JP2006197051A - Network communication control unit and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exhibit original functions of equipment by reducing a network load on the equipment when the equipment is connected to a network. <P>SOLUTION: A network communication control unit 1 for controlling communication between the equipment A and network N has a control section (CPU 10) which makes a response corresponding to a broadcast packet or multicast packet without transferring it to the equipment A when the packet is sent from the side of the network N, and transfers a unicast packet to the equipment A when the packet is sent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a network communication control apparatus and a network communication control method for controlling communication between a device and a network.

  Conventionally, when an ARP (Address Resolution Protocol) packet is received in a bridge circuit that interconnects two or more networks via a public line, the sender's MAC (Medium Access Control) address and IP (Internet Protocol) address in advance Is stored in the filtering table of the bridge circuit, and when the response request destination IP address of the received ARP packet is the IP address stored in the filtering table of the bridge circuit, a response is made using the MAC address in the filtering table. There is disclosed a bridge circuit provided with means for preventing the ARP frame from being transferred to another network via a public line (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-50685

  In general, devices connected on a network normally communicate with each other. Therefore, the MAC address and IP address held by the device are transferred from devices connected to other networks to ARP packets and RARP (Reverse Address Resolution Protocol). ) When an inquiry is received via a packet, the device needs to respond.

  However, when there are many devices on the same subnet of the network and broadcasts between devices occur frequently, or when devices that inadvertently send broadcast packets such as ARP packets exist, so-called broadcast storm Is likely to occur frequently. In the above invention, a mechanism is described in which the broadcast packet is not inadvertently transferred to another network via a public line. However, when a device is connected to the above network even on the same network, the device uses a lot of CPU resources for receiving or responding to it, and there is a problem that the original performance of the device deteriorates. . In addition, as a method for the frequent occurrence of broadcasts, a method of dividing a network into subnets by using an IP router is generally known. However, there is a problem of IP packet exhaustion due to subnet division and packets other than IP packets ( In order to use packets of SMB, NetBEUI, Apple Talk, etc., there is a problem that a more complicated and expensive multi-protocol router must be used.

  The present invention has been made to solve such problems. That is, according to the present invention, in a network communication control device that controls communication between a device and a network, when a broadcast packet or a multicast packet is sent from the network side, the packet is handled without being transferred to the device. When a unicast packet is sent in response, the control unit executes a first mode for transferring the packet to the device.

  Further, the present invention is a network communication control method for controlling communication between a device and a network, and when a broadcast packet or multicast packet is sent from the network side, the packet is handled without being transferred to the device. This is a method for executing a first mode in which a response is made and, when a unicast packet is sent, the packet is transferred to the device.

  In the present invention, when a broadcast packet or a multicast packet is sent from the network side, a response is made on behalf of the device without transferring the packet to the device, and only the unicast packet specifying the device is transferred to the device. Therefore, the load of network communication on the device can be reduced.

  Therefore, according to the present invention, even when a device is connected to a heavily loaded network, it is possible to efficiently use CPU resources for the functions of the device without using excessive CPU power for network processing. It becomes. As a result, it becomes possible to demonstrate the performance of the original functions of the device, and it is also possible to continue to use network devices that cannot improve the performance of the device due to the software used. Even when a broadcast packet from a device is transmitted, it is possible to respond to the packet, leading to a reduction in the broadcast packet on the network side and a load on the network.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a network communication control device according to the present embodiment, (a) is an overall view, and (b) is an internal configuration diagram of the network communication control device. As shown in FIG. 1A, the network communication control device 1 (device B) according to the present embodiment is provided between the device A and the network N and is sent from the network N to the device A. And the transfer and response of packets sent from the device A to the network N are controlled.

  As shown in FIG. 1B, the network communication control apparatus 1 includes a CPU (Central Processing Unit) 10 that controls each unit, a bus bridge 11, a RAM (Random Access Memory) 13 connected to the bus 12, and a ROM (Read Only memory) 14 is provided, and the CPU 10 executes the program written in the ROM 14 to realize the packet transfer and response processing. Hereinafter, the network communication control method of this embodiment using the CPU 10 as a control unit will be described.

  First, the network communication control device 1 transfers the packet sent from the network N to the device A side as it is when the device A is not turned on or when the network communication control device 1 is powered on by default. Is set to a mode (first mode) in which a packet sent from is directly transferred to the network N side.

