JP2006285903A - Method of avoiding duplication of communication port - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent data from being simultaneously transmitted on a network relating to a duplicated port number by a protocol stack provided to a first network device and a protocol stack provided to a second network device. <P>SOLUTION: When data for requesting transmission is transferred to the second network device from the first network device via a connection interface, the data for requesting transmission is discarded and transmission error is notified to a transmission requesting source if a used port number of the data for requesting transmission and a port number used by a second network device are duplicated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a second network device connectable to a first network device via a connection interface, a protocol stack provided in the first network device and a protocol stack provided in the second network device. It is related to a method for determining whether or not duplication has occurred in communication ports used at the time of transmission, and for avoiding duplication.

  Large network environments, such as networks to support business office environments, often include a large number of different types and generations of network devices with different functional capabilities, such as printing devices with network capabilities There is. As new technologies emerge and improved functionality is implemented in new models or generations of network devices, the functionality available in the network varies significantly depending on which network device is being utilized. there's a possibility that. For example, some newer printing devices in a network environment can support secure printing, while older printing devices that exist in the network environment do not support secure printing. obtain.

  It is generally desirable to implement new technologies and improvements throughout the network environment, thereby making the same set of capabilities available to all network users for all network devices. Otherwise, if a network device assigned to some network user does not support the new functionality supported by other newer network devices, the network user may New useful features such as email printing will not be available.

  One problem-solving approach to this problem is simply to replace all legacy network devices with new network devices with the desired new functional capabilities. However, the effort and cost of implementing this problem-solving approach is tremendous and not practical when new enterprise applications that require new functional capabilities are frequently implemented.

  Another problem-solving approach to the above problem is to modify the legacy network device by downloading new firmware to each legacy network device. However, in this problem-solving approach, a network administrator or service representative can physically access each legacy network device, then download the appropriate version of firmware, and the legacy device can It is necessary to support functionality that is consistent with the device, which requires significant effort. Also, in many cases, because legacy devices have hardware and design limitations, it is not possible to download new versions of firmware to legacy devices to implement new functionality.

  Another possible solution to this problem is to use a network module that supports the desired additional functionality for the legacy network device that can be connected to the legacy network device through the connection interface. It is done.

  As a specific example of the network module, there is an intelligent network card module that can be attached to a printing apparatus via a connection interface (for example, Patent Document 1).

  In this case, the printer main unit and network card module are intelligent forms with individual CPUs, and the network card module usually has a print server function that performs overall control of various print services via the network. The device and the network card module communicate with each other via a connection interface to implement a desired service.

On the contrary, this makes it possible to drive out heavy functions to the network card module, relatively lowering the CPU and peripheral performance of the printing apparatus body, and reducing the cost of the printing apparatus body.
Japanese Patent Laid-Open No. 2002-259075

  In the network card module, a protocol stack provided in the network card module and a protocol stack provided in the printing apparatus are asynchronously connected to each other via a physical interface provided in the network card module, such as a host computer. Communicate with clients using TCP / IP or other communication protocols. To enable this, when the network card module receives data from the physical interface, the received data is sent to the appropriate protocol stack provided in the network card module or the protocol stack provided in the printing device. Has a function of sorting. The distribution function is located in a layer between a protocol stack provided in the network card module and a driver that controls the physical interface, and specifically performs the following processing. First, when received data is passed from the driver of the physical interface, the header information of the received data is prefetched to acquire destination network information such as a destination network address and a destination port number. Next, the socket information of the socket in which the protocol stack provided in the network card module is open is acquired, and there is an open socket with network information such as the network address and port number that matches the destination network information. Search if you want to. If there is a matching socket as a result of the search, the received data is distributed to the protocol stack provided in the network module itself. If there is no matching socket, the received data is transferred to the printing apparatus via the connection interface.

  In the distribution function for performing the above processing, if there is a duplication of communication port numbers between the protocol stack provided in the network card module and the protocol stack provided in the printing apparatus, reception for the duplicate port number is performed. Data is always distributed to the protocol stack provided in the network card module. That is, a system that always prioritizes the protocol stack provided in the network card module for reception is realized.

