... 3rd port 16c ... 3rd port 17 ... Bus 21 ... Device A
22 ... Device B
23 ... Device C
24 ... Device D
25 ... Equipment E
30 ... hub 32 ... up port 34a ... first down port 34b ... second down port 34c ... third down port 34d ... fourth down port DF1 ... [stage number] data field DF2 ... [address] data field HD ... Host driver MN ... Internal management information

Claims (9)

A node management device comprising a root hub of a predetermined interface and managing nodes hierarchically connected to the root hub,
A memory for storing management information;
In the first data field of n bits (n is an integer) included in the management information, information indicating the depth of the connection hierarchy for the node is stored in the lower k bits (k is an integer smaller than n). First information storage means for
Second information for storing information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node in at least a part of the first data field excluding the lower k bits. A node management device comprising storage means. The node management device according to claim 1,
The node management apparatus, wherein the predetermined hub is the root hub. The node management device according to claim 1 or 2,
A node management device comprising third information storage means for storing an assigned address for the node in a second data field of the management information. The node management device according to any one of claims 1 to 3,
A node management device comprising notification means for collectively notifying information stored in the first data field to the node. A node that receives information notified from a node management device that manages nodes hierarchically connected to a root hub of a predetermined interface,
Of the first data field of n bits (n is an integer) for storing information indicating the depth of the connection hierarchy for the node that constitutes the information, the lower k bits (k is smaller than n) Information extracting means for extracting information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node from at least a part of a portion excluding the integer);
A node comprising operation restriction means for restricting the operation of the node based on the information extracted by the information extraction means. A node management method for storing management information in a memory and managing nodes hierarchically connected to a root hub of a predetermined interface,
In the first data field of n bits (n is an integer) included in the management information, information indicating the depth of the connection hierarchy for the node is stored in the lower k bits (k is an integer smaller than n). A first step of:
A second step of storing information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node in at least a part of the first data field excluding the lower k bits; A node management method comprising: In a computer comprising a root hub of a predetermined interface and a memory, a computer program for managing nodes hierarchically connected to the root hub,
In the first data field of n bits (n is an integer) included in the management information, information indicating the depth of the connection hierarchy for the node is stored in the lower k bits (k is an integer smaller than n). A first function to
A second function of storing information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node in at least a part of the first data field excluding the lower k bits. And a computer program for causing the computer to realize the above. A computer program according to claim 7,
A computer program for causing a computer to further realize a third function of collectively notifying the node of information stored in the first data field. A computer program for executing in a node that receives information notified from a node management device that manages nodes hierarchically connected to a root hub of a predetermined interface,
Of the first data field of n bits (n is an integer) for storing information indicating the depth of the connection hierarchy for the node that constitutes the information, the lower k bits (k is smaller than n) A function of extracting information indicating a port connected to the node in a predetermined hub located in a hierarchy above the node from at least a part of a portion excluding the integer);
A computer program that causes the node to realize a function of restricting an operation in the node based on the extracted information.

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