JP4983674B2 - Communication system, processing request device, processing response device, and program thereof - Google Patents

Description

  The present invention relates to a communication technique that uses UDP to communicate by a communication protocol in which a processing response device responds to a predetermined processing request transmitted by a processing request device by multicast or broadcast.

  Conventionally, for example, SLP (Service Location Protocol) is known as a communication protocol that a processing response device responds to a processing request transmitted by multicast or broadcast by a processing request device using UDP (User Datagram Protocol). Yes.

  SLP is a protocol that can search for services on the network. When a processing requesting device (user agent) requests acquisition of attribute information from a processing response device (service agent) on the network, the processing response device The attribute information is returned to the process requesting device. At this time, the upper limit of the message length excluding the UDP header from the UDP datagram is about 1400 octets from the MTU (Maximum Transmission Unit) of Ethernet (registered trademark). Therefore, when the response message length exceeds 1400 octets, the processing response device turns ON the OVERFLOW bit defined in the SLP standard and responds a part of the message that fits in 1400 octets. When receiving a response message whose OVERFLOW bit is ON, the process requesting device uses TCP (Transmission Control Protocol) instead of UDP again to request acquisition of attribute information, and after a plurality of exchanges, Get the whole thing.

  However, since the above method uses TCP, it is assumed that an IP address is assigned to the processing requesting device, and cannot be used at a stage before the IP address is assigned. This problem is not limited to SLP communication, but is a problem common to communication using a communication protocol in which a processing response device responds to a predetermined processing request transmitted by multicast or broadcast by a processing request device using UDP. Met.

JP 2006-202195 A

  Based on the above-described problems, the problem to be solved by the present invention is in communication using a communication protocol in which a processing response device responds to a predetermined processing request transmitted by multicast or broadcast using UDP. , Exchanging data exceeding the upper limit of the data length that can be transmitted by UDP.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 Using UDP, the process request apparatus and the process response apparatus are connected to each other by a communication protocol in which the process response apparatus responds to a predetermined process request transmitted by the process request apparatus by multicast or broadcast. A communication system for communicating via
The processing requesting device is:
When response data to be responded to the processing request exceeds a predetermined capacity that can be transmitted by the UDP, a division instruction means for including a division instruction for dividing and transmitting the response data in the processing request;
Processing request means for transmitting the processing request including the division instruction,
The process response device is:
A division unit that receives a processing request including the division instruction and divides the response data into a capacity that can be transmitted by the UDP when the response data exceeds the predetermined capacity;
Adding means for adding order information indicating the arrangement order of the divided data in the response data to each of the divided data;
And a processing response means for transmitting the divided data to which the order information is added as the response to the processing requesting device.

  In the communication system having such a configuration, when the response data exceeds a predetermined capacity that can be transmitted by UDP, the processing request device transmits the processing request by multicast or broadcast including a division instruction for dividing and transmitting the response data. To do. On the other hand, when the response data exceeds a predetermined capacity, the process response device adds a sequence information to the divided data obtained by dividing the response data and responds. Therefore, in communication using a communication protocol in which a processing response device responds to a predetermined processing request transmitted by multicast or broadcast using UDP, data exceeding the upper limit of the data length that can be transmitted by UDP is received. Can communicate. In addition, even if the data exceeds the upper limit of the data length that can be transmitted by UDP, the network load can be reduced because exchange can be performed using UDP, which has a smaller traffic volume compared to communication using TCP.

Application Example 2 The communication system according to Application Example 1, wherein the communication protocol is SLP.
In the communication system having such a configuration, the effect of Application Example 1 can be obtained even when the communication protocol is SLP.

Application Example 3 In the communication system according to Application Example 2, the adding unit further adds a flag indicating whether or not the divided data is the last divided data constituting the response data to each divided data. The processing requesting apparatus further includes a first determination unit that determines that all the divided data has been received with reference to the flag.

  In the communication system having such a configuration, the process response device adds a flag indicating whether or not the divided data is the last divided data constituting the response data, and makes a response. On the other hand, the processing requesting device refers to the flag and determines that all the divided data has been received. Therefore, the processing requesting device can easily know that all the divided data has been received, and can terminate the exchange with the processing response device at an appropriate timing.

Application Example 4 In the communication system according to Application Example 2 or Application Example 3, the adding unit further adds size information indicating the size of the response data to each divided data, and the processing requesting device further includes: A communication system comprising second determination means for determining that all the divided data has been received with reference to the size information.

  In the communication system having such a configuration, the process response device adds a size information indicating the size of the response data and responds. On the other hand, the processing requesting device refers to the size information and determines that all the divided data has been received. Therefore, the processing requesting device can easily know that all the divided data has been received, and can terminate the exchange with the processing response device at an appropriate timing.

