JP3256567B2 - Connectionless message billing system in ATM network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Connectionless information such as LAN data is accommodated in an asynchronous communication (ATM) network which is a connection-oriented system, and a connectionless communication accounting system for an ATM network interconnecting a plurality of LANs. About.

[0002]

2. Description of the Related Art With the development of advanced communication networks in recent years, there is an increasing demand for realizing so-called inter-LAN communication (MAN: metropolitan area network) in which data in a LAN is used between different LANs. .

On the other hand, in the electronic switching network, with the spread of ISDN, A can transfer a large amount of information at high speed and efficiently.
TM is considered to be the mainstream, and it is expected that an ATM network will be constructed in a manner that includes the MAN.

[0004] Connectionless information in a LAN is generally of variable length, and a destination (address) is registered at the head thereof. To accommodate this in an ATM network for exchanging fixed-length information as ATM cells, a header and a trailer are added to the LAN data (message), respectively, and these are stored in the information field of the ATM cell.

As described above, single LAN data is divided into a plurality of ATM cells and transferred. An ATM cell corresponding to the divided position of LAN data (message) is given an identifier called a segment type.

[0006] The types of the segment type include SSM indicating that the message is all contained in a single cell, BOM indicating the so-called first cell indicating destination information of the message, and intermediate data of LAN data. COM and EOM indicating the last cell.

As a result, the head of the message is included only in the BOM cell or the SSM cell, so that the connectionless server (CL) is connected.
In order to identify a plurality of messages on the same transfer path, a message ID (MESSEGE
IDENTITY; MI).

Therefore, the same message ID (MID) is assigned to a plurality of ATM cells obtained by dividing one message. Connectionless server (CL
When the BOM cell arrives, the server) secures an empty message ID (MID) and obtains its routing information. When an EOM cell corresponding to this BOM arrives, the message ID (MI
D) is released.

[0009] If an error occurs in the data of the COM cell constituting the middle part of the message, the connectionless server (CL server) stops transmission of the remaining cells following this and temporarily stores the data. Message ID
(MID) is erased.

As a billing system for message communication in the ATM network, there is a billing system for each cell. This is a system that measures the number of cells that have passed through the ATM exchange for each MID from when a message ID (MID) is set to when it is released, and calculates a charge corresponding to the number of cells.

[0011]

In connection with the communication of connectionless messages in an ATM network, charging cannot be calculated by the above-described charging method in units of cells.

That is, the connectionless message in the ATM network includes a BOM cell corresponding to a so-called first cell storing the address of the destination exchange, the address of the calling / receiving subscriber, and the message length information of the connectionless message, and the LAN data of the LAN data. It is composed of a COM cell which is intermediate data and stores the address information of the destination exchange of the connectionless message, and an EOM cell which is the last cell and stores the address of the destination exchange and the message length information of the connectionless message. When the charging is performed in units of cells,
The cell and the EOM cell do not store the address of the destination subscriber that is the ultimate destination, and it is not known to which subscriber the billing calculation result is to be charged.

Further, when a failure occurs in the COM cell, charging is performed on the entire cell constituting the connectionless message, whereas the connectionless message is not restored due to the failure of the COM cell, and Does not reach. That is, there is a problem in that a cell constituting the unrecoverable message is charged.

Accordingly, the present invention has been made in view of the above problems, and has as its technical object to provide a system that can accurately charge connectionless messages in an ATM network.

[0015]

The present invention has been made as follows to solve the above-mentioned problems. This will be described with reference to the principle diagram of FIG.

A cell conversion means for converting and dividing connectionless message data sent from the LAN into at least one ATM cell;
A connection in an ATM network composed of a plurality of ATM exchanges 2 for performing cell exchange processing, and a connectionless server (hereinafter referred to as a CL server) 3 connected to each of the ATM exchanges 2 and having a message processing unit and a billing unit. Reless message billing system.

In the CL server 3, the message processing unit analyzes the address of the connectionless information in the connectionless cell converted from the connectionless message by the cell conversion unit 1, and routes the connectionless cell. Is managed by a message ID (hereinafter referred to as MID).

