JP2005065342A - Data converter, signal, data conversion method, dce, and gateway - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the amount of transmission of data by preventing octet/bit insertion in a section in which the octet/bit insertion is not required, when performing communication based on PPP, and to increase the throughput. <P>SOLUTION: When a data signal is transmitted from a DTE 2 to DTE 14, the octet/bit insertion is made to data in the DTE 2 for transmission. In DCE, data that have a PPP frame configuration and are subjected to octet/bit insertion are converted to data that have an improved PPP frame configuration and is not subjected to the octet/bit insertion. In a gateway (NW), data that have the improved PPP frame configuration and is not subjected to the octet/bit insertion are converted into data that have the frame configuration of a protocol in a data link layer other than PPP. After the data are converted, the gateway transmits a signal containing the converted data to the DTE 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data converter, a signal, a data conversion method, a DCE (Data Circuit-terminating Equipment), and a gateway, and more specifically, octet insertion or bit insertion in communication based on PPP (Point-to-Point Protocol). The present invention relates to a data conversion apparatus or the like that prevents octet / bit insertion from being performed in a section in which insertion (hereinafter referred to as “octet / bit insertion”) is unnecessary.

  There is PPP as a data link layer protocol of the OSI reference model. PPP is a bit / byte synchronous and asynchronous link control protocol over serial lines. PPP is defined in RFC (Request For Comments) 1661 and RFC 1662 of the Internet Engineering Task Force (IETF).

  FIG. 1 is a diagram showing a PPP frame configuration (frame format). The PPP frame has a flag field, an address field, a control field, a protocol field, an information field, and an FCS field. The number of bytes in each field is 1 byte for the flag field, 1 byte for the address field, 1 byte for the control field, 1 or 2 bytes for the protocol field, and 2 or 4 bytes for the FCS field. The address field and the control field may be compressed by negotiation of LCP (Link Control Protocol) ACFC (Address and Control Field Compression). Further, the protocol field may be compressed by negotiation of LCPPFC (Protocol Field Compression). Further, the FCS (Frame Check Sequence) field may be compressed by LCPFCS negotiation.

  FIG. 2 is a diagram illustrating an example of communication between a DTE (Data Terminal Equipment) via a communication network and a PSTN (Public Switched Telephone Network). In FIG. 2, the exchange 8 and the gateway 10 form a communication network 5. The DTE 2 and the DTE 14 communicate with each other via the DCE 4, the exchange 8, the gateway 10, and the PSTN 12. The communication network 5 can be a mobile communication network, for example, and the DCE 4 can be a mobile station, for example.

  At that time, it is conceivable to perform data communication between DTE2 and DTE14 based on PPP. Conventionally, when a data signal is transmitted from DTE2 to DTE14, the data signal is transmitted after octet / bit insertion is performed in DTE2. The DTE 14 performs octet deletion or bit deletion (hereinafter referred to as “octet / bit deletion”) on the received data signal. On the other hand, when a data signal is transmitted from DTE 14 to DTE 2, octets / bits are inserted by DTE 14 and octets / bits are deleted by DTE 2.

  It is also conceivable that only data communication between the DTE 2 and a certain point on the network (a point where the PPP is terminated) is performed based on the PPP. For example, the exchange 8 and the gateway 10 can be considered as a certain point of the network. Here, the case where the gateway 10 is set as the termination point is considered. Conventionally, when a data signal is transmitted from DTE2 to DTE14, octet / bit insertion is performed in DTE2, octet / bit deletion is performed on the data signal received by gateway 10, and the data signal is transmitted to DTE14. It was. On the other hand, when a data signal is transmitted from DTE 14 to DTE 2, octet / bit insertion is performed by gateway 10 and octet / bit deletion is performed by DTE 2.

  However, in conventional data communication based on PPP, data signals are transmitted and received in a state where octets / bits are inserted even in a section where octets / bits are not inserted. For example, although it is considered that octet / bit insertion is unnecessary in the section between the DCE 4 and the gateway 10 in FIG. 2, octet / bit insertion has been conventionally performed in this section. If octet / bit insertion is performed, the amount of data transmission increases and the throughput deteriorates. Octet insertion is, for example, to generate 2-byte data by escaping specific data of 1 byte with a 1-byte escape character (1 byte) (described in detail below with reference to FIG. 9). To do). Further, bit insertion will be described with an example. When it is desired to identify a flag (binary number “01111110”) and the other data portion, bit insertion is performed with five “1” s for data other than the flag. This is done by inserting “0” after the consecutive cases.