  In addition, a MAC address is prepared for the network port of the network communication control device 1, and the network is accessed through an interface such as a serial prepared in the network communication control device 1 or by accessing the preset IP address from the network. An IP address can be set on both the N side and the device A side.

  The IP address of the device A is input to the network communication control device 1 in advance, the network communication control device 1 detects the power ON of the device A, transmits an ARP packet for the device A from the network communication control device 1, and the device According to the response from A, the MAC address and IP address of the device A are set as a table in the RAM 13 in the network communication control device 1.

  Note that the IP address of device A that is set in advance and the MAC address that is obtained as an ARP packet based on the information is the information from the ARP packet (so-called self-explanatory ARP packet) that contains its own IP address when device A starts up. You may obtain it. At this time, the network communication control device 1 transfers the obvious ARP packet as it is to the network N side, and also transfers the response as it is to the device A side.

  If the device A is set to obtain an IP address from DHCP (Dynamic Host Configuration Protocol), the IP address and MAC address of the device A are obtained from the IP request packet sent from the device A to the DHCP server and its response. You may obtain it. At this time, the network communication control device 1 transfers the IP address request for DHCP to the network N side as it is, and also transfers the response to the device A side as it is.

  The network communication control device 1 changes the mode after obtaining information on the connected device A. That is, the network communication control device 1 transfers to the device A broadcast packets received from the network N such as ARP for the IP address of the device A and broadcast packets such as RARP addressed to the MAC address of the device A. Instead, the network communication control device 1 executes a mode (second mode) in which a response packet is transmitted to the network N side.

  Also, in the second mode, when the network communication control device 1 receives a multicast packet including addressed to the device A from the network N, the network communication control device 1 does not forward to the device A, but instead the network communication control device 1 sends a response packet to the network N side. Send. If the multicast packet does not include the device A address, the multicast packet is blocked without responding. On the other hand, when the network communication control device 1 receives a packet addressed to the device A and not the broadcast address from the network side, the network communication control device 1 performs a process of transferring the packet to the device A as it is.

  That is, when the second mode is executed, only the unicast packet addressed to the device A is transferred to the device A, and when the broadcast packet or the multicast packet including the address addressed to the device A is received, the network communication control device 1 The proxy response makes it possible to reduce the network load on the device A.

  Further, since the network communication control device 1 is connected on the network N, it can easily create a table of MAC addresses and IP addresses for other devices connected on the network N. Therefore, the network communication control device 1 holds the table in the RAM 13 for a certain period of time, returns a response when the ARP packet or RARP packet from the device A is sent to the device A with reference to its own table, and N may have a function not to transmit. As a result, the load on the network N can be reduced.

  The network communication control device 1 may have a function of setting the MAC address and IP address table holding time of other devices from an interface such as a serial cable of the network communication control device 1.

  The holding time of this table may be set by network access to the MAC address and IP address of the network communication control device 1 or may be set by the user interface of the network communication control device 1.

  The data in this table can be cleared from an interface such as a serial cable of the network communication control device 1, or can be cleared by network access to the MAC address and IP address of the network communication control device 1. You may enable it to clear by the user interface which the communication control apparatus 1 has.

  The network communication control device 1 transmits a command such as Ping to the device A at regular intervals to grasp the state of the device A, and if there is no response or no response multiple times, the device A is stopped. Recognize and stop the second mode of responding to the broadcast packet on behalf of the device A, and transfer the packet from the network N to the network on the device A side or the packet from the device A side to the network N side as it is. Set to the mode.

  The interval of the Ping packet that the network communication control device 1 sends to the device A is cleared from the communication interface such as a serial cable of the network communication control device 1 or is set by network access to the MAC address and IP address of the network communication control device 1 It may be possible to set it or clear it through the user interface of the network communication control device 1.

There are four possible means for the network communication control device 1 to detect the power ON of the device A as follows.
(1) A packet such as a ping is always transmitted to the device A at regular time intervals, and is detected based on the presence or absence of a response. At this time, the packet interval is fixed or can be set by a communication interface of the device, a user interface, network access, or the like.
(2) Detected by a trivial ARP packet transmitted by device A.
(3) Detection is performed by an IP address request packet transmitted from the device A to the DHCP server.
(4) The power ON is detected by some packet transmitted from the device A.

  The power ON detection means of the device A shown in (1) to (4) above can be selected from an interface such as a serial cable of the network communication control device 1, or the MAC address and IP address of the network communication control device 1 Can be selected by the network access to the network, or can be selected by the user interface of the network communication control device 1.

