JP2008141466A - Method and apparatus of handling header compressed packet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology for achieving processing efficiency and memory reduction in a method and apparatus of handling a packet of a compressed header. <P>SOLUTION: This header compressed packet communication equipment 101 has a header compressed packet processing part 102, a UDP/IP protocol processing part 103, an application processing part 104, a session information storing part 106, or the like. The equipment transmits and receives a header compressed packet without developing a compressed header to a full header. Session information including a fixed part checksum value related to a checksum calculation is stored in the session information storage part 106. The fixed part checksum value is calculated from fixed part information of the full header. Each processing part in the equipment shares the session information. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to data transmission / reception in a communication system such as a network, and more particularly to packet processing using a header compression technique.

  In recent years, there has been a growing demand for higher functionality using networks and applied service systems for devices such as air conditioning equipment in buildings and homes, lighting equipment, and control system equipment such as sensors. For example, a human sensor or a temperature / humidity sensor transmits a peripheral information to an air conditioner or a lighting device, and a remote control function for automatically turning on / off a power source and adjusting a set temperature / illuminance automatically.

  When information is transmitted through the network in this way, a header indicating information for specifying a transmission source and a reception destination is added to the target information / data (referred to as user data), and packetized transmission. The way to do it has become mainstream. For example, when a packet is transmitted on an IP (Internet Protocol) network, IP is used as a communication protocol. The IP header has a data amount of 20 bytes for IPv4 and 40 bytes for IPv6.

  Since the amount of data in these headers is constant regardless of the amount of user data, the header occupies most of the packet when the amount of user data is small. In particular, the amount of user data is generally small in remote control of the above-described control system devices.

  Since the header of the packet is not user data that is originally the object of transmission / reception, it is not preferable that the header occupies a large proportion. For this reason, among the original header information (full header), a method of reducing the amount of transmission data by using a compressed header, which is a new header configured (created) by removing fixed information, may be applied. Many.

  There are a plurality of types of header compression methods defined by IETF (Internet Engineering Task Force). For example, IP header compression (Non-Patent Document 1) targeting TCP / UDP / IP and RTP / UDP / IP as protocol sets, and 6LoWPAN (IPv6 over Low, which is a standard for transmitting IPv6 packets over a low power consumption network) The method used in (Power WPAN) (Non-Patent Document 2).

  In 6LoWPAN packet processing, a 60-byte header of UDP / IPv6 can be compressed to a minimum of 8 bytes (FIG. 7).

  Further, in the technique using the compressed header (IP header compression) of Non-Patent Document 1 (first technique), the packet (user data) has almost the same configuration as the header in the normal (no compressed header) format. A full header is sporadically added, and a compressed header is added to most other packets (user data). Thereby, the header of 60 bytes of UDP / IPv6 can be compressed to a minimum of 4 bytes, and the amount of information to be transmitted is reduced (FIG. 8).

Further, as a configuration example corresponding to the technique for processing the header compressed packet of Non-Patent Document 1, there is one disclosed in Japanese Patent Laid-Open No. 2005-252855 (Patent Document 1).
JP 2005-252855 A “IP Header Compression (RFC 2507)”, M. Degermark, B. Nordgren and S. Pink, IETF, February, 1999 “Transmission of IPv6 Packets over IEEE 802.15.4 Networks draft-ietf-6lowpan-format-04 (work in progress)”, G. Montenegro and N. Kushalnagar, IETF, August, 2006

  In the conventional technique such as the first technique, in the transmission / reception of the header compressed packet, the compressed header is expanded (reconstructed) into a full header and a protocol process such as checksum calculation is performed. There is a problem that the memory efficiency is consumed and the processing efficiency is not good. This is detailed below.

  In the conventional configuration (first technique), CID (Context Identifier) information is stored in the compressed header (FIG. 8), and a full header transmitted sporadically based on the information. Is associated. When a header compressed packet is received, a normal format (compressed) is obtained by using the CID that is information in the compressed header and the corresponding session information stored in the session information storage unit and associated with the corresponding CID. A full header (in the first technique, a pseudo UDP / IP header) is once constructed, and protocol processing (network protocol processing) such as checksum calculation (error detection) is performed. For this reason, the corresponding session information stored in the session information storage unit must be copied to a memory space for constructing (decompressing) a full header. Also, when a header compressed packet is transmitted, a data copy for a full header configuration is generated as in the case of the reception. A working memory is required for the construction of the full header and data copying. Most packets transmitted are compressed headers, and the data copy occurs each time the compressed headers are transmitted / received. Therefore, the protocol processing efficiency in the packet processing device is not good. In other words, the packet processing time is lengthened and the communication processing speed is reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to solve the above problems and improve processing efficiency and memory reduction in a method and apparatus for processing a packet of a compressed header. It is to provide a technology that can be used.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows. In order to achieve the above-mentioned object, the present invention provides data (users) to which header information (compressed header) configured to be compressed (omitted) so that the data amount is smaller than the full header instead of the full header is added in the communication system. A method and apparatus for transmitting / receiving packet data (header compressed packet) composed of data), characterized by the following configuration.

  This header compressed packet processing method is configured to include a process of transmitting / receiving a header compressed packet to / from a network or the like (header compressed packet processing) and protocol processing corresponding to the transport layer and the network layer. The header compressed packet processing apparatus includes processing for transmitting / receiving header compressed packets to / from a network or the like (header compressed packet processing), and protocol processing means corresponding to the transport layer and the network layer. The In addition, means (process) such as higher-level application processing may be provided. Also, session information storage means (memory) for storing a table of session information and other related information is provided at any location in the apparatus. Each processing means (process) in this apparatus is configured to share information in the table of the session information storage means.

