JP2010258787A - Signaling compression device, signaling elongation device, and signaling compression and elongation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a signaling compression device capable of efficiently compressing a signaling message even including a number of firstly appearing character string patterns. <P>SOLUTION: A fixed/variable pattern separation part 1 differentiates fixed character string patterns from variable character string patterns in the signaling message to permutate the character strings so that the fixed character strings continue. A compressor 2 compresses the signaling message output from the fixed/variable pattern separation part 1. A fixed/variable pattern coupling part 5 permutates the character strings of the signaling message elongated by an elongating device 4 so as to restore them in the order of the format regulated by the signaling protocol. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a signaling compression apparatus that compresses a signaling message used for call control, a signaling expansion apparatus that expands a compressed signaling message, and a signaling compression / expansion apparatus that compresses / decompresses a signaling message.

  With the recent development of IP (Internet Protocol) networks, VoIP (Voice over IP) technology for transmitting telephone voice signals and facsimile signals in IP packets has attracted attention. Communication carriers in various countries are replacing conventional line-switching communication equipment with IP equipment. For this reason, VoIP is rapidly spreading particularly in the field of wired communication. For telephone call control by VoIP, SIP (Session Initiation Protocol), which is a protocol for starting and ending a session necessary for performing multimedia communication such as voice and images, is widely used. Further, the spread of IP networks extends to wireless, and in recent years, wireless VoIP is expected to be put into practical use, but there is a problem that the bandwidth of the wireless transmission path is narrower than that of wired. The SIP is a protocol for transmitting a text message with a large amount of data on an IP packet, and when used on a narrow bandwidth line, the message transmission delay increases. For this reason, there is a demand for a technique for compressing and transmitting a message having a large amount of data such as SIP.

  As a signaling compression method for compressing such a SIP message, for example, in a conventional method as disclosed in Patent Document 1, a compressor (compressor), a compression dictionary (codebook), and a decompressor (decompressor) are provided. Prepare. The compressor uses a template prepared in advance to delete a character string that matches the template and generates a character string to be transmitted. The compression dictionary includes a static dictionary that stores a character string pattern unique to a SIP message and a dynamic dictionary that stores a new character string pattern when a new character string pattern appears. The compressor uses these dictionaries to further encode the character string generated using the template. The decompressor performs the reverse process of the compressor and restores the compressed message.

Japanese Unexamined Patent Publication No. 2004-96717 (paragraph numbers [0028] to [0043], FIG. 4)

  In the conventional signaling compression method, the character string unique to the SIP message is compressed by the template or the static dictionary, and the other character strings are compressed by the dynamic dictionary. For compression by a dynamic dictionary, an LZ (Lempel-Ziv) type compression method is usually used. This compression method can efficiently compress repeatedly appearing character string patterns by incorporating character string patterns that have appeared in the past into the dynamic dictionary. However, the first character string pattern that does not exist in the dictionary is not compressed. That is, the conventional signaling compression method based on the LZ type compression method has a problem that the compression efficiency is poor for the SIP message including many character string patterns that appear for the first time.

  The present invention has been made in order to solve the above-described problems. A signaling compression apparatus, a signaling expansion apparatus, and a signaling compression capable of efficiently compressing even a signaling message including a large number of character string patterns that appear for the first time. The object is to obtain a stretching device.

  A signaling compression apparatus according to the present invention includes a compressor that compresses a signaling message using at least one of a static dictionary and a dynamic dictionary, and a fixed character string in the signaling message on the upstream side of the compressor. A fixed / variable pattern separation unit that distinguishes patterns and variable character string patterns and rearranges the character strings so that the fixed character strings continue is provided.

  The signaling compression apparatus according to the present invention identifies the fixed character string pattern and the variable character string pattern in the signaling message on the front side of the compressor, and arranges the character strings so that the fixed character strings are continuous. Since the replacement is performed, efficient compression can be performed even for a signaling message including many character string patterns that appear for the first time.

It is a block diagram which shows the signaling compression apparatus and signaling expansion | extension apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the uncompressed message before the character string rearrangement in the signaling compression apparatus of Embodiment 1 of this invention. It is explanatory drawing which shows the message after fixed / variable pattern isolation | separation in the signaling compression apparatus of Embodiment 1 of this invention. It is a block diagram which shows the signaling compression apparatus and signaling expansion | extension apparatus by Embodiment 2 of this invention. It is explanatory drawing which shows the uncompressed message in the signaling compression apparatus of Embodiment 2 of this invention. It is explanatory drawing which shows the message after header order rearrangement in the signaling compression apparatus of Embodiment 2 of this invention. It is a block diagram which shows the signaling compression apparatus and signaling expansion | extension apparatus by Embodiment 3 of this invention. It is explanatory drawing which shows the message after the essential header deletion in the signaling compression apparatus of Embodiment 3 of this invention. It is explanatory drawing which shows the message after essential header insertion in the signaling expansion | extension apparatus of Embodiment 3 of this invention. It is explanatory drawing which shows the network component regarding SIP, and the flow of the message transmitted. It is a block diagram which shows the signaling compression expansion | extension apparatus by Embodiment 4 of this invention. It is explanatory drawing which shows the uncompressed message which the SIP server (B) outputs in the signaling compression expansion | extension apparatus of Embodiment 4 of this invention. It is explanatory drawing which shows the message after Via header deletion in the signaling compression expansion | extension apparatus of Embodiment 4 of this invention. It is explanatory drawing which shows the uncompressed message which SIP-UA (B) outputs in the signaling compression expansion | extension apparatus of Embodiment 4 of this invention. It is explanatory drawing which shows the expansion | extension message in the signaling compression expansion | extension apparatus of Embodiment 4 of this invention. It is a block diagram which shows the signaling compression / decompression apparatus by Embodiment 6 of this invention. It is explanatory drawing which shows the message after Via header deletion in the signaling compression expansion | extension apparatus of Embodiment 6 of this invention. It is explanatory drawing which shows the uncompressed message which SIP-UA (B) outputs in the signaling compression expansion | extension apparatus of Embodiment 6 of this invention. It is explanatory drawing which shows the expansion | extension message in the signaling expansion | extension apparatus of Embodiment 6 of this invention. It is explanatory drawing which shows the uncompressed message which SIP-UA (B) outputs in the signaling compression expansion | extension apparatus of Embodiment 6 of this invention. It is explanatory drawing which shows the message after the Route header insertion in the signaling compression expansion | extension apparatus by Embodiment 6 of this invention. It is a block diagram of the signaling compression / decompression apparatus according to Embodiment 8 of the present invention. It is explanatory drawing which shows the message after Call-ID shortening encoding received from the SIP server (B) side in the signaling compression / decompression apparatus of Embodiment 8 of this invention. It is explanatory drawing which shows the message after Call-ID character string transmission transmitted to SIP-UA (B) in the signaling compression expansion | extension apparatus of Embodiment 8 of this invention. It is explanatory drawing which shows the uncompressed message which SIP-UA (B) outputs in the signaling compression expansion | extension apparatus of Embodiment 8 of this invention. It is explanatory drawing which shows the message after Call-ID shortened code | symbol transmitted to the SIP server (B) in the signaling compression / decompression apparatus of Embodiment 8 of this invention. It is explanatory drawing which shows the message after Call-ID character string conversion in the signaling compression expansion | extension apparatus of Embodiment 8 of this invention. It is a block diagram which shows the signaling compression expansion | extension apparatus by Embodiment 10 of this invention. It is a block diagram which shows the signaling compression / decompression apparatus by Embodiment 11 of this invention. It is a block diagram which shows the signaling compression / decompression apparatus by Embodiment 12 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a signaling compression apparatus and a signaling expansion apparatus according to Embodiment 1 of the present invention.
In the figure, the signaling compression device comprises a fixed / variable pattern separation unit 1 and a compressor 2, and the signaling decompression device comprises a decompressor 4 and a fixed / variable pattern combination unit 5. When an uncompressed message (SIP message) is input, the signaling compression apparatus compresses the uncompressed message (SIP message) by the fixed / variable pattern separation unit 1 and the compressor 2 and outputs the obtained compressed message. Device. The signaling decompression device is a device that receives a compressed message transmitted through the transmission path 3 and restores it into an uncompressed message (SIP message) by the decompressor 4 and the fixed / variable pattern combining unit 5.

  The fixed / variable pattern separation unit 1 in the signaling compression apparatus is in a state in which a fixed character string pattern in an input uncompressed message (SIP message) and a variable character string pattern that differs for each message are separated. Sort the strings. The compressor 2 uses the DEFLATE encoding method that combines the general LZ77 (Lempel-Ziv 77) method and the Huffman encoding as the LZ (Lempel-Ziv) type compression method, and then the message after the character string rearrangement is performed. And the obtained compressed message is output to the transmission line 3. The decompressor 4 in the signaling decompression device decompresses the compressed message input from the transmission path 3 by the LZ77 method and outputs the decompressed message to the fixed / variable pattern combining unit 5. The fixed / variable pattern combining unit 5 inputs a message in which the fixed character string pattern and the variable character string pattern are separated from the decompressor 4 and outputs the separated fixed character string pattern and the variable character string pattern. The original uncompressed message (SIP message) is restored by combining to conform to the SIP message format.

