Abstract:
There is provided with an access management apparatus which connects a communication network to a local area network and which manages access from the communication network to the local area network, the access management apparatus including: a packet receiver which receives a packet according to TCP or UDP from the communication network; a database storage unit which stores a database having a port number of the TCP or UDP in association with a MAC address; a MAC address detector which detects a MAC address associated with a destination port number in the packet received by the packet receiver, from the database; a start-up request packet generator which generates a start-up request packet to start up a terminal device having the detected MAC address on the local area network; and an output unit which outputs the generated start-up request packet to the local area network.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of priority under 35USC § 119 to Japanese Patent Application No. 2004-268274, filed on Sep. 15, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an access management apparatus and a program used to start-up a terminal device, such as a personal computer or a network electric home appliance, disposed, for example, in a house from a distant place via a communication network such as Internet, and relates to a remote start-up method of a terminal device used to start-up the terminal device from a distant place.  
         [0004]     2. Related Art  
         [0005]     Various methods of accessing a terminal device, such as a personal computer or a network electric home appliance, disposed in a house from a distant place via the Internet and making the terminal device execute various services have been proposed.  
         [0006]     As a paper describing a method of setting a terminal device to a standby mode in order to hold down the power dissipation in the terminal device waiting in a house and starting up the terminal device when a Wake On signal is input, there is, for example, Japanese Patent Application Laid-Open Publication No. 2003-319083.  
         [0007]     According to Japanese Patent Application Laid-Open Publication No. 2003-319083, an access management apparatus disposed in a house accepts specification of a name of a terminal device to be started up, from an external requesting terminal (start-up requesting terminal). The access management apparatus in the house specifies a MAC address associated with the name received from the requesting terminal, and transmits a Wake On signal to the terminal device having the MAC address. As a result, the terminal device is started up.  
         [0008]     In this method, however, there is a procedure that an external requesting terminal specifies a terminal device to be started up to the access management apparatus in the house. Because of this procedure, work of newly adding a code to communication software using an existing protocol becomes necessary in the requesting terminal and the access management apparatus in the house.  
         [0009]     Port forwarding setting to a home router function included in the access management apparatus in the house is conducted by using association of port numbers with IP addresses. If IP addresses of terminal devices are fixed, it takes plenty of time and labor to manage IP addresses of respective terminal devices. On the other hand, if a terminal device in a house is dynamically provided with an IP address, when the IP address is provide, the terminal device needs to notify a home router function of an IP address and the home router function needs to set port forwarding, resulting in a complicated system.  
       SUMMARY OF THE INVENTION  
       [0010]     According to a first aspect of the present invention, there is provided with an access management apparatus which connects a communication network to a local area network and which manages access from the communication network to the local area network, the access management apparatus comprising: a packet receiver which receives a packet according to TCP or UDP from the communication network; a database storage unit which stores a database having a port number of the TCP or UDP in association with a MAC address; a MAC address detector which detects a MAC address associated with a destination port number in the packet received by the packet receiver, from the database; a start-up request packet generator which generates a start-up request packet to start up a terminal device having the detected MAC address on the local area network; and an output unit which outputs the generated start-up request packet to the local area network.  
         [0011]     According to a second aspect of the present invention, there is provided with a program for inducing an access management device which connects a communication network to a local area network and which manages access from the communication network to the local area network, to execute: a packet receiving step which receives a packet according to TCP or UDP from the communication network; a MAC address detecting step which detects a MAC address associated with a destination port number in the received packet, from a database having a port number of the TCP or UDP in association with a MAC address; a start-up request packet generating step which generates a start-up request packet to start-up a terminal device having the detected MAC address on the local area network; and an outputting step which outputs the generated start-up request packet to the local area network.  