  Accordingly, an object of the present invention is to prevent octet / bit insertion in a section in which octet / bit insertion is not required in data communication based on PPP, thereby reducing the amount of data transmission and improving throughput. is there.

  In order to achieve the above object, according to the first aspect of the present invention, the data conversion device has a PPP frame configuration and performs octet deletion or bit deletion on data in which octet insertion or bit insertion is performed. It is characterized by.

  In the second aspect of the present invention, the data conversion apparatus has a PPP frame configuration, and performs deletion of octets or bits for data with octet insertion or bit insertion, and octets by the deletion unit. And additional information adding means for adding additional information including information for identifying a frame delimiter to the deleted or bit-deleted data.

  In the third aspect of the present invention, the data conversion apparatus has a PPP frame structure, and a flag deletion unit that deletes a flag from data in which octets or bits are inserted, and the flag is deleted by the flag deletion unit It is characterized by comprising deletion means for deleting octets or bits with respect to data.

  In the fourth aspect of the present invention, the data conversion apparatus has a PPP frame configuration, and a flag deletion unit that deletes a flag from data in which octets or bits are inserted, and the flag is deleted by the flag deletion unit Deletion means for performing octet deletion or bit deletion on data, and additional information addition means for adding additional information including information for identifying a frame delimiter to the data subjected to octet deletion or bit deletion by the deletion means It is characterized by comprising.

  In a fifth aspect of the present invention, the data conversion device has a PPP frame configuration and is characterized in that octet insertion or bit insertion is performed on data that has not been octet inserted or bit inserted.

  In the sixth aspect of the present invention, the data conversion device has a frame configuration in which additional information including information for identifying a frame delimiter is added to the PPP frame configuration, and data in which octets or bits are not inserted The additional information deleting means for deleting the additional information, and the inserting means for performing octet insertion or bit insertion for the data from which the additional information has been deleted by the additional information deleting means. .

  In the seventh aspect of the present invention, the data conversion device has a frame configuration in which a flag is deleted from the PPP frame configuration, and an insertion unit that performs octet insertion or bit insertion on data that has not been octet inserted or bit inserted And flag adding means for adding a flag to the data in which octets or bits are inserted by the inserting means.

  In the eighth aspect of the present invention, the data conversion device has a frame configuration in which additional information including information for identifying a frame delimiter is added to the frame configuration in which the flag is deleted from the PPP frame configuration, and octet insertion is performed. Alternatively, additional data deletion means for deleting the additional information from data that has not been bit-inserted, and insertion means for performing octet insertion or bit insertion on the data from which the additional information has been deleted by the additional information deletion means, Flag addition means for adding a flag to the data in which octets or bits are inserted by the insertion means is provided.

  In a ninth aspect of the present invention, a data conversion apparatus includes the data conversion apparatus according to any one of the first to fourth aspects of the present invention and the data conversion apparatus according to any of the fifth to eighth aspects of the present invention. It is characterized by comprising.

  According to a tenth aspect of the present invention, the DCE includes the data conversion device according to any one of the first to ninth aspects of the present invention.

  In an eleventh aspect of the present invention, a gateway includes the data conversion device according to any one of the first to ninth aspects of the present invention.

  In a twelfth aspect of the present invention, a data conversion apparatus has a PPP frame configuration, and converts data having no octet insertion or bit insertion into data having a data link layer protocol frame configuration other than PPP. It is characterized by.

  In a thirteenth aspect of the present invention, the data conversion device has a frame configuration in which additional information including information for identifying a frame delimiter is added to the PPP frame configuration, and data in which octets or bits are not inserted Is converted into data having a frame structure of a data link layer protocol other than PPP.

  In a fourteenth aspect of the present invention, a data conversion apparatus has a frame configuration in which a flag is deleted from a PPP frame configuration, and data in which no octet or bit is inserted is converted into a data link layer protocol frame configuration other than PPP. It converts into the data which have.

  In a fifteenth aspect of the present invention, the data conversion device has a frame configuration in which additional information including information for identifying a frame delimiter is added to the frame configuration in which the flag is deleted from the PPP frame configuration, and octet insertion Alternatively, data in which no bit is inserted is converted into data having a frame structure of a protocol of a data link layer other than PPP.

  In a sixteenth aspect of the present invention, the data conversion device converts data having a frame structure of a protocol of a data link layer other than PPP into data having a PPP frame structure and having no octet insertion or bit insertion. It is characterized by.

  In a seventeenth aspect of the present invention, the data conversion apparatus adds data having a data link layer protocol frame structure other than PPP to the PPP frame structure and additional information including information for identifying a frame delimiter. It is characterized in that the data is converted into data without octet insertion or bit insertion.

