JP2011044923A - Method for automatically setting transmission range of multicast packet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processing apparatus capable of reducing the load of a user to determine a transmission range and more reliably transmitting data to the intended transmission range when transmitting the data to devices on a network. <P>SOLUTION: The method actively and automatically determines the transmission range of the multicast packet according to other devices connected with the network without the user's setting the transmission range of the multicast packet. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information processing apparatus capable of communicating with a device on a network and a communication method with a network device.

  Conventionally, a user inputs a TTL value when data is multicast.

  Therefore, if the TTL value is smaller than the required value, data will not reach the desired device, and if it is larger than the required value, data will be transmitted to more devices than necessary. It will be.

  As described above, it is inconvenient for the user to input the value of TTL because it is burdensome for the user and there is a possibility that the input is wrong.

  Furthermore, even if the user sets an appropriate TTL value, if a new device that should send a multicast is added to the current TTL value range, the user must change the TTL value each time. Don't be.

JP 2001-086158 A

  Therefore, when transmitting data to a device on the network, the present invention reduces the load on the user for determining the transmission range or data, and enables data transmission to a desired transmission range or more reliably. An object of the present invention is to provide an information processing apparatus.

  In order to achieve the above object, when the information processing apparatus of the present invention detects that there is a device or service that the multicast is desired to reach on the network, the TTL value for the multicast packet to reach the device or service. As a result, if a TTL larger than the currently set TTL value is required, the TTL calculated this time is changed as a multicast transmission TTL.

  According to the present invention, when data is transmitted to a device on the network, the load on the user for determining the transmission range or transmission destination is reduced, and data is more reliably transmitted to the desired transmission range or transmission destination. Can be sent.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

It is the figure which showed the structure of the network system in a present Example. FIG. 2 is a block diagram illustrating a hardware configuration of a printer according to the present exemplary embodiment. It is an example of a sequence in a present Example. It is a flowchart in a present Example. It is an example of a screen setting in a present Example. It is a figure which shows the structure of a TCP / IP packet.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a network system in the present embodiment.

  In FIG. 1, reference numeral 101 denotes a network device, which is an image processing apparatus such as a printer, a copier, a fax machine, a scanner, or a multifunction machine, or an information processing apparatus such as a personal computer. Reference numerals 102, 104, 105, 107, 108, and 109 are information processing apparatuses such as personal computers, which are systems that receive multicast packets in this embodiment. In this embodiment, a case where a printer is used as a device will be described as an example. Reference numerals 103 and 106 denote routers as connection devices for connecting the sub-networks. These devices are connected to a network and can communicate with each other. The network communication protocol can be realized by an arbitrary protocol such as TCP / IP, Network, Appletalk, etc. In this embodiment, network communication using the TCP / IP protocol will be described as an example.

  The network configuration example in FIG. 1 is configured by three sub-networks connected by a router 103 and a router 106. Hereinafter, these sub-networks will be described more specifically.

  A printer 101, a computer 102, and a router 103 exist on the subnetwork 110.

  A multicast transmission module (SLP, WS-Discovery, SSDP) provided in the printer 101 transmits a status change notification to the network using a multicast technique in order to notify the computer or the like existing on the network of the printer status.

  FIG. 2 is a block diagram illustrating the hardware configuration of the printers 102, 104, 105, 107, 108, and 109 in this embodiment. In FIG. 3, reference numeral 300 denotes a printer, which is equivalent to the printers 102, 104, 105, 107, 108, 109 in FIG. The printer 300 includes a CPU (Central Processing Unit) 301. The CPU 301 executes a program stored in a ROM (Read Only Memory) 302 or a hard disk 310 to control each device connected to the system bus 304 in a comprehensive manner. A RAM (Random Access Memory) 303 functions as a main memory and work area for the CPU 301. A printer I / F control unit 305 is a device that controls the printer 306. Each unit of the present embodiment is configured by a program stored in the CPU 301, the ROM 302, or the hard disk 310 of the printer 300. Reference numeral 307 denotes a non-volatile memory NVRAM for storing various setting values of the printer, and stores data such as MIB exchanged in the SNMP protocol. The panel control unit 308 controls the operation panel 309 to display various information and input instructions from the user. The network I / F control unit 311 controls data transmission / reception with the LAN 312. In the present embodiment, the LAN 310 is the same as one of the sub-networks 110, 111, and 112 in FIG.

