JP3960607B2 - Relay device, message transmission method, and message transmission program - Google Patents

Description

  The present invention relates to a relay device that relays communication between a communication device and another communication device. In particular, the present invention relates to a relay device that monitors the status of communication devices connected to the relay device and notifies other communication devices.

  The spread of communication equipment in accordance with the UPnP (Universal Plug and Play) technology that provides information between communication devices connected to the network and the ECHONET (R) standard defined for the purpose of controlling home appliances and equipment Expected. When such a technique is used, the communication device can be automatically connected to the network.

On the other hand, when these communication devices connected to a certain network leave, if the communication partner is notified in advance that they are leaving, they can leave without any problem. However, portable communication devices and the like are often used while moving, and the network at the connection destination must be changed for each movement destination. In particular, when radio is used as a communication medium, a situation in which the user is disconnected from the currently connected network may not be predicted in advance. The device in communication with this communication device waits for a predetermined time until there is a response if there is a disconnection due to such a sudden disconnection or power-off due to movement, and if there is still no response (timeout) from the network It was judged that it has left (see Patent Document 1).
JP 2000-82053 A

  When checking the existence of any communication device from a remote location via a network, it is common to use a method for checking the existence of a communication device based on a timeout, but this method always sends a confirmation signal to the device to be checked. However, the existence of a response to the confirmation signal is judged to be alive. Therefore, when it is desired to quickly grasp the disconnection, it is necessary to frequently transmit this confirmation signal. However, if the number of confirmation signal exchanges not related to the original communication increases, the burden on the device to be confirmed for processing this increases, and the network bandwidth is wasted.

  In addition, if the waiting time for determining timeout is shortened, the time for determining disconnection is shortened, but conversely, there is a high risk that it is determined that the communication device that is slow in response but disconnected is in a normal state. .

  The present invention has been made in view of the above-described problems, and promptly performs a survival check performed by another communication device on a communication device disconnected from the network without using a detection means such as a timeout. Objective.

With the relay device according to the present invention,
"The packet received from the first communication device received from the first communication port, a transfer means for transferring via the second communication port to the destination to which the received packet is shown, the first communication port status Monitoring means for determining the state of the first communication device from the monitoring result of the monitoring means, and the determination means determines that the first communication device is in a state incapable of communication. A notification registration receiving unit that receives from the first communication device a notification registration packet that includes a notification destination address of the communication device that should be notified in this case and a notification message to be notified, and is included in the notification registration packet A notification registration storing means for storing a notification address and a notification message in association with at least one of the first port and the first communication device; and the determination means. When it is determined that the first communication device is in a state where communication is not possible, the notification registration storage unit stores the information in association with at least one of the first communication port and the first communication device. A notification unit that acquires a notification destination address and the notification message and generates a notification packet including the notification message, and the notification packet generated by the generation unit via the second communication port A relay device comprising a transmission means for transmitting to a destination communication device. "
Is provided.

If the message transmission method according to the present invention is implemented,
“A message transmission method in a relay apparatus that transfers a received packet from a first communication device received from a first communication port to a transmission destination indicated by the received packet via a second communication port,” The state of the first communication device is monitored, the state of the first communication device is determined from the monitoring result, and if it is determined by the determination that the first communication device is in a state where communication is not possible, that effect A notification registration packet including a notification destination address of a communication device to be notified of and a notification message to be notified is received from the first communication device, and a notification address and a notification message included in the notification registration packet are received from the first communication device. 1 port or at least one of the first communication device and stored, and it is determined by the determination that the first communication device is in a communication disabled state. A notification packet including the notification destination address and the notification message stored in association with at least one of the first communication port and the first communication device, and the generated notification packet And a transmission device that transmits to the destination communication device indicated by the notification packet via the second communication port ”.

  A program for realizing the relay device according to the present invention is also provided.

  It is possible to speed up the survival confirmation process for communication devices disconnected from the network.

  FIG. 1 shows an example of a relay system according to the present invention. FIG. 1 shows a mobile PC 101, a server 102, a network 103, and a relay device 104.

  The mobile PC 101 is a portable terminal that can be easily moved, and is connected to the network 103 via the relay device 104. The mobile PC 101 and the relay device 104 are connected by wire or wireless. In this embodiment, for example, Ethernet (R) can be considered as long as it is wired, but it is not limited to this. If it is wireless, it can be realized even with a communication medium such as wireless LAN such as 802.11a / b / g, Bluetooth (TM) effective for near field communication, or IrDA which is an infrared communication standard.

