JP4013153B2 - Communication apparatus and program - Google Patents

Description

  The present invention relates to a communication apparatus and program for communicating various data such as voice data, moving image data, image data, and text data in a media session established by a call control protocol such as SIP (Session Initiation Protocol).

  In recent years, communication devices that transmit and receive various data over an IP network, such as IP telephone communication and IP facsimile communication, have become widespread, and multifunction devices that perform data communication corresponding to both voice data and image data have been proposed. For example, as disclosed in Patent Document 1, an IP telephone communication function and an ITU-T recommendation T.264. There is a communication apparatus that has an IP facsimile communication function conforming to H.38 and can simultaneously perform transmission and reception by IP telephone communication and IP facsimile communication.

In such a communication device, when performing IP telephone communication or the like, the control corresponding to the control performed by the switch of the general public network, such as calling of the other party communication device and management of the call, is performed by a call control protocol. The call control protocol includes H.264. 323, SIP, etc. are often used. In particular, SIP only establishes, changes, and terminates a session and does not know the contents of the session. Therefore, the SIP is not limited to IP telephone communication, but various types such as SMTP (Simple Mail Transfer Protocol) and HTTP (Hypertext Transfer Protocol). Various types of communication protocols can be used in a media session established between a sender and a receiver. That is, according to SIP, various types of data such as voice data, moving image data, and image data can be transmitted and received in an established media session. It is also possible to simultaneously establish a plurality of media sessions and perform a plurality of types of data communication simultaneously.
JP 2002-101256 A

  In a media session established by SIP, UDP (User Datagram Protocol) may be used as a lower transport layer instead of TCP having an error correction function. Data communication is performed without error correction. When sending and receiving voice data, if a packet fails due to noise or the like, some of the speaker's words may be lost. However, the listener can understand the meaning of the words before and after the missing part, so IP phone etc. As such, there are few problems when using a media session for a call. However, when transmitting and receiving image data and text data, if a failure occurs in the packet, the original image data and text data cannot be reproduced from the data received on the receiving side. On the other hand, if TCP is used as a lower transport layer of a media session, an error correction function can be used, but conversely, there is a problem in IP telephone communication that requires real-time data transmission.

  The present invention has been made in view of such a problem, and can enable or disable an error correction function for each type of data transmitted and received in a media session established by a call control protocol. An object of the present invention is to provide a communication apparatus that can perform data transmission suitable for a type.

The communication apparatus according to claim 1, wherein the communication apparatus includes means for performing data communication with a partner in a media session established by SIP (Session Initiation Protocol) which is a call control protocol. Whether or not to perform correction processing is determined based on the IP address or port number that is information acquired in the call control session based on the SIP call control protocol formed before the media session is established, and error correction processing is performed. If it is determined that the data communication is to be performed, it is determined that the data communication is performed by the UDP while performing the error correction process while performing the error correction process if the TCP can be used , and the error correction process is not performed. In such a case, a means for performing the data communication by UDP without performing error correction processing is provided. It is said.

  The information on the media session to be established includes, for example, various information acquired in a call control session formed before establishing the media session (for example, type information of communication data used in the media session, communication protocol, destination IP Address, destination port number, etc.) and various information determined by forming the call control session (for example, type information of communication data used in the media session, communication protocol, destination IP address, destination port number, etc.) is there.

  The communication device according to claim 2 is the communication device according to claim 1, wherein the error correction processing is performed by a communication protocol used in a media session and an error correction protocol not related to a content of data exchanged by the communication protocol. It is characterized by being performed.

The program according to claim 3, wherein means for performing data communication with a partner in a media session established by SIP as a call control protocol, whether to perform error correction processing for the data communication performed with the partner, If the decision is made based on the IP address or port number, which is the information acquired in the call control session based on the SIP call control protocol formed before the establishment, and error correction processing is performed, the use of TCP If it is possible to use TCP, and if it is impossible to use TCP, the data communication is performed using UDP while performing error correction processing. If it is decided not to perform error correction processing, the error correction processing is not performed. A computer is caused to function as means for performing the data communication by UDP .

  According to the communication device of the first aspect, it is determined whether or not to perform the error correction processing based on the information regarding the media session to be established. In many cases, the type of communication data transmitted / received in the media session can be specified by the information related to the media session, so depending on the characteristics of the transmitted / received data, for example, for image data that requires error correction, etc. Thus, it is possible to perform error correction processing and not to perform error correction processing on voice call data or the like that should not be corrected.