  FIG. 3 is a diagram illustrating the present invention using the printer 101, the computer 102, and the computer 105 of FIG.

  In F100, the printer 101 detects an event that has occurred inside the printer, and determines that it is necessary to notify the network of the event according to the content of the event. In F101, the printer 101 uses multicast for the network. Event transmission.

  In this figure, it is assumed that the TTL value is 1 as the transmission range of the multicast transmitted by the printer 101. In this case, the event can be received up to the computer 102, but the multicast data reaches the computer 105. I can't.

  In this situation, when information acquisition or printing is executed from the computer 105 to the printer 101 in F102, the printer 101 determines the content in F103, and the requesting computer 105 is in the future. When it is determined whether it is necessary to notify an event by multicast, and when it is determined that transmission is necessary, a TTL value for the multicast data to reach the computer 105 is calculated, and as a result, it is larger than the current TTL value The value is stored as the subsequent multicast TTL value.

  In F104, the printer 101 detects an event that has occurred inside the printer, and determines that it is necessary to notify the network of the event according to the content of the event. In F105, the printer uses the TTL value determined in F103. Event transmission using multicast to the network.

  As a result, when the printer 101 detects a computer that should receive a multicast event, the printer 101 adjusts the TTL value so that the multicast reaches the computer and transmits the multicast data.

  FIG. 4 is a flowchart showing the present invention, and is a flowchart for automatically determining the reach of multicast data.

  In S100, when a delivery destination of multicast data that is newly transmitted by itself is detected due to network access or the like, a TTL value necessary to reach the multicast delivery destination is calculated in S101.

  In S102, the TTL value calculated in S101 is compared with the TTL value used in the existing multicast transmission. If the calculated TTL value is equal to or smaller than the existing TTL value, the subsequent operation is performed with the existing TTL value. Do.

  When the calculated TTL value is larger than the existing TTL value, the subsequent multicast transmission TTL value is changed to the calculated value.

  FIG. 5 is a diagram showing a printer setting screen according to the present invention. D100 is an example of a setting screen for event transmission settings, and is a screen on which various settings relating to event transmission can be made.

  D101, D102, and D103 are screens for selecting event contents to be transmitted by multicast.

  D104 is an item for setting the initial multicast transmission range. In this example, the initial value is set to 2.

  D105 and D106 are items to be selected exclusively. When D105 is enabled, the TTL value dynamically changes according to the multicast transmission range determination process of this patent, but the maximum TTL value is 5. As described above, it is set not to allow the TTL to be increased.

  When D106 is selected, the multicast transmission range determination process of this patent is invalid.

  In the case of the setting as shown in FIG. 5, when a job status confirmation request is received from a network that requires a TTL value of 4 for communication, the multicast reach is increased from 2 to 4, and then an event is transmitted by multicast. When it does, TTL value is transmitted with 4.

  FIG. 6 is a diagram illustrating a packet structure. The TCP / IP packet has a structure 801, and the IP header portion 802 therein has a TTL 803 (Time To Live) area. The initial value of the TTL value is set by the device that is the transmission source of the packet. The router that has received this packet decrements the value by one and forwards it to another network. If the TTL value of the received packet is 1 or less, the router discards the packet without transferring it. As a result, it is guaranteed that a situation in which unnecessary packets continue to be transferred over the network forever does not occur. According to this rule, the packet transmission source can control the reach of the packet by first setting the TTL value of the packet transmitted by the packet to an appropriate value.