  However, when the protocol stack provided in the network card module and the protocol stack provided in the printing apparatus simultaneously transmit data to the duplicate port number, both data are transmitted over the network. Conceivable. Further, when response data for data transmitted using a duplicate port number from the protocol stack provided in the printing apparatus comes to the duplicate port number, the response data is provided in the network card module by the distribution function. Assigned to the designated protocol stack. Therefore, for example, in the case of communication using a connectionless protocol such as the user datagram protocol (UDP) in the TCP / IP protocol, unnecessary received data is passed to the application program installed in the network card module. Even in the case of communication using a connection-type protocol such as the transmission control protocol (TCP), unnecessary data is passed to the protocol stack provided in the network card module. In either case, there is a possibility that the work load due to reception processing of unnecessary data in the network card module increases.

The present invention has been made in view of the above problems,
A second network device connectable to the first network device via a connection interface,
Transmission request data transferred from the first network device via the connection interface or transmission request data transferred from a protocol stack provided in the second network device is provided in the second network device. Transmission request data transmission means for transmitting to the network from the physical interface,
Received data transfer means for transferring received data received from the physical interface to either or both of the protocol stacks provided in the first network device and the second network device;
In the second network device, comprising:
Port information storage means for storing port information currently used by the protocol stack provided in the second network device;
Source port information acquisition means for acquiring source port information from the transmission request data when transmission request data is transferred from the first network device via the connection interface;
Port information duplication judgment means for judging whether or not the transmission source port information obtained by the transmission source port information acquisition means is duplicated with the port information stored in the port information storage means;
Means for discarding the transmission request data and notifying a transmission request source of a transmission error when duplication of port information is detected by the port information duplication determination means;
Is a method for avoiding duplication of port information.

  According to the present invention, when transmission request data is transferred from the first network device to the second network device via the connection interface, the use port number of the transmission request data is set to the second network. If the port number used by the device is duplicated, the transmission request data is discarded, and a transmission error is notified to the transmission request source, whereby the protocol stack provided in the first network device and the first It is possible to prevent the protocol stack provided in the second network device from simultaneously sending data on the network to the duplicate port number. For this reason, response data for data transmitted using a duplicate port number from the protocol stack provided in the first network device does not come to the duplicate port number, and the response data is not sent to the second network device. The received data distribution function provided in the network device is not distributed to the protocol stack provided in the second network device. As a result, it is possible to reduce the work load required for unnecessary data reception processing in the second network device.

Example 1
FIG. 1 is a block diagram illustrating a hardware configuration of a printing system according to an embodiment of the present invention. Reference numeral 1000 denotes a printer, which is mainly composed of devices that control different control systems, including a network printer server 1500 and a printer controller 1600. In the network print server 1500, 1 is a CPU for the network print server, which is connected to the local area network (LAN2000) via a network controller (LANC5) connected to the system bus 4 based on a control program stored in the rewritable Flash ROM 3. By using a plurality of external devices (not shown) such as connected host computers and a predetermined network communication protocol, it collectively controls various data transmission / reception requests such as print data and printer control commands sent from the external device, Appropriate data transfer control is performed for the printer controller 1600 connected via the expansion interface controller (EXPC7). FlashROM 3 also stores a port information duplication determination / duplication avoidance program as shown in the flowcharts of FIGS.

  The RAM 2 is used as a temporary storage area such as the main memory and work area of the CPU 1.

  The LED 6 is used as a display unit that shows the operating status of the network print server.For example, the electrical connection status (LINK) between the network controller (LANC5) and the local area network (LAN2000) and the network communication mode (10Base and 100Base, all Various operating states such as double and half duplex can be indicated by the blinking pattern and color of the LED.

  Furthermore, the expansion interface 17 that connects the network print server 1500 and the printer controller 1600 is configured with a connector (not shown). Only the network print server 1500 can be attached and detached, and the network print server 1500 can be attached to another printer 1000 having the same configuration. Is also possible.

  In the printer controller 1600, 8 is a CPU for the printer controller, such as a control program stored in the ROM 9, or a control program or resource data (resource information) stored in the external memory 10 connected via the disk controller (DKC15). And the raster controller 12 based on print data received from the network print server 1500 connected via the expansion interface controller (EXPC 13). To generate output image information and output an image signal to the print engine 16.