  The communication apparatus according to claim 2 performs the error correction processing by executing a communication protocol used in the established media session and an error correction protocol not related to the contents of data exchanged in the communication protocol. There is an advantage that the communication protocol used in is not limited to a specific one.

  By incorporating the program according to claim 3 into a computer and executing the program, the communication apparatus according to claim 1 can be configured, and the above-described effects are exhibited.

  According to the communication device of the fourth aspect, for example, error correction processing is performed on image data that requires error correction, and error correction processing is not performed on voice call data that should not be error corrected. It becomes possible to.

  Hereinafter, as a communication apparatus according to an embodiment of the present invention, a facsimile multifunction machine having a G3 facsimile communication function, an Internet facsimile communication function, and the like will be described as an example. Of course, the present invention can be applied to other types of communication apparatuses as well as facsimile multifunction machines as long as various data communications can be performed with a partner in a media session established by a call control protocol. .

  FIG. 1 shows a configuration example of the facsimile multifunction machine 1. That is, the facsimile MFP 1 includes a CPU (Central Processing Unit) 2, a ROM (Read Only Memory) 3, a RAM (Random Access Memory) 4, an image memory 5, a modem 6, an NCU 7, a codec 8, a reading unit 9, and a recording unit. 10, a display unit 11, an operation unit 12, and a LAN interface 13. The units 2 to 13 are connected by a bus 14.

  The CPU 2 functions as a control unit that controls each part of the facsimile multifunction peripheral 1 according to a control program stored in the ROM 3. The ROM 3 stores the control program and the like. The RAM 4 functions as a main memory and work area for the CPU 2. The RAM 4 stores an error correction necessity determination table 4a.

  As shown in FIG. 2, the error correction necessity determination table 4a includes data types such as voice, moving image, device data (communication device), image (still image), etc. For each substantive content type, setting information indicating whether or not to perform error correction processing is stored. That is, in the error correction necessity determination table 4a, the validity or invalidity of the error correction function is set for each type of data transmitted and received in the media session.

  The image memory 5 stores image data compressed and encoded by the codec 8. The modem 6 is, for example, an ITU-T (International Telecommunication Union) recommendation V.3. Modulate and demodulate transmitted / received data according to the 34 standard or the like. The NCU 7 is a line network control device that performs operations of closing and opening a line with the PSTN (Public Switched Telephone Network) 15 and connects the modem 6 to the PSTN 15 as necessary. The codec 8 compresses and encodes image data by JPEG method or MH, MR, MMR method or the like, and decodes received image data or the like, for facsimile transmission or the like.

  The reading unit 9 reads image data of a document, and includes, for example, a CCD color line sensor, an A / D converter, an image processing circuit, and the like. The recording unit 10 takes out the recording paper from the paper feed cassette and records the received image data, the read image data, etc. on the recording paper. The display unit 11 includes, for example, an LCD (Liquid Crystal Display) arranged in parallel with the operation unit 12 and displays various screen information. The operation unit 12 includes various operation keys and the like, and various operations by the user are performed in the operation unit 7.

  The LAN interface 13 is an interface for connecting the facsimile multifunction peripheral 1 and a LAN (local area network) 16. Through this, the facsimile multifunction peripheral 1 communicates with a client PC (not shown) or a router 19 also connected to the LAN 16. I do. Furthermore, various data communication is performed with another SIP-compatible communication device 18 on the IP network 17 through the router 19.

  The facsimile multifunction machine 1 having the above-described configuration includes UDP / IP, TCP / IP, SIP, RTP (Real-time Transport Protocol), RTSP (Real-time Streaming Protocol), SDP (Session Description Protocol), and SMTP (Simple Mail Transfer). Protocol), HTTP (Hypertext Transfer Protocol), etc. are implemented. As a result, various data such as voice data, moving image data, image data (still image data), and text data can be transmitted and received over a media session established by SIP call control.