  In an eighteenth aspect of the present invention, the data conversion device has a frame configuration in which a flag is removed from the PPP frame configuration and data having a data link layer protocol frame configuration other than PPP is inserted, and octets or bits are inserted. It is characterized in that it is converted to data that is not.

  In a nineteenth aspect of the present invention, a data conversion apparatus is provided for identifying a frame delimiter in data having a frame structure of a data link layer protocol other than PPP into a frame structure in which a flag is deleted from the PPP frame structure. It has a frame structure to which additional information including information is added, and is converted to data without octet insertion or bit insertion.

  In a twentieth aspect of the present invention, a data conversion apparatus includes the data conversion apparatus according to any one of the twelfth to fifteenth aspects of the present invention and the data conversion apparatus according to any of the sixteenth to nineteenth aspects of the present invention. It is characterized by comprising.

  In a twenty-first aspect of the present invention, the gateway is provided with the data conversion device according to any one of the twelfth to twentieth aspects of the present invention.

  In a twenty-second aspect of the present invention, the signal has a PPP frame structure and includes data in which octets or bits are not inserted.

  In the twenty-third aspect of the present invention, the signal has a frame structure in which additional information including information for identifying a frame delimiter is added to the PPP frame structure, and includes data in which octets or bits are not inserted. It is characterized by that.

  In a twenty-fourth aspect of the present invention, the signal has a frame structure in which a flag is deleted from the PPP frame structure, and includes data in which octets or bits are not inserted.

  In the twenty-fifth aspect of the present invention, the signal has a frame configuration in which additional information including information for identifying a frame delimiter is added to the frame configuration in which the flag is deleted from the PPP frame configuration, and an octet insertion or bit It includes data that has not been inserted.

  In a twenty-sixth aspect of the present invention, the data conversion method has a PPP frame configuration and is characterized in that octet deletion or bit deletion is performed on data in which octets are inserted or bits are inserted.

  In a twenty-seventh aspect of the present invention, a data conversion method has a PPP frame configuration, a deletion step of performing octet deletion or bit deletion on data with octet insertion or bit insertion, and an octet by the deletion step. And an additional information adding step of adding additional information including information for identifying a frame delimiter to the deleted or bit-deleted data.

  In a twenty-eighth aspect of the present invention, the data conversion method has a PPP frame configuration, and the flag is deleted by the flag deletion step of deleting the flag from the data in which octets or bits are inserted, and the flag deletion step. And a deletion step of performing octet deletion or bit deletion on the data.

  In a twenty-ninth aspect of the present invention, the data conversion method has a PPP frame configuration, and the flag is deleted by the flag deletion step of deleting the flag from the data in which octets or bits are inserted, and the flag deletion step. Deletion step for octet deletion or bit deletion for data, and additional information addition step for adding additional information including information for identifying a frame delimiter to the data octet deleted or bit deleted by the deletion step It is characterized by providing.

  In a thirtieth aspect of the present invention, the data conversion method has a PPP frame configuration and is characterized in that octet insertion or bit insertion is performed on data that has not been octet inserted or bit inserted.

  In a thirty-first aspect of the present invention, the data conversion method has a frame configuration in which additional information including information for identifying a frame delimiter is added to a PPP frame configuration, and data in which octets or bits are not inserted The additional information deleting step for deleting the additional information, and the inserting step for inserting octets or bits into the data from which the additional information has been deleted by the additional information deleting step.

  In a thirty-second aspect of the present invention, the data conversion method has an insertion step of having a frame configuration in which a flag is deleted from the PPP frame configuration, and performing octet insertion or bit insertion on data that has not been octet inserted or bit inserted. And a flag adding step for adding a flag to the data in which octets or bits are inserted in the inserting step.

  In a thirty-third aspect of the present invention, the data conversion method has a frame configuration in which additional information including information for identifying a frame delimiter is added to a frame configuration in which a flag is deleted from the PPP frame configuration, and octet insertion is performed. Alternatively, an additional information deleting step for deleting the additional information from data that has not been bit-inserted, and an insertion step for performing octet insertion or bit insertion on the data from which the additional information has been deleted by the additional information deleting step, A flag addition step of adding a flag to the data in which octets or bits are inserted in the insertion step.

  In a thirty-fourth aspect of the present invention, a data conversion method has a PPP frame configuration, and converts data having no octet insertion or bit insertion into data having a data link layer protocol frame configuration other than PPP. It is characterized by.

  In a thirty-fifth aspect of the present invention, the data conversion method has a frame configuration in which additional information including information for identifying a frame delimiter is added to the PPP frame configuration, and data in which octets or bits are not inserted Is converted into data having a frame structure of a data link layer protocol other than PPP.

