JP2014179844A - Packet transmission device, packet transmission method and packet transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform data transmission even when converting a legacy system into an IP-enabled system.SOLUTION: The system includes: a header type determining part which determines a header included in a transmitting packet is an internally-added header or an externally-added header; an overhead analysis part which calculates a session ID depending on the type determination performed by the header determining part and creates a header table which associates the session ID with the header; and a data generation part which reduces a data amount of transmitting packet in accordance with the session ID and the header table.

Description

  The present invention relates to a packet transmission device, a packet transmission method, and a packet transmission system.

  Today, information devices are making remarkable progress in terms of downsizing and weight reduction, lower prices, and enhanced functions. On the other hand, users are often required to update information devices according to progress in business contents. However, the inconvenience that the information handled by the existing information device cannot be used together with the device update is not allowed. Therefore, it is necessary to transfer the existing information to the new device and transplant it with the update of the device.

  Transmission of existing information may be performed using communication means. At this time, it is preferable to transmit the existing information with high efficiency. As a proposal related to an information transmission method, there is a technique for transmitting one or a plurality of client signals via a packet transport network disclosed in, for example, JP-T-2011-507430.

  The packet of one or more client signals is then received at the ingress node of the network. Timing information characterizing the timing of these received packets is determined and these received packets are mapped into the container. This container and this timing information are transmitted via a network. At the egress node of the network, these packets are extracted from this container, and the packets are timed for further transmission based on the transmitted timing information.

  Even in a situation where the communication infrastructure (wireless bandwidth) is limited and the bandwidth cannot be increased, there are many requests from users of the system to update an IP-based new system, and IP packets can be accommodated and transmitted efficiently. It was expected.

Special table 2011-507430 gazette

  However, if the legacy system accommodated in the transmission apparatus is converted to IP even if the data transmission method according to JP 2011-507430 A is used, the required transmission capacity increases, so that the data transmission efficiency The problem of lowering was met.

  Therefore, a main object of the present invention is to provide a packet transmission apparatus and a packet transmission method packet transmission system that can efficiently perform data transmission even when a legacy system is converted to IP.

  In order to solve the above-mentioned problem, the invention according to the packet transmission apparatus for transmitting an IP packet from the transmission side to the reception side provides a header type in which a header included in the packet to be transmitted is a header by internal addition or a header by external addition According to the type determination by the header type determination unit, an overhead analysis unit that creates a header table that associates the session ID with the header, and the session ID and the header table And a data creation unit that reduces the data amount of the packet to be transmitted.

  The invention according to the packet transmission method for transmitting an IP packet from the transmission side to the reception side is a header type for determining whether the header included in the packet to be transmitted is a header by internal addition or a header by external addition. The session ID is calculated according to the determination procedure and the type determination determined by the header type determination procedure, and is transmitted according to the overhead analysis procedure for creating a header table that associates the session ID with the header, and the session ID and header table. And a data creation procedure for reducing the amount of packet data.

  According to the present invention, duplicate headers and the like are deleted and transmitted, and at that time, the deleted position and contents are transmitted as a header table prior to data transmission, so that efficient data transmission is possible.

1 is a block diagram of a packet transmission system using a packet transmission apparatus according to the present invention. It is a detailed block diagram of a packet transmission apparatus. It is a detailed block diagram of an overhead analysis unit. It is the table which illustrated the contents of data amount reduction processing. It is the figure which illustrated the header table. It is a figure explaining the data amount reduction process with respect to header item_1. It is a figure explaining the data amount reduction process with respect to header item_2. It is a figure explaining the data amount reduction process with respect to header item_3. It is a figure which shows the specification of the header in an IP packet. It is a figure explaining the data amount reduction process with respect to header item_4. It is the figure which illustrated the data format before and behind the data amount reduction process with respect to header item_4. It is a figure explaining the data amount reduction process with respect to header item_5. It is a figure explaining the data amount reduction process with respect to header item_6. It is a figure explaining the data amount reduction process with respect to header item_7. It is a flowchart which shows a data transmission procedure.

<First Embodiment>
An embodiment of the present invention will be described. FIG. 1 is a block diagram of a packet transmission system 2 using a packet transmission device 3 (3A, 3B) according to the present invention.