[0018] On the other hand, the charging unit calculates charging for the connectionless message from the connectionless cell based on the message length of the connectionless message.

Further, the charging unit identifies whether the connectionless cell is the first cell, the last cell, or the middle cell, and detects the message length information from the last cell. I do.

Further, the message processing unit is provided with an error detection unit for detecting a message error and / or cell discard. When the error detection unit detects an error, the message processing unit stops transmitting the message.

[0021]

According to the present invention, in the charging unit of the CL server, among the cells into which the connectionless message is divided, the cell is the first BOM cell, the middle COM cell, or the last EOM cell. Or identify.

Then, a sender address and a receiver address are detected from the BOM cell, and message length information as a parameter for accounting calculation is detected from the EOM cell.

Further, a charge to be imposed on the message communication can be calculated based on the parameter. Further, the billing can be charged to the caller or the callee.

As described above, the connectionless message is charged each time the sender address / recipient address is detected.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG.
1 is a block diagram showing the overall configuration of a connectionless message communication system in an ATM network according to the present invention.

In the present system, when connectionless message data is transmitted from the originating terminal 5a of the LAN, the connectionless message data is divided into fixed-length cells handled by the ATM network 10 by the cell conversion means 6a on the transmitting side. Is converted. Here, the head cell of one connectionless message data is BOM as a segment type described later, and the cell in the middle of the message is COM.
OM and EOM are added to the last cell of the message.

When one connectionless message can be accommodated in a single cell, SSM is added as the above segment type. The destination information including the source address (SA) and the destination address (DA) of the connectionless message data is accommodated in a cell to which a segment type of BOM or SSM is assigned, and accommodated in a cell to which COM or EOM is assigned. Not done.

Each of the divided cells has an ATM network 10
An ATM header required for performing the exchange processing in the above is added, but the cell conversion means 6a on the transmission side identifies a fixed path to the CL server 8a on the transmission side without analyzing the destination of the connectionless message data. (VIRTUAL CHANNEL IDENTITY: virtual channel identifier) or the like is added as an ATM header.

As described above, the connectionless cell into which the connectionless message data is divided is transmitted to the C
And arrives at the L server 8a and passes through the ATM network 10 based on the routing control by the CL server 8a described later.
The data is transferred to the server 8b, and further converted from the fixed-length ATM cell into connectionless message data by the called-side cell converting means 6b via the fixed path, and transferred to the called terminal 6b of the called-side LAN.

A plurality of terminals on the receiving side LAN monitor the data transferred on the LAN, and the destination terminal 5b recognizes that the information is addressed to itself, and takes in the connectionless message data.

In the figure, connectionless message communication between a pair of CL servers 8a and 8b has been described. However, when a wide-area ATM network is used, a plurality of CL servers are used.
By using the server 8 and repeating the routing between the pair of CL servers 8 sequentially based on the destination information of the connectionless message data, it is possible to perform the routing in the entire ATM network. As a result, compared to performing a wide range of routing with one CL server 8,
The routing range of one CL server 8 can be reduced, and the amount of hardware and the processing time can be reduced.

FIG. 3 is a diagram showing a format of an ATM cell in this embodiment. In the figure, the ATM cell has a fixed length of 53 bytes, and the first 5 bytes are ATM cells.
The remaining 48 bytes of the header are information fields in which information should be stored.

The information field includes a segment type (ST) and a sequence number (S
N) and 2 bytes of a header that stores a message identifier MID, 44 bytes that store connectionless message data, and a payload that indicates the length of valid information in the connectionless message data when the length is shorter than 44 bytes It is composed of 2 bytes of a trailer that stores the length and the like.

The 44-byte area for storing the connection message data stores information obtained by dividing a level 3 protocol data unit (L3-PDU) into 44-byte units. In the figure, PAD is an adjustment bit for adjusting the message length to the ATM cell when the cell is formed. That is, when the connectionless message has a message length that cannot be divided by 44 bytes, 4
The message length is slightly expanded by this PAD so as to be divisible by 4 bytes.