  In a thirty-sixth aspect of the present invention, a data conversion method has a frame configuration in which a flag is deleted from a PPP frame configuration, and data in which no octet or bit is inserted is converted into a data link layer protocol frame configuration other than PPP. It converts into the data which have.

  In a thirty-seventh aspect of the present invention, a data conversion method has a frame configuration in which additional information including information for identifying a frame delimiter is added to a frame configuration in which a flag is deleted from a PPP frame configuration, and octet insertion Alternatively, data in which no bit is inserted is converted into data having a frame structure of a protocol of a data link layer other than PPP.

  In a thirty-eighth aspect of the present invention, the data conversion method converts data having a frame structure of a data link layer protocol other than PPP into data having a PPP frame structure and having no octet insertion or bit insertion. It is characterized by.

  In a thirty-ninth aspect of the present invention, in the data conversion method, additional data including information for identifying a frame delimiter is added to data having a data link layer protocol frame configuration other than PPP in the PPP frame configuration. It is characterized in that the data is converted into data without octet insertion or bit insertion.

  In a forty-sixth aspect of the present invention, the data conversion method has a frame configuration in which a flag is deleted from the PPP frame configuration and data having a data link layer protocol frame configuration other than PPP is inserted, and octets or bits are inserted. It is characterized in that it is converted to data that is not.

  In a forty-first aspect of the present invention, a data conversion method is provided for identifying a frame delimiter in data having a data link layer protocol frame configuration other than PPP in a frame configuration in which a flag is deleted from the PPP frame configuration. It has a frame structure to which additional information including information is added, and is converted to data without octet insertion or bit insertion.

  In the forty-second aspect of the present invention, when the DCE of the tenth aspect of the present invention receives an LCP echo request transmitted from one of two apparatuses that perform data communication based on PPP to the other, An LCP echo reply is transmitted to the device.

  In the forty-third aspect of the present invention, when the DCE of the tenth aspect of the present invention receives an LCP discard request transmitted from one of two devices that perform data communication based on PPP to the other, The LCP discard request is discarded.

  In the forty-fourth aspect of the present invention, when DCE receives an LCP echo request transmitted from one of two apparatuses that perform data communication based on PPP to the other, the DCE transmits an LCP echo reply to the one apparatus. It is characterized by doing.

  In the forty-fifth aspect of the present invention, when DCE receives an LCP discard request transmitted from one of two apparatuses that perform data communication based on PPP to the other, the DCE discards the LCP discard request. It is characterized by.

  In the forty-sixth aspect of the present invention, when the gateway according to the eleventh or twenty-first aspect of the present invention receives an LCP echo request transmitted from one of two devices that perform data communication based on PPP to the other, The LCP echo reply is transmitted to the one apparatus.

  In the forty-seventh aspect of the present invention, when the gateway according to the eleventh or twenty-first aspect of the present invention receives an LCP discard request transmitted from one of two devices that perform data communication based on PPP to the other The LCP discard request is discarded.

  In the forty-eighth aspect of the present invention, when the gateway receives an LCP echo request transmitted from one of two devices that perform data communication based on PPP to the other, the gateway transmits an LCP echo reply to the one device. It is characterized by doing.

  In the forty-ninth aspect of the present invention, when a gateway receives an LCP discard request transmitted from one of two devices that perform data communication based on PPP to the other, the gateway discards the LCP discard request. It is characterized by.

  According to the present invention, during communication based on PPP, octet / bit insertion can be prevented from being performed in a section where octet / bit insertion is not required, the amount of data transmission can be reduced, and throughput can be improved. If the amount of data transmission can be reduced, various services can be provided to the user at a low charge.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The communication between the DTE via the communication network and PSTN shown in FIG. 2 will be described as an example.

(First embodiment)
In the first embodiment of the present invention, data communication between DTE 2 and DTE 14 is performed based on PPP.

  FIG. 3 is a diagram illustrating an example of an improved PPP frame configuration according to the present embodiment. The improved PPP frame has an additional information field, an address field, a control field, a protocol field, an information field, and an FCS field. That is, it has a frame configuration in which additional information is added to the frame configuration in which the flag is deleted from the PPP frame configuration. The additional information includes identification information for identifying a frame break. In this embodiment, the length of the frame (the number of bytes of the frame) is used as the identification information.

  Note that a frame configuration in which a flag is added to the frame configuration of FIG. 3 may be used. That is, a frame configuration in which additional information is simply added without deleting the flag from the PPP frame configuration can be used.