  In the table of the session information storage means, session information with the communication partner (in other words, information related to the flow of transmission / reception of a plurality of packets) including address information for specifying the communication partner is stored. Note that creating session information at the time of storage is not a condition, and session information may be given from the outside. The session information includes or is associated with information (session identifier) that identifies the session information. In addition, information (application identifier) for identifying an application (upper processing unit) that exchanges user data is associated with or included in the session information of this table. Each processing unit in the apparatus shares table information using a session identifier or the like.

  In addition, in this table, a fixed part checksum value (first calculated value), which is a partial value of error detection processing such as checksum calculation (in-process value and different from the final calculated value), is stored. Store. The fixed part checksum value is calculated from the fixed part information in the full header. The fixed part information in the full header is information that is highly likely to be omitted in the compressed header. On the other hand, the variable part checksum value (second calculated value), which is a partial value of the same processing, is calculated from the variable part information in the full header.

  With this configuration, when the transmission / reception packet is a header compressed packet, each processing unit in the apparatus can obtain and use the corresponding session information corresponding to the compressed header from the session information storage means when performing its own processing. . Also, for information that is included in the full header but omitted in the compressed header, checksum calculation (error detection processing) can be performed on information corresponding to the full header. Therefore, in this processing method and apparatus, packet transmission / reception and protocol processing can be performed even when only header compressed packets are transmitted.

  In this processing method and apparatus, when a header compressed packet is transmitted to a certain communication partner for the first time, the corresponding session information is stored in the table of the session information storage means. When configuring the compressed header, only necessary information is extracted from this table and used. Further, when a header compressed packet is transmitted to a communication partner already existing as information in the table, the corresponding session information in the table is continuously used.

  When a header compressed packet is received, the information stored in the compressed header of the packet is compared with the corresponding session information in the session information storage means table. If the session information already exists in the table, the identifier of the session information is passed to each processing unit in the device. If the session information does not exist, the session information is newly stored in the table. Is transferred to each processing unit in the apparatus. In this way, by sharing the information in the table among the processing units in the apparatus, only the necessary information can be used when each processing unit is needed.

  Further, in the present processing apparatus and method, partial checksum calculation for the fixed part information in the full header (pseudo UDP / IP header as an example) is performed in advance, and the fixed part checksum value (first calculated value) as a result thereof is calculated. ) Is stored in the session information storage table (for example, when a packet is transmitted to a new communication partner for the first time). The fixed part information included in the full header is often omitted and not included in the compressed header in many cases (for example, 6LoWPAN), but the first calculation stored in the table when the checksum calculation of the compressed header is performed. By using the value, the checksum calculation can be performed by combining the first and second calculation values without bothering to construct a pseudo header (full header). With the above configuration, packet processing including protocol processing such as checksum calculation can be performed without expanding the compressed header into a full header.

  This header compressed packet processing method has the following configuration, for example. In the present processing method, as error detection processing related to transmission / reception of a header compressed packet, the first calculation value for the fixed part information and the second calculation value for the variable part information in the full header are calculated and processed. A calculated value of 1 is stored in the session information storage means, and a header compressed packet in which a compressed header including the second calculated value is added to user data is constructed (created). Then, when transmitting and receiving the header compressed packet, error detection processing is performed using the second calculated value included in the compressed header and the first calculated value of the session information storage means. Also, the first and second calculated values are calculated at different timings, and both are added later to obtain a calculated value for error detection processing. When the header compressed packet is transmitted / received, the calculated value of the error detection process is obtained using the calculated second calculated value and the first calculated value stored in the session information storage means.

  Moreover, this header compression packet processing apparatus is the following structures, for example. In the processing information storage means and the error detection processing related to the transmission / reception of the header compressed packet, the processing apparatus calculates the first calculation value and the second calculation value, and the first calculation value is stored in the session information storage means. A header compressed packet is stored by including in session information, and a compressed header including the second calculated value is added to the user data. When the header compressed packet is transmitted and received, the second calculated value included in the compressed header is Means for performing header detection packet processing and protocol processing, including performing error detection processing using the first calculated value of the session information storage means.

  Further, the means for performing header compressed packet processing and protocol processing includes processing for constructing a compressed header based on session information when transmitting a header compressed packet, and header compression received when receiving the header compressed packet. A compressed header processing means (105) for interpreting the information of the compressed header based on the compressed header of the packet and the session information stored in the session information storage means, and error detection processing of the full header. A partial value calculating means (107) for calculating a partial value for error detection processing using the first calculated value and the second calculated value; and a processing (108) for calculating a second calculated value for error detection processing; When transmitting the header compressed packet, the identification information of the application that transmits / receives user data and the session information stored in the session information storage means A process (109) of comparing user information to the application associated with the session information identification information and the application identification information when the identification information of the session information is compared and the header compressed packet is received. Network layer and transport layer protocol processing means.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows. According to the present invention, it is possible to improve processing efficiency and reduce memory in a method and apparatus for processing a compressed header packet. In particular, protocol processing is performed without the need to construct (decompress) a full header from a compressed header, so that the packet processing time can be shortened and the communication processing speed can be improved, and the memory required for data copying is not required.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

<Example of conventional technology>
Hereinafter, in order to explain the present invention and the embodiments more easily compared with the prior art, the respective prior arts related to the header compression format and the device configuration example will be briefly described with reference to FIGS.