         [0012]     According to a third aspect of the present invention, there is provided with a remote start-up method that is used in an access management device which connects a communication network to a local area network and which manages access from the communication network to the local area network, comprising: receiving a packet according to TCP or UDP from the communication network; detecting a MAC address associated with a destination port number in the received packet, from a database having a port number of the TCP or UDP in association with a MAC address; generating a start-up request packet to start-up a terminal device having the detected MAC address on the local area network; and outputting the generated start-up request packet to the local area network. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a diagram showing an illustrative example of a system being capable of performing a remote start-up method of a terminal device according to the present invention;  
         [0014]      FIG. 2  is a block diagram schematically showing a configuration of a home router;  
         [0015]      FIG. 3  is a diagram showing an example of a DHCP management table;  
         [0016]      FIG. 4  is a diagram showing an example of an expanded NAT management table;  
         [0017]      FIG. 5  is a block diagram showing a configuration example of a portion of a terminal device concerning automatic start-up; and  
         [0018]      FIG. 6  is a flow chart showing an operation example of a home router. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Hereafter, embodiments of the present invention will be described with reference to the drawings.  
         [0020]      FIG. 1  is a diagram showing an illustrative example of a system being capable of performing a remote start-up method of a terminal device according to the present invention.  
         [0021]     A requesting terminal  150 , such as a cellular phone, carried by a user can be connected to Internet  140  serving as a communication network via a cellular phone packet network  180  and a gateway  160  of a telephone company that manages a cellular phone packet network.  
         [0022]     A requesting terminal  170 , such as a personal computer or a PDA, disposed in a company, a hot spot (a street corner Internet), an Internet cafe or the like can be connected to the Internet  140  directly or via an ISP (Internet Service Provider).  
         [0023]     In a user&#39;s house, a home router  120  is installed to connect the Internet  140  and a LAN  130  disposed in the user&#39;s house to each other. The home router  120  is adapted to communicate with terminal devices  100  and  110  such as a personal computer or a network electric home appliance via the LAN  130 .  
         [0024]      FIG. 2  is a block diagram schematically showing a configuration of the home router  120 .  
         [0025]     The home router  120  includes a LAN side network interface  210  for connection to the LAN  130 , and an Internet side network interface  220  for connection to the Internet  140 . A table storage unit  230  stores a DHCP management table, an expanded NAT table, and an ARP table. A control unit  240  conducts packet transfer processing, setting of the DHCP management table and the expanded NAT table, and various kinds of processing described later (including a process shown in  FIG. 6 ).  
         [0026]     In the Internet side network interface  220 , the home router  120  is always connected to the Internet  140  via, for example, an ADSL line or an optical fiber line. The home router  120  had a global IP address used in the Internet  140 . The global IP address may be a fixed IP address previously assigned by the ISP or the like, or may be a dynamic IP address provided by the ISP or the like according to the DHCP or PPPOE each time connection to the Internet  140  is conducted. The requesting terminals  150  and  170  can acquire an IP address of the home router  120  on the basis of a name of the home router  120  by using the DNS if the IP address is a fixed IP address and using the dynamic DNS if the IP address is a dynamic IP address.  
         [0027]     The control unit  240  in the home router  120  has a function of serving as a DCHP server. In other words, the home router  120  provides a terminal device connected to the LAN  130  with service as the DHCP server. In providing this service, the home router  120  uses the DHCP management table shown in  FIG. 3 . The DHCP management table manages association of the IP address with the MAC address. In addition, the DHCP management table also manages a lease term (validity term) of the IP address assigned to the terminal device. Since an operation procedure of the DHCP is well known, its detailed description will be omitted.  
         [0028]     In addition, the control unit  240  in the home router  120  also has a function of serving as a UPnP-IGD (Internet Gateway Device). Owing to this function, the home router  120  can set IP port forwarding on the basis of a message according to the UPnP-IGD protocol sent from the terminal device  100  or the terminal device  110 . More particularly, upon receiving an IP port forwarding setting request according to the UPnP-IGD protocol from the terminal device  100  or  110 , the home router  120  writes an IP address, a port number, and a classification of the TCP (Transmission Control Protocol) or the UDP (User Datagram Protocol) into the expanded NAT management table shown in  FIG. 4 . According to this IP port forwarding setting, the home router  120  can conduct IP port forwarding of a packet received from the Internet  140 , for a specific terminal device on the basis of a destination port number of the packet. It should be observed that the IP port forwarding setting using the UPnP-IGD is an example, and another scheme as described later may be used.  