FIG. 4 shows the stored contents of the ATM header in the cell format of FIG. Of the 5 bytes of the ATM header, the first 4 bits are Generic Flow Control (GFC) used for flowchart control between links, and the next 8 bits are virtual path identifiers (VP).
I), the next 16 bits are a virtual channel identifier (VC synonymous with the above-described virtual channel identifier,
I), the next two bits are a payload type (PT) indicating the type of cell, the next one bit is reserved, and the next one bit is a cell priority (PR) used for controlling cell discarding during congestion. And the last 8 bits are ATM
This is a header error control (HEC) for correcting 1-bit errors and 2-bit errors in the header.

FIG. 5 shows the contents in the information field in the cell format of FIG. The storage contents of each field other than the connectionless message data of 44 bytes out of the 48 bytes of the information field will be described below.

The 2-bit segment type (ST) stored at the top indicates the position of the cell when the connectionless message data is divided into a plurality of cells. That is, as described above, the BEGI is added to the cell in which the cell position of the level 3 protocol data unit is at the head.
NNING OF MESSEGE: BOM and CONTINUA for cells in the middle of the level 3 protocol data unit
TION OF MESSEGE: COM, and END to the cell at the end of the cell position of the Level 3 protocol data unit
OF MESSEGE: EOM is assigned. When the connectionless message data of the level 3 protocol data unit is accommodated in one cell, SINGLE SEGMENT MESSEGE: SSM is added to the cell, and "0" is set to the empty area of the SSM cell. Embed.

The four bits occupied by the sequence number (SN) are cyclically assigned to cells in units of level 3 protocol data units, and are used for detecting discard in units of cells.

Then, 10 bits of a message identifier (MID) in which the same value is set for the same connectionless message data, 6 bits occupied by the payload length indicating the effective length of the connectionless message data, error correction and detection CR for cyclic redundancy check code for
10 bits occupied by C10.

Next, a specific configuration of the connectionless server (CL server) 8 in this embodiment will be described with reference to FIGS. First, FIG. 6 shows a configuration of the CL server 8. The CL server 8 includes a message processing unit 11 and a billing unit 12, and the message processing unit 11
It absorbs differences in transmission speed, format, media, etc., depending on N, and converts LAN data into connection cells in a unified format. Then, routing control, outgoing / incoming call screening, flow control, and the like are executed.

FIG. 7 shows the configuration of the message processing unit 11 in FIG. In the figure, a message processing unit 11 includes an input interface unit 13, an input format check unit 14, a routing unit 15, an output format generation unit 16, and an output interface unit 17.
It is composed of

The input interface unit 13 is an ATM interface.
The interface with the exchange 7 is performed, and the input format check unit 14 checks the CRC 10, the sequence number (S
N) is used to confirm the normality of the input cell. Then, the routing unit 15 determines the segment type (ST) such as BOM and COM described above from the input connection cell and detects the content.

If the segment type obtained as a result of the above detection is BOM or SSM, the source address (SA) and the destination address (DA) of the connectionless message data contained in the cell are analyzed, and the ATM is analyzed.
Retrieves routing information in the network and rewrites its contents.

The routing information searched for the cell added with the BOM or SSM segment type is
Message identifier (MID) added to the cell
When a cell with a segment type of COM or EOM added thereto is input, M is temporarily stored.
The IDs are compared and stored, and the matching routing information stored first is compared with that of the cell, and the routing information is rewritten.

On the other hand, when a cell to which an EOM segment type is added is input, the MID is deleted from storage after rewriting of the routing information is completed. Next, the output format generation unit 16 adds a CRC 10 and a sequence number (SN) corresponding to the newly rewritten routing information of the connection cell to the connection cell transmitted from the routing unit.

The output interface unit 17
Interfaces with an ATM switch. Also, the charging unit 12 charges the connectionless message communication using the message length as a parameter, as long as the message constituting the same message is successfully transmitted among the connection cells in the format unified by the message processing unit 11. Is calculated.

FIG. 8 is a diagram showing the configuration of the charging unit 12 in FIG. In FIG. 1, a billing unit 12 includes a segment type separating unit 18 and an SA / DA information detecting unit 1.
9, a message length information detection unit 20, a calculation unit 21, and a charging memory 22.