<Header compression (6LoWPAN)>
The case of 6LoWPAN will be described with reference to FIG. 7 as an example of a full header and a compressed header. In FIG. 7, the 6LoWPAN compressed header 401 is composed of a compressed header code 402, a compressed IPv6 header 403, and a compressed UDP header 404.

  The compressed header code 402 is not omitted from the information included in the full header (corresponding to the UDP / IPv6 full header (501 in FIG. 8)) in 6LoWPAN (for example, the information 406 and the information 407). 2 bytes of information 405 indicating information to be stored in (). The information 405 of the compressed header code 402 is a code indicating the compressed information (information stored in the compressed header) of the IPv6 header (503 in FIG. 8): HC1, and a code indicating the compressed information of the UDP header (504 in FIG. 8): HC2. Information 406 is a part of the IPv6 header 503 in FIG. 8, and information 407 is a part of the UDP header 504 in FIG.

  The compressed IPv6 header 403 is configured based on the number of hops in IPv6, a source address, a destination address, a traffic class, a flow label, and 39-byte information 406 of the next header. The actual packet compressed IPv6 header 403 is variable-length information of 2 to 39 bytes including only the information designated by the HC1 from the information 406.

  The compressed UDP header 404 is configured based on 8-byte information 407 of a transmission source port number, a reception destination port number, a data length, and a checksum in UDP. The compressed UDP header 404 of the actual packet is 4 to 8 byte variable length information including only the information 407 designated by the HC2.

  With these configurations, in 6LoWPAN packet processing, a 60-byte header (501 in FIG. 8) of UDP / IPv6 can be compressed to a minimum of 8 bytes (2 + 2 + 4 = 8 bytes) like the 6LoWPAN compressed header 401. Is possible.

  Note that, in the compressed IPv6 header 403 and the compressed UDP header 404, information that is not specified by the compressed header code 402, that is, information that is lost due to compression (omitted) with respect to the full header is not changed. Therefore, the full header can be completely restored.

  Note that 6LoWPAN itself can process both full headers and compressed headers, but in this embodiment, 6LoWPAN handles compressed headers in 6LoWPAN.

<Header compression (UDP / IP)>
The configuration of the UDP / IPv6 full header 501 and its compressed header 502 in RFC 2507 (Non-Patent Document 1) will be described with reference to FIG. The UDP / IPv6 full header 501 is a combination of the IPv6 header 503 and the UDP header 504 defined by RFC2460.

  Information including a CID (Context Identifier) 505 is written in a length (length # 1, # 2) portion of the UDP / IPv6 full header 501 (not shown). Note that the lengths # 1 and # 2 are portions where the payload length and the datagram length are written in the case of a UDP / IPv6 header in the normal (no compressed header) header format, and the CID 505 is not written. The CID 505 is identification information for specifying a flow, in other words, identification information for specifying a full header, as a conventional technique. The CID 505 in the lengths # 1 and # 2 can be associated with the CID 505 in the compressed header 502.

  The compressed header 502 is composed of information including a checksum and a CID 505, which are variable parts, of information constituting a normal (no compressed header) UDP / IPv6 header.

  In the technique (first technique) using the compressed header of RFC2507 (Non-Patent Document 1), a full header having a configuration almost the same as the normal (no compressed header) format is sporadically added, and most of the other parts are added. A compressed header is added to the packet. Thereby, the header of 60 bytes of UDP / IPv6 can be compressed to a minimum of 4 bytes, and the amount of information and data to be transmitted is reduced.

  The checksum (checksum calculation), which is a known technique, is one of error detection methods in data transmission / reception. That is, on the transmission side, the sum of the numerical values of each block of the target data is taken, and this (checksum value) is added to the target data for transmission. On the receiving side, a checksum value is similarly calculated from the received data, and it is checked whether or not it matches the received checksum value. If both are different, an error has occurred in the target data in the transmission path.

<Pseudo UDP / IP header>
FIG. 9 shows the configuration of a pseudo UDP / IP header 601 related to the processing of the prior art example described later. The pseudo UDP / IP header 601 includes a pseudo IP header 602 and a UDP header 603. The checksum value is the one's complement of the sum obtained by adding the pseudo UDP / IP header 601 and user data 16 bits at a time. The pseudo UDP / IP header 601 is configured for checksum calculation processing without being transmitted over the network. The pseudo IP header 602 includes only information necessary for the checksum calculation process. The pseudo header is so called because the information is not transmitted over the network.

<Example of header compressed packet processing device>
The header compressed packet processing and apparatus, which is a prior art example described in Patent Document 1, will be briefly described with reference to FIGS. The configuration example shown in FIGS. 10 and 11 is an example of processing the packet and header configuration of FIG. These configurations show the case of header compressed packet reception processing.

  The schematic structure of the header compression packet processing apparatus (header compression packet receiving apparatus 901) of this prior art example in FIG. 10 is shown. The header compressed packet receiver 901 includes a PPP frame receiver 902, a compressed header reception processor 903, a UDP / IP reception processor 904, a pseudo UDP reception processor 905, a session information storage unit 906, and a user data output unit 907. Has been. The data is output from the user data output unit 907 to each UDP / IP application 908.

  In the detailed configuration of FIG. 11, the compressed header reception processing unit 903 includes a full header receiving unit 1001, a compressed header receiving unit 1002, and a context information storage unit 1003. The UDP / IP reception processing unit 904 includes an IP reception processing unit 1004 and a UDP reception processing unit 1005. The pseudo UDP reception processing unit 905 includes a checksum confirmation unit 1007 and a pseudo UDP / IP header generation unit 1008.

