Patent Application
20080092187
An embodiment as the best mode to carry out the present invention will be described in detail below based on drawings.
(1) Entire Configuration of CATV System 1
As shown in
The CATV center 100 is provided with a network management unit 110 and a broadcasting service management unit 120 (i.e. headend). The network management unit 110 and the broadcasting service management unit 120 are connected to the CATV network N1 via a mixer 130.
The network management unit 110 is provided with a management device 10, a DHCP server 20, a router 30 and a cable modem termination system (CMTS) 40. The management device 10, the DHCP server 20, the router 30 and the CMTS 40 are connected to one another via a hub 50.
The management device 10 includes a well-known computer system. More specifically, the management device 10 is provided with a control unit 11, a memory unit 12 and a transmission unit 13 (see
The control unit 11 includes a well-known CPU, a well-known main memory device (e.g. ROM, RAM) and a well-known peripheral circuitry (e.g. I/O). The control unit 11 executes various processes in accordance with various programs stored in the memory unit 12.
The memory unit 12 includes a well-known secondary memory device (e.g. a hard disk drive). Programs are preinstalled in the memory unit 12. One of the programs is for the control unit 11 to gather relevant information about the set top box 200. In the present embodiment, a SNMP (Simple Network Management Protocol) manager is preinstalled in the memory unit 12 as the program to gather the relevant information. Specifically, the relevant information in the present embodiment refers to a history of channels selected by a TV set 300, which will be hereinafter described, via the set top box 200, a signal level of selected channels, quality information about a SN ratio or a bit error rate of selected channels, and status information indicating a version of a software (a firmware) of the set top box 200.
The transmission unit 13 includes a well-known transmission interface.
The DHCP server 20 is a well-known DHCP server. The DHCP server 20 assigns an IP address to each device on the CATV network N1 in accordance with DHCP (Dynamic Host Configuration Protocol).
The router 30 is a well-known router. The router 30 is connected to the network management unit 110 and an internet N2. The router 30 allows two-way communication between the network management unit 110 and the internet N2.
The CMTS 40 is a well-known CMTS. The CMTS 40 is connected to the network management unit 110 and the CATV network N1. The CMTS 40 allows two-way communication between the network management unit 110 and the CATV network N1 via the mixer 130.
The set top box 200 is integrally provided with a cable modem (CM) unit 210 and a set top box (STB) unit 220. The cable modem unit 210 and the set top box unit 220 are connected to one another.
The cable modem unit 210 is connected to the CATV center 100 via the CATV network N1 in addition to the set top box unit 220. The cable modem unit 210 functions as a so-called bridge, and relays the CATV network N1 and the set top box unit 220 at the level of the data link layer of the OSI (Open System Interconnection) reference model.
More specifically, the cable modem unit 210 is provided with a control unit 211 and a memory unit 212 (see
The control unit 211 includes a well-known CPU, a well-known peripheral circuitry and a well-known transmission interface. The control unit 211 executes various processes in accordance with various programs stored in the memory unit 212.
The memory unit 212 includes a well-known main memory device. The memory unit 212 stores a database (MIB: Management Information Base in the present embodiment) where various information is registered, a program (SNMP agent in the present embodiment) for the control unit 211 to perform notification or change of information registered in the database according to a command from outside, and a program for the control unit 211 to set up an IP address, which is assigned to the cable modem 210 by the DHCP server 20, in the memory unit 12.
The set top box unit 220 is connected to a TV set 300 in addition to the cable modem unit 210.
More specifically, the set top box unit 220 is provided with a control unit 221 and a memory unit 222 (See
The control unit 221 includes a well-known CPU, a well-known peripheral circuitry and a well-known transmission interface. The control unit 221 executes various processes in accordance with various programs stored in the memory unit 222.
The memory unit 222 includes a well-known main memory device. The memory unit 222 stores a database (MIB in the present embodiment) where the relevant information is registered, a program (SNMP agent in the present embodiment) for the control unit 211 to perform notification or change of the relevant information registered in the database according to a command from outside, and a program for the control unit 221 to set up an IP address, which is assigned to the set top box unit 220 by the DHCP server 20 in the memory unit 222.
(2) Process of Monitoring Address
With reference to
The control unit 211 waits until the control unit 211 receives send data (packet) from the set top box unit 220 (S10: NO). More specifically, the control unit 211 determines whether or not the control unit 211 receives the send data including unique MAC (Media Access Control) address of the set top box unit 220.
When the control unit 221 receives the send data from the set top box unit 220 (S10: YES), the control unit 221 extracts an IP address within header information of the send data as a source of the send data (S20).
Then, the control unit 211 stores the extracted IP address in the memory unit 212 as an IP address of the set top box unit 220 (S30).
The control unit 211 monitors the address of the set top box unit 220 by repeating the above processes of S10 to S30.
(3) Process of Gathering the Relevant Information
With reference to
The control unit 11 of the management device 10 sends a command for requesting the relevant information stored in the set top box unit 220 to the cable modem unit 210 (S110) when a timing (e.g. a preset time or a timing for the operator to perform operation) for gathering the relevant information comes. The control unit 11 of the management device 10 waits until the control unit 11 receives a response to the command from the cable modem unit 210 (S120: NO). At S110, the control unit 11 sends the above command to the IP address of the cable modem unit 210 (which is assigned by the DHCP server 20) that is managed by the CATV center 100. More specifically, as the above command, the control unit 11 sends SNMP request (Get-Request) specifying an ID (Object ID) of the relevant information in the MIB, which is stored in the set top box unit 220.