  Reference numeral 14 denotes a RAM that functions as a main memory, work area, and the like for the CPU 8, and is configured so that the memory capacity can be expanded by an optional RAM connected to an expansion port (not shown).

  Reference numeral 18 denotes an operation panel (operation unit) with buttons for performing operations such as setting the operation mode of the printer 1000 and canceling print data, and a display unit such as a liquid crystal panel and an LED indicating the operation state of the printer 1000. Yes.

  The printer engine 16 shown in the figure uses a known printing technique, and examples of suitable implementation systems include an electrophotographic system (laser beam system), an inkjet system, and a sublimation (thermal transfer) system.

  FIG. 2 is a block diagram illustrating a software configuration in a control program stored in each storage device of the network print server 1500 and the printer controller 1600 that are control devices in the printer 1000 in the printing system suitable for the embodiment of the present invention. It is.

  Each control program is analyzed and processed by the CPU of each control device.

  An operating system 1501 controls basic data input / output control of the network print server 1500. Further, the operating system 1501 includes a file system 1505 for controlling input / output with the program / data storage unit 1509, an expansion interface driver 1506 for controlling communication with the printer controller 1600 and the expansion interface 17, and a local area network (LAN2000). A network interface driver 1507 that communicates with an external device such as a host computer (not shown) via the communication medium, a protocol stack 1508 that performs communication control using the TCP / IP protocol, and an intermediate module 1510 are included.

  The intermediate module 1510 is located between the protocol stack 1508, the extension interface driver 1506, and the network interface driver 1507, and the transmission request data passed from the protocol stack 1508 or the printer controller via the extension interface 17 and the extension interface driver 1506. Sending request data passed from the 1600 is sent from the network interface driver 1507, and the receiving destination judgment for sorting the received data passed from the network interface driver 1507 to one or both of the protocol stack 1508 and the printer controller 1600 And means for distributing received data to one or both of the protocol stack 1508 and the printer controller 1600 based on the determination result. Further, the intermediate module 1510 further includes a transmission port number duplication detection and duplication avoidance means that is the subject of the present invention.

  Reference numeral 1502 denotes an application program interface (API), which provides various functions of the operating system for application programs such as a user application 1503 that runs on the network print server 1500, a printer 1000, and a management application that registers and manages user applications. provide. The functions provided by the application program interface 1502 include a data transfer API that provides a print data transmission / reception function, a resource control API that controls input / output of resource data such as bitmap images and display messages, and a restart of the printer 1000. Printer control API that controls settings and initialization of settings and settings, job control API that controls print job cancellation and reprint instructions, restarting network print server 1500, initialization and setting of settings, and A print server control API for starting, registering, and deleting application programs is provided.

  1601 is an operating system that controls various processing controls of the printer controller 1600. The print engine control unit 1603 that performs communication control with the print engine and models such as bitmap images and error messages that are referred to from the network print server 1500 A file system 1604 that performs input / output control with model-dependent resources / program storage units that store dependent resources and model-dependent application programs that run on the network print server, and a protocol stack 1605 that performs communication control using the TCP / IP protocol Contains.

  Reference numeral 1602 denotes an expansion interface control unit that controls communication with the network print server 1500 via the expansion interface 17. The extended interface control unit further includes a data transfer logical interface for controlling input / output of print data for each control type, a resource control logical interface for controlling input / output of various data stored in the model-dependent resource / program storage unit 9, It has a printer control logical interface that controls the restart of the printer 1000, initialization of setting values, settings, etc., and a job control logical interface that controls cancellation of print jobs and reprint instructions. The command requested from the network print server 1500 is transferred to the operating system 1601, and the processing result is returned to the network print server 1500.

  FIG. 3 is a flowchart showing an embodiment of the transmission port number duplication detection / avoidance processing function operating on the network print server 1500 according to the present invention. S301 to S310 indicate each processing step. In the network print server 1500, the intermediate module 1510 when the transmission request data is delivered from either the protocol stack 1508 provided in the network print server 1500 or the printer controller 1600. Corresponds to the processing flow. The control procedure corresponding to each step is stored in the Flash ROM 3 of the network print server 1500. The printer controller use port list is a finite area secured on the RAM 2 of the network print server 1500 in order to register the port numbers used by the printer controller 1600 for data transmission.