  The PPP frame receiving unit 902 receives a PPP frame transmitted from an external device, and analyzes a PPP header included therein.

  The compressed header reception processing unit 903 determines and classifies whether the header added to the user data is a full header or a compressed header, and causes a subsequent processing unit to perform different processing.

  The UDP / IP reception processing unit 904 processes a packet (UDP / IP packet) to which a full header, that is, a normal UDP / IP header is added (UDP / IP reception processing), and displays an application (908) corresponding to the packet. Select.

  The pseudo UDP reception processing unit 905 generates the pseudo UDP / IP header 601 of FIG. 9 from the compressed header (including CID and checksum) and the session information stored in the session information storage unit 906, and performs reception processing. (Pseudo UDP reception processing) is performed, and an application (908) corresponding to the packet is selected.

  The session information storage unit 906 stores session information corresponding to a combination of an IP address and a UDP port number, and information for identifying a corresponding application (application identifier: AID).

  The user data output unit 907 outputs the received user data to the designated UDP / IP application 908.

  Next, an outline of the operation at the time of packet reception in this prior art example will be described. When a packet is received, the PPP frame receiving unit 902 determines whether the header added to the packet is a compressed header or a full header. The user data to which the full header is added is passed to the full header receiving unit 1001. The full header receiving unit 1001 compares the information included in the full header with the identification information (session identifier: SID) for specifying the session information, and receives the user data delivery destination to which the full header is added. Application (908) is selected. At this time, the checksum confirmation unit 1006 confirms (calculates) the checksum in the header and checks whether there is an error in the received packet. If there is no abnormality as a result of the checksum calculation, the UDP / IP reception processing unit 904 passes the user data and the application identifier (AID) to the user data output unit 907. At the same time, the session identifier (SID) and the context identifier (CID) in the full header are stored in the context information storage unit 1003 in association with each other.

  On the other hand, when the compressed header is added, the PPP frame receiving unit 902 passes the packet to the compressed header receiving unit 1002. The compressed header receiving unit 1002 extracts the CID from the compressed header, and reads the SID associated with the CID from the context information storage unit 1003. Based on the session information corresponding to the read SID, a pseudo UDP / IP header 601 is once generated, and the SID and the pseudo UDP / IP header 601 are passed to the pseudo UDP reception processing unit 905. The pseudo UDP reception processing unit 905 (checksum confirmation unit 1007) calculates the checksum as in the case of the full header, and if there is no abnormality, receives the user data to which the compressed header is added based on the session information. The application (908) to be passed is determined, and the user data and AID are passed to the user data output unit 907. With such a configuration example, it is possible to process a packet to which a compressed header is added.

<Problems etc.>
However, the above-described conventional technique is common to the technique of the present embodiment in that it processes header compressed packets, but differs in that it processes a full header. In the conventional configuration (first technique), the CID information is stored in the compressed header (FIG. 8), and the association with the full header transmitted sporadically is performed based on the information. . However, when all headers added to a packet are compressed headers as in 6LoWPAN, the device configuration for processing a full header as in the first technique is not necessary in the first place.

  In the first technique, when a header compressed packet is received, the CID, which is information in the compressed header, and the corresponding session information associated with the corresponding CID stored in the session information storage unit are used. Thus, a full header (pseudo UDP / IP header 601 in the first technique) of a normal format (a format that is not compressed) is once configured, and protocol processing such as checksum calculation is performed. For this reason, the corresponding session information stored in the session information storage unit must be copied to a memory space for forming a full header. Also when sending header compressed packets, a full header is constructed from the session information, checksum calculation, etc. is performed, and a compressed header is constructed and sent, so the same data copy as when receiving the header compressed packet occurs Was. Working memory is required for full header construction (development) and data copying.

  In the first technique, most transmitted packets are compressed headers, and the data copy occurs each time the compressed headers are transmitted and received. Therefore, the protocol processing efficiency in the packet processing device is not good. In other words, the packet processing time is lengthened and the communication processing speed is reduced.

<Embodiment>
Based on the above-described technique, a header compressed packet processing method and a header compressed packet using the method according to an embodiment of the present invention are described with reference to FIGS. 1 to 6 and FIGS. A processing apparatus will be described. As a feature of the present method and apparatus, in a configuration having a function of transmitting / receiving (both transmitting and receiving) a packet (header compressed packet) in 6LoWPAN, each processing unit in the apparatus includes a fixed part checksum value. Share session information. Then, in the protocol processing at the time of transmission / reception of each packet, the checksum value is obtained by calculating the variable portion checksum value and adding it to the fixed portion checksum value. Thereby, transmission / reception processing of the header compressed packet is realized without expanding the compressed header into a full header at all.

<Outline configuration>
FIG. 1 shows a schematic configuration of a header compressed packet communication device (abbreviated as a communication device) 101 which is a header compressed packet processing device of the present embodiment. The communication device 101 mainly includes a header compressed packet processing unit 102, a UDP / IP protocol processing unit 103, and an application processing unit 104.

  The header compressed packet processing unit 102 includes a compressed header processing unit 105, a session information storage unit 106, and a checksum partial value addition unit 107. The UDP / IP protocol processing unit 103 includes a checksum calculation unit 108 and a UDP / IP processing unit 109. The application processing unit 104 includes each UDP / IP application 110 (110-1, 110-2, 110-3) that uses UDP / IP.