  The packet transmission system 2 has a packet transmission device 3 (3A, 3B), an information device 4 (4A, 4B), and a wireless device 5 (5A, 5B) as a basic configuration. Hereinafter, as in the packet transmission apparatus 3A, the general number “3” is denoted by “A” to indicate a transmission side element, and “B” is denoted to indicate a reception side element. Further, since the configurations on the transmission side and the reception side are the same, common explanation will be given using general numbers.

  FIG. 2 is a detailed block diagram of the packet transmission device 3. The packet transmission device 3 includes a reception unit 31 (31A, 31B), a header type determination unit 32 (32A, 32B), an overhead analysis unit 33 (33A, 33B), a data creation unit 34 (34A, 34B), and a header information storage unit. 35 (35A, 35B) and a transmission unit 36 (36A, 36B).

  FIG. 3 is a detailed block diagram of the overhead analysis unit 33. The overhead analysis unit 33 includes an internal header analysis unit 41 (41A, 41B), an external header analysis unit 42 (42A, 42B), and a header table creation unit 43 (43A, 43B).

  With such a configuration, the data transmission side packet transmission device 3A reduces the amount of data by compressing, deleting (partially or all), sharing, etc. the header included in the transmission data. Hereinafter, such processing is collectively referred to as data amount reduction processing. At this time, as a matter of course, the data receiving side needs to be able to restore the original data. That is, rules regarding data reduction / restoration are set.

  These rules include individual rules (individual processing rules) and general rules (common processing rules). The individual processing rule is an agreement used when reduction is performed according to the request on the receiving side, and the common processing rule is an agreement common to the packet transmission system 2 like a rule determined according to the IP protocol. It is. These rules are registered in the header information storage unit 35 and read when performing a data amount reduction process or a data restoration process.

  FIG. 4 is a table illustrating the contents of the data amount reduction process. The data restoration process has the same processing contents as the data amount reduction process, and the reduction process in the data amount reduction process may be read as the restoration process, and will not be described.

  As shown in FIG. 4, the header included in the packet can be divided into an internal additional overhead G1 and an external additional overhead G2.

  For the header of the internal additional overhead G1, (Item_1) Overhead reduction specialized for P-P connection, (Item_2) Reduction of overhead by original specification, (Item_3) Encapsulating multiple VoIP packets with GFP Reduction is realized. For the header included in the external additional overhead G2, (item_4) MAC header compression, (item_5) IP header compression, (item_6) UDP header compression, and (item_7) RTP header compression are performed. Done. Item_1 and item_2 are processed according to individual processing rules, and item_3 to item_7 are processed according to common processing rules.

  Hereinafter, item_1 to item_7 are appropriately described as header items, individual processing rules, and common processing rules as processing rules.

  Then, the header type determination unit 32 determines whether the header corresponds to the internal additional overhead G1 or the external additional overhead G2. Corresponding to the type determination, the overhead analysis unit 33 calculates which session item corresponds, calculates the session ID when the data amount is reduced, and creates a header table.

  The session ID is a unique value for identifying the session unit of the packet, and is calculated by calculating the hash value of the MAC address, IP address, UDP header, and RTP header. Further, as shown in FIG. 5, the header table creates a header table including a session ID and a raw header (input data before data amount reduction / restoration processing).

  The session ID is calculated by the header table creation unit 43 using the analysis results of the internal header analysis unit 41 and the external header analysis unit 42. The data creation unit 34 accesses the header information storage unit 35 according to the header table, searches for registered processing rules, and reduces (restores) data according to the search results.

  The overhead analysis unit 33 will be described in detail. The internal header analysis unit 41 of the overhead analysis unit 33 performs analysis processing on the internal additional overhead G1, and the external header analysis unit 42 performs analysis processing on the external additional overhead G2.

  The internal header analysis unit 41 determines whether the header of the input packet is the header item_3, the header item_1, or the header item_2. In the case of the header item_1 and the header item_2, the individual processing rule is acquired from the header information storage unit 35 and output. In the case of header item_3, the common processing rule is acquired and output. On the other hand, the external header analysis unit 42 determines whether the header corresponds to any of the header item_4 to the header item_7, and acquires and outputs a common processing rule regarding the header item. These analyzes can be determined from the position of the corresponding header address or the like.

  Then, the header table creation unit 43 calculates a session ID based on the analysis results from the internal header analysis unit 41 and the external header analysis unit 42, and creates the header table shown in FIG.

  In other words, the data amount reduction processing in this embodiment is used, for example, by deleting a header item and transmitting the session ID indicating the position and the deleted header (corresponding to the raw header) together, for example. The transmission time is shortened by avoiding repeated transmission of headers.