When the control unit 211 of the cable modem unit 210 receives the command from the management device 10 (S210), the control unit 211 sends a command for requesting the relevant information to the set top box unit 220 connected to the cable modem unit 210 (S220) and waits until the control unit 211 receives a response to the command from the set top box unit 220 (S230: NO). At S220, if the ID specified by the SNMP request from the management device 10 is not one of the IDs in the MIB of the cable modem unit 210, the control unit 211 sends the SNMP request specifying the ID to the IP address of the cable modem unit 220 as a request to the above command.
When the control unit 221 of the set top box unit 220 receives the command from the cable modem unit 210 (S310), based on the command, the control unit 221 retrieves the relevant information from the MIB stored in the memory unit 222 of the set top box unit 220 (S320) and sends the relevant information to the cable modem unit 210 as the response to the cable modem unit 210 (S330). At S320 and S330, the control unit 221 retrieves the relevant information from the MIB in the memory unit 222 based on the ID assigned by the SNMP request from the cable modem unit 210 and sends the relevant information to the IP address of the cable modem unit 210 as a SNMP response (Get-Response).
When the control unit 211 of the cable modem 210 receives the response from the set top box unit 220 (S230: YES), the control unit 211 extracts the relevant information from the response (S240) and sends the relevant information to the management device 10 (S260). At S230 to S250, the control unit 211 receives the response to the IP address of the cable modem unit 210 and extracts the relevant information included in the response. Then, the control unit 211 sends the relevant information to the IP address of the management device 10 as the SNMP response.
When the control unit 11 of the management device 10 receives the response from the cable modem unit 210 (S120: YES), the control unit 11 extracts the relevant information from the response (S130) and executes a process to manage the relevant information (S140). At S140, the control unit 11 performs a process for compiling the relevant information and the like after storing the relevant information in the predetermined memory area of the memory unit 12 of the management device 10.
(4) Operation and Effect of the CATV System 1
As discussed above, in the CATV system 1, the cable modem unit 210 requests the set top box unit 220 to send relevant information about the set top box unit 220 by proxy for the management device 10. Thereby, there is only need for the management device 10 to manage (ascertain) the IP address of the cable modem unit 210, and no need for the management device 10 to verify the IP address of the set top box unit 220 when the management device 10 requests for sending the relevant information.
Also, in this CATV system 1, the cable modem unit 210 monitors the IP address of the set top box 220 and requests for the relevant information to the IP address indicated by the monitoring result. Thereby, the cable modem unit 210 can surely request the set top box unit 220 for the relevant information even though the IP address of the set top box unit 220 is changed.
Therefore, the CATV system 1 can surely request the set top box unit 220 to send the relevant information without increasing processing load of the management device 10.
The cable modem unit 210 extracts the IP address of the set top box unit 220 provided to the send data each time the cable modem unit 210 receives the send data from the set top box unit 220, and thereby the cable modem unit 210 can identify the IP address of the set top box unit 220 each time the cable modem unit 210 receives the send data from the set top box unit 220.
Moreover, in the CATV system 1, the cable modem unit 210 receives the relevant information from the set top box unit 220 by proxy for the management device 10 and sends the relevant information to the management device 10. Thereby, the management device 10 can gather the relevant information without increasing processing load of the management device 10.
In addition, in the CATV system 1, the cable modem unit 210 is integrated with the set top box unit 220, and the connection between the cable modem unit 210 and the set top box unit 220 is fixed. The cable modem unit 210 monitors only the send data including the MAC address of the set top box unit 220.
Therefore, in the CATV system 1, the cable modem unit 210 can be prohibited mismonitoring an address of a device other than the address of the set top box.
(1) Entire Structure of CATV System 2
A CATV system 2 is the CATV system 1 in the first embodiment with modification in some parts.
Therefore, in here, only structural and processing differences between the CATV system 1 and the CATV system 2 will be explained in detail, while the same numeral will be used for the same structures and processes, and the explanation for the same structures and processes will be abbreviated.
As shown in
And, each cable modem 210 is connected to a plurality of set top box units 220 via an intermediary device 400 such as a hub and a router.
The number of the set top box units 220 connected to the cable modem unit 210 and identification numbers to specify these set top box units 220 are prestored in the memory unit 212 of the cable modem unit 210.
(2) Process of Gathering the Relevant Information
As shown in
(3) Operation and Effect of CATV System 2
In the CATV system 2, the management device 10 can obtain the relevant information about all the set top box units 220 without managing the IP addresses of all the set top box units 220 connected to the cable modem unit 210 as long as the management device 10 manages (ascertains) the IP address of the cable modem unit 210.
The cable modem unit 210 may regularly monitor whether or not the cable modem unit 210 can perform transmission with each set top box unit 220 connected to the cable modem unit 210, and request for the relevant information only to the transmissionable set top box unit 220.
3. Modification
Although the embodiments of the present invention have been described above, this invention is not limited to the first and the second embodiments discussed above. It will be obvious that this invention can take various forms without departing from the scope of this invention.
For example, in the first and the second embodiments, the relevant information refers to the status information about the set top box 200 (or the TV set 300). However, the relevant information may include information other than the status information.
Moreover, in the first and the second embodiments, the addressee of the relevant information of the set top box unit 220 is set to the cable modem unit 210. However, the addressee may be set to other than the cable modem unit 210. In this case, the management device 10 may gather the relevant information from the addressees other than the cable modem unit 210.
In the first and second embodiments, the CATV system 1 is provided with only one management device 10, but the CATV system 1 may be provided with a plurality of the management devices 10.
Additionally, in the first and the second embodiments, the CPUs are the components of the control unit 11 of the management device 10, the control unit 211 of the cable modem unit 210 and the control unit 221 of the set top box unit 220. However, an ASIC (Application Specific Integrated Circuit) or a Programmable Logic Device (e.g. FPGA) and the like, for example, can be components for those units instead of the CPUs.