  The communication apparatus 101 is characterized by a header compressed packet processing unit 102 and a UDP / IP protocol processing unit 103. The communication apparatus 101 is implemented by software / hardware (circuit IC or the like), but there are various implementation details such as which part is integrated into an IC. In addition, each processing unit can be configured as one processing unit without being divided. Each processing unit also has a work memory (not shown) for processing the compressed header.

  The session information storage unit 106 stores session information (session information table) as shown in FIG. The compressed header processing unit 105, the UDP / IP processing unit 109, and the like can create session information as necessary.

  The UDP / IP protocol processing unit 103 corresponds to a transport layer / network layer processing unit. The header compressed packet processing unit 102 is an adaptation unit (adapter) provided between the upper UDP / IP protocol processing unit 103 (transport layer / network layer processing unit) and the lower physical / MAC layer (not shown).

  Note that, as necessary for explanation, P: packet (header compressed packet), D: user data, H1: full header, H2: compressed header, S: session information, C: checksum value, etc.

<Detailed configuration>
Next, FIG. 2 shows a detailed configuration of the communication apparatus 101. In particular, it also shows the exchange of data and information between processing units in a packet processing example. The compressed header processing unit 105 is a processing part that receives the packet (P) from the network or transmits the packet (P) to the network. When transmitting the packet (P), the compressed header processing unit 105 configures (creates) the compressed header (H2) based on the session information (S). When receiving the packet (P), the compressed header processing unit 105 receives the compressed header (H2) based on the session information (S) and the packet (P) to which the compressed header (H2) is added. ) Information.

  The session information table of the session information storage unit 106 stores information such as session information (S) and an application identifier (AID) associated therewith. In this example, the session information (S) includes a session identifier (SID) (included in the session information (S)), a source IP address (A1), a destination IP address (A2), and a source UDP port number. (N1), destination UDP port number (n2), and fixed part checksum value (Ca). In this session information table, the CID used in the prior art example is not necessary. Note that the data structure of the session information table is not limited to that shown in FIG.

  In the session information storage unit 106, when transmitting the packet (P), the session information (S) received from the UDP / IP processing unit 109 is stored in the session information table, and when the packet (P) is received. The session information (S) received from the compressed header processing unit 105 is stored in the session information table.

  When transmitting the packet (P), the checksum part value adding unit 107 adds the checksum part value (C) received from the UDP / IP processing unit 109 to the checksum part value ( C1) is added, and when the packet (P) is received, the checksum value (C1) received from the session information storage unit 106 is added to the checksum value (C) received from the compressed header processing unit 105. It is a processing site.

  The checksum calculation unit 108 receives data to be subjected to checksum calculation (checksum calculation target data: C2) from the UDP / IP processing unit 109, performs checksum calculation, and returns a checksum calculation result (C3). .

  The UDP / IP processing unit 109 performs protocol processing such as checksum calculation and application determination when transmitting and receiving a packet (P), and passes the user data (D) to and from the corresponding UDP / IP application 110. It is.

  The session information (S) mainly includes an address (A1, A2) and a port number (n1, n2), and additionally includes a fixed part checksum value (Ca). The fixed portion checksum value (Ca) is a checksum partial value, that is, a calculated value during partial processing of the checksum processing of the packet (P). Furthermore, in this example, an application identifier (AID) is associated with the session information (S) (particularly, the receiving destination UDP port number: n2).

  In the prior art, every time a packet is transmitted / received, checksum processing is performed on all data in the packet. On the other hand, in the present embodiment, only the information of the fixed part of the full header (H1) is pre-checksummed and stored in the session information table as a fixed part checksum value (Ca) and shared by each part. At the time of packet transmission / reception, the information of the variable part of the full header (H1) included in the compressed header (H2) is checksummed each time, and the fixed part checksum value (Ca) and the variable part checksum value ( Cb) is added to obtain a complete checksum value (C).

<Transmission processing operation>
Next, a schematic operation of the transmission / reception process of the header compressed packet (P) composed of user data (D) to which the compressed header (H2) is added according to the present embodiment will be described with reference to FIGS.

  First, the operation of packet (user data) transmission processing in the flow of FIG. 3 will be described. In S301 (S represents a processing step), the UDP / IP application 110 passes the user data (D) to be transmitted to the UDP / IP processing unit 109.

  In S302, the UDP / IP processing unit 109 uses the user data (D) received from the UDP / IP application 110 and the data length that is the variable part information of the pseudo UDP / IP header 601 in FIG. As (C2), it is passed to the checksum calculator 108. The checksum calculator 108 calculates the variable part checksum value (Cb) from these data (C2), and returns the result (C3) to the UDP / IP processor 109.

  In S303, the UDP / IP processing unit 109 checks whether or not the session information (S) determined from the UDP / IP application 110 that has received the user data (D) already exists in the table of the session information storage unit 106. To do. If it exists (Y), the process proceeds to S308, and otherwise (N), the process proceeds to S304.

  In S304, the UDP / IP processing unit 109 stores the session information (S) determined from the UDP / IP application 110 that received the user data (D) in the table of the session information storage unit 106, and stores the session identifier (SID). Received from the session information storage unit 106.

  In step S <b> 305, the UDP / IP processing unit 109 stores a source IP address (A1) and a destination IP address (A2) that are fixed part information of the pseudo UDP / IP header 601 in the table of the session information storage unit 106. It is confirmed whether the fixed part checksum value (Ca) calculated from the transmission source UDP port number (n1), the next header, and the reception destination UDP port number (n2) already exists. If it exists (Y), the process proceeds to S308, and otherwise (N), the process proceeds to S306.