  The data creation unit 34 creates transmission data by executing a data amount reduction process on the data to be transmitted based on the header table created by the header table creation unit 43.

  Thereafter, the transmission data is sent together with the session ID to the wireless device 5B via the wireless device 5A. The transmission data received by the wireless device 5B is restored by the data restoration process in the packet transmission device 3B and output to the information device 4B.

The data amount reduction process is performed as follows.
[A] Data Amount Reduction Processing for Internal Additional Overhead The header table creation unit 43 performs overhead reduction specialized for P-P connection on the header of header item_1 according to the individual processing rule, and generates a header for header item_2 The overhead is reduced by the original specification. On the other hand, a plurality of VoIP packets are reduced by GFP encapsulation for the header of header item_3.

(A) Data amount reduction processing for header item_1 (overhead reduction processing specialized for PP connection)
FIG. 6 is a diagram illustrating headers related to the PP connection and the multipoint connection in the GFP overhead. In the present embodiment, the header item_1 is realized by reducing the multipoint connection (12 bytes) and specializing in the P-P connection.

(B) Data amount reduction processing for header item_2 (overhead reduction processing by original specification)
FIG. 7 is a diagram showing a header relating to a PP connection in the GFP overhead. Since the packet transmission apparatuses on the transmission side and the reception side have the same specifications and the payload type is also fixed, headers that are unnecessary when not interconnected with other PKGs are deleted. Since the CORE header is necessary for synchronization, it cannot be deleted. This implements header item_2.

(C) Data amount reduction processing for header item_3 (reduction processing by encapsulating multiple VoIP packets with GFP)
FIG. 8 is a diagram showing the specification of a VoIP packet. One GFP header is provided for one VoIP packet. In the present embodiment, the VoIP packets accumulated in the queue are encapsulated by collecting them with one GFP header. At this time, the number of VoIP packets to be encapsulated is not particularly limited, but can be about 1 to 10. This reduces the data amount of the header item_3 for a plurality of GFP headers.
[B] Data amount reduction processing for external additional overhead The external header analysis unit 42 analyzes the header of the packet and performs data amount reduction processing of header item_4 to header item_7. As shown in FIG. 9, the IP packet defined in RFC 2508 includes a 14-byte MAC header to be reduced by header item_4, a 20-byte IP header to be reduced by header item_5, and a header item_6 reduced. A target 8-byte UPD header, a header item_7 includes a 12-byte RTP header, 160-byte audio data, and 4-byte FCS are included.

(A) Data amount reduction processing for header item_4 (MAC header compression processing)
As shown in FIG. 10, the MAC header includes a destination MAC address, a source MAC address, a type / size, and an FCS. The destination MAC address and the source MAC address are 6 bytes, and the values are repeated in the same session. The type / size is 2-byte data, the value is repeated in the same session, and the size can be calculated from the size of the GFP. FCS is 4 bytes and is a different value each time. Therefore, when it is repeated or can be calculated, it can be restored even if it is reduced by a repetition rule and a calculation formula.

  For example, as shown in FIG. 11, when a call is made with VoIP, the same value is repeatedly given to the MAC address, IP address, etc. during the call. Is replaced with a session ID with a smaller number of bytes. Accordingly, when restoring, it is possible to restore by putting a value such as a MAC address or an IP address in the position of the session ID. In FIG. 11, since the header Ha of each packet is repeated, the data amount is reduced by replacing with the session ID after the second time. When restoring, the header of the first packet is inserted at the position of the session ID to restore.

(B) Data amount reduction processing for header item_5 (IP header compression processing)
FIG. 12 is a diagram showing the format of the IP header. The IP header includes data that repeats a value such as version information and header length, data length, data that can be calculated such as a header checksum, and data of an arbitrary value such as an option. Therefore, in the data amount reduction process, repeated data and data that can be calculated (maximum 20 bytes) are reduced.

(C) Data amount reduction process for header item_6 (UDP header compression process)
FIG. 13 is a diagram showing the format of the UDP header. This UDP header also includes a source port number for which a value is repeated and a UDP length that can be calculated. Therefore, in the data amount reduction process, repeated data and data that can be calculated (maximum 8 bytes) are reduced.

(D) Data amount reduction processing for header item_7 (RTP header compression processing)
FIG. 14 is a diagram showing the format of the RTP header. The RTP header includes data such as a fixed value version, a sequence number where the value is repeated, and data depending on the VoIP device such as a marker. Therefore, in the data amount reduction process, fixed value data and data (maximum 8 bytes) in which values are repeated are reduced.