Hereinafter, the character string rearrangement operation of the fixed / variable pattern separating unit 1 and the fixed / variable pattern combining unit 5 will be described with reference to FIGS.
FIG. 2 shows an uncompressed message (SIP message) before character string rearrangement. In the figure, up to “INVITE” in the first line is a SIP-specific fixed character string pattern with a request name, but “sip: bob@abcdefg.example.com” is a URI indicating the transmission destination of this request, and thus variable. It is a character string. “SIP / 2.0” is a part indicating that the version is 2.0 in the protocol of SIP, and is a fixed character string. Therefore, the fixed / variable pattern separation unit 1 determines that “INVITE SIP / 2.0” is a fixed character string and “sip: bob@abcdefg.example.com” is a variable character string, and separates them. For the second line, “Via:” is a fixed character string with a header name defined by SIP, and “SIP / 2.0” is a fixed character string as in the first line. "Indicates that the transport layer used for transmission of the SIP message is UDP, and since it does not change for each message, this is determined as a fixed character string. From the From header on the fourth line to the Content-Length header on the tenth line, the header name and “:” are fixed character strings, and the subsequent parameters are header parameters and variable character strings. From v = 0 on the 12th line, it is an SDP (Session Description Protocol) body part, which is a description for controlling media streams such as audio and images. Every line is a character string unique to SDP up to “=”, and the control parameters are after “=”. Therefore, up to “=” of each line is a fixed character string, and the subsequent lines are variable character strings.

  The output of the fixed / variable pattern separation unit 1 based on the determination criteria for the fixed character string and the variable character string described above is as shown in FIG. In the figure, the first line to the 18th line (from “a =”) are fixed character string pattern parts, and the 21st line (“sip: bob@abcdefg.example.com”) and subsequent lines are variable character string pattern parts. Become. Two blank lines are provided at the boundary between the fixed character string pattern portion and the variable character string pattern portion. Since there are no two or more blank lines in the SIP message format, these blank lines are used to determine the boundary.

  In the LZ type compression method, the dictionary is searched for a pattern that matches the character string pattern in the input message, and information on the position and length of the character string pattern found in the dictionary is encoded. This is called a compressed block. Conversely, if there is no matching pattern in the dictionary, the input character string is output as it is. This is called an uncompressed block. Therefore, as shown in FIG. 2, when the fixed character string pattern portion and the variable character string pattern portion appearing for the first time are mixed, compressed blocks and uncompressed blocks appear alternately in the entire compressed message. On the other hand, when fixed character string patterns are concentrated and arranged as shown in FIG. 3, this portion is encoded as one compressed block. Specifically, in the message shown in FIG. 3, the first line (“INVITE SIP / 2.0”) to the 18th line (“a =”) is one compressed block. That is, since the number of characters is one compressed block, the compression efficiency is improved as compared with the case of compressing the message shown in FIG.

  As described above, in the signaling compression apparatus according to the first embodiment, the fixed / variable pattern separation unit 1 separates the fixed character string pattern and the variable character string pattern in the input message before compression by the DEFLATE encoding method. Since the character strings are rearranged in such a state, a signaling compression method capable of efficiently compressing a SIP message including many character string patterns that appear for the first time can be obtained.

  As described above, according to the signaling compression apparatus of the first embodiment, the compressor that compresses the signaling message using at least one of the static dictionary and the dynamic dictionary, and the upstream side of the compressor, Since the fixed / variable pattern separation unit for recognizing the fixed character string pattern and the variable character string pattern in the signaling message and rearranging the character strings so that the fixed character string continues, Even a signaling message containing many character string patterns that appear for the first time can be efficiently compressed.

  Further, according to the signaling decompression apparatus of the first embodiment, the messages in which the character strings are rearranged so that the fixed character strings are continuous are arranged in the order according to the format defined by the signaling protocol. Since the fixed / variable pattern combination unit for rearranging the character strings to be returned is provided, even a compressed message can be output as a message according to a format defined by the signaling protocol.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing a signaling compression apparatus and signaling expansion apparatus according to Embodiment 2 of the present invention.
In the figure, the signaling compression device is composed of a fixed / variable pattern separation unit 1, a compressor 2, and a header order rearrangement unit 6, and the signaling decompression device is composed of an decompressor 4 and a fixed / variable pattern combination unit 5.
The header order rearrangement unit 6 in the signaling compression apparatus is a functional unit that rearranges the order of headers in the input SIP message in accordance with a predetermined rule. The other blocks in the signaling compression apparatus and the blocks in the signaling decompression apparatus are the same as those in the first embodiment shown in FIG. 1, and thus description thereof is omitted here.

  Here, the operation of the header order rearranging unit 6 when the uncompressed message (SIP message) shown in FIG. 5 is input will be described. In the header order rearrangement unit 6, the header order rules are as follows: Via header, Max-Forwards header, From header, To header, Call-ID header, CSeq header, Contact header, Content-Type header, Content-Length header. It shall be rearranged. When the message shown in FIG. 5 is input to the header order rearrangement unit 6, the header order rearrangement unit 6 performs the rearrangement according to the above-mentioned header order definition and outputs the message shown in FIG.

  The header order of input SIP messages is usually always the same as long as they are messages output from the same SIP terminal, but this signaling compression method is used for compressing and transmitting messages from a plurality of SIP terminals. In this case, the order is undefined. This is because there is no particular restriction on the header order in the message due to the SIP specification. In such a case, the header order is always kept constant by the header order rearranging unit 6 so that the fixed character string pattern portion always has the same pattern, and the compression rate by the DEFLATE encoding method can be improved.

  The operation of each block other than the header order rearranging unit 6 is the same as that in FIG. The message shown in FIG. 6 is compressed by the fixed / variable pattern separation unit 1 and the compressor 2, and further decompressed by the decompressor 4 and the fixed / variable pattern combination unit 5, after the header order rearrangement shown in FIG. Will be restored to the message. In other words, the original uncompressed message shown in FIG. 5 is not restored, but as described above, there is no restriction on the header order according to the SIP rules, so there is no inconvenience even if the original order is not restored. In addition, the lines are not rearranged for the SDP body part in the SIP message because the order of appearance of the lines is fixed according to the SDP rules.

  As described above, in the signaling compression apparatus according to the second embodiment, the header order rearranging unit 6 rearranges the header order according to a predetermined rule, so that it is used for compressing and transmitting messages from a plurality of SIP terminals. Even when it is used, it is possible to obtain a signaling compression method capable of efficiently compressing a SIP message including many character string patterns that appear for the first time.

  As described above, according to the signaling compression apparatus of the second embodiment, the header order rearrangement unit 6 that changes the header description order in the signaling message according to a predetermined priority and the header order rearrangement unit 6 arrange the header description order. A fixed / variable pattern separation unit 1 that identifies a fixed character string pattern and a variable character string pattern in the replaced signaling message and rearranges the character strings so that the fixed character strings are continuous. Thus, even when used for compressing and transmitting signaling messages from a plurality of terminals, it is possible to efficiently compress a signaling message including a large number of character string patterns that appear for the first time.

Embodiment 3 FIG.
FIG. 7 is a block diagram showing a signaling compression apparatus and signaling expansion apparatus according to Embodiment 3 of the present invention.
In the figure, the signaling compression apparatus includes a fixed / variable pattern separation unit 1, a compressor 2, a header order rearranging unit 6, and an essential header deletion unit 7. The signaling expansion apparatus includes an expansion unit 4, a fixed / variable pattern combination unit 5. And an essential header insertion portion 8.

  The mandatory header deletion unit 7 in the signaling compression device is a functional unit that deletes a header that is determined to be essential for each message type according to the SIP regulations. The mandatory header insertion unit 8 in the signaling decompression device is a functional unit that inserts a header that is determined to be essential for each message type according to the SIP regulations. The operation of other blocks is the same as that of each block of the signaling compression apparatus and signaling expansion apparatus shown in FIGS.

  The operation when the message after separation of fixed / variable patterns shown in FIG. 3 is input to the essential header deleting unit 7 will be described below. According to the SIP specification, the mandatory headers of the INVITE message are a Via header, a Max-Forwards header, a From header, a To header, a Call-ID header, a CSeq header, and a Contact header. Therefore, the mandatory header deletion unit 7 inputs the message shown in FIG. 3, deletes these essential headers, that is, the second to eighth lines in FIG. 3, and outputs the message shown in FIG. This message is compressed by the DEFLATE encoding method in the compressor 2, and the compressed message is output to the transmission path 3. When the decompressor 4 receives the compressed message from the transmission line 3, it performs decompression processing by the DEFLATE encoding method, and restores the same message as shown in FIG. The mandatory header insertion unit 8 adds a Via header, a Max-Forwards header, a From header, a To header, a Call-ID header, a CSeq header, and a Contact header, which are mandatory headers of the INVITE message, to the message shown in FIG. Insert them from the second line in this order. As a result, the message shown in FIG. 9 is obtained. Further, when the fixed / variable pattern combining unit 5 processes the message shown in FIG. 9, the same message as in FIG. 6 is obtained.