  FIG. 4 is a diagram for explaining data communication between DTE 2 and DTE 14. When a data signal is transmitted from DTE2 to DTE14, octet insertion is performed on the data in DTE2 in the same manner as in the prior art, and then transmitted. DCE4 performs a special process (this process is described below) and has a PPP frame structure and octet inserted data, and an improved PPP frame structure (Figure 3) and octet inserted. Convert the data to not yet. The gateway 10 (indicated by NW in FIG. 4) performs special processing, and data having an improved PPP frame structure and not having octets inserted therein is designated as data having a PPP frame structure and having octets inserted therein. Convert to After the data conversion, the gateway 10 transmits a signal including the converted data to the DTE 14. Then, the octet deletion is performed in the DTE 14 as in the conventional case.

  On the other hand, when a data signal is transmitted from the DTE 14 to the DTE 2, the octet is inserted into the data in the DTE 14 in the same manner as in the prior art and transmitted. The gateway 10 performs special processing to convert data having a PPP frame structure and having octets inserted into data having an improved PPP frame structure and having no octets inserted. The DCE 4 performs a special process to convert data having an improved PPP frame structure and not having octets inserted into data having a PPP frame structure and having octets inserted. Then, octet deletion is performed in DTE2 as in the conventional case.

  As described above, the DCE 4 and the gateway 10 transmit / receive a signal including data having the improved PPP frame configuration shown in FIG. 3 and having no octet insertion. As a result, the data transmission amount is reduced and the throughput is improved.

  The DCE 4 and the gateway 10 include a first data conversion device 20 and a second data conversion device 30 in order to perform the above special processing.

  FIG. 5 is a diagram illustrating a configuration example of the first data conversion apparatus. The first data conversion device 20 includes a flag deletion unit 22, an octet deletion unit 24, and an additional information addition unit 26. When using a frame configuration in which a flag is added (remaining) to the frame configuration of FIG. 3 between the DCE 4 and the gateway 10, the flag deletion unit 22 is unnecessary.

  FIG. 6 is a diagram illustrating a configuration example of the second data conversion apparatus. The second data conversion device 30 includes an additional information deletion unit 32, an octet insertion unit 34, and a flag addition unit 36. When the frame configuration in which a flag is added to the frame configuration in FIG. 3 is used between the DCE 4 and the gateway 10, the flag adding unit 36 is unnecessary.

  FIG. 7 is a diagram illustrating an example of a negotiation process when data is generated in DTE2. When data is generated, the DTE 2 transmits an LCP link setting request to the PPP termination (DTE 14) in order to establish a PPP link ((1) in FIG. 7). In this embodiment, the PPP termination is the DTE 14, but it may be the gateway 10 or the like. The case where the PPP termination is the gateway 10 will be described in the second embodiment of the present invention. The DCE 4 monitors the response of the LCP, stores the ACCM (Async Control Character Map) if the response from the DTE 14 side is included, receives the PPP frame from the DTE 14 side, and transmits the octet to the DTE 2 side. This is used for insertion processing ((2) in FIG. 7). In the network layer protocol phase after the authentication phase (which can be omitted), the NCP (Network Control Protocol) protocol negotiates what to use for the network layer protocol (eg, IP (Internet Protocol)) ((3) in FIG. 7). As a result, network layer packets can be used. In this embodiment, IP is used as the network layer protocol, but other protocols may be used. Thereafter, data transfer is performed using the IP packet ((4) in FIG. 7). The negotiation process when data is generated in the DTE 14 can be performed in the same manner as the negotiation process described above.

  FIG. 8 is a diagram illustrating a processing example of DTE2 and DCE4 when data is transferred from DTE2 to DTE14. In DTE2, an address (A), control (C), protocol (P), and FCS field are assigned to data received from the network layer (NW layer), and octet insertion processing is performed according to LCP negotiation ((1 in FIG. 8). )), Data transmission is performed after adding a flag (F) field. Here, since processing for converting 1 byte into 2 bytes is performed in the octet insertion, the data after the octet insertion is larger than the original data. In addition, the default octet insertion is performed before the negotiation is completed.

  In DCE 4, the flag deletion unit 22 extracts a data portion surrounded by the data flag received from DTE 2 (deletes the flag). The octet deletion unit 24 performs an octet deletion process that is completely opposite to the octet insertion process performed by the DTE 2 for the extracted data portion ((2) in FIG. 8). In the additional information adding unit 26, additional information including identification information (information for recognizing the one frame) for identifying the break of the one frame is added to the data subjected to the octet deletion process (FIG. 8). (3)). In this embodiment, only identification information is added as additional information. Further, the frame length is used as the identification information. The data to which the additional information is added is transferred toward the DTE 14.