Application Example 5 The communication system according to any one of Application Example 2 to Application Example 4, wherein the adding means further adds identification information of the processing response device to each divided data.

  In the communication system having such a configuration, the process response device adds a response processing device identification information and responds. Therefore, even when the response requesting device receives responses from a plurality of response processing devices, it can accurately determine which response processing device is the response.

[Application Example 6] The communication system according to any one of Application Example 1 to Application Example 5, wherein the processing requesting device further includes command adding means for including an execution command of a predetermined protocol in the processing request. The apparatus further includes command execution means for interpreting and executing the execution command when the execution request is included in the processing request, and the processing response apparatus handles the execution result of the execution command as response data.

  In the communication system having such a configuration, the processing request device transmits a processing request including an execution command of a predetermined protocol. On the other hand, when an execution command is included in the processing request, the processing response device interprets and executes the execution command, and returns the execution result as response data. Therefore, although the response data length may become long, even in such a case, the response data can be exchanged by the configuration of any one of the application examples 1 to 5.

Application Example 7 The communication system according to Application Example 6, wherein the processing response device handles the execution result of the execution command as response data when the execution result of the execution command satisfies a predetermined condition.

  In the communication system having such a configuration, the process response device responds with a result of the execution command when the execution result of the execution command satisfies a predetermined condition. Therefore, the process requesting apparatus receives a response only from a specific process responding apparatus, so that the response of the process responding apparatus can be efficiently obtained. In addition, the load on the network can be reduced.

  In addition to the configuration as a communication system, the present invention can also be realized as a processing response device, a processing request device, a computer program, and a communication method.

Examples of the present invention will be described.
A. Example:
A-1. General configuration of communication system:
A schematic configuration of a communication system 20 as an embodiment of the present invention is shown in FIG. In the communication system 20, a user agent UA and service agents SA1, SA2 are connected via a local area network LAN. The user agent UA is a general-purpose personal computer on which a predetermined program is installed, the service agent SA1 is a so-called multifunction printer, and the SA2 is a so-called single printer. Note that the number of user agents or user agents constituting the communication system 20 is not limited to this example, and an arbitrary number can be set.

A-2. Schematic configuration of user agent:
FIG. 2 shows a schematic configuration of the user agent UA that constitutes the communication system 20. As described above, the user agent UA is a general-purpose personal computer in which a predetermined program is installed, and includes a CPU 30, a hard disk drive 41, a ROM 42, a RAM 43, an input mechanism 45, a display 46, and an interface 49.

  The CPU 30 manages the user agent UA by deploying the firmware and OS stored in the hard disk drive 41 and the ROM 42 to the RAM 43 and executing them. Further, the CPU 30 functions as a division instruction unit 31, a process request unit 32, a determination unit 33, and a command addition unit 34 by executing a program stored in the hard disk drive 41. Details of this functional unit will be described later. Note that the command adding unit 34 has a configuration as a modified example to be described later.

  The input mechanism 45 includes a keyboard and a pointing device (here, a mouse). The display 46 is a liquid crystal display. The interface 49 is an interface for connecting the user agent UA to the local area network LAN.

A-3. General configuration of service agent:
A schematic configuration of the service agent SA1 constituting the communication system 20 is shown in FIG. As described above, the service agent SA1 is a multifunction printer, and includes a CPU 50, an EEPROM 61, a ROM 62, a RAM 63, an input mechanism 65, a printing mechanism 66, a scanner 67, a FAX transmission mechanism 68, and an interface 69. The service agent SA2 has the same configuration as the service agent SA1 except that the service agent SA2 does not have the scanner 67 and the FAX transmission mechanism 68, and a description thereof will be omitted.

  The CPU 50 manages the entire service agent SA1 by deploying firmware and OS stored in the EEPROM 61 and ROM 62 to the RAM 63 and executing them. Further, the CPU 50 functions as a dividing unit 51, an adding unit 52, a processing response unit 53, and a command execution unit 54 by executing a program stored in the EEPROM 61. Details of this functional unit will be described later. Note that the command execution unit 54 is configured as a modified example to be described later.

  The input mechanism 65 includes a keyboard and a display that displays a UI. In this embodiment, the printing mechanism 66 is an ink jet printing mechanism. The interface 69 is an interface for connecting the service agent SA1 to the local area network LAN.

