JP4089653B2 - 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 includes 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 perform a plurality of types of data communications at the same time to establish multiple media sessions simultaneously.
JP 2002-101256 A

  In a media session established by SIP, UDP (User Datagram Protocol) is often 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 audio data, if a packet failure occurs due to noise or the like, a part of the speaker's words may be lost, but the listener can understand the meaning from before and after the lost part, so the media session can be used for a call. When used, there is little problem. 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, problems occur in IP telephone communication and the like where real-time data transmission is an essential condition.

In addition, when data communication is performed over a media session established by SIP, unlike data communication over a direct TCP connection, various restrictions are imposed on data transmission. Data communication cannot be performed. However, in a conventional SIP-compatible communication device that performs data communication with a destination specified by an IP telephone number, regardless of the type of data to be communicated (voice data, moving image data, still image data, text data, etc.), there because that looks like communicating data on the media session, the still image data on the direct TCP connection, a problem that many time-consuming compared to the IP communication device that performs transmission processing such as text data to the data transfer It was.

The present invention has been made in view of these problems, in the communication apparatus, and a program having means for data communication by the call control protocol, the type of communication data, destination port number, or destination of the IP It is another object of the present invention to provide a communication device and a program capable of enabling or disabling an error correction function according to an address .

In order to achieve the above object, the communication device according to claim 1 communicates with a means for performing data communication with a partner in a media session established by a call control protocol, and whether or not error correction is performed in the data communication. Means for determining based on the type of data to be processed, means for determining whether or not the partner can perform error correction by TCP when it is determined to perform error correction, and the partner can perform error correction by TCP If it is determined that there is a means for error correction according to TCP, and if the partner is determined not to be able to perform error correction by TCP, the partner can perform error correction using a protocol that performs retransmission control higher than UDP. It means for determining whether it is possible to correspond, and the error correction by protocol destination performs upper retransmission control than UDP is adaptable If it is sectional, means for error correction by protocol for upper retransmission control than UDP, if it is determined not to be associated with the error corrected by protocol for counterparty upper retransmission control than UDP, or error Means for performing the data communication without correcting the error when it is determined that the correction is not performed.
The communication device according to claim 2, wherein the communication device determines whether or not to perform the data communication based on a type of data to be communicated, and when it is determined that the data communication is not to be performed, After acquiring various information of the other party in the control session, the means for executing the end call control session without performing the data communication, and specifying the position information included in the acquired other party information, It is characterized by comprising means for establishing a TCP connection and performing data communication over the established TCP connection, and means for performing error correction according to TCP in data communication over the established TCP connection.

The communication device according to claim 3 determines, based on the port number of the partner, whether to perform data communication with the partner in the media session established by the call control protocol, and whether to perform error correction in the data communication. And means for determining whether or not the partner can perform error correction by TCP when it is determined that error correction is to be performed, and TCP if the partner is determined to be capable of error correction by TCP And means for determining whether or not the partner can cope with error correction by a protocol that performs retransmission control higher than UDP when it is determined that the partner cannot perform error correction by TCP. If, when it is determined to be corresponding to the error correction by protocol destination performs upper retransmission control than UDP, above UDP The means for error correction by retransmission control performs protocol, if the destination is determined not to when it is determined not to be associated with the error corrected by protocol for upper retransmission control than UDP, or an error correction And means for performing the data communication without error correction.
5. The communication apparatus according to claim 4, wherein means for determining whether to perform the data communication based on a port number of a counterpart, and a start call control by a call control protocol when it is determined not to perform the data communication After acquiring various information of the other party in the session, the means for executing the end call control session without performing the data communication, and specifying the position information included in the acquired other party information, the destination and the TCP It is characterized by comprising means for establishing a connection and performing data communication over the established TCP connection, and means for performing error correction in accordance with TCP in data communication over the established TCP connection.