  Note that when the frame configuration in which a flag is added (remained) to the frame configuration in FIG. 3 between the DCE 4 and the gateway 10 is used, the flag deletion unit 22 does not delete the flag.

  FIG. 9 is a diagram illustrating a specific example of octet insertion processing performed in DTE2. In FIG. 9, octet insertion processing is shown by taking as an example a case where all of 00h to 1Fh (h indicates hexadecimal) are escaped with an escape character (7Dh) by LCP negotiation. In addition to 00h to 1Fh, escape processing is also performed for the escape character (7Dh) and the flag value (7Eh). In the present embodiment, the escape process is performed by adding an escape character (7Dh) before the target data and taking the exclusive OR of the target data and 20h. For example, when octet insertion processing is performed on data 00h, data 7D20h is generated. When octet insertion processing is performed in this way, the original data of 1 byte becomes 2 bytes of data.

  FIG. 10 is a diagram illustrating a specific example of the octet deletion process performed by the DCE 4. In the octet deletion process, a process completely opposite to the octet insertion process performed in DTE2 is performed.

  FIG. 11 is a diagram illustrating a processing example of DTE2 and DCE4 when data is transferred from DTE14 to DTE2. In DCE 4, the additional information deletion unit 32 extracts a data portion other than the additional information of the received signal (deletes the additional information) ((1) in FIG. 11). The octet insertion unit 34 performs octet insertion on the extracted data based on the result of the ACCM negotiation performed in the LCP ((2) in FIG. 11), adds a flag in the flag addition unit 36, and transmits data. Do. Here, since processing for converting 1 byte into 2 bytes is performed in the octet insertion, the data after the octet insertion is larger than the original data. In addition, the default octet insertion is performed before the negotiation is completed.

  Note that when the frame configuration in which a flag is added (remained) to the frame configuration in FIG. 3 between the DCE 4 and the gateway 10 is used, the flag adding unit 36 does not add a flag.

  In DTE2, octet deletion processing is performed based on the result of ACCM negotiation performed in LCP as in the past ((3) in FIG. 11).

  FIG. 12 is a diagram showing a specific example of octet insertion processing performed by DCE 4. The octet insertion process performed by DCE 4 is the same as the octet insertion process performed by DTE 2 (FIG. 9).

  FIG. 13 is a diagram illustrating a specific example of octet deletion processing performed in DTE2. In the octet deletion process, a process completely opposite to the octet insertion process performed in DCE4 is performed.

  The processing (such as octet insertion processing) performed by the gateway 10 when transferring data from the DTE 2 to the DTE 14 is the same as the processing (FIGS. 11 and 12) performed by the DCE 4 when transferring data from the DTE 14 to the DTE 2.

  In addition, processing (such as octet deletion processing) performed by the gateway 10 when data is transferred from the DTE 14 to the DTE 2 is similar to processing (FIGS. 8 and 10) performed by the DCE 4 when data is transferred from the DTE 2 to the DTE 14. .

  FIG. 16 is a diagram for explaining processing performed by DCE.

  Examples of codes in the LCP format include an LCP echo request (code: 09h) and an LCP discard request (code: 0Bh).

  In DCE4, when one of two apparatuses (for example, DTE2) that performs data communication based on PPP receives an LCP echo request transmitted to the other (for example, DTE14), an LCP echo reply (LCP Echo) is sent to the one apparatus. -Reply) (code: 0Ah) is transmitted. As a result, the LCP echo request is not transmitted to the other device (previously transmitted), and the data transmission amount is reduced.

  Moreover, in DCE4, when one of two apparatuses that perform data communication based on PPP receives an LCP discard request transmitted to the other, the LCP discard request is discarded (deleted). As a result, the LCP discard request is not transmitted to the other device (previously transmitted), and the data transmission amount is reduced.

  Similarly, when the gateway 10 receives an LCP echo request transmitted from one of two apparatuses (for example, DTE 14) that performs data communication based on PPP to the other (for example, DTE 2), the gateway 10 transmits the LCP to the one apparatus. Send an echo reply. As a result, the LCP echo request is not transmitted to the other device (previously transmitted), and the data transmission amount is reduced.

  Further, when the gateway 10 receives an LCP discard request transmitted from one of two apparatuses that perform data communication based on PPP to the other, the gateway 10 discards (deletes) the LCP discard request. As a result, the LCP discard request is not transmitted to the other device (previously transmitted), and the data transmission amount is reduced.