A-4. UDP split transmission / reception processing:
UDP division transmission / reception processing in the communication system 20 will be described with reference to FIGS. 4 and 5. The UDP division transmission / reception processing in the present embodiment means that transmission can be performed by UDP by dividing and transmitting / receiving data when performing SLP communication using UDP between the user agent UA and the service agent SA1. This is a process that enables exchange of data exceeding a certain capacity. The UDP split transmission / reception process includes a split request process in the user agent UA shown in FIG. 4 and a split response process in the service agent SA1 shown in FIG.

  As shown in FIG. 4, in the user agent UA division request processing, the user agent UA activates the SLP program and uses the UI shown on the display 46 and the input mechanism 45 to set the service search condition. Input is started when the CPU 30 of the user agent UA accepts this search instruction (step S100). In this case, the search instruction is used to request an attribute response for all printers on the local area network LAN.

  When receiving the search instruction, the CPU 30 creates an SLP attribute request message Rq1 as a process of the process request unit 32, and transmits it by multicast using UDP (step S110). In this embodiment, the transmission is performed by multicast, but may be transmitted by broadcast.

  The structure of this attribute request message Rq1 is shown in FIG. The attribute request message Rq1 shown in the figure is a data portion obtained by removing the UDP header from the UDP datagram, and includes an SLP header and a message portion. As shown in the figure, a special tag by the vendor extension function is added to the tag list of the attribute request message Rq1. This special tag is added by the CPU 30 as a process of the division instruction unit 31. When the attribute response message Rp for the attribute request message Rq1 exceeds the capacity (1400 octet in this case) that can be transmitted by UDP, the response data It plays a role as a parameter that conveys a division instruction for dividing and transmitting.

  On the other hand, as shown in FIG. 5, the service agent SA1 waits for the attribute request message Rq1 to be received as the divided response process (step S200). If the service agent SA1 receives the attribute request message Rq1 (step S200: YES), The CPU 50 interprets the attribute request message Rq1, creates an attribute list At for the attribute request message Rq1, and determines whether or not the data length of the attribute response message Rp including the attribute list At is less than or equal to 1400 octets. Step S210).

  As a result, if it is 1400 octets or less (step S210: NO), it means that the attribute response message Rp is less than the data size that can be transmitted at one time by UDP, and the CPU 50 creates it as the process of the process response unit 53. The attribute response message Rp1 including all of the attribute list At is transmitted to the user agent UA by unicast using UDP (step S300), and the process is returned to the original. At this time, since the service agent SA1 transmits all of the attribute list At, the OVERFLOW flag of the SLP header is “OFF”.

  On the other hand, if it is larger than 1400 octets (step S210: YES), it means that the attribute response message Rp exceeds the data size that can be transmitted at one time by UDP, and the CPU 50 continues to receive the attribute request message Rq1. It is determined whether or not a special tag is included therein (step S220).

  As a result, if the special tag is not included (step S220: NO), the attribute list At need not be divided and transmitted. Therefore, as a process of the process response unit 53, the CPU 50 creates an attribute response message Rp1 within a range in which the size of the attribute response message Rp falls within 1400 octets, based on a part of the created attribute list At. Using this, unicast is transmitted to the user agent UA (step S290), and the process is restored. At this time, since the service agent SA1 can transmit only a part of the attribute list At, the OVERFLOW flag of the SLP header is “ON”.

  On the other hand, if a special tag is included (step S220: YES), it is necessary to divide and transmit the attribute list At, and the CPU 50 processes the attribute response message Rp as 1400 as processing of the division unit 51. The attribute list At is divided into n pieces so as to fit in octets (step S230). Then, the CPU 50 creates an attribute response message Rp1 based on the divided attribute list At1 that forms the head of the attribute list At among the divided attribute lists Ati (i = 1 to n) divided into n pieces, and processes the response. As a process of the unit 53, it transmits by unicast to the user agent UA using UDP (step S240). At this time, since the service agent SA1 transmits all of the division attribute list At1, the OVERFLOW flag of the SLP header is “OFF”.

  The structure of this attribute response message Rp1 is shown in FIG. The attribute response message Rp1 is a data portion obtained by removing the UDP header from the UDP datagram, and includes an SLP header and a message portion. As shown in the figure, in the vendor extension area of the attribute list of the attribute response message Rp1, the special tag included in the attribute request message Rq, the identification information of the service agent SA1, and the sequence number indicating the arrangement order of the divided attribute list Ati SN is added. These pieces of information are added by the CPU 50 as processing of the adding unit 52. The special tag has a flag bit indicating whether there is another split attribute list to be received following the split attribute list At1. Here, since there is another division attribute list to be received following the division attribute list At1, the flag is “ON” indicating that. The sequence number SN corresponds to the order information in the claims, and is “1” corresponding to the division attribute list At1. In this embodiment, the identification information is the MAC address of the service agent SA1.