  In S301, it is determined whether or not the transmitted transmission request data has been transmitted from the printer controller 1600 via the extension interface 17.

  If the transmission request data is not passed from the printer controller 1600, it is determined that the transmission request data is passed from the protocol stack 1508 provided in the network print server 1500, and the process proceeds to S302, where the header information of the transmission request data is obtained. Read and acquire the source port number. In step S303, the printer controller use port list is searched to determine whether the same port number as the acquired transmission source port number is registered.

  If the same port number is registered, the printer controller 1600 determines that the port number is in use, and the process proceeds to S304, where the transmission request data is discarded and the network print server 1500 that is the transmission request source prepares. After the transmission error is notified to the protocol stack 1508, the processing is terminated.

  If the same port number is not registered in S303, the process proceeds to S310, where transmission request data is transmitted to an external device such as a host computer (not shown) via the LAN 2000, and the process is terminated.

  If the transmission request data is passed from the printer controller 1600 in S301, the header information of the transmission request data is read in S305 to acquire the transmission source port number.

  In step S306, the printer controller use port list is searched to check whether the same port number as the transmission source port number acquired in step S305 is registered.

  If the same port number is not registered, the process proceeds to S307, and the protocol stack 1508 provided in the network print server 1500 searches the socket information of the socket being used, and is using the same port number as the source port number. Determine if there is no socket.

  If there is a socket using the same port number, it is determined that the protocol stack 1508 provided in the network print server 1500 is in use, and the process proceeds to S308, where the transmission request data is discarded. Then, the printer controller 1600 that is the transmission request source is notified of the transmission error via the extension interface 17, and the processing is ended.

  If there is no socket using the same port number in S307, the source port number is registered in the printer controller use port list in S309. In step S310, transmission request data is transmitted to an external device such as a host computer (not shown) via the LAN 2000, and the processing is terminated.

  In S306, if the same port number as the acquired transmission source port number is registered in the printer controller use port list, it is determined that the printer controller 1600 is the port number being used, and the process proceeds to S310, where the transmission request data Is transmitted to an external device such as a host computer (not shown) via the LAN 2000, and the processing is terminated.

(Example 2)
FIG. 4 is a flowchart showing a second embodiment of a function for performing duplication detection and duplication avoidance processing of a transmission port operating on the network print server 1500 according to the present invention. S401 to S412 indicate processing steps, and correspond to the processing flow of the intermediate module 1510 when transmission request data is delivered from either the protocol stack 1508 provided in the network print server 1500 or the printer controller 1600. The control procedure corresponding to each step is stored in the Flash ROM 3 of the network print server 1500. The printer controller use port list is a finite area secured on the RAM 2 of the network print server 1500 in order to register the port numbers used by the printer controller 1600 for data transmission.

  In S401, it is determined whether or not the transmitted transmission request data has been transmitted from the printer controller 1600 via the extension interface 17.

  If the transmission request data is not passed from the printer controller 1600, it is determined that the transmission request data has been passed from the protocol stack 1508 provided in the network print server 1500, and the process proceeds to S402, where the header information of the transmission request data is obtained. Read and acquire the source port number.

  In step S403, the printer controller use port list is searched to determine whether the same port number as the acquired transmission source port number is registered.

  If the same port number is registered, the process proceeds to S404, and an alternative port number is acquired from the protocol stack 1508 provided in the network print server 1500. In step S405, the transmission request data is discarded, the alternative port number is notified to the protocol stack 1508 provided in the network print server 1500, which is the transmission request source, and the processing ends.

  If the same port number is not registered in S403, the process proceeds to S412 and the transmission request data is transmitted to an external device such as a host computer (not shown) via the LAN 2000, and the process is terminated.

  If the transmission request data is passed from the printer controller 1600 in S401, the process proceeds to S406, where the header information of the transmission request data is read, and the transmission source port number is acquired.

  In step S407, the printer controller use port list is searched to determine whether the same port number as the acquired transmission source port number is registered.