  Furthermore, the facsimile multifunction peripheral 1 is implemented with a unique error correction protocol that operates in a protocol layer higher than SIP, RTP, etc., and lower than a communication protocol that transmits and receives image data and text data. Therefore, the error correction processing executed by this original error correction protocol is not related to the communication protocol used in the media session and the contents of data exchanged by the communication protocol, so the communication protocol used in the media session is specified. There is an advantage that it is not limited to.

  This unique error correction protocol, for example, forms the following procedure between the transmission side and the reception side. That is, when sending data to the receiving side in a media session established by SIP, the sending side divides the data into fixed units, adds a sequence number to the divided blocks, and converts the data in the block to A total value obtained by adding all of them is added to a predetermined portion of the block, for example, at the end of the block. The receiving side divides the received data in the same way as above, calculates the total value of all the data in the block, compares it with the value added to the predetermined location of the block, and the values match. For example, it is determined that there is no problem in the data in the block. Then, the data already received as no problem and the data sent from the transmission side again by the retransmission request are reconstructed according to the sequence number.

  Next, the processing operation when the facsimile multifunction peripheral 1 having the above configuration and functions establishes a media session by SIP (call control protocol) and performs data communication with the facsimile multifunction peripheral 1 having the same configuration and functions as the own apparatus 1. Will be described based on the sequence diagram shown in FIG. 3 and the flowcharts shown in FIGS. The processing operations described based on these drawings are executed according to instructions issued by the CPU 2 as the control means based on the control program stored in the ROM 3. For convenience of explanation, the facsimile multifunction device 1 on the transmission side will be described as a transmitter 1A, and the facsimile multifunction device 1 on the reception side will be referred to as a receiver 1B.

  As shown in the sequence diagram of FIG. 3, first, a call control session (hereinafter referred to as “start call control session”) is formed between the transmitter 1A and the receiver 1B by SIP. That is, the transmitter 1A requests the SIP server 20 to call the receiver 1B by a session participation request “INVITE” in which the IP telephone number of the receiver 1B is designated, and also includes an IP address as various information of the transmitter. Then, information such as a port number used in the media session is sent to the receiver 1B (T1).

  Upon receiving the information such as “INVITE”, the SIP server 20 sets the IP address corresponding to the IP phone number designated by the transmitter 1A to a location server (not shown) having IP phone number / IP address correspondence information. To the acquired IP address of the receiver 1B by sending information such as “INVITE” received from the transmitter 1A.

  When the receiver 1B responds to the call of the SIP server 20, the receiver 1B receives various information such as the positional information of the transmitter 1A together with “INVITE”, and sends a success response code “200” to the SIP server 20. "Is sent out. In addition to the success response code “200”, as information about the receiver 1B, the IP address that is the location information of the receiver 1B, the port number used in the media session, the type information of communication data that can be used by the receiver 1B, Information such as whether or not the communication protocol and the error correction function based on the original protocol are supported is transmitted (R1).

  The transmitter 1A that has received the success response code “200” and the various information of the receiver 1B, together with the information “ACK” indicating that the success response code “200” has been received, is information regarding the media session to be established, Information such as the type of communication data used in the media session, the communication protocol, and the port number is transmitted to the receiver 1B via the SIP server 20 (T2). Thereafter, a media session is established between the transmitter 1A and the receiver 1B, and various types of data communication are performed depending on the type of communication data, communication protocol, communication port, etc. determined by the negotiation performed by the start call control session. Is executed.

  After the data communication in the media session is completed, the transmitter 1A sends “BYE” requesting disconnection of the SIP connection to the SIP server 20, and the SIP server 20 receiving this sends “BYE” to the receiver 1B. Transmit (T3). Then, the receiver 1B sends a success response code “200” to the SIP server 20 (R3), and when the SIP server 20 sends a success response code “200” to the transmitter 1A, a series of sessions is terminated. Communication is disconnected. A call control session that is formed until communication is terminated after the media session is terminated is hereinafter referred to as an “end call control session”.

  Next, processing operations performed by the transmitter 1A to determine whether or not to perform error correction processing for data communication performed in the established media session will be described based on the flowchart shown in FIG.

  The transmitter 1A calls the receiver 1B by SIP at T1 (S1), and when there is a response from the R1 (S2: YES), forms a start call control session with the receiver 1B. While exchanging various information as described above, that is, performing negotiation necessary for establishing the media session (S3), information on the media session such as the type of data communication used in the media session, communication protocol, communication port, etc. Confirm (S4). Then, it is determined whether or not to perform error correction processing for data communication transmitted / received in the media session based on the data communication type information in the information related to the determined media session (S5).