  When the attribute response message Rp1 is transmitted, the CPU 50 waits for reception of the attribute request message Rqi (step S250). This attribute request message Rqi is further transmitted by the user agent UA after transmitting the attribute request message Rq1, and requests transmission of the i-th divided attribute list Ati constituting the attribute list At. This will be described later.

  When the attribute request message Rqi is received (step S250: YES), the CPU 50 refers to the sequence number SN (= i) included in the attribute request message Rqi, and SN is set to n which is the division number of the attribute list At. It is determined whether or not they are equal (step S260). As a result, if the sequence number SN is not n (step S260: NO), the attribute request message Rqi does not request the last divided attribute list Atn constituting the attribute list At. Therefore, as shown in FIG. 7B, the CPU 30 performs processing of the adding unit 52 on the identification information and the i-th divided attribute list Ati corresponding to the sequence number SN “i” included in the attribute request message Rqi. In addition to adding the sequence number SN “i”, to indicate that there is a continuation in the divided attribute list Ati to be transmitted, the flag of the special tag is set to “ON”, an attribute response message Rpi is created, and the processing response unit 53 In step S280, UDP is transmitted to the user agent UA using unicast. Then, the process returns to step S250, and the processes of steps S250, S260 and S280 are repeated until the sequence number SN of the received attribute request message Rqi becomes n.

  On the other hand, if the sequence number SN is n (step S260: YES), the attribute request message Rqi is a request for the last divided attribute list Atn constituting the attribute list At. Therefore, as shown in FIG. 7C, the CPU 30 adds the identification information and the sequence number SN “n” to the division attribute list Atn and transmits the division attribute list Atn as processing of the addition unit 52. In order to indicate that there is no continuation, the flag of the special tag is set to “OFF”, an attribute response message Rpn is created, and the processing of the processing response unit 53 is unicast to the user agent UA using UDP. Transmit (step S270).

  Here, the description returns to the user agent UA. As shown in FIG. 4, the user agent UA transmits the attribute request message Rq1 in step S110, and then waits for reception of the attribute response message Rpi from the service agent SA1 (step S120). When the attribute response message Rpi (initially Rq1) is received (step S120: YES), the CPU 30 determines whether the flag of the special tag included in the attribute response message Rpi is “ON” as the processing of the determination unit 33. Is determined (step S130).

  As a result, if the flag is “OFF” (step S130: NO), this means that there is no continuation in the attribute list to which the service agent SA1 should respond, and the CPU 30 ends the division request process. When the CPU 30 receives a plurality of divided attribute lists Ati, the CPU 30 combines them to generate an attribute list At. The CPU 30 displays the contents of the attribute list At thus obtained on the display 46.

  On the other hand, if the flag is “ON” (step S130: YES), this means that there is a continuation in the divided attribute list Ati included in the received attribute response message Rpi. Therefore, the CPU 30 increments the sequence number SN included in the attribute response message Rpi by 1 (SN: i → i + 1) (step S140), and sends the SLP attribute request message Rq (i + 1) to which the sequence number SN is added. It is created as a process of the process request unit 32 and is transmitted by multicast using UDP (step S150).

  The structure of this attribute request message Rq (i + 1) is shown in FIG. In the attribute request message Rq (i + 1), in addition to the configuration of the attribute request message Rq1 transmitted in step S110 (see FIG. 6A), the sequence number SN (i + 1) is added to the vendor extension area. Based on the added sequence number SN, the user agent UA requests the service agent SA1 for the division attribute list At (i + 1).

  When the attribute request message Rq (i + 1) is transmitted in this way, the CPU 30 returns the process to step S120, and receives all the divided attribute list Ati until the flag of the received special tag becomes “OFF”. Until then, the processing of steps S120 to S150 is repeated.

  A specific example of the flow of processing between the user agent UA and the service agent SA1 is shown in FIG. First, the user agent UA transmits the attribute request message Rq1 including the special tag “x-1248-p-usediv” to the service agent SA1. On the other hand, the service agent SA1 includes the special tag flag “x-1248-p-usediv = ON”, the identification information “p-1248-ID-000048AAAAAAA”, the sequence number of the service agent SA1 in the division attribute list At1. “P-1248-seq = 1” is added and an attribute response message Rp1 is returned.

  On the other hand, when the user agent UA receives the attribute response message Rp1, since the flag of the special tag included in the attribute response message Rp1 is “ON”, the special tag “x-1248-p-usediv” and the sequence number “p-1248- An attribute request message Rq2 including “seq = 2” is transmitted to the service agent SA1. In response to this, the service agent SA1 includes the special tag flag “x-1248-p-usediv = ON”, the identification information “p-1248-ID-000048AAAAAAA”, and the sequence number “p-1248” in the division attribute list At2. -Seq = 2 "is added and an attribute response message Rp2 is returned.