6. The communication apparatus according to claim 5, wherein means for performing data communication with a partner in a media session established by a call control protocol and whether or not to perform error correction in the data communication are determined based on the IP address of the partner. And means for determining whether or not the partner can perform error correction by TCP when it is determined that error correction is to be performed, and TCP if the partner is determined to be capable of error correction by TCP And means for determining whether or not the partner can cope with error correction by a protocol that performs retransmission control higher than UDP when it is determined that the partner cannot perform error correction by TCP. If, when it is determined to be corresponding to the error correction by protocol destination performs upper retransmission control than UDP, from UDP Means for error correction by protocol for position of retransmission control, when it is determined not to be associated with the error correction by the protocol destination performs upper retransmission control than UDP, or if it is determined not to error correction And means for performing the data communication without error correction.
7. The communication apparatus according to claim 6, wherein means for determining whether to perform the data communication based on an IP address of a counterpart, and a start call control by a call control protocol when it is determined not to perform the data communication After acquiring various information of the other party in the session, the means for executing the end call control session without performing the data communication, and specifying the position information included in the acquired other party information, the destination and the TCP It is characterized by comprising means for establishing a connection and performing data communication over the established TCP connection, and means for performing error correction in accordance with TCP in data communication over the established TCP connection.
The communication device according to claim 7 is provided with means for executing a plurality of data communications in parallel when there are a plurality of data communications to be performed.

8. Symbol mounting program, based on a computer, means for the destination data communication with the media session established by the call control protocol, whether the error correction in the data communication, the type of data to be communicated If it is determined that error correction by TCP is possible, if the partner is determined to be capable of error correction by TCP, Means for performing error correction according to TCP, means for judging whether or not the other party can cope with error correction by a protocol that performs retransmission control higher than UDP when it is judged that the other party cannot perform error correction by TCP , if it is determined to be corresponding to the error correction by protocol destination performs upper retransmission control than UDP, Means for error correction by protocol for upper retransmission control than DP, and, determines that the other party if it is found not to be adaptable to the error correction by the protocol for the upper retransmission control than UDP, or no error correction In this case, the data communication means functions as a means for performing the data communication without error correction.
The program according to claim 9 is a means for determining whether or not to perform the data communication based on a type of data to be communicated with the computer. When it is determined that the data communication is not performed, the program is started by a call control protocol. Means for executing an end call control session without performing the data communication after acquiring various information of the other party in the call control session, and specifying the position information included in the acquired other information of the other party It is intended to function as a means for establishing a TCP connection and performing data communication over the established TCP connection, and a means for performing error correction according to TCP in data communication over the established TCP connection. It is said.
According to a tenth aspect of the present invention, there is provided a program for causing a computer to function as means for executing a plurality of data communications in parallel when there are a plurality of data communications to be performed.

According to the communication device according to any one of claims 1 to 7, in the communication device provided with means for performing data communication according to a call control protocol, an error may occur depending on a type of communication data, a partner port number, or a partner IP address. The correction function can be enabled or disabled.

A communication apparatus according to claim 1, claim 2, or claim 7 that is dependent on claim 1 or 2 is configured by executing the program according to claim 8 in a computer. And the above-described effects are achieved.

  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. The present invention can be applied not only to a facsimile machine but also to other types of communication devices as long as it can perform various data communications with a partner over a media session and TCP connection established by a call control protocol. It is.

  FIG. 1 shows a configuration example of the facsimile multifunction machine 1. That is, the facsimile multifunction peripheral 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 a communication method determination table 4a.

  As shown in FIG. 2, the communication method determination table 4 a is a type of the substantial content of communication data such as each type of communication data, that is, voice, video, device data (communication device), image (still image), etc. Each time, setting information on whether data communication is performed on the media session or data communication is performed on the direct TCP connection instead of on the media session is stored. Also, setting information indicating whether or not to perform error correction processing for each type of communication data is stored.

  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 configuration includes UDP / IP, TCP / IP, SIP, RTP (Real-time Transport Protocol), RTSP (Real-time Streaming Protocol), SDP (Session Description Protocol), SMTP (Simple Mail Transfer). Protocol), HTTP (Hypertext Transfer Protocol), etc. are implemented. For this reason, transmission / reception of image data (still image data), text data, etc. by SMTP, HTTP, etc. directly over a TCP connection, audio data by RTP, video data, SMTP, etc. in a media session established by SIP call control In addition, transmission / reception of image data (still image data), text data, and the like using HTTP or the like can be performed.