The segment type separation unit 18 determines the BO of the connection cells input to the CL server 8.
The cell to which the segment type of M, EOM, or SSM is added is determined and detected, and is transmitted to the SA / DA information detecting unit 19 in the case of BOM or SSM and to the message length information detecting unit 20 in the case of EOM.

Then, in the SA / DA information detecting section 19,
A caller address (SA) and a callee address (DA) are detected from the BOM or SSM cell, and are detected by the charging memory 2.
2 is stored. Here, in the case of the SSM cell, SA · D
After the A information is detected, the SSM cell is transmitted to the message length information detecting unit 20.

On the other hand, in the message length information detecting section 20,
Detect message length information from EOM or SSM cell,
This is sent to the arithmetic unit 21. The calculation unit 21 performs the following calculation based on the message length information detected by the message length information detection unit 20.

[0051] Further, a communication charge is calculated based on the number of received cells obtained from the calculation.

The obtained communication fee is stored in the charging memory 2.
2 together with the corresponding SA / DA. Thereafter, the charge for the connectionless message communication performed in the same SA / DA is added.

In this embodiment, if an error occurs in the connection cell to which the COM has been added and communication of the connectionless message is no longer performed, in this embodiment, message length information serving as a charging parameter is output from the EOM. Therefore, the message is not charged.

[0054]

Thus, according to the present invention, there is provided a highly accurate accounting system which can perform accounting for connectionless message communication in an ATM network and does not perform accounting for a message in which an ATM cell has an error in the middle. Can be provided.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is an overall configuration block diagram of a connectionless message communication system in an ATM network according to the embodiment;

FIG. 3 is a diagram showing a format of an ATM cell in the embodiment;

FIG. 4 is an explanatory diagram showing stored contents of an ATM header in the cell format of FIG. 3;

FIG. 5 is an explanatory diagram showing contents in an information field in the cell format of FIG. 3;

FIG. 6 is a configuration diagram of a CL server according to the present embodiment.

FIG. 7 is a configuration diagram of a message processing unit 11 in FIG. 6;

8 is a configuration diagram of a charging unit 12 in FIG.

[Explanation of symbols]

 1. Cell conversion means 2. ATM exchange 3. CL server 4. Transfer path 5a Calling terminal 5b Calling terminal 6. Cell conversion means 7. ATM switch 8. CL server 9. ATM switch 10 ATM switching network 11 Message processing unit 12 Billing unit 13 Input interface 14 Input format check unit 15 Routing unit 16 Output format generation unit 17 Output interface unit 18 ..Segment type separation section 19.SA/DA information detection section 20.Message length information detection section 21.Calculation section 22.Charging memory

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Haruo Mukai 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Shichiro Hayami 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited ( 72) Inventor Kazuo Hatsukano 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-4-138739 (JP, A) JP-A-1-100547 (JP, U) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/56

Claims (3)

(57) [Claims] 1. An asynchronous transfer mode (ATM) network in which a connectionless message in a LAN is divided and transferred in units of cells, and cells for converting and dividing connectionless message data sent from the LAN into at least one ATM cell. A conversion means (1a, 1b); a plurality of ATM exchanges (2a, 2b) for exchanging ATM cells through a transfer path (4); a message processing unit connected to each of the ATM exchanges (2a, 2b); A connectionless server (3a, 3b) having a charging unit. The connectionless server (3a, 3b) analyzes an address of connectionless information in the connectionless cell by a message processing unit, and Manages the routing for message by message ID and Connectionless Message billing system in an ATM network, characterized in that for calculating the charging for the message the connectionless message based on the length of connectionless messages from the connectionless cell by the charging unit. 2. The charging unit identifies whether the connectionless cell is a first cell, a last cell, or an intermediate cell, and detects message length information from the last cell. 2. The connectionless message accounting system in an ATM network according to claim 1, wherein: 3. The message processing unit further includes an error detection unit that detects a message error and / or cell discard, and when the error detection unit detects an error, the message processing unit stops transmitting the message. 2. The connectionless message accounting system in an ATM network according to claim 1, wherein