  Similarly, when the user agent UA receives the attribute response message Rp2, since the flag of the special tag included in the attribute response message Rp2 is “ON”, the special tag “x-1248-p-usediv” and the sequence number “p-1248” are included. An attribute request message Rq2 including “-seq = 3” is transmitted to the service agent SA1. On the other hand, the service agent SA1 adds a special tag flag “x-1248-p-usediv = OFF”, identification information “p-1248-ID-000048AAAAAAA”, and sequence number “p-1248” to the division attribute list At3. -Seq = 3 "is added and an attribute response message Rp3 is returned.

  Then, when the user agent UA receives the attribute response message Rp3, the flag of the special tag included in the user agent UA is “OFF”. Therefore, the user agent UA receives all the divided attribute lists Ati (here, the divided attribute lists At1 to At3). Judgment is made and the division request processing is terminated.

  Although explanation is omitted, since the user agent UA transmits the attribute request message Rq1 by multicast in step 110 of FIG. 4, other than the communication between the user agent UA and the service agent SA1 described above. In addition, similar communication is performed between the user agent UA and the service agent SA2. In this case, the user agent UA receives the attribute response message Rpi from the service agent SA1 and the service agent SA2, respectively, and the attribute response message Rpi includes identification information of the service agents SA1 and UA2. Therefore, the user agent UA can accurately determine the response from the service agent SA1 and the response from the service agent SA2.

  In the present embodiment, the UDP split transmission / reception processing for SLP communication is shown. However, the communication protocol is not particularly limited to SLP, and the processing requesting device transmits by multicast or broadcast using UDP. Any communication protocol may be used as long as the processing response device responds to a predetermined processing request, or a manufacturer-defined protocol may be used.

  In the communication system 20 having such a configuration, when the response to the attribute request message Rq of the user agent UA exceeds a predetermined capacity that can be transmitted by UDP, the user agent UA indicates a special instruction indicating a division instruction for dividing the response content and transmitting it. The attribute request message Rq1 including the tag is transmitted by multicast or broadcast. On the other hand, when the attribute list At, which is a response to the attribute request message Rq1, exceeds the predetermined capacity, the service agent SA1 responds by adding the sequence number SN to the divided attribute list Ati obtained by dividing the attribute list At. Therefore, in SLP communication using UDP, data exceeding the upper limit of the data length that can be transmitted by UDP can be exchanged. In addition, this makes it possible to perform SLP communication even in an environment where no IP address is assigned to the service agent. Furthermore, even if the data exceeds the upper limit of the data length that can be transmitted by UDP, the network load can be reduced because the traffic can be exchanged using UDP, which has a smaller traffic volume compared to communication using TCP.

  In the communication system 20 configured as described above, the service agent SA1 sets a special tag flag indicating whether or not the divided attribute list Ati transmitted by the service agent SA1 is the last divided attribute list Atn constituting the attribute list At. Add and respond. On the other hand, the user agent UA refers to the flag and determines that all the division attribute lists Ati have been received when the flag is “OFF”. Therefore, the user agent UA can easily know that all the divided attribute list Ati has been received, and can terminate the exchange with the service agent SA1 at an appropriate timing.

  Note that in the SLP standard, the service agent does not return a tag when an unknown tag is included in the received attribute request message Rq. That is, in an environment where unsupported service agents not corresponding to the present invention are mixed on the local area network LAN, the unsupported service agent receives the attribute request message Rq including the special tag transmitted by the user agent by multicast. However, there will be no trouble. Therefore, the present invention is also compatible with existing service agents.

B. Variations:
A modification of the above-described embodiment will be described.
B-1. Modification 1:
In the embodiment, when the attribute list At is divided and transmitted, the service agent SA1 responds to the attribute request message Rq1 transmitted by the user agent UA in step S110 with an attribute response message Rp1 including the divided attribute list At1. However, it is not limited to such a configuration. For example, the first response does not include the divided attribute list At1, and the attribute request message is transmitted again from the user agent UA that recognizes that the divided transmission is necessary by the flag of the special tag included in the first response. A configuration may be adopted in which the division attribute list Ati is responded to Rqi.