  Furthermore, the facsimile multifunction peripheral 1 is equipped with a unique error correction protocol that operates in a protocol layer that is higher than SIP, RTP, etc. and that is lower than the 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. Receiving side, the received data is divided in the same manner as above, compared to the added value at a predetermined position of all adding the combined total value of the calculated to the block of data in the block, it matches the value For example, it is determined that there is no problem with the data in the block, and if the values do not match, there is a problem, and a data retransmission request is sent to the transmission side for 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, FIG. 3 and FIG. 4 show the sequence operations shown in FIGS. 3 and 4 regarding the processing operation when the facsimile multifunction peripheral 1 having the above-described configuration and functions performs data communication with the facsimile multifunction peripheral 1 having the same configuration and functions as the own apparatus 1. It demonstrates based on the flowchart shown to thru | or FIG. Note that the processing operation described based on these drawings is executed in accordance with a command 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 diagrams of FIGS. 3 and 4, first, a 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). In the present specification, the call control session that is formed before the media session is established is referred to as a “start call control session”.

  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 various information related to the receiver 1B, the IP address that is the location information of the receiver 1B, the port number to be used, the type information and communication protocol of the communication data that can be used by the receiver 1B, Information indicating whether or not the error correction function based on the unique protocol is supported is sent (R1).

  The transmitter 1A that has received the success response code "200" and various information of the receiver 1B uses various information of the receiver 1B (communication protocols that can be used by the receiver 1B, etc.) and the transmitter 1A uses it for data transmission. The type of communication data is determined based on the communication protocol to be used. Then, the transmitter 1A adopts the first communication means for performing data communication with the other party in the SIP media session based on the determined type of communication data, or ends without performing data communication in the media session. After the call control session is formed, a new TCP connection is established with the same destination, and the second communication means for performing data communication over the directly established TCP connection is selected (the details of the selection operation will be described later). ), Data communication is performed by the selected communication means. Note that information for designating one of the communication means is registered in advance as a communication means to be used for the device setting information of the transmitter 1A, and any one of the communication means is based on the registered designation information. May be selected.

  When it is selected that data communication with the other party is performed in the media session, as shown in FIG. 3, information “ACK” indicating that the successful response code “200” has been received is transmitted and the medium 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 as information determined for the session (T2). Then, a media session is established between the transmitter 1A and the receiver 1B, and the receiver 1B and the receiver 1B are set according to the type of communication data, the communication protocol, the communication port, and the like determined by the negotiation performed by the start call control session. Various data communications are performed.

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, when the receiver 1B sends a success response code “200” to the SIP server 20 (R 2 ), and the SIP server 20 also sends a success response code “200” to the transmitter 1A, a series of sessions ends. Communication is cut off. A call control session that is formed until communication is terminated after the media session is terminated is referred to as an “end call control session” in this specification.

  On the other hand, after receiving the successful response code “200” and various information transmitted from the receiver in R1, the transmitter 1A establishes a new TCP connection without performing data communication with the other party in the media session. If it is selected to do so, as shown in FIG. 4, immediately after sending the information of T2, "BYE" requesting disconnection of the SIP connection is sent to the SIP server 20 to receive the receiver. An end call control session is formed with 1B to disconnect the SIP connection. Then, the transmitter 1A newly requests a TCP connection to the receiver 1B, establishes a TCP connection between them (T4), and transmits data to the receiver 1B over the directly established TCP connection. (T5). After the data transmission process is completed, a TCP connection disconnection process is performed (T6).

  In the above description, the transmitter 1A performs data communication over a media session established by SIP or direct TCP connection. Of course, when performing data communication simultaneously using a plurality of types of communication protocols, Data communication is performed on the media session (see FIG. 3), and other data communication can be performed on the newly established TCP connection (see the lower diagram in FIG. 4).

  Next, regarding the processing operation performed by the transmitter 1A when performing data communication by selecting whether to perform data communication in a media session or data communication over a direct TCP connection when performing a start call control session, This will be described based on the flowcharts shown in FIGS.