         [0029]     The expanded NAT management table manages the port number and the MAC address so as to associate them with each other. Association of the port number with the MAC address is previously set by user input. The association of the port number with the MAC address may be set at time of the IP port forwarding setting conducted by the UPnP-IGD or the like. In other words, the home router  120  refers to the ARP table (information of association of the IP address with the MAC address) retained in the table storage unit  230 , detects a MAC address associated with an IP address registered in the expanded NAT management, and adds the detected MAC address to the expanded NAT management table. As a result, the home router  120  manages association of the port number with the MAC address. Here, the MAC address is detected by using the ARP table. However, the MAC address may be detected by using the DHCP management table.  
         [0030]      FIG. 5  is a block diagram showing a configuration example of a portion of the terminal device  100  concerning automatic start-up.  
         [0031]     The terminal device  100  includes a LAN board  102  having a remote power throw-in (Wakeup on LAN which is hereafter referred to as WoL) function, and a motherboard  101  associated with the WoL function.  
         [0032]     Upon receiving a Wake On signal (WakeOn packet) such as a magic packet (registered trade mark) from the LAN  130 , the LAN board  102  outputs a Power On signal to the motherboard  101 . Upon receiving the Power On signal, the mother board  101  outputs a power on signal to a power supply  103 . As heretofore described, automatic power throw-in is implemented.  
         [0033]     However, automatic power throw-in using a magic packet is an example, and another scheme may be used. Furthermore, the motherboard  101  may have the function of the LAN board including the WoL function.  
         [0034]     Heretofore, the configuration of the portion concerning the automatic start-up of the terminal device  100  has been described. A portion concerning automatic start-up of the other terminal device  110  can be also made in the same way.  
         [0035]     Hereafter, operation of the system shown in  FIG. 1  will be described by taking the case where the requesting terminal  150  accesses the terminal device  100  in the user&#39;s house as one example.  
         [0036]      FIG. 6  is a flow chart showing an operation example of the home router  120  in the present system.  
         [0037]     First, the requesting terminal  150  transmits a packet including a certain destination port number toward the home router  120 . As for the port number, for example, a number to be used is predetermined, or the port number is previously stored in the requesting terminal  150 . It is possible that the user can set the port number for the terminal  100  or  110  in the requesting terminal  150  and in the case, the contents of the setting may be rendered to be reflected in the home router  120 . A packet transmitted from the requesting terminal  150  is received by the home router  120  via the cellular phone packet network  180 , the gateway  160 , and the Internet  140  (step S 11 ).  
         [0038]     Upon receiving the packet, the home router  120  checks whether or not an IP address associated with the destination port number contained in the packet is registered in the expanded NAT management table (step S 12 ).  
         [0039]     In the case where the IP address is registered (YES at the step S 12 ), the home router  120  transmits the packet to a target terminal device (step S 20 ). At this time, the home router  120  rewrites a destination IP address and a destination port number in the packet by using a NAT function. The destination IP address obtained after the rewriting is an IP address registered in the expanded NAT management table. The destination port number obtained after the rewriting is previously set in the home router in association with the port number included in the expanded NAT table. Since the NAT function is well known technique, description of details thereof will be omitted.  
         [0040]     In the case where the IP address is not registered (NO at the step S 12 ), the home router  120  refers to the expanded NAT management table (see  FIG. 4 ), and determines whether the destination port number contained in the packet is already registered in the expanded NAT management table. If the destination port number is already registered, the home router  120  determines whether a MAC address is registered for the destination port number, i.e., determines whether the MAC port forwarding has already been set (step S 13 ). If the MAC port forwarding setting is not conducted yet (NO at the step S 13 ), the home router  120  returns, for example, an error message to the requesting terminal  150  (step S 14 ).  
         [0041]     If the MAC port forwarding is set (YES at the step S 13 ), the home router  120  gets a MAC address associated with the port number from the expanded NAT management table (step S 15 ).  