  In S306, the UDP / IP processing unit 109 passes the fixed part information of the pseudo UDP / IP header 601 to the checksum calculation unit 108 as checksum calculation target data (C2). The checksum calculator 108 calculates the fixed part checksum value (Ca) from these data (C2), and returns the result (C3) to the UDP / IP processor 109.

  In S307, the UDP / IP processing unit 109 stores the fixed part checksum value (Ca) calculated in S306 in the session information table related to the session identifier (SID).

  In S <b> 308, the checksum partial value adding unit 107 receives the session identifier (SID), variable portion checksum value (Cb), and user data (D) from the UDP / IP processing unit 109. Then, the fixed part checksum value (Ca) related to the session identifier (SID) is extracted from the session information table, the variable part checksum value (Cb) is added to the checksum value (C2) and stored in the compressed header (H2). C) is calculated. The session identifier (SID), checksum value (C), and user data (D) are passed to the compressed header processing unit 105.

  In S309, the compressed header processing unit 105 generates a compressed header (H2) from the session information (S) related to the session identifier (SID), the checksum value (C), and the user data (D). A header compressed packet (P) composed of user data (D) with (H2) added is transmitted to the network.

<Reception processing operation>
Next, the operation of packet (user data) reception processing in the flow of FIG. 4 will be described. In S401, the compressed header processing unit 105 transmits the session information (S) from the header compressed packet (P) received from the network, the source IP address (A1), the destination IP address (A2), and the source UDP port. The number (n1) and the destination UDP port number (n2) are extracted.

  In S <b> 402, the compressed header processing unit 105 confirms whether the session information (S) of the received header compressed packet (P) already exists in the table of the session information storage unit 106. If it exists (Y), the session identifier (SID), the checksum value (C) in the received header compressed packet (P), and the user data (D) are passed to the checksum partial value adding unit 107. , S404, otherwise (N), the process proceeds to S403.

  In S403, the compressed header processing unit 105 stores the session information (S) of the received packet (P) in the table of the session information storage unit 106, receives the session identifier (SID) from the session information storage unit 106, and receives the session identifier. (SID), the checksum value (C) in the received packet (P), and user data (D) are passed to the checksum partial value adding unit 107.

  In S404, the checksum partial value addition unit 107 adds the source IP address (A1), the destination IP address (A2), which are fixed part information of the pseudo UDP / IP header 601, to the table of the session information storage unit 106. It is confirmed whether the fixed part checksum value (Ca) calculated from the transmission source UDP port number (n1), the next header, and the reception destination UDP port number (n2) already exists. If it exists (Y), the process proceeds to S407, and otherwise (N), the process proceeds to S405.

  In S405, the checksum partial value adding unit 107 calculates a fixed part checksum value (Ca) for the fixed part information of the pseudo UDP / IP header 601 of the received packet (P).

  In S406, the checksum partial value adding unit 107 stores the fixed part checksum value (Ca) calculated in S405 in the session information table related to the session identifier (SID).

  In S407, the checksum partial value adding unit 107, for the checksum value of the received packet (P), that is, the checksum partial value (C1), the fixed part checksum value (SID) associated with the session identifier (SID) from the session information table. Ca) is taken out and added to the checksum value partial value (C1). Then, the checksum partial value (C1), the session identifier (SID), and the user data (D), which are the addition results, are passed to the UDP / IP processing unit 109.

  In S408, the UDP / IP processing unit 109 converts the data length, which is the variable part information of the pseudo UDP / IP header 601, and the user data (D) received from the checksum partial value adding unit 107 into the checksum calculation target data ( C2) is passed to the checksum calculator 108. The checksum calculator 108 calculates the variable part checksum value (Cb) from these data (C2) and returns the result (C3) to the UDP / IP processor 109.

  In S409, the UDP / IP processing unit 109 adds the variable part checksum value (Cb) calculated in S408 to the checksum value of the received packet (P), that is, the checksum part value (C1).

  In S410, the UDP / IP processing unit 109 checks whether or not the checksum calculation result calculated in S409 is 0 (OK). When it is 0 (OK) (Y), the process proceeds to S412. When it is not (NG) (N), the process proceeds to S411. In S411, the UDP / IP processing unit 109 discards the user data (D) of the received packet (P) and ends the receiving process.

  In S412, the UDP / IP processing unit 109 extracts the application identifier (AID) related to the session identifier (SIv) from the session information table, passes the user data (D) to the corresponding UDP / IP application 110, and performs reception processing. finish.

<Effect>
The main effects of the present embodiment are as follows. In the prior art, when a packet including a compressed header is received, the header of the packet is expanded into a full header (pseudo UDP / IP header 601 as an example) and protocol processing is performed. Similarly, when a packet including a compressed header is transmitted, the full header is processed. Therefore, when processing the compressed header, necessary information is extracted from the session information table, and a data copy for configuring a full header and a memory space for storing the full header are required.

  On the other hand, in the communication apparatus 101, when transmitting / receiving the header compressed packet (P) including the compressed header (H2), each processing unit in the apparatus only requires necessary information from the session information table of the session information storage unit 106. It is not necessary to expand (configure) the pseudo UDP / IP header 601 corresponding to the full header (H1). Also in the checksum calculation (error detection process), the fixed part checksum value (Ca) for the fixed part information of the pseudo UDP / IP header 601 is stored in the session information table, so that the number of additions during the checksum calculation can be calculated. Reduce. This reduces the checksum calculation processing when communicating with the same communication partner, that is, the partner who has communicated in the past and whose session information (S) is stored in the session information table.