  The network communication control device 1 stores the IP address and MAC address of the device A connected to the network communication control device 1 in the RAM 13 and analyzes the IP address and MAC address when the device A is turned on next time. There may be a function to omit.

  The function of holding the IP address and MAC address of the device A may be changed or cleared by the communication interface, user interface, network access, etc. of the network communication control device 1.

  FIG. 2 is a schematic diagram showing an example in which the network communication control apparatus according to the present embodiment is applied to a copying machine. As shown in FIG. 2A, the copying machine 100 is connected to the network communication control apparatus 1 according to the present embodiment via a local network, and is connected to a subnet via the network communication control apparatus 1. A PC (Personal Computer) or the like is connected to the subnet, and an image processing request can be sent from the PC to the copying machine 100. In this configuration, the device A described above is a copying machine and the network N is a subnet.

  In this configuration, FIG. 2B shows an operation when a packet is sent from the subnet to the local net, and FIG. 2C shows an operation when the packet is sent from the local net to the subnet. The operation within the one-dot chain line frame in FIG. In the example of FIG. 2, A is set as the IP address of the copying machine 100 and a is set as the MAC address.

  As shown in FIG. 2B, when a packet is sent from the subnet to the local network, the network communication control device 1 transfers only the packet whose IP address is addressed to A to the local network, and the copying machine. To send to 100. On the other hand, when a broadcast packet, multicast packet (including IP address A), or Ping packet is sent, the work network communication control device 1 responds on behalf of the copier 10 without transferring the packet to the local network. (Proxy response). Also, multicast packets that do not include IP address A are irrelevant to copying machine 100 and are blocked without forwarding or proxy response.

  In this way, since the IP address A and MAC address a of the copying machine 100 are set in advance in the network communication control device 1, since the packets other than those required for the copying machine 100 can be responded by proxy, the copying machine 100 CPU resources can be used for the original image forming function without processing unnecessary packets.

  Further, as shown in FIG. 2C, when a packet is sent from the local net on the copier 100 side into the subnet, the network communication control device 1 for unicast packets, broadcast packets, multicast packets, and ping packets. Forward packets into the subnet.

  If the network communication control device 1 has a table of MAC addresses and IP addresses for other devices connected on the subnet, ARP packets and RARP packets sent from the copier 100 are transferred to the subnet. Instead, the user may reply to the copying machine 100 with reference to his / her table. This eliminates the need to transfer the packet to the subnet, thereby reducing the network load.

It is a schematic block diagram of the network communication control apparatus which concerns on this embodiment. 1 is a schematic diagram illustrating an example in which a network communication control apparatus according to an embodiment is applied to a copying machine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Network communication control apparatus, 10 ... CPU, 11 ... Bus bridge, 12 ... Bus, 13 ... RAM, 14 ... ROM, 100 ... Copier, N ... Network

Claims (8)

In a network communication control device that controls communication between a device and a network,
When a broadcast packet or multicast packet is sent from the network side, a response corresponding to the packet is made without forwarding to the device, and when a unicast packet is sent, the packet is sent to the device. A network communication control device comprising: a control unit that executes a first mode of transfer. The network communication control device according to claim 1, wherein the control unit executes the first mode after detecting power-on of the device. The control unit executes a second mode in which all packets sent from the network side are transferred to the device before the device is turned on, and the first unit is turned on after the device is turned on. The network communication control device according to claim 1, wherein switching to the mode is performed. 2. The network communication according to claim 1, wherein, when a broadcast packet is sent from the device to the network side, the control unit performs a response corresponding to the packet without transferring the broadcast packet to the network side. Control device. In a network communication control method for controlling communication between a device and a network,
When a broadcast packet or multicast packet is sent from the network side, a response corresponding to the packet is made without forwarding to the device, and when a unicast packet is sent, the packet is sent to the device. A network communication control method characterized by executing a first mode of transfer. The network communication control method according to claim 5, wherein the first mode is executed after the device is powered on. Before the device is turned on, execute a second mode in which all packets sent from the network side are transferred to the device, and after the device is turned on, switch to the first mode The network communication control method according to claim 5, wherein: 6. The network communication control method according to claim 5, wherein when a broadcast packet is sent from the device to the network side, a response corresponding to the packet is made without being transferred to the network side.

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