  In this way, the data amount is reduced. For example, it is necessary to distinguish between version and padding (section identification), and the header table is held based on the information, and the header table is synchronized on the compression / decompression side.

  Next, a data transmission procedure in the packet transmission system 2 will be described in detail with reference to a flowchart shown in FIG.

  Steps S1 and S2: Transmission data is input from the information device 4A to the packet transmission device 3A. The packet transmission device 3A determines whether or not the session ID has been notified through a procedure described later. The fact that the session ID has been notified means that transmission data for which the data amount reduction processing has been performed on the packet is being transmitted. If the ID has been notified, it means that the packet is being transferred, and the process proceeds to step S7. If not, the process proceeds to step S3.

  Steps S3 to S5: The header table creation unit 43A of the overhead analysis unit 33A calculates a session ID and creates a header table according to the header items and processing rules of the target header by the internal header analysis unit 41A and the external header analysis unit 42A. Then, the session ID, raw header, and payload are transmitted.

  Steps S6 to S9: When receiving the session ID, raw header, and payload from the packet transmission device 3A, the receiving side packet transmission device 3B determines whether or not the received session ID is an existing ID. In the case of an existing session ID, the process proceeds to step S9 and a reception response signal is output. However, if it is not an existing session ID, the session ID and the header table of the raw header are temporarily stored in an internal memory or the like, and the process proceeds to step S9 to output a reception response signal.

  Step S10: Upon receiving the response signal from the reception side packet transmission apparatus 3B, the transmission side packet transmission apparatus 3A primarily stores the header table in an internal memory or the like.

  Steps S11 and S12: Thereafter, transmission data is created by performing a data amount reduction process according to the header table stored temporarily, and transmitted to the packet transmission apparatus 3B on the receiving side. The packet transmission device 3B restores and outputs the received transmission data in accordance with a header table that is temporarily stored.

  As described above, since the transmission data amount is reduced by the data amount reduction process for deleting duplicate headers and the like, efficient data transmission can be performed.

2 Packet transmission system 3 (3A, 3B) Packet transmission device 4 (4a, 4B) Information device 5 (5A, 5B) Wireless device 31 (31A, 31B) Receiver 32 (32A, 32B) Header type determination unit 33 (33A) , 33B) Overhead analysis unit 34 (34A, 34B) Data creation unit 35 (35A, 35B) Header information storage unit 36 (36A, 36B) Transmission unit

Claims (7)

A packet transmission device for transmitting an IP packet from a transmission side to a reception side,
A header type determination unit that determines whether the header included in the packet to be transmitted is a header type by internal addition or a header by external addition;
An overhead analysis unit that calculates a session ID according to the type determination by the header type determination unit and creates a header table that associates the session ID with the header;
A packet transmission apparatus comprising: a data creation unit configured to reduce a data amount of the packet to be transmitted according to the session ID and the header table. The packet transmission device according to claim 1,
The data creation unit transmits the header table to the receiving side so that the receiving side can restore the transmission data transmitted by reducing the amount of data from the transmitting side according to the header table. A packet transmission apparatus. The packet transmission apparatus according to claim 2,
The overhead analysis unit calculates a hash value of data to be transmitted and uses it as the session ID. The transmission side and the reception side include at least the packet transmission device according to any one of claims 1 to 3,
The packet transmission device on the transmission side creates the header table and reduces the amount of transmission data, and the transmission data reduced in data amount by the packet transmission device on the reception side is restored based on the header table. Packet transmission system. A packet transmission method for transmitting an IP packet from a transmission side to a reception side,
A header type determination procedure for determining whether the header included in the packet to be transmitted is a header type by internal addition or a header by external addition;
An overhead analysis procedure for calculating a session ID according to the type determination determined by the header type determination procedure and creating a header table that associates the session ID with the header;
And a data creation procedure for reducing data amount of the packet to be transmitted according to the session ID and the header table. The packet transmission method according to claim 5, comprising:
The data creation procedure transmits the header table to the receiving side so that the receiving side can restore the transmission data transmitted by reducing the amount of data from the transmitting side according to the header table. A packet transmission method comprising a procedure. The packet transmission method according to claim 6, wherein
The overhead analysis procedure calculates a hash value of data to be transmitted and uses it as the session ID.