  Therefore, in this communication apparatus 101 and method, it is possible to reduce the transmission / reception processing when transmitting / receiving the packet (P) including the compressed header (H2), thereby shortening the processing time and improving the processing speed. The required memory (including work memory and session information storage unit 106) can be reduced.

<Modification>
5 and 6, another configuration (modification) of the header compressed packet processing device (communication device 101) of the above-described embodiment (first configuration) is shown. These differ in the position of the session information storage unit 106. In these configurations, the function of each processing unit, the operation of transmission / reception processing of the header compressed packet (P), and the like are the same.

  In FIG. 5, the communication apparatus 101B in the second configuration includes a header compression packet processing unit 102B, a UDP / IP protocol processing unit 103B, and an application processing unit 104, and not the header compression packet processing unit 102B but the UDP / IP protocol. The processing unit 103B includes a session information storage unit 106B. For example, the compressed header processing unit 105 accesses the session information storage unit 106B in the UDP / IP protocol processing unit 103B to read / write information.

  In FIG. 6, the communication apparatus 101C in the third configuration includes a header compressed packet processing unit 102C, a UDP / IP protocol processing unit 103C, and an application processing unit 104. The header compressed packet processing unit 102C and the UDP / IP protocol processing unit In addition to 103C, a session information storage unit 106C is provided. For example, the compressed header processing unit 105 and the UDP / IP processing unit 109 access the session information storage unit 106B in the communication apparatus 101 to read / write information.

<Others>
Other possible configurations will be described. As another configuration, an apparatus configuration including only one function of transmission / reception processing of the header compressed packet (P) is also possible.

  For example, if the compressed header processing unit 105 is configured to add a function for determining whether the packet to be processed is a compressed header (H2) or a full header (H1) and a corresponding full header processing unit, only the compressed header (H2) is added. In addition, processing such as transmission / reception of the full header (H1) is also possible.

  Further, the compressed header format applicable in this configuration is not limited to 6LoWPAN. Further, the communication protocol applicable in this configuration is not limited to UDP / IP, and for example, TCP / IP or the like is also possible.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention can be used for an apparatus that performs packet data communication in a wireless communication system, for example.

It is a figure which shows the structure of the header compression packet communication apparatus in one embodiment of this invention. It is a figure which shows the detailed structure of the principal part (a header compression packet process part and a UDP / IP protocol process part) in the header compression packet communication apparatus of one embodiment of this invention. It is a figure which shows the operation | movement flow of a user data transmission process (header compression packet transmission process) in the header compression packet communication apparatus of one embodiment of this invention. It is a figure which shows the operation | movement flow of a header compression packet reception process (user data reception process) in the header compression packet communication apparatus of one embodiment of this invention. It is a figure which shows another structure (the 1) of a header compression packet communication apparatus in the header compression packet communication apparatus of one embodiment of this invention. It is a figure which shows another structure (the 2) of a header compression packet communication apparatus in the header compression packet communication apparatus of one embodiment of this invention. It is a figure which shows the structure of the compression header (6LoWPAN compression header) in 6LoWPAN which is a prior art example and is handled by one embodiment of the present invention. It is a figure which shows the structure of a UDP / IPv6 full header and its compression header which is a prior art example, and is referred in one embodiment of the present invention. It is a figure which shows the structure of a pseudo | simulated UDP / IP header which is a prior art example and is referred in one embodiment of this invention. It is a figure which shows the structure of the header compression packet receiver in a prior art example. It is a figure which shows the detailed structure of the header compression packet receiver in a prior art example.

Explanation of symbols

  101, 101B, 101C ... header compressed packet communication device (header compressed packet processing device), 102, 102B, 102C ... header compressed packet processing unit, 103, 103B, 103C ... UDP / IP protocol processing unit, 104 ... application processing unit, 105 ... compressed header processing unit, 106, 106B, 106C ... session information storage unit, 107 ... checksum partial value addition unit, 108 ... checksum calculation unit, 109 ... UDP / IP processing unit, 110 (110-1, 110-) 2, 110-3) ... Application (UDP / IP application), 401 ... 6LoWPAN compressed header, 402 ... Compressed header code, 403 ... Compressed IPv6 header, 404 ... Compressed UDP header, 405 ... Information, 406 ... Information, 407 ... Information 501 ... UDP / IP 6 full header, 502 ... compressed header (UDP / IPv6 compressed header), 503 ... IPv6 header, 504 ... UDP header, 505 ... CID (context identifier), 601 ... pseudo UDP / IP header, 602 ... pseudo IP header, 603 ... UDP Header, 901... Header compressed packet receiver, 902. PPP frame receiving unit, 903... Compressed header reception processing unit, 904... UDP / IP reception processing unit, 905 .. pseudo UDP reception processing unit, 906. ... User data output unit, 908 ... UDP / IP application, 1001 ... Full header receiving unit, 1002 ... Compressed header receiving unit, 1003 ... Context information storage unit, 1004 ... IP reception processing unit, 1005 ... UDP reception processing unit, 1006,1007 ... Checksum confirmation part, 008 ... pseudo UDP / IP header generating unit.