B-2. Modification 2:
In the embodiment, the user agent UA is configured to determine whether or not there is a message based on the flag of the special tag included in the attribute response message Rpi received from the service agent SA1. Completion determination is not limited to such a configuration. For example, the CPU 30 of the user agent UA determines from the accumulated size of the received divided attribute list Ati and the total length size of the attribute list At included in the attribute response message Rpi (for example, “length of” in FIG. 7A). A message reception completion determination may be made. Also with this configuration, the user agent UA can easily know that all the divided attribute list Ati has been received, and can terminate the exchange with the service agent SA1 at an appropriate timing.

  Further, in the embodiment, the user agent UA is configured to end the division request processing shown in FIG. 4 when it is determined that the division attribute list Ati has been received from the service agent SA1. The end timing is not limited to this. For example, it may be configured to end after a predetermined time has elapsed from the start of processing. Alternatively, it may be configured to retry from the beginning after a lapse of a predetermined time from the start of processing. If the attribute response message Rpi from the service agent SA1 is not received within a predetermined time despite the attribute response message Rpi being transmitted in step S150 of FIG. 4 (step S120: NO), the attribute response message Rpi It is good also as a structure which resends. In this way, even if the UDP datagram is lost on the local area network LAN for some reason, it is possible to cope with it.

B-3. Modification 3:
If the service agent SA1 fails to divide the attribute list At in step S230 of FIG. 5, the service agent SA1 may add a configuration in which the flag of the special tag is “FAILED”. In this case, the user agent UA that has received the attribute response message Rp1 including the special tag whose flag is “FAILED” may end the division request processing.

  In addition, the service agent SA1 creates a divided attribute list Ati, and if the sequence number SN included in the received attribute request message Rqi is invalid when the divided session is in the divided session with the user agent UA, the attribute request message If Rqi is multicast, no response is made, and if attribute request message Rqi is unicast, an error may be returned. Further, when the sequence request SN is included in the received attribute request message Rq1 when the divided session is not in progress, no response is made if the attribute request message Rqi is multicast, and an error occurs if the attribute request message Rqi is unicast. It is good also as a structure to return.

B-4. Modification 4:
In the embodiment, the service agent SA1 is configured to transmit the divided attribute list Ati in the order in which the attribute list At is arranged in accordance with the divided attribute list Ati from the user agent UA, but the transmission order is particularly limited. Instead, for example, the attribute list At may be transmitted in the reverse order of the arrangement order, or may be transmitted in a random order. The user agent UA transmits an attribute request message Rqi with a sequence number SN of 1 to n, and the service agent SA1 adds order information indicating the arrangement order of the divided attribute list Ati uniquely corresponding to the sequence number SN. Then, it is sufficient to respond.

  Further, the order information added by the service agent SA1 is not limited to a number indicating a unique arrangement order, but may be any information that allows the user agent UA to interpret the arrangement order of the received divided attribute list Ati. For example, the number of the divided attribute list Ati transmitted immediately before the transmission of the divided attribute list Ati to be transmitted or the number of the divided attribute list Ati transmitted immediately after the transmission may be indicated.

B-5. Modification 5:
In the embodiment, all the service agents SA1 and SA2 respond to the attribute request message Rq1 transmitted by the user agent UA by multicast. However, the attribute information is received only from a specific service agent, for example, the service agent SA1. It is good also as a structure which acquires. Such a configuration can be realized, for example, as follows.

  First, in step S110 of FIG. 4, the CPU 30 of the user agent UA creates an attribute request message Rq1 including a predetermined SLP search condition and an execution command of a predetermined protocol, and transmits it by multicast using UDP. The execution command is added as a process of the command adding unit 34. Various protocols can be used as the predetermined protocol. For example, SNMP (Simple Network Management Protocol) can be used.

  A specific example of the content of the attribute request message Rq1 is shown in FIG. FIG. 9A is a conceptual diagram of a service search request when an SNMP execution command is not included. Here, as a specific example, a case where a product name of an EPSON printer connected to a LAN is searched will be described. In the URL of the attribute request message Rq1, “p-dev.1248” (representing EPSON) indicating the manufacturer name of the apparatus and “printer” indicating the service type to be searched are stored as information on the service to be searched. The list includes unique information to be searched such as “x-1248-p-dev.” Indicating a vendor extension function and “pn” indicating a product name, and a special tag “x-1248-p-usediv”. Is stored.

  On the other hand, FIG. 9B is a conceptual diagram of a service search request when an SNMP execution command is included. In this case, the tag list of the attribute request message Rq1 includes “x-1248” indicating the vendor's extended function, “p-spt” that is an attribute for processing the SNMP defined by the extended function, and SNMP GetRequest- “Snmpget” indicating that the PDU is processed, “V1” indicating that the snmpget is performed by SNMPv1, “public” as the community name, and “1.3.6.1.2.1. 1.5.0 ”(representing sysName), information to be searched such as“ result: noError ”as a process execution condition defined to execute a response to the search request when the execution result of the command is matched And a special tag “x-1248-p-useddiv” is stored. That is, the contents of the tag list are defined so that a response to the search request is returned when the result of executing the SNMP command is “noError”.