  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. The negotiation is performed (S3), and the communication type, communication protocol, communication port, and the like that can be handled by the receiver 1B are acquired.

  When the data communication that the transmitter 1A should exchange with the receiver 1B is performed by a single data communication (S4: YES), a communication process described in detail later is executed (S5). On the other hand, data communication performed between the transmitter 1A and the receiver 1B, such as voice data communication and image data communication, voice data communication and video data communication, is performed by a plurality of data communications. If it is performed, a communication process described in detail later is executed for each data communication (S6).

  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. (S7). 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 communication process of S5 and S6 of the transmitter 1A will be described in detail based on the flowchart of FIG. Note that the content of the communication process executed in S5 and S6 differs in that the communication process described later is performed for one data communication in S5, and the communication process described later is performed for each of the plurality of data communications in S6. However, the content of the communication process executed for each data communication is the same.

  First, the transmitter 1A selects whether or not to perform data communication on the media session based on the type of data communication to be executed (S101). That is, according to the setting of the communication method determination table 4a corresponding to the type of data communication to be performed, whether data communication is performed on the media session or whether the data communication is performed after the SIP connection is terminated and a new TCP connection is established. select. For example, as shown in FIG. 2, when the type of data communication to be performed is voice or video, the communication method is set to media session / RTP, so when data communication is performed on the media session When the type of data communication to be performed is device data or image, the selection is made to terminate the SIP connection and newly establish a TCP connection to perform data communication (S101).

If the transmitter 1A has selected to perform data communication in the media session (S101: YES), then information related to the media session, such as the type of data communication used in the media session, the communication protocol, and the communication port, is determined. (S102). Then, to determine whether to perform error correction processing of the data communication for transmitting and receiving a media session based on the determined type information of information sac Chide Data Communications relating to the media session (S103). That is, it is determined whether or not to perform error correction processing according to the setting of the communication method determination table 4a corresponding to the type of data communication performed in the media session. For example, as shown in FIG. 2, when the type of data communication to be performed is voice or moving image, the error correction function is set to be invalid, so that the error correction process is determined not to be performed. If the type of data communication to be performed is device data or image, the error correction function is set to be valid, and it is determined to perform error correction processing (S103).

  If it is determined to perform error correction processing (S103: 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 (S104: YES), “ACK” or the like is transmitted to the receiver 1B (S105), and data is transmitted to the receiver 1B while performing error correction processing by TCP on the established media session (S106). .

  In S104, when the receiver 1B determines that the error correction processing cannot be performed using TCP (S104: NO), the receiver 1B is obtained from various information of the receiver 1B acquired in the start call control session. Is compatible with the error correction processing based on the original protocol (S107), and if it is compatible (S107: YES), "ACK" or the like is transmitted to the receiver 1B (S108). ), Data is transmitted to the receiver 1B while performing error correction processing by the original protocol on the established media session (S109).

  On the other hand, when it is determined in S103 that error correction processing is not performed (S103: NO) and when a negative determination is made in S107 (S107: NO), “ACK” or the like is transmitted to the receiver 1B ( S110), data transmission is performed to the receiver 1B without performing error correction processing (S111). Note that information indicating that the error correction processing is not performed may be transmitted in S110.

  Then, an end call control session is formed with the receiver 1B, and SIP connection disconnection processing is performed (S112).

  On the other hand, in S101, when the transmitter 1A terminates the SIP connection and newly establishes a TCP connection and selects to perform data communication (S101: NO), immediately with the receiver 1B. Then, an end call control session is formed and SIP connection disconnection processing is performed (S113). Next, TCP connection processing specifying the location information (IP address, port number) of the receiver 1B acquired in the start call control session is performed to establish a TCP connection (S114). Then, data is transmitted directly over the TCP connection to the receiver 1B while performing error correction processing by TCP (S115). After the data transmission process is completed, a TCP connection disconnection process is performed (S116).

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

  When the receiver 1B responds to the SIP call from the transmitter 1A in T1 (S151), 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 (S152), and confirmed information regarding the media session to be established is received together with ACK from the transmitter 1A (S153).