  In the present embodiment, the DCE 4 and the gateway 10 include the first data conversion device 20 and the second data conversion device 30. For example, the DCE 4 includes only the first data conversion device 20, and the gateway 10 includes only the second data conversion device 30. And an improved PPP frame structure can be used only for one-way data communication.

  In this embodiment, special processing (octet insertion, deletion, etc.) is performed by the gateway 10, but this processing can also be performed by the exchange 8, for example.

(Second Embodiment)
In the second embodiment of the present invention, data communication between the DTE 2 and the gateway 10 is performed based on PPP.

  FIG. 14 is a diagram for explaining data communication between the DTE 2 and the gateway 10. It is assumed that the gateway 10 and the DTE 14 are connected by a dedicated line or the like. In the present embodiment, the negotiation process (FIG. 7) is performed between the DTE 2 and the gateway 10.

  When a data signal is transmitted from DTE2 to DTE14, octet insertion is performed on the data in DTE2 in the same manner as in the prior art, and then transmitted. DCE4 performs the same processing as in the first embodiment, and converts data having a PPP frame configuration and having octets inserted into data having an improved PPP frame configuration (FIG. 3) and having no octets inserted. To do.

  The gateway 10 (indicated by NW in FIG. 14) has an improved PPP frame structure, and converts data having no octet inserted into data having a data link layer protocol frame structure other than PPP. Data conversion can be performed in the same manner as when data having a PPP frame configuration is converted to data having a frame configuration of a data link layer protocol other than PPP. This is because the improved PPP frame configuration includes identification information for identifying a frame break instead of a flag. After the data conversion, the gateway 10 transmits a signal including the converted data to the DTE 14.

  On the other hand, when a data signal is transmitted from DTE 14 to DTE 2, data having a frame structure of a data link layer protocol other than PPP transmitted from DTE 14 is transmitted from gateway 10 to DTE 14 and has an improved PPP frame structure. And converted to data without octets inserted. Data conversion can be performed in the same manner as when data having a frame structure of a protocol of a data link layer other than PPP is converted to data having a PPP frame structure. After the data conversion, the gateway 10 transmits a signal including the converted data to the DCE 4.

  The DCE 4 performs the same processing as in the first embodiment, and converts data having an improved PPP frame structure and not having octets inserted into data having a PPP frame structure and having octets inserted. Then, octet deletion is performed in DTE2 as in the conventional case.

  As described above, the DCE 4 and the gateway 10 transmit / receive a signal including data having the improved PPP frame configuration shown in FIG. 3 and having no octet insertion. As a result, the data transmission amount is reduced and the throughput is improved.

  Also in the present embodiment, as in the first embodiment, it is possible to use an improved PPP frame configuration for only one-way data communication.

  In the present embodiment, the gateway 10 performs special processing (conversion to data having a different frame configuration). However, this processing may be performed by the exchange 8, for example.

  Also in this embodiment, the DCE 4 and the gateway 10 perform the processing shown in FIG.

(Other)
Although the additional information is used in the first and second embodiments, the additional information is unnecessary if there is a mechanism capable of recognizing one PPP frame in a lower layer than PPP. Therefore, in such a case, the additional information adding unit 26 and the additional information deleting unit 32 are unnecessary.

  In the first and second embodiments, the present invention has been described in relation to octet insertion and deletion. However, the present invention can be similarly applied to bit insertion and deletion.

  FIG. 15 is a diagram for explaining bit insertion. An example of performing octet insertion with DTE2 has been described with reference to FIG. 9, but when bit insertion with DTE2 is performed, for example, FIG. In the example of FIG. 15, bit insertion is performed by inserting “0” after five consecutive “1” s for data other than the flag. Since bit deletion is the reverse of bit insertion, bit deletion deletes the subsequent “0” when five “1” s continue for data other than the flag.

It is a figure which shows a PPP frame structure. It is a figure which shows the example of communication between DTE via a communication network and PSTN. It is a figure which shows the example of the improved PPP frame structure which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the data communication between DTE2 and DTE14. It is a figure which shows the structural example of a 1st data converter. It is a figure which shows the structural example of a 2nd data converter. It is a figure which shows the example of a negotiation process when data generate | occur | produce in DTE2. It is a figure which shows the process example of DTE2 and DCE4 at the time of transferring data from DTE2 to DTE14. It is a figure which shows the specific example of the octet insertion process performed by DTE2. It is a figure which shows the specific example of an octet deletion process performed by DCE4. It is a figure which shows the process example of DTE2 and DCE4 at the time of transferring data from DTE14 to DTE2. It is a figure which shows the specific example of an octet insertion process performed by DCE4. It is a figure which shows the specific example of the octet deletion process performed by DTE2. It is a figure for demonstrating the data communication between DTE2 and the gateway 10. FIG. It is a figure for demonstrating bit insertion. It is a figure for demonstrating the process performed by DCE.