  The server 102 has a function of communicating with the mobile PC 101 and providing a predetermined service. For example, any file server capable of storing / reading electronic files via a network, a mail server, a home banking server, and the like can be considered.

  The network 103 is a network in which the server 102 and the relay device 104 are connected. The network 103 may be configured by any network regardless of wired or wireless.

  The relay device 104 has a function of relaying communication between the mobile PC 101 and the network 103. If the relay device 104 is a concentrator such as a hub or an access point, for example, the relay device 104 has a function of collecting communication packets of the mobile PC 101 and flowing them to the network 103. Alternatively, it may have a router function for transferring communication packets between networks, or may be a device having at least a function for transferring communication packets, such as a bridge, firewall, or gateway.

  FIG. 2 is a diagram illustrating an example of a block configuration of the relay device 104 as a preferred embodiment of the present invention. FIG. 2 shows a monitoring-side communication processing unit 201, a connection monitoring unit 202, a transfer unit 203, a communication processing unit 204, a message receiving unit 205, a message storage unit 206, and a message generation unit 207.

The monitoring-side communication processing unit 201 has a function of connecting to a communication device such as the mobile PC 101 connected to the relay device 104. When the monitoring communication processing unit 201 receives a packet from a communication device such as the mobile PC 101, the monitoring communication processing unit 201 passes the packet to the transfer unit 203. Conversely, when a packet is received via the transfer unit 203, the packet is transmitted to the mobile PC 101. The monitoring-side communication processing unit 201 is a part to which a communication device such as the mobile PC 101 is directly connected, and acquires the connection state of the device from the exchange of the physical layer and data link layer of the connected communication device in the OSI reference model. It also has a function.

  The connection monitoring unit 202 acquires the connection status of a communication device such as the mobile PC 101 from the monitoring side communication processing unit 201. The connection status indicates, for example, whether the communication device is connected to a wired network, whether it is connected to the relay device 104 with a LAN cable, etc., and if it is a wireless network, whether it is within the reach of radio waves. . If it is determined that there is no communication device as a result of the determination, the message creation unit 207 is notified of that fact. The transfer unit 203 determines the content of the packet received from the monitoring communication processing unit 201 and passes the packet to the communication processing unit 204 if the mobile PC 101 transmits it to another communication device. The data is transferred to the unit 205.

  The communication processing unit 204 has a function of connecting to the network 103. For example, when a communication packet transmitted by the mobile PC 101 is received via the transfer unit 203, this packet is transmitted to the network 103 side. Conversely, when a communication packet destined for the mobile PC 101 is received from the network 103 side, it is transferred to the transfer unit 203.

  The message receiving unit 205 has a function of processing packets other than the communication packet to be transferred that are transferred from the transfer unit 203 and extracting predetermined information. The information extracted here is stored in the next message storage unit 206.

  The message storage unit 206 has a function of storing information extracted by the message reception unit 205. The stored information is read in response to a request from the message creation unit 207.

  When the message creation unit 207 receives a notification from the connection monitoring unit 202 that a communication device no longer exists, the message creation unit 207 acquires information corresponding to the communication device stored in the message storage unit 206, and the communication device exists. Create a message telling you not to. The created message acquires the address of the transmission destination from the information stored in the message storage unit 206, and is transmitted to the communication device of the transmission destination via the communication processing unit 204.

  FIG. 3 shows an example of the contents of a notification registration packet transmitted by a communication device such as the mobile PC 101. The notification registration packet is transferred to the transfer unit 203 via the monitoring side communication processing unit 201. When the transfer unit 203 determines that this packet is a notification registration packet, the transfer unit 203 transfers the packet to the message reception unit 205. Then, the message receiving unit 205 extracts necessary information from the content of the notification registration packet and stores it in the message storage unit 206. The notification registration packet is information transmitted by the relay device 104 to, for example, the communication partner of the communication device that has transmitted the notification registration packet when the communication device such as the mobile PC 101 is disconnected from the network to which the communication device is currently connected, for example, the network 103. Is a packet containing

The notification registration packet includes fields of a transmission destination address 301, a setting parameter 302, a notification destination address 303, and a notification message 304. The transmission destination address 301 is an address indicating the transmission destination of this notification registration packet. In the relay system according to the present invention, when this packet is used as a notification registration packet, a special address different from the generally used address system is described. When the relay device 104 itself has a fixed address in the network, it can be designated as a transmission destination address. For example, a hub or an access point may not have an address.