  When TCP is used as a transport layer in the media session (S154: YES), data reception is performed while performing error correction processing by TCP in the established media session (S155).

When performing error correction processing using a unique protocol (S154: NO, S156 : YES), data is received while performing error correction processing using a unique protocol (S157). In this case, UDP is used as the transport layer.

  When error correction processing is not performed (S154: NO, S156: NO), data reception is performed without performing error correction processing (S158). In this case, UDP is used as the transport layer.

  After the data reception process of S155, S157 or S158 is completed and “BYE” is received from the transmitter 1A through the SIP server 20, an end call control session is formed with the transmitter 1A to disconnect the SIP connection. Processing is performed (S159).

  On the other hand, when the receiver 1B establishes a TCP connection with the transmitter 1A by the TCP connection request in S114 of the transmitter 1A (S201), the receiver 1B performs the error correction process using the TCP while directly performing the TCP connection. Data reception is performed (S202). After the data reception is completed, a TCP connection disconnection process is performed (S203).

  The transmission process (S101 to S116) of the transmitter 1A and the reception process (S151 to S159, S201 to S203) of the receiver 1B described above have a plurality of data communications that the transmitter 1A should perform with the receiver 1B. In this case (S6), each data communication is executed in parallel. For this reason, for example, when data communication is performed for both audio data and still image data as a type of data communication performed between the transmitter 1A and the receiver 1B, a media session and a still image for performing the audio data communication are static. Both TCP connections for performing image data communication are established simultaneously.

  As is apparent from the above description, according to the facsimile multifunction peripheral (communication device) 1 according to the embodiment of the present invention, when the type of communication data to be transmitted / received is voice data that requires real-time characteristics, Data communication is performed without error correction on the media session. In addition, for data communications that require complete reproduction of original data on the receiving side, such as image data, a new TCP connection is made while performing error correction or disconnecting the SIP connection on the media session. Thus, data communication can be performed while performing error correction processing. Therefore, according to the facsimile multifunction peripheral 1, data communication processing suitable for the characteristics and purpose of communication data transmitted / received using SIP is performed.

  Further, since the transmitter 1A requests a TCP connection using the location information of the receiver 1B acquired in the SIP start call control session, it is possible to omit a query process to a DNS (domain name resolution system) or the like. . Furthermore, if the user on the transmission side designates only the IP phone number of the other party, data can be transmitted to the other party, and the operation for designating the other party's mail address or URI can be omitted.

  In addition, when data communication is performed in a media session, various restrictions are imposed on the data communication, and there is a problem that the bandwidth cannot be fully used. However, if data communication such as a still image is directly performed on a TCP connection, it is sufficient. It is possible to perform highly efficient data communication.

  For communication data such as image data that requires complete reproduction of the original data on the receiving side, error correction using TCP or a proprietary protocol is performed on the media session established by SIP by setting the communication method table 4a. Data communication can be performed while processing.

  Next, a modification of the above embodiment will be described. The facsimile multifunction peripheral 1 according to the modified example has a communication method determination table as shown in FIG. 9 or FIG. 10 instead of the communication method determination table 4a. Based on the table, the selection process of S101 and the S103 are performed. The determination process is performed. However, in applying the communication determination table shown in FIG. 10, it is assumed that a negative determination is made in S4 and the processing operation in S6 is not executed.

  The communication method determination table 4b illustrated in FIG. 9 includes setting information indicating whether data communication is performed in a media session or data communication is performed directly over a TCP connection instead of a media session, and an error associated with each destination port number. Setting information for determining whether or not to perform correction processing is stored. The transmitter 1A having the table 4b performs data communication in the media session according to the setting of the communication method determination table 4b corresponding to the destination port number acquired in S3 in the selection process of S101, or is not a media session. Select whether to perform data communication over a direct TCP connection. For example, as shown in FIG. 9, when the destination port number is “4004 or 4006”, since the communication method is set to media session / RTP, if data communication is performed by RTP in the media session, When the destination port number is “4008 or 4010”, since the communication method is set to TCP connection, it is selected that data communication is performed directly on the TCP connection instead of the media session. In the determination process of S103, it is determined whether or not to perform error correction processing according to the setting of the communication method determination table 4b corresponding to the destination port number acquired in S3. For example, as illustrated in FIG. 9, when the destination port number is “4004 or 4006”, the error correction function is set to be invalid, so the error correction process is determined not to be performed, When the destination port number is “4008 or 4010”, since the error correction function is set to be valid, it is determined to perform the error correction process.