  In this signaling compression method, in the compressor 2, there is one from the first line (“INVITE SIP / 2.0”) to the eleventh line (“a =”) in the message after the mandatory header deletion shown in FIG. This is a compressed block. The signaling compression method shown in FIG. 1 or 4 is the same in that the fixed pattern portion becomes one compressed block, but there is a difference in the number of characters in the fixed pattern portion. That is, when the number of matching pattern characters is small, the processing time required for dictionary search is shortened, and the processing speed can be increased.

  As described above, in the signaling compression apparatus according to the third embodiment, the header order rearranging unit 6 rearranges the header order according to a predetermined rule, so that it can be used for compressing and transmitting messages from a plurality of SIP terminals. Even when it is used, the compression efficiency of the SIP message is improved, and the mandatory header deletion unit 7 reduces the number of characters in the fixed pattern portion. Therefore, a signaling compression method capable of speeding up the compression processing in the compressor 2 can be obtained. .

  In the third embodiment, the compressor 2 and the expander 4 are provided. However, the compressor 2 and the expander 4 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the amount of messages can be reduced by deleting the essential header.

  As described above, according to the signaling compression apparatus of the third embodiment, it is essential to delete a mandatory header predetermined for each message type from the character string rearranged by the fixed / variable pattern separation unit 1 Since the header deletion unit 7 is provided, it is possible to obtain a signaling compression method capable of speeding up the compression processing in the compressor 2.

  Further, according to the signaling decompression apparatus of the third embodiment, since the mandatory header insertion unit 8 for inserting the mandatory header defined by the signaling protocol is provided on the upstream side of the fixed / variable pattern combination unit 5, the mandatory header is The deleted message can also be output as a message according to a format defined by the signaling protocol.

Embodiment 4 FIG.
FIG. 10 is an example showing a flow of messages transmitted and network components related to SIP in a network in which call control is performed using SIP. In the figure, a SIP-UA (User Agent) (A) 11 is connected to the SIP server (A) 10, and a SIP-UA (B) 13 is connected to the SIP server (B) 12. In such a network, a line between the SIP server (B) 12 and the SIP-UA (B) 13 is a narrow band, and is a transmission path that is a compression target of the SIP message.

  FIG. 11 is a block diagram showing a signaling compression / decompression apparatus according to Embodiment 4 of the present invention, which is inserted between the SIP server (B) 12 and the SIP-UA (B) 13 in FIG. Is shown. In the figure, the SIP server (B) side compression / decompression unit 100 compresses the SIP message input from the SIP server (B) 12 and decompresses the SIP message output to the SIP server (B) 12. A decompressor 102, a Via header deletion unit 103, a Via header holding unit 104, and a Via header insertion unit 105. The SIP-UA (B) side compression / decompression unit 200 compresses the SIP message input from the SIP-UA (B) 13 and decompresses the SIP message output to the SIP-UA (B) 13. The internal configuration is the same as that of the SIP server (B) side compression / decompression unit 100. That is, a compressor 201, an expander 202, a Via header deletion unit 203, a Via header holding unit 204, and a Via header insertion unit 205 are provided. Here, the compressors 101 and 201 and the decompressors 102 and 202 are the same as the compressor 2 and the decompressor 4 in FIGS.

  Further, when there are a plurality of Via headers in the SIP request message, the Via header deleting units 103 and 203 delete the other Via headers while leaving the last inserted Via header. The Via header holding units 104 and 204 hold the Via header deleted by the Via header deleting units 103 and 203. The Via header insertion units 105 and 205 insert the Via header held by the Via header holding units 104 and 204 in response to the request message from which the Via header has been deleted by the Via header deletion units 103 and 203. It has a function.

Hereinafter, as shown in FIG. 10, an INVITE request message, which is the first message for call connection, is transmitted from SIP-UA (A) 11 to SIP-UA (B) 13, and a 200 OK response corresponding to this request is sent. The SIP message compression / decompression operation when a message is transmitted from the SIP-UA (B) 13 to the SIP-UA (A) 11 will be described with reference to FIGS.
FIG. 12 shows an uncompressed message (INVITE request) output from the SIP server (B) 12. When the uncompressed message shown in FIG. 12 is input to the Via header deletion unit 103 in the SIP server (B) side compression / decompression unit 100, three of the Via headers in the second to sixth lines in the message are displayed. The other Via header is deleted while leaving the Via header in the second line at the head. As a result, the message shown in FIG. 13 is generated and output to the compressor 101. Also, the Via header deletion unit 103 stores the deleted Via headers in the third to sixth lines in the Via header holding unit 104 together with the branch parameter “z9hG4bK721e4.1” of the remaining Via header. This branch parameter is used as a key when searching for a saved Via header later. The compressor 101 receives the message after deleting the Via header shown in FIG. 13 by the DEFLATE encoding method, compresses the message, and outputs the compressed message to the transmission path 301. The decompressor 202 in the SIP-UA (B) side compression / decompression unit 200 that has received the compressed message from the transmission path 301 performs decompression processing by the DEFLATE encoding method. As a result, the message after deletion of the Via header shown in FIG. 13 is restored and output to the Via header insertion unit 205. The Via header insertion unit 205 does not perform any processing on the request message. Accordingly, the message shown in FIG. 13 is output to the SIP-UA (B) 13 as it is.

  As described above, after a part of the Via header in the INVITE request transmitted from the SIP server (B) 12 is deleted, compression by DEFLATE encoding is performed, so the size of the compressed message is reduced accordingly. I can do it. However, this INVITE request is transferred to the SIP-UA (B) 13 without the deleted Via header being restored. The SIP entity (SIP-UA or SIP server) needs only the Via header inserted by the last-stage SIP entity in the Via header of the received request message. Of the Via header in the INVITE request message shown in FIG. 12, the one inserted by the SIP server (B) 12 is the Via header on the second line. Therefore, only the second line is necessary for the SIP-UA (B) 13. Specifically, the branch parameter “z9hG4bK721e4.1” in this header is used for request identification. That is, requests with the same branch parameter are regarded as the same request, that is, a retransmission request, and requests with different branch parameters are regarded as different requests. Since the Via header is used in this way, there is no inconvenience in the operation of the SIP-UA (B) 13 even if the Via headers in the third and subsequent lines are all or partly deleted.

  When the SIP-UA (B) 13 receives the INVITE request and accepts the request, it returns a 200 OK response message. FIG. 14 shows an uncompressed message (200 OK response message) output from the SIP-UA (B) 13. According to the SIP specification, when generating a response message for all requests, the SIP-UA needs to retain the Via header included in the original request and insert it. Accordingly, the second line of the uncompressed message (200 OK response message) shown in FIG. 14 and the second line of the message after the deletion of the Via header shown in FIG. 13 (INVITE request message received by the SIP-UA (B) 13). The same Via header is inserted.

  The Via header deletion unit 203 in the SIP-UA (B) side compression / decompression unit 200 inputs the uncompressed message (200 OK response message) shown in FIG. 14, but performs no processing on the response message. Instead, the data is transferred to the compressor 201 as it is. The compressor 201 performs compression using the DEFLATE encoding method and outputs a compressed message to the transmission path 302. When receiving the compressed message from the transmission path 302, the decompressor 102 in the SIP server (B) side compression / decompression unit 100 performs decompression processing by the DEFLATE encoding method, and outputs the decompressed message to the Via header insertion unit 105. To do. Since the input of the compressor 201 in the SIP-UA (B) side compression / decompression unit 200 is restored, the message input by the Via header insertion unit 105 is the uncompressed message (200 OK response message) shown in FIG. Be the same.

  The Via header insertion unit 105 searches the Via header holding unit 104 using the branch parameter “z9hG4bK721e4.1” in the Via header in this message as a key, extracts a Via header that matches this key, and starts the fourth and subsequent lines. insert. As described above, when the INVITE request is transmitted from the SIP server (B) 12, the key for saving the Via header deleted from the request message in the Via header holding unit 104 is “z9hG4bK721e4.1”. Therefore, the Via header insertion unit 105 extracts and inserts the same character string as the third to sixth lines of the uncompressed message (INVITE request message output from the SIP server (B) 12) shown in FIG. The entire message is as shown in FIG. This message is output to the SIP server (B) 12. This is equivalent to the response message output by the SIP-UA (B) 13 if the INVITE request message shown in FIG. 12 is completely restored and reaches the SIP-UA (B) 13. Due to the operation of the SIP server (B) 12, there is a problem if the Via header included in the response message is not the same as the Via header included in the corresponding request. However, this problem is avoided because the Via header deleted by the Via header insertion unit 105 is restored as described above.