  However, since the relay device 104 directly receives and forwards the packet of the communication device that transmits the notification registration packet, in practice, any value of the transmission destination address is described as a problem for other communications. Don't be. This is because even if the address is a problem if it is transmitted over the network 103, a specific address that cannot be used for normal communication is determined, and when this address is transmitted from the communication device, the packet is relayed to the network 103 side. First, it may be determined that the packet is a notification registration packet.

  The setting parameter 302 is for performing additional setting at the same time as registering information of the notification registration packet in the relay apparatus 104. For example, it is conceivable to set the number of transmissions when a notification packet that informs that a certain communication device does not exist is repeatedly transmitted.

  The notification destination address 303 indicates a transmission destination of a notification packet to be transmitted when it is determined that the communication monitoring unit 202 is disconnected for a certain communication device. Normally, it seems that the address of the communication partner of the communication device that sent the notification registration packet is generally described, but if there is another communication device responsible for disconnection processing from the connected network It is also conceivable that the address of this other communication device is described.

  The notification message 304 stores a message described in the notification packet. The communication device to which this message is delivered by the notification packet should be able to recognize that at least the communication device that has registered this message has become unable to communicate. As long as the above object can be achieved, any message may be described.

  FIG. 4 is a diagram showing an example of a processing flow when a packet is received from a communication device such as the mobile PC 101 of the relay device 104 according to the present invention.

  First, the connection monitoring unit 202 determines whether there is a communication device to be monitored by the relay device 104 by checking whether the information of the communication device to be monitored is stored in the message storage unit 206 (step 401). If there is no communication device to be monitored, it is next determined whether or not a packet has been received from the mobile PC 101 (step 402). If there is no received packet, one process is terminated.

  If a packet has been received, the transfer unit 203 determines whether the destination address 301 of the packet received by the monitoring communication processing unit 201 is a special address (step 403). If not addressed to a special address, this packet is transmitted to the network 103 via the communication processing unit 204 (step 404). On the other hand, if a special address is described in the transmission address 301, it is determined that this packet is a notification registration packet (step 403), and the sending notification destination address 303 and the notification message 304 are extracted to the message receiving unit 205. . At this time, various settings are made based on the value of the setting parameter 302 if necessary. The extracted notification destination address and notification message are sent to the message storage unit 206 and stored as information of the notification message of the communication device that transmitted the notification registration packet (step 405). This processing flow is performed for each communication device that has transmitted the notification registration packet, or for each port to which the communication device is connected when there are a plurality of connection ports.

When there is a communication device being monitored in the previous step 401, it is determined from the information of the notification message stored in the message storage unit 206 whether or not each communication device to be monitored is connected (step 406). When making a determination, in the case of a wired network, for example, it is possible to determine the presence of a communication device connected to the port by measuring the voltage of the physical layer applied to the connection port included in the relay device 104 and the flowing current. For wireless networks,
For example, if information up to the data link layer is acquired, it can be determined whether or not any communication device exists. In any case, it is possible to quickly confirm existence by using a method of detecting in lower layers such as the physical layer and the data link layer rather than the network layer used in the survival confirmation of the timeout method. In order to confirm the presence in the lower layer as described here, it is necessary to make a determination with a communication device closer to the monitored communication device such as the relay device according to the present invention.

  If it is determined in step 406 that the connection is established, the flow returns to the flow when monitoring is not performed, and the processing is continued from step 402.

  When it is determined in step 406 that the connection has been disconnected, the connection monitoring unit 202 notifies the message creating unit 207 to create a notification packet based on the message information stored in the message storage unit 206 for the determined communication device. Receiving this notification, the message creation unit 207 transmits the generated notification packet via the communication processing unit 204 (step 407). The transmission destination of the notification packet at this time is the communication device indicated by the notification destination address 303 stored together with the notification message 304 used to create the notification packet.

  When the notification packet is transmitted, since it is not necessary to monitor the communication device confirmed to be disconnected, the subsequent monitoring is stopped (step 408).