  If the same port number is not registered, the process proceeds to S408, and the protocol stack 1508 provided in the network print server 1500 searches the socket information of the socket in use, and the same port as the source port number acquired in S406. Determine if there are any sockets using numbers. If the same port number is registered, the process proceeds to S409, and an alternative port number is acquired from the protocol stack 1508 provided in the network print server 1500. In step S410, the transmission request data is discarded, the transmission request source printer controller 1600 is notified of the alternative port number via the extension interface 17, and the processing is terminated.

  If the same port number is not registered in S408, the process proceeds to S411, and the port number is registered in the printer controller use port list. In step S412, the transmission request data is transmitted to an external device such as a host computer (not shown) via the LAN 2000, and the processing is terminated.

  If the same port number is registered in the printer controller port list in S410, the process immediately proceeds to S412 and the transmission request data is transmitted to an external device such as a host computer (not shown) via the LAN 2000, and the processing is terminated. To do.

(Example 3)
In the second embodiment, when there is a duplicate port number in the transmission request data, the alternative port number is acquired from the protocol stack 1508 provided in the network print server 1500, and the transmission request data is transmitted to the alternative port number. The protocol stack 1508 or printer controller 1600 provided in the original network print server 1500 is notified.

  However, when the acquisition of an alternative port is requested to the protocol stack 1508 provided in the network print server 1500, there is a possibility that the alternative port number cannot be acquired because there is no available port number. Even if the alternative port number can be acquired, there is a possibility that the alternative port number is already in use by the printer controller 1600.

  FIG. 5 is a flowchart in which a countermeasure for the above problem is added to the alternative port number acquisition process shown in FIG. S501 to S505 indicate each processing step. In the network print server 1500, duplication of port numbers occurs in the transmission request data passed from either the protocol stack 1508 provided in the network print server 1500 or the printer controller 1600. This corresponds to the processing flow of the intermediate module 1510. S501 to S505 are processing steps that are derived from the processing steps S404 to S405 and S409 to S410 in FIG. The control procedure corresponding to each step is stored in the Flash ROM 3 of the network print server 1500. The printer controller use port list is a finite area secured on the RAM 2 of the network print server 1500 in order to register the port numbers used by the printer controller 1600 for data transmission.

  The intermediate module 1510 first receives the network print server in S501 when there is a duplicate port number in the transmission request data passed from either the protocol stack 1508 provided in the network print server 1500 or the printer controller 1600. An alternative port number acquisition request is issued to the protocol stack 1508 provided in 1500, and it is determined in S502 whether the alternative port has been acquired. If the alternative port number could not be acquired because there is no available port number, etc., the process proceeds to S503, the transmission request data is discarded, and the protocol stack 1508 provided in the network print server 1500 that is the transmission source of the transmission request data Alternatively, the process ends after notifying the printer controller 1600 of a transmission error.

  If the alternative port number can be acquired in S502, the process proceeds to S504, and it is determined whether or not the acquired alternative port number overlaps with the port information registered in the printer controller use port list. If not, proceed to S505, discard the transmission request data, notify the protocol stack 1508 provided in the network print server 1500 that is the transmission source of the transmission request data or the printer controller 1600 with the alternative port number and process it Exit.

  In S504, if the acquired alternative port number overlaps with the port information registered in the printer controller use port list, the process returns to S501 and repeats the processes of S501 to S505.

Example 4
In the first to third embodiments, the network printer server 1500 is a separate device that is physically separated from the printer 1000, and the printer 1000 includes a device that controls the control system including the printer controller 1600. In the network printer server 1500, the extended interface controller (EXPC7) shown in FIG. 1 is a second network controller connected to the system bus 4, and the extended interface driver 1506 shown in FIG. In the printer controller 1600, the extended interface controller (EXPC13) shown in FIG. 1 is a network controller connected to the system bus 11, and the extended interface controller shown in FIGS. The network 17 is a second local area network, and the network print server 1500 and the printer controller 1600 may be connected to the second local area network.

(Example 5)
In the first to fourth embodiments, when the transmission request data passed from the printer controller 1600 via the expansion interface 17 is transmitted to an external device such as a host computer (not shown) via the LAN 2000, the intermediate module 1510 transmits the transmission request data. Is registered in the printer controller port list. If there is transmission request data from the protocol stack 1508 provided in the network print server 1500, the port number used by the transmission request data does not overlap with the port number registered in the printer controller use port list. Judgment whether or not. This avoids a situation in which the port number being used by the printer controller 1600 is duplicated by the protocol stack 1508 provided in the network print server 1500.