  In this tag list, by using characters other than those stipulated in the SLP tag list description, such as “{” at the beginning, “}” at the end, and “|” at the end of the content, It is easy to determine whether or not an SNMP execution command is stored. Here, for convenience of explanation, the SNMP command or the like has been described as a character such as “noError”. However, in actuality, the content of the tag list is “020100” (hexadecimal number representing noError). It is described in accordance with the SNMP convention.

  FIG. 10 shows the flow of the division response processing of the service agent SA1 when such attribute request message Rq1 is received, which is different from the division response processing shown in FIG. When the attribute request message Rq1 is received in step S200 (step S200: YES), the CPU 50 determines whether or not the SNMP command is included in the attribute request message Rq1 (step S310).

  As a result, if the SNMP command is included (step S310: YES), the CPU 50 acquires the SNMP command from the tag list stored in the attribute request message Rq1, and this command is processed as the command execution unit 54. Is executed (step S320). Then, the CPU 50 determines whether or not the result of executing the command satisfies the process execution condition described in the tag list (step S330). In this example, as described above, whether or not the process execution condition is satisfied is determined based on whether or not the command execution result is “noError”.

  As a result, if the processing execution condition is not satisfied (step S330: NO), the CPU 50 returns the processing to the original without performing a response to the attribute request message Rq1. On the other hand, if the process execution condition is satisfied (step S330: YES), the CPU 50 advances the process to step S210. The subsequent processing is as described in FIG.

  If the SNMP command is not included in step S310 (step S310: NO), the CPU 50 matches the search condition specified in the tag list with the information of the service agent SA1 stored in the EEPROM 61 or the like. It is determined whether or not the search condition is satisfied (step S340). As a result, if the search condition is not matched (step S340: NO), the CPU 50 returns the processing to the original without performing a response to the attribute request message Rq1. On the other hand, if it matches the search condition (step S340: YES), the CPU 50 advances the process to step S210. The subsequent processing is as described in FIG.

  In this modification, the user agent UA creates and transmits the attribute request message Rq1 including the search condition and the process execution condition. However, the user agent UA creates and transmits only one of these conditions. Also good. In addition, the service agent SA1 determines whether or not the process execution condition is satisfied in step S330, and the process proceeds to step S210 only when the process execution condition is satisfied. With this configuration, the user agent UA can acquire necessary information only from a specific service agent, so that the processing of the user agent UA becomes efficient and the load on the local area network LAN is reduced. Because it can be done. However, it is not necessary to be limited to such a configuration, and when the SNMP command is executed with step S330 omitted, the processing may be advanced to step S210 without fail.

  In the communication system 20 having such a configuration, the user agent UA transmits an attribute request message Rq1 including a search condition, an SNMP execution command, and a process execution condition based on the SNMP execution result. On the other hand, the service agents SA1 and SA2 respond only when the search condition and the process execution condition are satisfied. Therefore, the user agent UA can efficiently acquire only information on a specific service agent. Thereby, the traffic amount of the local area network LAN can be reduced.

  In the communication system 20 having such a configuration, the user agent UA transmits the attribute request message Rq1 including the SNPM execution command. On the other hand, the service agents SA1 and SA2 respond with the SNMP execution result as an attribute response message when the search condition and the process execution condition are satisfied. Therefore, the capacity of the attribute response message tends to be larger than that of normal SLP communication. However, even if the capacity of the attribute response message exceeds the UDP communicable capacity, the communication system 20 is not limited to the embodiment. As shown, the attribute list At can be divided and transmitted using UDP.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. For example, the present invention exemplifies a configuration as a personal computer as a user agent and a printer as a service agent. However, the user agent and the service agent are realized as various network devices such as a mobile phone, a digital camera, a FAX, and a router. can do. Further, the present invention is not limited to the configuration as the communication system, the user agent, or the service agent shown in the embodiments, and can be realized in the form of a program, a communication method, and the like.

1 is an explanatory diagram showing a schematic configuration of a communication system 20. FIG. It is explanatory drawing which shows schematic structure of the user agent UA. It is explanatory drawing which shows schematic structure of service agent SA1. It is a flowchart which shows the flow of the division | segmentation request | requirement process in the user agent UA. It is a flowchart which shows the flow of the division | segmentation response process in service agent SA1. It is explanatory drawing which shows the example of an attribute request message notionally. It is explanatory drawing which shows the specific example of an attribute response message notionally. It is explanatory drawing which shows the communication between user agent UA and service agent SA1. It is explanatory drawing which shows notionally the specific example of the attribute request message as a modification. It is a flowchart which shows the flow of the division | segmentation response process in service agent SA1 as a modification.