Claims (12)

Process for transmitting and receiving the header compressed packet used in a communication system in which a header compressed packet made up of user data to which a compressed header compressed so as to reduce the amount of data instead of the full header is transmitted is transmitted A header compressed packet processing method in a device that performs packet processing including:
The session information storage means provided in the device stores session information including information for specifying a transmission / reception destination of the user data, and the information is shared by each processing unit in the device.
As the error detection processing related to transmission / reception of the header compressed packet, the first calculation value for the fixed portion information and the second calculation value for the variable portion information in the full header are calculated and processed. Storing the calculated value in the session information storage means, and configuring the header compressed packet in which the compressed header including the second calculated value is added to the user data,
The header performing the error detection process using the second calculated value included in the compressed header and the first calculated value of the session information storage unit when transmitting and receiving the header compressed packet Compressed packet processing method. The header compressed packet processing method according to claim 1,
In the process of transmitting the header compressed packet, the second calculation value is calculated, and if the session information corresponding to the communication partner is not stored in the session information storage unit, the session information is stored, If the calculated value of 1 is not stored, it is calculated and stored, and using the session information stored in the session information storage means, the first calculated value and the second calculated value are used. As a calculated value of error detection processing, configure the compressed header including the calculated value of error detection processing, add it to the user data and configure the header compressed packet to transmit to the communication partner,
In the process of receiving the header compressed packet, the compressed header information of the header compressed packet received from the communication partner is interpreted to extract session information, and the session information storage means corresponds to the extracted session information. If the corresponding session information is not stored, the extracted session information is stored. If the first calculated value corresponding to the extracted session information is not stored in the session information storage means, it is stored. And using the first calculated value stored in the session information storage means for the second calculated value in the calculated value of the error detection processing in the received header compressed packet. The error detection process is performed, and the result is confirmed to obtain the user data. Header compressed packet processing method. The header compressed packet processing method according to claim 1,
The error detection process is a checksum calculation process, the first calculation value is a fixed part checksum value, the second calculation value is a variable part checksum value, and the first and first 2. A header compressed packet processing method, wherein a checksum calculation value is obtained by adding two calculation values. The header compressed packet processing method according to claim 1,
The calculation process of the first calculation value is performed in advance, and the first calculation value is included in or associated with the session information of the session information storage unit, and stored.
When the header compressed packet is transmitted / received, the calculated value of the error detection process is calculated using the second calculated value calculated and the first calculated value stored in the session information storage unit. A method for processing a header compressed packet, characterized by comprising: The header compressed packet processing method according to claim 1,
When the header compressed packet is transmitted or received for the first time to a new communication partner, the session information corresponding to the compressed header information of the header compressed packet is stored in the session information storage means, and thereafter A header compressed packet processing method characterized by using the session information for the same communication partner. The header compressed packet processing method according to claim 1,
The information stored in the session information storage means includes identification information of the session information, a source network layer address of the header compressed packet, a source transport layer port number, a destination network layer address, a destination transport layer port A header compressed packet processing method comprising: a number, the first calculated value, and identification information of the application. Process for transmitting and receiving the header compressed packet used in a communication system in which a header compressed packet made up of user data to which a compressed header compressed so as to reduce the amount of data instead of the full header is transmitted is transmitted A header compressed packet processing device that performs packet processing including:
Session information storage means for storing session information including information for specifying the transmission / reception destination of the user data, the information being shared by each processing unit in the apparatus,
In the error detection processing related to transmission / reception of the header compressed packet, the first calculation value for the fixed part information and the second calculation value for the variable part information in the full header are calculated and processed. A calculated value is stored in the session information storage means, the header compressed packet is configured by adding the compressed header including the second calculated value to the user data, and the compression is performed when the header compressed packet is transmitted and received. Means for performing header compression packet processing and protocol processing, including performing the error detection processing using the second calculation value included in the header and the first calculation value of the session information storage means. A header compressed packet processing apparatus. The header compressed packet processing device according to claim 7, wherein
Means for performing the header compressed packet processing and protocol processing,
Processing for configuring the compressed header based on the session information when transmitting the header compressed packet, and storing the compressed header and the session information of the received header compressed packet when receiving the header compressed packet Processing for interpreting the information of the compressed header based on the session information stored in the means;
Partial value calculating means for calculating a partial value of the error detection process using the first calculated value and the second calculated value of the error detection process of the full header;
Processing for calculating the second calculation value of the error detection processing, identification information of an application for transmitting / receiving the user data when transmitting the header compressed packet, and the session information storage means The session information is compared, the identification information of the session information is extracted, and when the header compressed packet is received, the user data is received by the application associated with the identification information of the session information and the identification information of the application. And a network layer and transport layer protocol processing means for performing a passing process. The header compressed packet processing device according to claim 7, wherein
The error detection process is a checksum calculation process, the first calculation value is a fixed part checksum value, the second calculation value is a variable part checksum value, and the first and first 2. A header compression packet processing apparatus, wherein a checksum calculation value is obtained by adding two calculation values. The header compressed packet processing device according to claim 7, wherein
Means for performing the header compressed packet processing and protocol processing,
The calculation process of the first calculation value is performed in advance, and the first calculation value is included in or associated with the session information of the session information storage unit, and stored.
When the header compressed packet is transmitted / received, the calculated value of the error detection process is calculated using the second calculated value calculated and the first calculated value stored in the session information storage unit. A header-compressed packet processing device characterized in that: The header compressed packet processing device according to claim 7, wherein
When the header compressed packet is transmitted or received for the first time to a new communication partner, the session information corresponding to the compressed header information of the header compressed packet is stored in the session information storage means, and thereafter A header compressed packet processing apparatus using the session information for the same communication partner. The header compressed packet processing device according to claim 7, wherein
The information stored in the session information storage means includes identification information of the session information, a source network layer address of the header compressed packet, a source transport layer port number, a destination network layer address, a destination transport layer port A header compressed packet processing apparatus comprising a number, the first calculated value, and identification information of the application.

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