  However, with this means, regarding the port number once used by the printer controller 1600 for transmission and registered in the printer controller use port list, even if the printer controller 1600 thereafter terminates communication using that port number, The port number remains in the printer controller use port list. Therefore, the port number once registered in the printer controller use port list cannot be used thereafter from the protocol stack 1508 provided in the network print server 1500.

  However, in the network print server 1500, information on which port number the printer controller 1600 is using can be known only when the transmission request data is passed from the printer controller 1600 via the expansion interface 17. . Therefore, the port number once used by the printer controller 1600 for transmission and registered in the printer controller use port list is deleted from the printer controller use port list when the printer controller 1600 finishes communication using the port number. The method cannot be realized.

  Therefore, as a countermeasure, a method of providing a timeout function in the printer controller use port list can be considered. If there is no transmission request data from the printer controller 1600 via the expansion interface 17 again within a certain period for the port number registered in the printer controller use port list, the port number is deleted from the printer controller use port list.

  According to this method, even if the printer controller 1600 once used for transmission and registered in the printer controller use port list, the transmission request data using the port is not received from the printer controller 1600 for a certain period or more. If not passed through the extension interface 17, the protocol stack 1508 provided in the network print server 1500 can use the port number.

1 is a block diagram of a hardware configuration of a printing system according to an embodiment of the present invention. Printing system software configuration block diagram according to an embodiment of the present invention The flowchart which shows one Embodiment of the duplication detection of the transmission port number based on this invention, and the duplication avoidance method The flowchart which shows 2nd embodiment of the duplication detection of the transmission port number based on this invention, and the duplication avoidance method. The flowchart which shows other embodiment of the alternative port number acquisition process in 2nd embodiment.

Explanation of symbols

1000 Printer 1500 Network Print Server 1600 Printer Controller 2000 Local Area Network 1 CPU
2 RAM
3 Flash ROM
4 System bus 5 LAN controller 6 LED
7 Expansion interface controller 8 CPU
9 ROM
10 External memory 11 System bus 12 Raster controller 13 Extended interface controller 14 RAM
15 Disk Controller 16 Print Engine 17 Expansion Interface Bus 18 Operation Panel

Claims (2)

A second network device connectable to the first network device via a connection interface,
Transmission request data transferred from the first network device via the connection interface or transmission request data transferred from a protocol stack provided in the second network device is provided in the second network device. Transmission request data transmission means for transmitting to the network from the physical interface,
Received data transfer means for transferring received data received from the physical interface to either or both of the protocol stacks provided in the first network device and the second network device;
In the second network device, comprising:
Port information storage means for storing port information currently used by the protocol stack provided in the second network device;
Source port information acquisition means for acquiring source port information from the transmission request data when transmission request data is transferred from the first network device via the connection interface;
Port information duplication judgment means for judging whether or not the transmission source port information obtained by the transmission source port information acquisition means is duplicated with the port information stored in the port information storage means;
Means for discarding the transmission request data and notifying a transmission request source of a transmission error when duplication of port information is detected by the port information duplication determination means;
A method for avoiding duplication of port information, comprising: A second network device connectable to the first network device via a connection interface,
Transmission request data transferred from the first network device via the connection interface or transmission request data transferred from a protocol stack provided in the second network device is provided in the second network device. Transmission request data transmission means for transmitting to the network from the physical interface,
Received data transfer means for transferring received data received from the physical interface to either or both of the protocol stacks provided in the first network device and the second network device;
In the second network device, comprising:
Port information storage means for storing port information currently used by the protocol stack provided in the second network device;
Source port information acquisition means for acquiring source port information from the transmission request data when transmission request data is transferred from the first network device via the connection interface;
Port information duplication judgment means for judging whether or not the transmission source port information obtained by the transmission source port information acquisition means is duplicated with the port information stored in the port information storage means;
Means for discarding the transmission request data and notifying the transmission request source of an alternative port number when duplication of port information is detected by the port information duplication determination means;
A method for avoiding duplication of port information, comprising:

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