Explanation of symbols

20 ... Communication system 30 ... CPU
31 ... Division instruction part 32 ... Processing request part 33 ... Judgment part 34 ... Command addition part 41 ... Hard disk drive 42 ... ROM
43 ... RAM
45 ... Input mechanism 46 ... Display 49 ... Interface 50 ... CPU
51 ... Division unit 52 ... Addition unit 53 ... Processing response unit 54 ... Command execution unit 61 ... EEPROM
62 ... ROM
63 ... RAM
65 ... Input mechanism 66 ... Printing mechanism 67 ... Scanner 68 ... FAX transmission mechanism 69 ... Interface UA ... User agent SA1, SA2 ... Service agent LAN ... Local area network

Claims (11)

Using UDP, the processing request device and the processing response device communicate with each other via a network using a communication protocol in which the processing response device responds to a predetermined processing request transmitted by the processing request device by multicast or broadcast. A communication system,
The processing requesting device is:
When response data to be responded to the processing request exceeds a predetermined capacity that can be transmitted by the UDP, a division instruction means for including a division instruction for dividing and transmitting the response data in the processing request;
Processing request means for transmitting the processing request including the division instruction,
The process response device is:
Division means for receiving a processing request including the division instruction and dividing the response data into a capacity that can be transmitted by the UDP when the response data exceeds the predetermined capacity;
Adding means for adding order information indicating the arrangement order of the divided data in the response data to each of the divided data;
And a processing response means for transmitting the divided data to which the order information is added as the response to the processing requesting device.   The communication system according to claim 1, wherein the communication protocol is SLP. A communication system according to claim 2,
The adding means further adds a flag indicating whether or not the divided data is the last divided data constituting the response data to each of the divided data,
The processing requesting apparatus further includes first determination means for determining that all the divided data have been received with reference to the flag. A communication system according to claim 2 or claim 3, wherein
The adding means further adds size information indicating the size of the response data to each of the divided data,
The processing requesting apparatus further includes second determination means for determining that all the divided data have been received with reference to the size information.   The communication system according to any one of claims 2 to 4, wherein the adding means further adds identification information of the processing response device to each of the divided data. A communication system according to any one of claims 1 to 5,
The processing requesting device further comprises command adding means for including an execution command of a predetermined protocol in the processing request.
The process response device further comprises command execution means for interpreting and executing the execution command when the execution request is included in the processing request,
The processing response device is a communication system that handles an execution result of the execution command as the response data. The communication system according to claim 6, wherein
The processing response device treats an execution result of the execution command as the response data when the execution result of the execution command satisfies a predetermined condition. A processing response device that responds to a predetermined processing request transmitted by multicast or broadcast from a processing request device connected via a network using UDP,
When the processing request including a predetermined parameter is received and the response data to be responded to the processing request exceeds a predetermined capacity that can be transmitted by the UDP, the response data is transmitted by the UDP. Dividing means for dividing into possible capacity;
Adding means for adding order information indicating the arrangement order of the divided data in the response data to each of the divided data;
And a response means for transmitting the divided data to which the order information is added to the process request device as the response. A processing request device that transmits a predetermined processing request by multicast or broadcast to a processing response device connected via a network using UDP,
When the response data that the process response device should respond to the processing request exceeds a predetermined capacity that can be transmitted by the UDP, a division instruction that divides the response data and transmits it is included in the processing request. Instruction means;
A processing requesting device comprising: requesting means for transmitting the processing request including the division instruction. A computer program for responding to a predetermined processing request transmitted by multicast or broadcast from a processing request device connected via a network using UDP,
When the processing request including a predetermined parameter is received and the response data to be responded to the processing request exceeds a predetermined capacity that can be transmitted by the UDP, the response data is transmitted by the UDP. Split function to divide into possible capacity,
An additional function of adding to each of the divided data the order information indicating the number of data that constitutes the response data.
A program that causes a computer to realize a response function of transmitting the divided data to which the order information is added as the response to the processing requesting device. A computer program for transmitting a predetermined processing request by multicast or broadcast using UDP to a processing response apparatus connected via a network,
When the response data that the process response device should respond to the processing request exceeds a predetermined capacity that can be transmitted by the UDP, a division instruction that divides the response data and transmits it is included in the processing request. An instruction function;
A program for causing a computer to realize a request function for transmitting the processing request including the division instruction.

Images