101 Printer 102, 104, 105, 107, 108, 109 Computer 103, 106 Router 110, 111, 112 Subnetwork

Claims (14)

In a system that sends multicast data to notify devices connected to the network of its own information,
Means for detecting the presence of a device for which the system needs to distribute multicast data outside the multicast data reachable range;
Means for changing the reach of the multicast data so that the multicast data reaches the device;
An information processing apparatus comprising:   The system detects the presence of a device that needs to distribute multicast data outside the multicast data reachable range, and notifies the network by multicast from the device outside the multicast reachable range transmitted by the information processing device. The information processing apparatus according to claim 1, wherein reception of an acquisition request for an item related to information is detected.   Means for detecting the presence of a device that needs to distribute multicast data outside the multicast data reachable range is that the device outside the multicast reachable range that the information processing apparatus is transmitting is monitoring the multicast data of the network. The information processing apparatus according to claim 1, wherein the information processing apparatus detects that the same information is notified by multicast.   The method for determining whether or not the device is out of the multicast reachable range is to calculate the TTL value for data to reach the device, and compare the calculated TTL value with the TTL value that is currently transmitting the multicast data, so that the multicast data The information processing apparatus according to claim 2, wherein the information processing apparatus is a means for confirming a reach of the information.   The information processing apparatus according to claim 1, wherein the means for changing the reachable range of the multicast data is a means for increasing the TTL value of the multicast data to be transmitted and changing it to a value that can reach the device.   The acquisition request for an item related to information notified to the network according to claim 2 is a device status information acquisition request using the IPP protocol or WSD protocol when the status information of the information processing apparatus is transmitted by multicast. The information processing apparatus according to claim 2.   A case where it is detected that a device outside the multicast reachable range transmitted by the information processing apparatus according to claim 3 is notifying the same information by multicast is a multicast transmitted by the information processing apparatus by a multicast protocol transmitted by the information processing apparatus. The information processing apparatus according to claim 3, wherein communication data with the same multicast protocol is received from outside the range.   Claim 7 is a case where the information processing apparatus notifies the network of a startup advertisement with WS-Discovery with TTL = 3, and receives a startup advertisement of WS-Discovery from a device connected to a place where TTL 4 is required. The information processing apparatus according to claim 7.   The means for calculating a TTL value for data to reach the device according to claim 4 transmits a Ping in which the TTL value is set to a small value with respect to the IP address of the device, and the TTL value when the response is returned for the first time The information processing apparatus according to claim 4, which is means for calculating TTL required for reaching.   The means for calculating the TTL value for data to reach the device of claim 4 obtains the initial TTL value of the device, compares the TTL value of the packet received from the device from the value, and uses the difference. 5. The information processing apparatus according to claim 4, wherein the information processing apparatus is means. When there is no longer a factor that increases the reach of multicast data by the means of claim 1,
The information processing apparatus according to claim 1, wherein the reachable range is reduced and unnecessary multicast data transmission is not performed.   The reason why the reach of the multicast data reachable range according to claim 11 is eliminated is that an information processing apparatus that has increased the TTL from 3 to 4 increases the TTL because the start advertisement is received from outside the multicast reachable range by WS-Discovery. The information processing apparatus according to claim 11, wherein the information processing apparatus is a case where it is detected that the device that has caused the connection is disconnected from the network.   The system for transmitting multicast data according to claim 1 includes SLP, WS-Discovery, and SSDP clients, and when the service is started or terminated, shifted to or returned to sleep, and its own setting change occurs to the network. The information processing apparatus according to claim 1, wherein the information processing apparatus is a system that performs notification by multicast.   12. The information processing apparatus according to claim 11, wherein the means for determining that the cause of expanding the reach of multicast data by the means of claim 11 is eliminated is a case where it is detected that the device having the cause is disconnected from the network.

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