  That is, it is determined whether or not to perform error correction processing according to the setting of the error correction necessity determination table 4a corresponding to the type of data communication performed in the media session. Specifically, as shown in FIG. 2, when the type of data communication determined in S4 is voice or moving image, the error correction function is set to invalid, and no error correction processing is performed. If the type of data communication determined in S4 is device data or image, the error correction function is set to be valid, and it is determined that error correction processing is to be performed (S5).

  When it is determined to perform error correction processing (S5: YES), it is determined from the various information of the receiver 1B acquired in the start call control session that the receiver 1B can perform error correction processing using TCP. In this case (S6: YES), “ACK” or the like is transmitted to the receiver 1B (S7), and data is transmitted to the receiver 1B while performing error correction processing by TCP on the established media session (S8). .

  In S6, when the receiver 1B determines that the error correction processing cannot be performed using TCP (S6: NO), the receiver 1B is obtained from various information of the receiver 1B acquired in the start call control session. Is compatible with error correction processing based on a unique protocol (S9), and if it is compatible (S9: YES), “ACK” or the like is transmitted to the receiver 1B (S10). ), Data is transmitted to the receiver 1B while performing error correction processing by the original protocol on the established media session (S11).

  On the other hand, when it is determined in S5 that error correction processing is not performed (S5: NO) and when a negative determination is made in S9 (S9: NO), “ACK” or the like is transmitted to the receiver 1B ( S12) Data is transmitted to the receiver 1B without performing error correction processing (S13). In S12, information indicating that the error correction process is not performed may be transmitted.

  Finally, an end call control session is formed between both parties, and SIP connection disconnection processing is performed (S14). If there is no response from the receiver 1B in S2, that is, if the response code indicating the error content is returned without returning the success response code “200” of R2, communication error processing is performed. (S15). As the communication error process, for example, a message indicating the cause of the communication error, an error code, and the like are displayed on the display unit 11 and printed out from the recording unit 10.

  Next, the processing operation of the receiver 1B on the communication partner side of the transmitter 1A will be described based on the flowchart shown in FIG.

  When the receiver 1B responds to the SIP call from the transmitter 1A in T1 (S51), the receiver 1B exchanges various information as described above while forming a start call control session with the transmitter 1A, that is, a media session. Negotiations necessary for establishment are performed (S52), and confirmed information regarding the media session to be established is received from the transmitter 1A together with ACK (S53).

  When TCP is used as a transport layer in the media session (S54: YES), data is received while performing error correction processing by TCP in the established media session (S55).

  When performing error correction processing using a unique protocol (S54: NO, S56 YES), data reception is performed while performing error correction processing using a unique protocol (S57). In this case, UDP is used as the transport layer.

  When error correction processing is not performed (S54: NO, S56: NO), data reception is performed without performing error correction processing (S58). In this case, UDP is used as the transport layer.

  After the data receiving process of S55, S57 or S58 is completed and “BYE” is received from the transmitter 1A through the SIP server 20, a termination call control session is formed with the transmitter 1A to disconnect the SIP connection. Processing is performed (S59).

  As is clear from the above description, according to the communication device according to the embodiment of the present invention, when the type of communication data transmitted and received in the media session is voice data communication that requires real-time characteristics, error correction is performed. For communication data that requires complete reproduction of the original data on the receiving side, such as image data, image data etc. are transmitted and received while performing error correction. It is possible to realize multimedia communication in accordance with the characteristics and purpose of communication data transmitted and received using SIP.

  Next, a modified example of the embodiment will be described. The facsimile multifunction peripheral 1 according to the modified example has an error correction necessity determination table as shown in FIG. 6 or 7 instead of the error correction necessity determination table 4a, and the determination of S6 is based on the table. Process.

  The error correction necessity determination table 4b shown in FIG. 6 sets validity / invalidity of the error correction function in association with each destination port number, and relates to the media session determined in S4 in the determination process of S5. It is determined whether or not to perform error correction processing according to the setting of the error correction necessity determination table 4b corresponding to the destination port number in the information. Specifically, as shown in FIG. 6, when the destination port number determined in S4 is “4006”, the error correction function is set to invalid, and no error correction processing is performed. If the destination port number determined in S4 is “4004”, the error correction function is set to be valid, and it is determined that error correction processing is to be performed.