  When configured as described above, a communication device that performs a survival check must make a determination based on a timeout using the network layer in order to check the existence of any communication device. The existence of the relay device can be confirmed by judging the state of the physical layer and the data link layer. Therefore, it is possible to reduce the time required for the survival confirmation and further suppress the increase in the load of the communication device and the network traffic due to the frequent survival confirmation. In addition, by sending a notification message indicating that the communication has been disconnected, it is possible to notify the communication partner that the communication partner has already disconnected from the network after disconnection from the network, and to properly process the end of communication. .

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is a figure which shows an example of the relay system concerning this invention. It is a figure which shows an example of the block configuration of the relay apparatus concerning this invention. It is a figure which shows an example of the notification registration packet of the relay apparatus concerning this invention. It is a figure which shows an example of a processing flow when a packet is received from the monitoring object communication apparatus of the relay apparatus concerning this invention.

Explanation of symbols

101: Mobile PC
102: Server 103: Network 104: Relay device 202: Connection monitoring unit 205: Message reception unit 206: Message storage unit 207: Message creation unit

Claims (8)

Transfer means for transferring a received packet from the first communication device received from the first communication port to a transmission destination indicated by the received packet via the second communication port;
Monitoring means for monitoring the state of the first communication port;
Determination means for determining a state of the first communication device from a monitoring result of the monitoring means;
A notification registration packet including a notification destination address of a communication device to be notified to that effect and a notification message to be notified when it is determined by the determination means that the first communication device is in a communication disabled state, Notification registration receiving means for receiving from the first communication device;
A notification registration storage means for storing a notification address and a notification message included in the notification registration packet in association with at least one of the first port and the first communication device;
When the determination unit determines that the first communication device is in a state where communication is impossible, the notification registration storage unit associates the first communication device with at least one of the first communication port and the first communication device. Creating means for acquiring the stored notification destination address and the notification message and creating a notification packet including them;
A relay apparatus comprising: a transmission unit configured to transmit the notification packet generated by the generation unit to a destination communication device indicated by the notification packet via the second communication port .   The relay apparatus according to claim 1, wherein the monitoring unit monitors a state of a signal level obtained from the first communication port. In the destination address as the transmission destination of the notification registration packet, a special address different from the address given to a normal communication device connected to the network is described,
The notification registration receiving means, a relay device according to claim 1, wherein the receiving receives a packet having the special address to the destination address the packet as the notification registration packet. A message transmission method in a relay device for transferring a received packet from a first communication device received from a first communication port to a transmission destination indicated by the received packet via a second communication port,
Monitoring the state of the first communication port;
Judging the status of the first communication device from the monitoring result,
When it is determined by the determination that the first communication device is in a communication disabled state, a notification registration packet including a notification destination address of a communication device to be notified to that effect and a notification message to be notified 1 from the communication device,
Storing a notification address and a notification message included in the notification registration packet in association with at least one of the first port and the first communication device;
The notification destination address stored in association with at least one of the first communication port and the first communication device when the determination determines that the first communication device is in a state where communication is impossible. Creating a notification packet including the notification message;
The message transmission method, wherein the created notification packet is transmitted to a destination communication device indicated by the notification packet via the second communication port . 5. The message transmission method according to claim 4 , wherein the monitoring is to monitor a state of a signal level obtained from the first communication port. A program for transmitting a message in a relay device that transfers a received packet from a first communication device received from a first communication port to a transmission destination indicated by the received packet via a second communication port,
Monitoring the state of the first communication port;
Determining a state of the first communication device from the monitoring result;
When it is determined by the determination that the first communication device is in a communication disabled state, a notification registration packet including a notification destination address of a communication device to be notified to that effect and a notification message to be notified A notification registration reception step received from one communication device;
Storing a notification address and a notification message included in the notification registration packet in association with at least one of the first port and the first communication device;
The notification destination address stored in association with at least one of the first communication port and the first communication device when the determination determines that the first communication device is in a state where communication is impossible. Creating a notification packet including the notification message;
Transmitting the created notification packet to the destination communication device indicated by the notification packet via the second communication port . The message transmission program according to claim 6 , wherein the monitoring step monitors a state of a signal level obtained from the first communication port. Wherein the destination to become the destination address of the notification registration packet describes a different special address to the address applied to the connected normal communication equipment to the network,
The notification registration receiving step, to claim 7, further comprising the step of checking whether a packet having the special address as the destination address to determine whether to receive as the notification registration packet The message sending program described.

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