  The communication method determination table 4c illustrated in FIG. 10 includes setting information indicating whether data communication is performed in a media session or data communication is performed over a direct TCP connection instead of a media session in association with each destination IP address, and an error. Setting information for determining whether or not to perform correction processing is stored. The transmitter 1A having the table 4c performs data communication in the media session according to the setting of the communication method determination table 4c corresponding to the destination IP address acquired in S3 in the selection process of S101, or is not a media session. Determine whether to perform data communication over a direct TCP connection. For example, as illustrated in FIG. 10, when the destination IP address is “128.2.3.1 or 12.2.2.3.2”, the communication method is set to media session / RTP. Therefore, when it is determined that data communication is performed by RTP in the media session, and the destination IP address is “128.2.3.3 or 128.2.3.4”, the communication method is set to TCP connection. Therefore, it is determined that data communication is performed directly on the TCP connection instead of the media session. In the determination process of S103, it is determined whether or not to perform error correction processing according to the setting of the communication method determination table 4c corresponding to the destination IP address acquired in S3. For example, as shown in FIG. 10, when the destination IP address is “12.2.2.3.1 or 12.2.2.3.2”, the error correction function is set to invalid. When it is determined that the error correction processing is not performed and the destination IP address is “128.2.3.3 or 128.2.3.4”, the error correction function is set to be valid. Decide to perform error correction processing.

  In the selection processing in S101 and the determination processing in S103, whether or not to perform error correction processing is determined based on the information related to the media session other than the type of communication data, the destination IP address, and the destination port number. May be performed.

  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 also be realized on a general-purpose computer such as a personal computer. is there. 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 communication system determination 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. The figure which showed the example of a session formed between both sides, when forming the call control session by SIP between the facsimile multifunction peripherals (communication apparatus) which concerns on embodiment of this invention, and performing data communication on a direct TCP connection It is. It is the flowchart which showed the processing operation which a transmitter (communication apparatus) performs. It is the flowchart which showed the transmission processing operation which a transmitter (communication apparatus) performs. It is the flowchart which showed the reception processing operation which a receiver (communication apparatus) performs. It is the flowchart which showed the reception processing operation which a receiver (communication apparatus) performs. It is the figure which showed other example embodiments of the communication system determination table. It is the figure which showed other example embodiments of the communication system determination table.

Explanation of symbols

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

Claims (10)