Explanation of symbols

2, 14 DTE
4 DCE
5 Communication network 8 Exchange 10 Gateway 12 PSTN
DESCRIPTION OF SYMBOLS 20 1st data converter 22 Flag deletion part 24 Octet deletion part 26 Additional information addition part 30 2nd data converter 32 Additional information deletion part 34 Octet insertion part 36 Flag addition part

Claims (20)

A data converter,
A data conversion apparatus characterized by converting data having a PPP frame configuration and having no octet insertion or bit insertion into data having a data frame layer protocol frame configuration other than PPP. A data converter,
It has a frame structure in which additional information including information for identifying a frame delimiter is added to the PPP frame structure, and data with no octet insertion or bit insertion is used for the data link layer protocol frame structure other than PPP. A data converter characterized by converting into data. A data converter,
A data conversion apparatus having a frame structure in which a flag is deleted from a PPP frame structure, and converting data in which octets or bits are not inserted into data having a frame structure of a data link layer protocol other than PPP . A data converter,
A frame structure in which additional information including information for identifying a frame delimiter is added to the frame structure in which the flag is deleted from the PPP frame structure, and data with no octet insertion or bit insertion is used as a data link other than PPP. A data conversion apparatus for converting data having a frame structure of a layer protocol. A data converter,
A data conversion apparatus for converting data having a frame structure of a data link layer protocol other than PPP into data having a PPP frame structure and having no octets or bits inserted therein. A data converter,
Data having a data link layer protocol frame configuration other than PPP is added to the PPP frame configuration with additional information including information for identifying frame delimiters, and octets or bits are inserted. A data conversion device characterized by converting into non-data. A data converter,
A data conversion apparatus characterized by converting data having a frame structure of a data link layer protocol other than PPP into data having a frame structure in which a flag is deleted from the PPP frame structure and having no octet or bit inserted . A data converter,
A frame structure in which data having a frame structure of a data link layer protocol other than PPP is added to additional information including information for identifying a frame delimiter in a frame structure in which a flag is deleted from the PPP frame structure; A data conversion apparatus characterized by converting data into octets or bits not inserted.   9. The data conversion apparatus according to claim 2, wherein the information for identifying a frame delimiter is a frame length. A data conversion method,
A data conversion method characterized by converting data having a PPP frame structure and having no octet or bit inserted into data having a frame structure of a data link layer protocol other than PPP. A data conversion method,
It has a frame structure in which additional information including information for identifying a frame delimiter is added to the PPP frame structure, and data with no octet insertion or bit insertion is used for the data link layer protocol frame structure other than PPP. A data conversion method characterized by converting the data into data. A data conversion method,
A data conversion method having a frame structure in which a flag is deleted from a PPP frame structure, and converting data with no octet insertion or bit insertion into data having a frame structure of a data link layer protocol other than PPP . A data conversion method,
A frame structure in which additional information including information for identifying a frame delimiter is added to the frame structure in which the flag is deleted from the PPP frame structure, and data with no octet insertion or bit insertion is used as a data link other than PPP. A data conversion method comprising: converting data having a frame structure of a layer protocol. A data conversion method,
A data conversion method comprising: converting data having a frame structure of a data link layer protocol other than PPP into data having a PPP frame structure and having no octets or bits inserted therein. A data conversion method,
Data having a data link layer protocol frame configuration other than PPP is added to the PPP frame configuration with additional information including information for identifying frame delimiters, and octets or bits are inserted. A data conversion method characterized by converting into non-data. A data conversion method,
A data conversion method comprising: converting data having a frame structure of a data link layer protocol other than PPP into data having a frame structure in which a flag is deleted from the PPP frame structure and having no octet or bit inserted therein . A data conversion method,
A frame structure in which data having a frame structure of a data link layer protocol other than PPP is added to additional information including information for identifying a frame delimiter in a frame structure in which a flag is deleted from the PPP frame structure; A data conversion method, characterized in that the data is converted into data without octet insertion or bit insertion.   18. The data conversion method according to claim 11, 13, 15 or 17, wherein the information for identifying a frame delimiter is a frame length. A gateway comprising the data conversion device according to claim 1,
A gateway characterized by transmitting an LCP echo reply to one of the two apparatuses that perform data communication based on PPP when the LCP echo request transmitted to the other is received. A gateway comprising the data conversion device according to claim 1,
A gateway characterized by discarding an LCP discard request when one of two devices performing data communication based on PPP receives an LCP discard request transmitted to the other.

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