  The Via header is the one in which the SIP-UA of the request transmission source and all SIP servers that transferred the request insert their own URIs. In the network form shown in FIG. 10, the message transmission / reception of the SIP-UA (B) 13 is assumed to be performed only with the SIP server (B) 12, but the message corresponding to the SIP-UA (A) 11 in FIG. The source SIP-UA is usually different for each call. Since the message transfer path changes when the SIP-UA is different, the SIP server corresponding to the SIP server (A) 10 in FIG. 10 (the SIP server located in the previous stage of the SIP server (B) 12) may be different for each call. is there. That is, in FIG. 10, it is necessary to assume a case where the SIP server corresponding to the SIP server (A) 10 (the SIP server located in the previous stage of the SIP server (B) 12) is different for each call. That is, for a request message transmitted from the SIP server (B) 12 to the SIP-UA (B) 13, other Via headers except for the Via header inserted by the SIP server (B) 12 appear for the first time at the head of the call. It becomes a character string. According to the signaling compression / decompression apparatus having the configuration shown in FIG. 11, a Via header character string that is difficult to compress by DEFLATE coding can be deleted because it differs for each call.

As described above, in the signaling compression apparatus according to the fourth embodiment, when the Via header deletion unit 103 includes a plurality of Via headers in the request message, the Via header deletion unit 103 deletes except for the last inserted Via header. It is possible to efficiently compress a SIP message including a large number of character string patterns. In addition, by deleting a part of the Via header included in the request, the Via header of the response message to the request is not output from the SIP-UA (B) 13, and as a result, the size of the response message can be reduced. is there.
In the above-described example, all the Via headers are deleted while leaving the last inserted Via header. However, instead of all the Via headers, only any Via header other than the last inserted Via header is deleted. But the effect is obtained.

  Further, the compressors 101 and 201 and the decompressors 102 and 202 in FIG. 11 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the amount of messages can be reduced by the amount of deleting the Via header.

  As described above, according to the signaling compression apparatus of the fourth embodiment, when the signaling protocol is SIP, a Via header deletion unit that deletes some Via headers when a plurality of Via headers are included in the request message. 103 is provided, it is possible to efficiently compress a SIP message including many character string patterns that appear for the first time.

  Further, according to the signaling compression / decompression apparatus of the fourth embodiment, when the signaling protocol is SIP, when a plurality of Via headers are included in the request message, some Via headers are deleted, and the deleted Via headers are deleted. A Via header deletion unit 103 that holds the message in the Via header holding unit 104, and a Via header insertion unit 105 that inserts the Via header held in the Via header holding unit 104 for the response message corresponding to the request message. Therefore, even a message from which the Via header has been deleted can be output as a response message according to a format defined by the SIP protocol.

Embodiment 5 FIG.
The Via header deletion unit 203 in the SIP-UA (B) side compression / decompression unit 200 illustrated in FIG. 11 has a function of deleting the Via header in the SIP request message output from the SIP-UA (B) 13. Then, the Via header is deleted when a plurality of Via headers exist in the SIP request message as described above. Since the Via header is inserted one by one for the SIP-UA that generated the request message and the SIP server that relays the message, a plurality of Vias are included in the request message output by the SIP-UA (B) 13. The header is not included and is always one. Therefore, in the network configuration as shown in FIG. 10, the Via header deletion unit 203 does not actually perform the Via header deletion operation, and the Via header insertion unit 205 does not insert the Via header. Therefore, the Via header deletion unit 203, the Via header holding unit 204, and the Via header insertion unit 205 in the SIP-UA (B) side compression / decompression unit 200 may be omitted.

  As described above, the configurations of the SIP server (B) 12 side and the SIP-UA (B) 13 side are not necessarily the same, and there is no case in which a plurality of Via headers are included in the request message due to the network configuration. If it is known in advance, the configuration can be simplified by omitting the Via header deletion unit 203, the Via header holding unit 204, and the Via header insertion unit 205.

Embodiment 6 FIG.
FIG. 16 is a block diagram showing a signaling compression / decompression apparatus according to Embodiment 6 of the present invention, which is inserted between the SIP server (B) 12 and the SIP-UA (B) 13 shown in FIG. The configuration is shown. In the figure, a SIP server (B) side compression / decompression unit 100a compresses a SIP message input from the SIP server (B) 12 and decompresses a SIP message output to the SIP server (B) 12. 101, a decompressor 102, a Record-Route header deletion unit 106, a Record-Route header holding unit 107, a Record-Route header insertion unit 108, and a Route header insertion unit 109. The SIP-UA (B) side compression / decompression unit 200a compresses the SIP message input from the SIP-UA (B) 13 and decompresses the SIP message output to the SIP-UA (B) 13. The internal configuration is the same as that of the SIP server (B) side compression / decompression unit 100a. That is, a compressor 201, an expander 202, a Record-Route header deletion unit 206, a Record-Route header holding unit 207, a Record-Route header insertion unit 208, and a Route header insertion unit 209 are provided. Note that the compressors 101 and 201 and the decompressors 102 and 202 are the same as the compressor 101 and the decompressor 102 in FIG.

  Further, the Record-Route header deletion units 106 and 206 delete the Record-Route header in the SIP message. The Record-Route header holding units 107 and 207 hold the Record-Route header deleted by the Record-Route header deletion units 106 and 206. The Record-Route header insertion units 108 and 208 respond to the request message from which the Record-Route header has been deleted by the Record-Route header deletion units 106 and 206 with the Record-Route header holding units 107 and 207, respectively. The retained Record-Route header is inserted. The Route header insertion units 109 and 209 generate and insert a Route header based on the deleted Record-Route header for the request message of the same call as the request from which the Record-Route header is deleted.

  Hereinafter, as shown in FIG. 10, an INVITE request message, which is the first message for call connection, is transmitted from SIP-UA (A) 11 to SIP-UA (B) 13, and a 200 OK response corresponding to this request is sent. The SIP message compression / decompression operation when a message is transmitted from the SIP-UA (B) 13 to the SIP-UA (A) 11 will be described with reference to FIGS. 12 and 17 to 21 described above. FIG. 12 shows an uncompressed message (INVITE request message) output from the SIP server (B) 12. When the Record-Route header deletion unit 106 in the SIP server (B) side compression / decompression unit 100a inputs the message shown in FIG. 12, the Record-Route header in the 8th to 9th lines in this message is deleted. The message shown in FIG. 17 is output to the compressor 101. Also, the Record-Route header deletion unit 106 replaces the deleted Record-Route header with the Via header branch parameter “z9hG4bK721e4.1” in the top row of this message and the Call-ID header character string in this message. The data is stored in the Record-Route header holding unit 107 together with “38482762982201888511@hijklmn.example.com”. The branch parameter and the Call-ID header are used as keys when searching for a Record-Route header stored later. The compressor 101 compresses the message shown in FIG. 17 by the DEFLATE encoding method and outputs the compressed message to the transmission path 301.

  The decompressor 202 in the SIP-UA (B) side compression / decompression unit 200a that has received the compressed message from the transmission path 301 performs decompression processing by the DEFLATE encoding method. As a result, the message after deletion of the Record-Route header shown in FIG. 17 is restored and output to the Record-Route header insertion unit 208. The Record-Route header insertion unit 208 performs no processing on the request message. Therefore, the same message as shown in FIG. 17 is output to the Route header insertion unit 209 as it is. When a request message is input, the Route header insertion unit 209 searches the Record-Route header holding unit 207 using the Call-ID header character string in the message as a key, and finds a Record-Route header that has been deleted in the past. In the case of a failure, a Route header is generated based on the Record-Route header. The Call-ID header character string is used to identify a call, and is generated by an originating SIP-UA that generates an INVITE request message to initiate a call connection, and messages in the same call are the same Call. -An ID header is attached. Here, since this INVITE request message is a message for call connection and becomes the first message in the call, the Call-ID header character string in this message is used as a key to search the Record-Route header holding unit 207. Even so, a Record-Route header that matches this key is not found. Therefore, the Route header insertion unit 209 outputs the same message after deleting the Record-Route header as shown in FIG. 17 to the SIP-UA (B) 13 as it is.

  As described above, after the Record-Route header in the INVITE request transmitted from the SIP server (B) 12 is deleted, compression by DEFLATE encoding is performed. Therefore, the size of the compressed message can be reduced accordingly. I can do it. However, this INVITE request is transferred to the SIP-UA (B) 13 without restoring the deleted Record-Route header. In SIP-UA, when a response message to an INVITE request is transmitted, it is necessary to insert a Record-Route header in the INVITE request into the response message as it is. Further, when the SIP-UA newly transmits a request message, if an INVITE request received in the past in the same call as the request has a Record-Route header, a new message is generated using the information of the Record-Route header. A Route header to be inserted into the message is generated. That is, when the Record-Route header is deleted or not, the response message and request message output by the SIP-UA are different, but the signaling compression method having the configuration shown in FIG. Includes means to avoid. In the following description, the avoidance method is shown.