Means for data communication with a partner in a media session established by a call control protocol;
Means for determining whether to perform error correction in the data communication based on the type of data to be communicated;
Means for determining whether or not the partner can perform error correction by TCP when it is determined to perform error correction;
Means for correcting an error in accordance with TCP when it is determined that the other party can perform error correction by TCP;
Means for determining whether or not the partner can handle error correction by a protocol that performs retransmission control higher than UDP when it is determined that the partner cannot perform error correction by TCP ;
Means for performing error correction by a protocol for performing retransmission control higher than UDP when it is determined that the partner can cope with error correction by a protocol for performing retransmission control higher than UDP;
Means for performing the data communication without error correction when it is determined that the partner cannot handle error correction by a protocol for performing retransmission control higher than UDP, or when it is determined not to perform error correction ; ,
A communication apparatus comprising: Means for determining whether to perform the data communication based on the type of data to be communicated;
Means for executing an end call control session without performing the data communication after acquiring various information of the other party in the start call control session by a call control protocol when it is determined that the data communication is not performed;
A means for establishing a TCP connection with the other party by designating position information included in the acquired other party information, and performing data communication over the established TCP connection;
Means for error correction according to TCP in data communication over an established TCP connection;
The communication device according to claim 1 . Means for data communication with a partner in a media session established by a call control protocol;
Means for determining whether to perform error correction in the data communication based on the port number of the other party;
Means for determining whether or not the partner can perform error correction by TCP when it is determined to perform error correction;
Means for correcting an error in accordance with TCP when it is determined that the other party can perform error correction by TCP;
Means for determining whether or not the partner can handle error correction by a protocol that performs retransmission control higher than UDP when it is determined that the partner cannot perform error correction by TCP ;
Means for performing error correction by a protocol for performing retransmission control higher than UDP when it is determined that the partner can cope with error correction by a protocol for performing retransmission control higher than UDP;
Means for performing the data communication without error correction when it is determined that the partner cannot handle error correction by a protocol for performing retransmission control higher than UDP, or when it is determined not to perform error correction ; ,
A communication apparatus comprising:   Means for determining whether to perform the data communication based on the port number of the other party;
  Means for executing an end call control session without performing the data communication after acquiring various information of the other party in the start call control session by a call control protocol when it is determined that the data communication is not performed;
  A means for establishing a TCP connection with the other party by designating position information included in the acquired other party information, and performing data communication over the established TCP connection;
  Means for error correction according to TCP in data communication over an established TCP connection;
  A communication apparatus according to claim 3. Means for data communication with a partner in a media session established by a call control protocol;
Means for determining whether to perform error correction in the data communication based on the IP address of the other party;
Means for determining whether or not the partner can perform error correction by TCP when it is determined to perform error correction;
Means for correcting an error in accordance with TCP when it is determined that the other party can perform error correction by TCP;
Means for determining whether or not the partner can handle error correction by a protocol that performs retransmission control higher than UDP when it is determined that the partner cannot perform error correction by TCP ;
Means for performing error correction by a protocol for performing retransmission control higher than UDP when it is determined that the partner can cope with error correction by a protocol for performing retransmission control higher than UDP;
Means for performing the data communication without error correction when it is determined that the partner cannot handle error correction by a protocol for performing retransmission control higher than UDP, or when it is determined not to perform error correction ; ,
A communication apparatus comprising:   Means for determining whether to perform the data communication based on the IP address of the other party;
  Means for executing an end call control session without performing the data communication after acquiring various information of the other party in the start call control session by a call control protocol when it is determined that the data communication is not performed;
  A means for establishing a TCP connection with the other party by designating position information included in the acquired other party information, and performing data communication over the established TCP connection;
  Means for error correction according to TCP in data communication over an established TCP connection;
  The communication apparatus according to claim 5.   The communication apparatus according to claim 1, further comprising means for executing a plurality of data communications in parallel when there are a plurality of data communications to be performed. Computer
Means for data communication with a partner in a media session established by a call control protocol;
Means for determining whether to perform error correction in the data communication based on the type of data to be communicated;
Means for determining whether or not the other party can perform error correction by TCP when it is determined to perform error correction;
Means for correcting an error in accordance with TCP when it is determined that the error can be corrected by TCP;
Means for determining whether or not the partner can cope with error correction by a protocol that performs retransmission control higher than UDP when it is determined that the partner cannot perform error correction by TCP ;
Means for performing error correction by a protocol for performing retransmission control higher than UDP when it is determined that the partner can cope with error correction by a protocol for performing retransmission control higher than UDP; and
Means for performing the data communication without error correction when it is determined that the partner is not compatible with error correction by a protocol for performing retransmission control higher than UDP, or when it is determined not to perform error correction ;
Program to function as.   Computer
  Means for determining whether to perform the data communication based on the type of data to be communicated;
  Means for executing an end call control session without performing the data communication after acquiring various information of the other party in the start call control session by a call control protocol when it is determined that the data communication is not performed;
  Means for establishing a TCP connection with the other party by designating position information included in the acquired other party information, and performing data communication over the established TCP connection; and
  Means for error correction according to TCP in data communication over an established TCP connection;
  The program according to claim 8 for functioning as well.   The program according to claim 8 or 9 for causing a computer to function as means for executing a plurality of data communications in parallel when there are a plurality of data communications to be performed.

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