         [0042]     And the home router  120  generates a WoL packet to be sent to a device having the MAC address (here, the terminal device  100 ), and sends the generated WoL packet to the terminal device  100  (step S 16 ). The home router  120  may detect an operational situation of the terminal device  100 , and send the WoL packet only when the terminal device  100  is in standby situation. For example, the home router  120  may record final time of access to the port number, and if receiving time of the packet containing the port number is within a fixed time from the final access time, the home router  120  may regard the device as being in the active state and omit the sending of the WoL packet. Furthermore, when coming in the standby state, the device may throw a secession message “byebye” of the UPnP so as to make it possible for the home router  120  to grasp the state (the active state or the standby state) of the device and omit sending of WoL when the device is in the active state.  
         [0043]     Upon receiving the WoL packet, the terminal device  100  comes in the active state (is automatically started up). The started up terminal device  100  sends a message (IP address acquisition request) according to the DHCP to the home router  120 , and attempts to acquire an IP address.  
         [0044]     Upon receiving an IP address acquisition request from the terminal device  100  (step S 17 ), the home router  120  refers to the DHCP management table (see  FIG. 3 ), specifies an available IP address, and provides the terminal device  100  with the specified IP address (step S 18 ).  
         [0045]     Upon providing the IP address, the home router  120  registers the IP address in the NAT management table (see  FIG. 4 ) in association with a MAC address of the terminal device  100  (or the port number for the terminal device  100 ), and thereby sets the IP port forwarding (step S 19 ). If a setting request of an IP port forwarding based on the UPnP-IGD is sent from a terminal device connected to the LAN  130 , the home router  120  may set IP port forwarding in accordance with the request.  
         [0046]     Upon setting the IP port forwarding, the home router  120  transmits the packet received from the requesting terminal  150  earlier, to the terminal device  100  (step S 20 ). At this time, the home router  120  rewrites a destination IP address and a destination port number in the received packet by using a NAT function. The destination IP address obtained after the rewriting is an IP address registered in the expanded NAT management table. The destination port number obtained after the rewriting is previously set in the home router in association with the port number included in the expanded NAT table. Since the NAT function is well known technique, description of details thereof will be omitted.  
         [0047]     The home router  120  that registered the IP address in the step S 19 , may check whether or not the terminal device  100  is present on the LAN  130 , periodically by using the ICMP (Internet Control Message Protocol) or the like. The home router  120  may erase the IP address assigned to the terminal device  100  from the expanded NAT table in the case where the terminal device is not present on the LAN  130 .  
         [0048]     The home router  120  may erase the IP address assigned to the terminal device  100  from the expanded NAT table in the case where the lease term of the IP address (see  FIG. 3 ) has expired.  
         [0049]     The home router  120  may erase the IP address assigned to the terminal device  100  from the expanded NAT table in the case of receiving the secession massage from the terminal device  100 .  
         [0050]     While an example of access to the terminal device  100  has been described heretofore, access to the terminal device  110  can be also conducted in the same way. Furthermore, while an example of access from the requesting terminal  150  has been described heretofore, access from the requesting terminal  170  can be also conducted in the same way.  
         [0051]     Furthermore, the home router  120  may permit access only from a requesting terminal having a specific IP address, and reject access from a requesting terminal having other IP address.  
         [0052]     Upon detecting port scan from the Internet  140 , the home router  120  may specify a transmission source IP address of the home scan as an IP address for which access is rejected.  
         [0053]     The function of the home router  120  may be implemented by using a program, or may be implemented by using hardware. The program may be hold in a data carrier.  
         [0054]     According to the present embodiment, a table that associates the destination port number with the MAC address is prepared in the home router as heretofore described. If a packet containing a destination port number is received, the home router sends a WoL packet to a terminal device having a MAC address associated with the destination port number. Therefore, the terminal device to be accessed can be automatically started up without adding a new function to the requesting terminal.  
         [0055]     Furthermore, according to the present embodiment, the port number is associated with the MAC address in the home router. When the home router provides a terminal device with an IP address, it becomes possible to set IP port forwarding to the terminal device. In other words, even if a terminal device in a house acquires an IP address dynamically according to the DHCP, it becomes possible to conduct automatic setting of IP port forwarding in the home router without using the function such as UPnP-IGD.