  When the SIP-UA (B) 13 receives the INVITE request and accepts the request, it returns a 200 OK response message. FIG. 18 shows an uncompressed message (200 OK response message) output from the SIP-UA (B) 13. As described above, when the SIP-UA generates the 200 OK response message for the INVITE request, it is necessary to hold the Record-Route header included in the original request and insert the same header according to the SIP specification. However, the INVITE request received first by the SIP-UA (B) 13 is as shown in FIG. 17, and there is no Record-Route header. Therefore, there is no Record-Route header in the message shown in FIG.

  The Record-Route header deletion unit 206 in the SIP-UA (B) side compression / decompression unit 200a inputs the uncompressed message shown in FIG. 18, but nothing is included in this message because the Record-Route header is not included. Without processing, the data is transferred to the compressor 201 as it is. The compressor 201 performs compression by the DEFLATE encoding method and outputs a compressed message to the transmission path 302. When the decompressor 102 in the SIP server (B) side compression / decompression unit 100 a receives this compressed message from the transmission path 302, it performs decompression processing by the DEFLATE encoding method and sends the decompressed message to the Record-Route header insertion unit 108. Output. The message input by the Record-Route header insertion unit 108 is an uncompressed message shown in FIG. 18 because the input message to the compressor 201 in the SIP-UA (B) side compression / decompression unit 200a is restored. The Record-Route header insertion unit 108 searches the Record-Route header holding unit 107 using the branch parameter “z9hG4bK721e4.1” in the Via header in this message as a key, and extracts the Record-Route header that matches this key. Inserted into the input message.

  As described above, when the INVITE request is transmitted from the SIP server (B) 12, the key when the Record-Route header deleted from the request message is stored in the Record-Route header holding unit 107 is “z9hG4bK721e4.1”. is there. Accordingly, the Record-Route header insertion unit 108 extracts and inserts the same character string as the Record-Route header (line 8 to line 9 in FIG. 12) of the uncompressed message shown in FIG. The message is as shown in FIG. This message is output to the SIP server (B) 12. This is equivalent to the response message output by the SIP-UA (B) 13 if the uncompressed message shown in FIG. 12 is completely restored and reaches the SIP-UA (B) 13. As described above, there is a problem if the Record-Route header included in the 200 OK response message for the INVITE request message is not the same as the Record-Route header in the corresponding INVITE request message. However, since the Record-Route header is restored by the Record-Route header insertion unit 108 as described above, this problem is avoided.

  Next, the case where the SIP-UA (B) 13 transmits a BYE request message to disconnect a call will be described. This BYE request message is as shown in FIG. The Record-Route header deletion unit 206 in the SIP-UA (B) side compression / decompression unit 200a does not perform processing because the Record-Route header is not included in the uncompressed message shown in FIG. Forward. The compressor 201 compresses the uncompressed message shown in FIG. 20 by the DEFLATE encoding method, and outputs the compressed message to the transmission path 302. The decompressor 102 in the compression / decompression unit 100a on the SIP server (B) side that has received the compressed message from the transmission path 302 performs decompression processing by the DEFLATE encoding method. As a result, the uncompressed message shown in FIG. 20 is restored and output to the Record-Route header insertion unit 108. Since the Record-Route header insertion unit 108 does not process any message other than the 200 OK response to the INVITE request, the Record-Route header insertion unit 108 transfers the input message to the Route header insertion unit 109 as it is. Therefore, the Route header insertion unit 109 inputs the uncompressed message shown in FIG.

  The Route header insertion unit 109 searches the Record-Route header holding unit 107 using the Call-ID header character string in the input request message, that is, “38448276298220188511@hijklmn.example.com” as a key, and matches this key. A Record-Route header is extracted, and a Route header is generated based on the extracted Record-Route header. As described above, when the INVITE request is transmitted from the SIP server (B) 12, the key when the Record-Route header deleted from the request message is stored in the Record-Route header holding unit 107 is “38482762982201888511@hijklmn.example. .Com ". Therefore, the Route header insertion unit 109 extracts the same character string as the Record-Route header (line 8 to line 9 in FIG. 12) of the uncompressed message shown in FIG.

In the extracted Record-Route header, two URI <sip: ss2. abcdefg. example. com; lr> and <sip: ss1. hijklmn. example. com; lr> is inserted, but when generating a Route header, these URIs are inserted in reverse order. Therefore, the output of the Route header insertion unit 109 is as shown in FIG.
The BYE request message output from the SIP-UA (B) 13 does not include a Route header, and as described above, this becomes a problem if it is transferred to the SIP server (B) 12 as it is. However, since the Route header insertion unit 109 generates a Route header instead, this problem is avoided.

  The Record-Route header is used by all SIP servers that have transferred the request to insert their own URIs. In the network form shown in FIG. 10, the message transmission / reception of the SIP-UA (B) 13 is assumed to be performed only with the SIP server (B) 12, but the message corresponding to the SIP-UA (A) 11 in FIG. The source or destination SIP-UA is different for each call. Since the message transfer path changes when the SIP-UA is different, the SIP server corresponding to the SIP server (A) 10 in FIG. 10 (the SIP server located in the previous stage of the SIP server (B) 12) may be different for each call. Many. That is, the Record-Route header character string in the message transmitted from the SIP server (B) 12 to the SIP-UA (B) 13 is often the first character string that appears at the beginning of a call. According to the signaling compression / decompression apparatus having the configuration shown in FIG. 16, the Record-Route header that is difficult to compress by DEFLATE coding can be deleted because it differs for each call.

  As described above, in the signaling compression / decompression apparatus according to the sixth embodiment, the Record-Route header deletion unit 106 deletes the Record-Route header in the INVITE request message, so that the SIP message including many first character string patterns appears. On the other hand, a signaling compression method capable of efficient compression can be obtained.

  In addition, by deleting the Record-Route header included in the INVITE request, the Record-Route header of the 200 OK response message for this request is not output from the SIP-UA (B) 13, resulting in the size of this response message. There is also an effect of reducing.

  Note that the compressors 101 and 201 and the decompressors 102 and 202 in FIG. 16 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the message amount can be reduced by deleting the Record-Route header.

  As described above, according to the signaling compression apparatus of the sixth embodiment, when the signaling protocol is SIP, the Record-Route header deletion unit 106 that deletes the Record-Route header when it is included in the request message. Therefore, it is possible to efficiently compress a SIP message including many character string patterns that appear for the first time.

  Also, according to the signaling compression / decompression apparatus of the sixth embodiment, when the signaling protocol is SIP, when the Record-Route header is included in the request message, this is deleted, and the deleted Record-Route header is replaced with Record. -Record-Route header deletion unit 106 to be held in the Route header holding unit 107, and Record- to insert the Record-Route header held in the Record-Route header holding unit 107 to the response message corresponding to the request message When the Route header insertion unit 108 and the request message from which the Record-Route header is deleted are received, the Re stored in the Record-Route header holding unit 107 Since the Route header is generated based on the ord-Route header and inserted into the request message, the format specified by the SIP protocol is provided for the message from which the Record-Route header is deleted. Can be output as a response message or request message.

Embodiment 7 FIG.
The Record-Route header deletion unit 206 in the SIP-UA (B) side compression / decompression unit 200a shown in FIG. 16 has a function of deleting the Record-Route header in the message output from the SIP-UA (B) 13. Have. However, since the Record-Route header is a header inserted into a message transferred by the SIP server, the INVITE request message output from the SIP-UA (B) 13 does not include the Record-Route header. Therefore, in the network configuration as shown in FIG. 10, the Record-Route header deletion unit 206 does not actually perform the Record-Route header deletion operation. Therefore, the Record-Route header is not stored in the Record-Route header holding unit 207, and the Record-Route header insertion unit 208 does not perform Record-Route header insertion. Further, the Route header insertion unit 209 does not insert a Route header. That is, even if the Record-Route header deletion unit 206, the Record-Route header holding unit 207, the Record-Route header insertion unit 208, and the Route header insertion unit 209 in the SIP-UA (B) side compression / decompression unit 200a are omitted. good.

  As described above, the configurations of the SIP server (B) 12 side and the SIP-UA (B) 13 side are not necessarily the same, and there is no case in which the Record-Route header is included in the message due to the network configuration. Is previously known, the Record-Route header deletion unit 206, the Record-Route header holding unit 207, the Record-Route header insertion unit 208, and the Route header insertion unit 109 are omitted to simplify the configuration. Can be planned.

Embodiment 8 FIG.
FIG. 22 is a block diagram showing a signaling compression / decompression apparatus according to Embodiment 8 of the present invention, which is inserted between SIP server (B) 12 and SIP-UA (B) 13 shown in FIG. The configuration is shown. In the figure, the SIP server (B) side compression / decompression unit 100b compresses the SIP message input from the SIP server (B) 12 and decompresses the SIP message output to the SIP server (B) 12. 101, an expander 102, a Call-ID shortened coding unit 110, a Call-ID shortened code / character string correspondence table 111, and a Call-ID character string creating unit 112. The SIP-UA (B) side compression / decompression unit 200b compresses the SIP message input from the SIP-UA (B) 13 and decompresses the SIP message output to the SIP-UA (B) 13. The internal configuration is the same as that of the SIP server (B) side compression / decompression unit 100b. That is, a compressor 201, an expander 202, a Call-ID shortened coding unit 210, a Call-ID shortened code / character string correspondence table 211, and a Call-ID character string creating unit 212 are provided. The compressors 101 and 201 and the decompressors 102 and 202 are the same as the compressor 101 and the decompressor 102 in FIGS.