  The error correction necessity determination table 4c shown in FIG. 7 sets validity / invalidity of the error correction function in association with each destination IP address, and relates to the media session determined in S4 in the determination process of S5. It is determined whether or not to perform error correction processing according to the setting of the error correction necessity determination table 4c corresponding to the destination IP address in the information. Specifically, as shown in FIG. 7, when the destination IP address determined in S4 is “12.2.2.3.1”, the error correction function is set to be invalid, and therefore an error has occurred. When it is determined that the correction process is not performed, and the destination IP address determined in S4 is “12.2.2.3.2”, the error correction function is set to be valid, and the error correction process is performed. And make a decision.

  In the determination process of S5, it may be determined whether or not to perform the error correction process based on the information regarding the media session other than the type of communication data, the destination IP address, and the destination port number. Good.

  In the above description, the case where the facsimile multifunction peripherals 1 establish a single media session has been described. However, when a plurality of media sessions are established at the same time and a plurality of types of communication data are simultaneously exchanged, 1A and the receiver 1B execute the processing operations of S5 to S13 and S54 to S58 for each media session. As a result, even when a plurality of media sessions are established, error correction processing is performed only for the types of communication data that need to be error-corrected, and the types of communication data that should not be subjected to error correction processing. On the other hand, it is possible not to perform error correction processing. When the transmitter 1A has one IP address of the receiver 1B, the error correction necessity determination table 4a or 4b is used instead of the error correction necessity determination table 4c in the determination process of S5. desirable.

  In the present embodiment and the above modification, the facsimile multifunction peripheral 1 has been described as an example. Of course, the processing operation of the facsimile multifunction peripheral 1 can be realized on a general-purpose computer such as a personal computer. Is possible. That is, a similar communication processing operation can be realized by incorporating a program for performing the processing operation described above into a facsimile communication software for a personal computer and executing the program.

  The present invention can be applied to a communication apparatus that transmits and receives various data such as voice data, moving image data, image data, and text data through an IP network using, for example, SIP.

1 is a diagram illustrating a configuration example of a facsimile multifunction peripheral (communication apparatus) according to an embodiment of the present invention. FIG. It is the figure which showed an example of the error correction necessity judgment table. It is the figure which showed the example of the session formed between both sides, when performing the data communication by SIP between the facsimile multifunction peripherals (communication apparatus) which concerns on embodiment of this invention. It is the flowchart which showed the processing operation which a transmitter (communication apparatus) performs. It is the flowchart which showed the processing operation which a receiver (communication apparatus) performs. It is the figure which showed other example embodiments of the error correction necessity determination table. It is the figure which showed other example embodiments of the error correction necessity determination table.

Explanation of symbols

1, 1A, 1B Facsimile MFP (communication device)
2 CPU
3 ROM
4 RAM
4a to 4c Error correction necessity determination table 20 SIP server

Claims (3)

Whether or not to perform error correction processing for the data communication performed with the other party in a communication apparatus having means for performing data communication with the other party in a media session established by SIP (Session Initiation Protocol), which is a call control protocol, If it is determined based on the IP address or port number, which is information acquired in the call control session based on the SIP call control protocol formed before establishing the media session, and error correction processing is performed, TCP If it is determined that the data communication is performed using the user datagram protocol (UDP) while performing the error correction process if the use of TCP is possible, and the error correction process is performed if the use of the TCP is not possible, characterized in that it comprises means for performing the data communication in UDP without performing error correction processing Communication apparatus.   The communication apparatus according to claim 1, wherein the error correction processing is performed by a communication protocol used in a media session and an error correction protocol not related to a content of data exchanged by the communication protocol. SIP that is formed before establishing a media session, means for performing data communication with a partner in a media session established by SIP, which is a call control protocol, and whether to perform error correction processing for the data communication performed with the partner If it is determined based on the IP address or port number, which is information acquired in a call control session of the call control protocol, and error correction processing is performed, the TCP is used if TCP is available. use performs the data communication with UDP while error correction If it is not, as determined not to perform error correction processing means for performing the data communication in UDP without performing error correction processing A program characterized by causing a computer to function.

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