  The Call-ID shortened coding units 110 and 210 shorten the Call-ID header character string in the input SIP message to a one-character code, and the character string in which this Call-ID header character string first appears. If it is, the correspondence between the Call-ID header character string and the shortened code is registered in the Call-ID shortened code / character string correspondence tables 111 and 211. The Call-ID character string converting unit 112 converts the Call-ID shortened code into a normal Call-ID header character string, and if this Call-ID shortened code is the code that first appeared, the Call-ID header character The correspondence between the column and the shortened code is registered in the Call-ID shortened code / character string correspondence tables 111 and 211.

  Hereinafter, as shown in FIG. 10, an INVITE request message, which is the first message for call connection, is transmitted from SIP-UA (A) 11 to SIP-UA (B) 13, and a 200 OK response corresponding to this request is sent. The SIP message compression / decompression operation when a message is transmitted from the SIP-UA (B) 13 to the SIP-UA (A) 11 will be described with reference to FIGS. 12 and 23 to 27 described above. FIG. 12 shows an uncompressed message (INVITE request message) output from the SIP server (B) 12.

  When the Call-ID shortened encoding unit 110 in the SIP server (B) side compression / decompression unit 100b receives the message shown in FIG. 12, the Call-ID header character string “38482762982201888511@hijklmn.example.com in this message is input. "Is already registered in the Call-ID shortened code / character string correspondence table 111. Since this INVITE request message is a message for call connection, and the Call-ID header character string is newly generated by the SIP-UA (A) 11, the Call-ID shortened code / character string correspondence table 111 contains Is not registered. Therefore, the Call-ID shortened encoding unit 110 assigns one character “0” as a shortened code to the Call-ID header character string “3848482762982201888511@hijklmn.example.com”, and the uncompressed message shown in FIG. 23, and the correspondence between the Call-ID header character string and the shortened code is registered in the Call-ID shortened code / character string correspondence table 111. The compressor 101 compresses the message after Call-ID shortened coding shown in FIG. 23 by the DEFLATE coding method, and outputs the compressed message to the transmission path 301.

  The decompressor 202 in the SIP-UA (B) side compression / decompression unit 200b that has received the compressed message from the transmission path 301 performs decompression processing by the DEFLATE encoding method. As a result, the message after Call-ID abbreviated coding shown in FIG. 23 is restored and output to the Call-ID character string converting unit 212. When the Call-ID character string converting unit 212 inputs the message after the Call-ID shortened code shown in FIG. 23, the shortened code “0” of the Call-ID header is stored in the Call-ID shortened code / character string correspondence table 211. Search whether it is registered. As described above, since this INVITE request message is a message for call connection and the Call-ID header is newly generated, this short code “0” is the Call-ID short code / character string correspondence table 211. Is not registered. Therefore, the Call-ID character string generating unit 212 generates “hgfedcba” as a character string corresponding to the Call-ID shortened code “0”, and FIG. 24 shows the message after the Call-ID shortened code shown in FIG. The message is converted into a message and output to the SIP-UA (B) 13 and the correspondence between the Call-ID header character string and the shortened code is registered in the Call-ID shortened code / character string correspondence table 211.

  When the SIP-UA (B) 13 receives the message (INVITE request message) after making the Call-ID character string shown in FIG. 24 and accepts this request, it returns a 200 OK response message. An uncompressed message (200 OK response message) output by the SIP-UA (B) 13 is shown in FIG. The Call-ID header character string of the 200 OK response message is the same as “hgfedcba” that is the Call-ID character string in the INVITE request message (FIG. 24) received by the SIP-UA (B) 13. When the Call-ID shortened encoding unit 210 in the SIP-UA (B) side compression / decompression unit 200b inputs this uncompressed message, the Call-ID header character string “hgfedcba” in the message is already the Call-ID shortened code. / Search whether it is registered in the character string correspondence table 211. As a result of the search, it is understood that this Call-ID header character string “hgfedcba” is registered, and the abbreviated code “0” is assigned. Therefore, the Call-ID shortened coding unit 210 converts the Call-ID header character string of the uncompressed message shown in FIG. 25 and outputs the message shown in FIG. The compressor 201 performs compression using the DEFLATE encoding method and outputs a compressed message to the transmission path 302.

  When the decompressor 102 in the SIP server (B) side compression / decompression unit 100 b receives this compressed message from the transmission path 302, the decompressor 102 performs a decompression process using the DEFLATE encoding method, and the decompressed message is converted into a Call-ID character string unit 112. Output to. Since the message input by the Call-ID character string converting unit 112 is restored to the input message to the compressor 201 in the SIP-UA (B) side compression / decompression unit 200b, the Call-ID shortened coding shown in FIG. Same as later message. When this message is input, the Call-ID character string converting unit 112 searches whether the shortened code “0” of the Call-ID header is registered in the Call-ID shortened code / character string correspondence table 111. As a result of the search, this shortened code “0” is registered, and it can be seen that the Call-ID header character string corresponding to this is “384848276298220188511@hijklmn.example.com”. Therefore, the Call-ID character string converting unit 112 converts the Call-ID header shortened code of the message after the Call-ID shortened code shown in FIG. 26 and outputs the message shown in FIG. 27 to the SIP server (B) 12. To do.

  Thus, the Call-ID header character string “3848482762982201888511@hijklmn.example.com” in the message output from the SIP server (B) 12 changes to “hgfedcba” when it reaches the SIP-UA (B) 13. , The same string is not restored. However, since the Call-ID header is used to identify a call, the same Call-ID header character string, that is, “SIP server (B) 12 side” is always used for the same call message transmitted and received thereafter. 38482762982201888511@hijklmn.example.com ", if" hgfedcba "is used on the SIP-UA (B) 13 side and the correspondence does not change, the SIP server (B) 12 side and the SIP-UA (B) It is not inconvenient if different character strings are used on the 13th side.

  As described above, in the Call-ID shortened code / character string correspondence table 111 in the SIP server (B) side compression / decompression unit 100b, the shortening corresponding to the Call-ID header character string “38484827629822018851@hijklmn.example.com”. In the Call-ID shortened code / character string correspondence table 211 in the SIP-UA (B) side compression / decompression unit 200b, “0” is set as the code, and “0” is set as the shortened code corresponding to the Call-ID header character string “hgfedcba”. “0” is registered. Therefore, thereafter, in the same call message transmitted and received, the correspondence between the Call-ID header character string on the SIP server (B) 12 side and the Call-ID header character string on the SIP-UA (B) 13 side does not change, There is no inconvenience in the operation of the SIP server (B) 12 and the SIP-UA (B) 13.

  The Call-ID header character string is different for each call. That is, the character string appears for the first time for each call. In the signaling compression apparatus according to the eighth embodiment, since the Call-ID header character string is converted into a shortened code with a small number of characters, signaling compression capable of efficiently compressing a SIP message including many character string patterns that appear for the first time. A scheme can be obtained.

  Further, the compressors 101 and 201 and the decompressors 102 and 202 in FIG. 22 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the amount of messages can be reduced by the amount of shortening of the Call-ID header character string.

  In the eighth embodiment, the SIP-UA (B) side compression / decompression unit 200b converts the shortened Call-ID code into a character string and sends it to the SIP-UA (B) 13. When the code is a character string (text data), the code may be sent as it is. In this case, the Call-ID shortened encoding unit 210 does nothing in particular. That is, in this configuration, the SIP-UA (B) side compression / decompression unit 200b does not further decompress or compress the SIP message.

  As described above, according to the signaling compression apparatus of the eighth embodiment, when the signaling protocol is SIP, the Call-ID shortened encoding unit 110 that converts the character string of the Call-ID header into a shortened code is provided. Therefore, it is possible to efficiently compress the SIP message including many character string patterns that appear for the first time.

  Further, according to the signaling compression / decompression apparatus of the eighth embodiment, when the signaling protocol is SIP, when the shortened code is included in the Call-ID header in the request message, the shortened code is converted into the Call-ID header character string. At the same time, with respect to the response message corresponding to the request message and the Call-ID character string converting unit 212 that holds the correspondence between the short code and the Call-ID header in the Call-ID short code / character string correspondence table 211, Since the Call-ID shortened code / character string correspondence table 211 is referred to and the Call-ID shortened code encoding unit 210 for converting the Call-ID shortened code / character string correspondence table 211 into a shortened code corresponding to the Call-ID header character string is provided. Mutual conversion can be easily performed and the SIP protocol It can be output as uncompressed message according to the format specified I.

Embodiment 9 FIG.
In the eighth embodiment, the character string of the Call-ID header is converted into a shortened code with a small number of characters. However, this may not be a character, for example, a binary value having a specific number of bits. In this configuration, conversion from a shortened code to a character string and conversion from a character string to a shortened code in the Call-ID character string converting unit 212 and the Call-ID short code converting unit 210 are essential.

Embodiment 10 FIG.
The tag parameter of the From header included in the SIP message is used to identify the call together with the Call-ID, and is an arbitrary value generated by the originating SIP-UA that transmits the INVITE request message to initiate the call connection. The same parameter is attached to messages of the same call transmitted / received thereafter. Therefore, the tag parameter of the From header can be shortened by a method similar to Call-ID, and such an example will be described as the tenth embodiment.

FIG. 28 is a block diagram showing a signaling compression / decompression apparatus according to Embodiment 10 of the present invention.
The illustrated apparatus shows a SIP server (B) side compression / decompression unit 100c and a SIP-UA (B) side compression / decompression unit 200c. The SIP server (B) side compression / decompression unit 100c includes a compressor 101, a decompressor 102, a Fromtag shortened encoding unit 110a, a Fromtag shortened code / character string correspondence table 111a, and a Fromtag character string converting unit 112a. Further, the SIP-UA (B) side compression / decompression unit 200c includes a compressor 201, a decompressor 202, a Fromtag shortened encoding unit 210a, a Fromtag shortened code / character string correspondence table 211a, and a Fromtag character string converting unit 212a. Yes. Here, the Fromtag shortening encoding units 110a and 210a, the Fromtag shortening code / character string correspondence tables 111a and 211a, and the Fromtag character string converting units 112a and 212a are subject to processing from the Call-ID to the From header in the eighth embodiment, respectively. The contents of the processing only by changing to the tag parameter of the Call-ID shortened coding units 110 and 210, the Call-ID shortened code / character string correspondence tables 111 and 211, and the Call-ID character string converting unit in the eighth embodiment. 112 and 212. Further, the compressors 101 and 201 and the decompressors 102 and 202 are the same as the compressor 101 and the decompressor 102 in the fourth and subsequent embodiments, respectively.

Since the tag parameter of the From header is a character string that is different for each call, it is difficult to compress only by DEFLATE encoding. However, according to this configuration, the tag parameter of the From header can be shortened. Since the operation of each part is the same as that when the Call-ID header character string is abbreviated, the description is omitted here.
Also in the tenth embodiment, when the abbreviated code is a character string, it may be transmitted as the abbreviated code as in the eighth embodiment.

  Thus, in the signaling compression method of the tenth embodiment, the tag parameter of the From header, which is difficult to compress by DEFLATE encoding, is converted into a 1-character shortened code. Therefore, for a SIP message that contains many character string patterns that appear for the first time. Thus, a signaling compression method capable of efficient compression can be obtained.

  Further, the compressors 101 and 201 and the decompressors 102 and 202 in FIG. 28 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the amount of messages can be reduced by the amount of shortening the tag parameter of the From header.

  As described above, according to the signaling compression apparatus of the tenth embodiment, when the signaling protocol is SIP, the Fromtag shortened encoding unit 110a that converts the tag parameter character string of the From header into a shortened code is provided. It is possible to efficiently compress a SIP message including many character string patterns that appear for the first time.

  Also, according to the signaling compression / decompression apparatus of the tenth embodiment, when the signaling protocol is SIP, when the shortened code is included in the tag parameter of the From header in the request message, the shortened code is converted into a tag parameter character string. In addition, the Fromtag shortening code / character string correspondence relationship between the shortening code / character string correspondence table 211a and the Fromtag shortening code / character string correspondence table 211a and the response message corresponding to the request message correspond to the Fromtag shortening code / character string correspondence. Since the table 211a is provided and the Fromtag shortened encoding unit 210a for converting into a shortened code corresponding to the tag parameter character string of the From header is provided, the mutual conversion between the shortened code and the character string can be easily performed. , S It can be output as uncompressed message according to the format specified by the P protocol.

Embodiment 11 FIG.
The tag parameter of the To header included in the SIP message is used to identify the call together with the tag parameter of the From header and the Call-ID, and the terminating SIP that has received the INVITE request message for starting the call connection is used. -The same parameters are attached to messages of the same call that are generated by the UA and subsequently transmitted and received. Therefore, the tag parameter of the To header can be shortened by the same method as Call-ID, and such an example will be described below as an eleventh embodiment.

FIG. 29 is a block diagram showing a signaling compression / decompression apparatus according to Embodiment 11 of the present invention.
The illustrated apparatus shows a SIP server (B) side compression / decompression unit 100d and a SIP-UA (B) side compression / decompression unit 200d. The SIP server (B) side compression / decompression unit 100d includes a compressor 101, a decompressor 102, a Totag shortened code encoding unit 110b, a Totag shortened code / character string correspondence table 111b, and a Totag character string convertor 112b. The SIP-UA (B) side compression / decompression unit 200d includes a compressor 201, a decompressor 202, a Totag shortened code encoding unit 210b, a Totag shortened code / character string correspondence table 211b, and a Totag character string convertor 212b. Yes. Here, the Totag abbreviated encoding units 110b and 210b, the Totag abbreviated code / character string correspondence tables 111b and 211b, and the Totag character string conversion units 112b and 212b are subject to processing from the Call-ID to the To header in Embodiment 8, respectively. The contents of the processing only by changing to the tag parameter of the Call-ID shortened coding units 110 and 210, the Call-ID shortened code / character string correspondence tables 111 and 211, and the Call-ID character string converting unit in the eighth embodiment. 112 and 212. Further, the compressors 101 and 201 and the decompressors 102 and 202 are the same as the compressor 101 and the decompressor 102 in the fourth and subsequent embodiments, respectively.

Since the tag parameter of the To header is a character string that is different for each call, it is difficult to compress only by DEFLATE encoding. However, according to this configuration, the tag parameter of the To header can be shortened. The operation of each part is the same as the case where the Call-ID header character string is abbreviated.
Also in the eleventh embodiment, when the abbreviated code is a character string, the abbreviated code may be transmitted as in the eighth embodiment.

  As described above, in the signaling compression apparatus of the eleventh embodiment, the tag parameter of the To header, which is difficult to compress by DEFLATE encoding, is converted into a 1-character shortened code. Thus, a signaling compression method capable of efficient compression can be obtained.

  Further, the compressors 101 and 201 and the decompressors 102 and 202 in FIG. 29 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the amount of messages can be reduced by the amount of shortening of the tag parameter of the To header.

  As described above, according to the signaling compression apparatus of the eleventh embodiment, when the signaling protocol is SIP, the Totag shortened encoding unit 110b that converts the tag parameter character string of the To header into a shortened code is provided. It is possible to efficiently compress a SIP message including many character string patterns that appear for the first time.

  Also, according to the signaling compression / decompression device of the eleventh embodiment, when the signaling protocol is SIP, if the shortened code is included in the tag parameter of the To header in the request message, the shortened code is replaced with the tag parameter character string of the To header. The Totag character string converting unit that stores the correspondence between the shortened code and the character string in the Totag shortened code / character string correspondence table, and the Totag shortened code / character string for the response message corresponding to the request message Since it includes a Totag abbreviated coding unit that refers to the correspondence table and converts it to abbreviated code corresponding to the tag parameter character string of the To header, it is possible to easily perform mutual conversion between the abbreviated code and the character string, According to the format defined by the SIP protocol It can be output as a compressed message.

Embodiment 12 FIG.
The branch parameter of the Via header included in the SIP message is used to identify the request and its response, and is an arbitrary character string generated by the SIP-UA that generates the request and the SIP server that transfers the request. The same parameter is attached to the same request (retransmission request) transmitted and received thereafter and the response message to the request. Therefore, this parameter can also be abbreviated by the same method as the Call-ID header character string, and such an example will be described below as a twelfth embodiment.

FIG. 30 is a block diagram showing a signaling compression / decompression apparatus according to Embodiment 12 of the present invention.
The illustrated apparatus shows a SIP server (B) side compression / decompression unit 100e and a SIP-UA (B) side compression / decompression unit 200e. The SIP server (B) side compression / decompression unit 100e includes a compressor 101, a decompressor 102, a branch shortened encoding unit 110c, a branch shortened code / character string correspondence table 111c, and a branch character string converting unit 112c. The SIP-UA (B) side compression / decompression unit 200e includes a compressor 201, a decompressor 202, a branch shortened encoding unit 210c, a branch shortened code / character string correspondence table 211c, and a branch character string converting unit 212c. Yes. Here, the branch abbreviated encoding units 110c and 210c, the branch abbreviated code / character string correspondence tables 111c and 211c, and the branch character string converting units 112c and 212c are processed from the Call-ID to the Via header in the eighth embodiment, respectively. The contents of the processing only by changing to the branch parameter are the Call-ID shortened coding units 110 and 210, the Call-ID shortened code / character string correspondence tables 111 and 211, and the Call-ID character string creating unit in the eighth embodiment. 112 and 212. Further, the compressors 101 and 201 and the decompressors 102 and 202 are the same as the compressor 101 and the decompressor 102 in the fourth and subsequent embodiments, respectively.

Since the branch parameter of the Via header is a different character string for each request, it is difficult to compress only by DEFLATE encoding. However, according to this configuration, the branch parameter of the Via header can be shortened. The operation of each part is the same as the case where the Call-ID header character string is abbreviated.
Also in the twelfth embodiment, when the abbreviated code is a character string, the abbreviated code may be transmitted as in the eighth embodiment.

  In this way, in the signaling compression apparatus of the twelfth embodiment, the branch parameter of the Via header, which is difficult to compress by DEFLATE encoding, is converted into a one-character shortened code. Therefore, for a SIP message that contains many character string patterns that appear for the first time. Thus, a signaling compression method capable of efficient compression can be obtained.

  Further, the compressors 101 and 201 and the decompressors 102 and 202 in FIG. 30 may be omitted. If these are omitted, message compression by the DEFLATE encoding method is not performed, but the amount of messages can be reduced by the amount of shortened coding of the branch parameter of the Via header.

  As described above, according to the signaling compression apparatus of the twelfth embodiment, when the signaling protocol is SIP, the branch shortened encoding unit 110c that converts the branch parameter character string of the Via header into a shortened code is provided. It is possible to efficiently compress a SIP message including many character string patterns that appear for the first time.

  Also, according to the signaling compression / decompression device of the twelfth embodiment, when the signaling protocol is SIP, when the shortened code is included in the tag parameter of the Via header in the request message, the shortened code is replaced with the branch parameter character string of the Via header. And a branch character string converting unit 212c that stores the correspondence between the shortened code and the character string in the branch shortened code / character string correspondence table 211c, and the branch shortened code / Since it includes the branch shortened encoding unit 210c that refers to the character string correspondence table 211c and converts it into a shortened code corresponding to the branch parameter character string of the Via header, the mutual conversion between the shortened code and the character string can be easily performed. In Rutotomoni can be output as uncompressed message according to the format specified by the SIP protocol.

  1 fixed / variable pattern separation unit, 2 compressor, 3 transmission line, 4 decompressor, 5 fixed / variable pattern combination unit, 6 header order rearrangement unit, 7 essential header deletion unit, 8 essential header insertion unit, 11 SIP- UA (A), 12 SIP server (B), 13 SIP-UA (B), 100, 100a, 100b, 100c, 100d, 100e SIP server (B) side compression / decompression unit 101, 201 compressor, 102, 202 Decompressor, 103 Via Header Deletion Unit, 104 Via Header Holding Unit, 105 Via Header Insertion Unit, 106 Record-Route Header Deletion Unit, 107 Record-Route Header Holding Unit, 108 Record-Route Header Insertion Unit, 109 Route Header Insertion 110 Call-ID abbreviated coding unit, 11 a Fromtag abbreviated coding unit, 110b Totag abbreviated coding unit, 110c branch abbreviated coding unit, 111 Call-ID abbreviated code / character string correspondence table, 111a Fromtag abbreviated code / character string correspondence table, 111b Totag abbreviated code / character string Correspondence table, 111c branch shortened code / character string correspondence table, 112 Call-ID character string conversion unit, 112a Fromtag character string conversion unit, 112b Totag character string conversion unit, 112c branch character string conversion unit, 200, 200a, 200b, 200c , 200d, 200e SIP-UA (B) side compression / decompression unit, 203 Via header deletion unit, 204 Via header holding unit, 205 Via header insertion unit, 206 Record-Route header deletion 207 Record-Route header holding unit 208 Record-Route header inserting unit 209 Route header inserting unit 210 Call-ID shortened coding unit 210a Fromtag shortened coding unit 210b Totag shortened coding unit 210c branch shortened Encoding unit, 211 Call-ID shortened code / character string correspondence table, 211a Fromtag shortened code / character string correspondence table, 211b Totag shortened code / character string correspondence table, 211c branch shortened code / character string correspondence table, 212 Call-ID Character string generation unit, 212a Fromtag character string generation unit, 212b Totag character string conversion unit, 212c branch character string conversion unit, 301, 302 transmission path.

Claims (17)

A compressor for compressing signaling messages using at least one of a static dictionary and a dynamic dictionary;
Fixed / variable for recognizing a fixed character string pattern and a variable character string pattern in the signaling message and rearranging the character strings so that the fixed character strings are continuous on the front side of the compressor A signaling compression apparatus comprising a pattern separation unit. A header order rearrangement unit that changes the header description order in the signaling message according to a predetermined priority;
Fixed to identify a fixed character string pattern and a variable character string pattern in a signaling message rearranged by the header order rearrangement unit and rearrange the character strings so that the fixed character strings are continuous. / Signaling compression apparatus comprising a variable pattern separation unit.   3. A mandatory header deletion unit for deleting a predetermined header predetermined for each message type with respect to a character string rearranged by a fixed / variable pattern separation unit. Signaling compression device.   When the signaling protocol is SIP, a signaling compression apparatus including a Via header deletion unit that deletes some Via headers when a plurality of Via headers are included in a request message.   A signaling compression apparatus comprising a Record-Route header deletion unit for deleting a Record-Route header in a request message when the signaling protocol is SIP.   A signaling compression apparatus comprising a Call-ID shortened encoding unit that converts a character string of a Call-ID header into a shortened code when the signaling protocol is SIP.   When the signaling protocol is SIP, a signaling compression apparatus comprising a Fromtag shortening encoding unit that converts a tag parameter character string of a From header into a shortening code.   A signaling compression apparatus comprising: a Totag shortening encoding unit that converts a tag parameter character string of a To header into a shortening code when the signaling protocol is SIP.   A signaling compression apparatus comprising: a branch shortened encoding unit that converts a branch parameter character string of a Via header into a shortened code when the signaling protocol is SIP.   A fixed / variable pattern combination unit that rearranges character strings that are returned to the order according to the format defined by the signaling protocol for messages that have been rearranged so that fixed character strings are continuous. A signaling decompressor comprising:   11. The signaling decompression apparatus according to claim 10, further comprising a mandatory header insertion unit that inserts a mandatory header defined by the signaling protocol, on the front side of the fixed / variable pattern coupling unit. When the signaling protocol is SIP, when a plurality of Via headers are included in the request message, a part of the Via header is deleted, and a Via header deleting unit that holds the deleted Via header in the Via header holding unit;
A signaling compression / decompression apparatus including a Via header insertion unit that inserts a Via header held in the Via header holding unit with respect to a response message corresponding to the request message. When the signaling protocol is SIP, when a Record-Route header is included in the request message, this is deleted, and a Record-Route header deletion unit for holding the deleted Record-Route header in the Record-Route header storage unit When,
A Record-Route header insertion unit that inserts a Record-Route header held in the Record-Route header holding unit for a response message corresponding to the request message;
When receiving a request message from which the Record-Route header has been deleted, a Route header is generated based on the Record-Route header held in the Record-Route header holding unit and inserted into the request message. A signaling compression / decompression apparatus including an insertion unit. When the signaling protocol is SIP and the shortened code is included in the Call-ID header in the request message, the shortened code is converted into a Call-ID header character string and the correspondence between the shortened code and the Call-ID header A Call-ID character string generation unit that stores the relationship in a Call-ID shortened code / character string correspondence table;
A Call-ID shortened code encoding unit that converts the Call-ID shortened code / character string correspondence table into a shortened code corresponding to the Call-ID header character string with respect to the response message corresponding to the request message. Provided signaling compression / decompression apparatus. When the signaling protocol is SIP, when a shortened code is included in the tag parameter of the From header in the request message, the shortened code is converted into a tag parameter character string, and the correspondence between the shortened code and the character string is changed to the Tag tag. Fromtag character string generation unit to be stored in the abbreviated code / character string correspondence table;
Signaling provided with a Fromtag shortening encoding unit that refers to the Fromtag shortening code / character string correspondence table with respect to the response message corresponding to the request message, and converts it into a shortening code corresponding to the tag parameter character string of the From header. Compression / decompression device. When the signaling protocol is SIP, when a shortened code is included in the tag parameter of the To header in the request message, the shortened code is converted into a tag parameter character string of the To header, and the correspondence between the shortened code and the character string A Totag character string generation unit that stores the relationship in the Totag shortened code / character string correspondence table;
Signaling provided with a Totag shortened encoding unit that refers to the Totag shortened code / character string correspondence table with respect to the response message corresponding to the request message and converts it into a shortened code corresponding to the tag parameter character string of the To header. Compression / decompression device. When the signaling protocol is SIP, if the shortened code is included in the tag parameter of the Via header in the request message, the shortened code is converted into the branch parameter character string of the Via header, and the correspondence between the shortened code and the character string A branch character string generating unit that holds the relationship in the branch shortened code / character string correspondence table;
Signaling provided with a branch shortened coding unit for referring to the branch shortened code / character string correspondence table with respect to the response message corresponding to the request message, and converting it into a shortened code corresponding to the branch parameter character string of the Via header Compression / decompression device.

Images