JP2864068B2 - Cell monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used in an ATM communication network (asynchronous communication network). The present invention relates to a code sequence in which a communication company and a user contract and an ATM communication network operated by the communication company sets a cell (header and information in a certain format, especially a packet communication network. The present invention relates to an apparatus for discarding a cell transmitted from a user in real time when a communication carrier violates a contract condition when transmitting the same.

[0002]

2. Description of the Related Art A user of an ATM communication network transmits a cell addressed to a partner user's terminal from a terminal installed by the user via the ATM communication network. The user terminal is, for example, ISDN
The cell is connected to a general line such as a line, and cells are sent from the general line to the ATM communication network. The communication company monitors at the entrance of the ATM communication network whether or not the user is transmitting cells according to the contract, and discards the cells transmitted on the spot in real time if there is a violation. The device for that is a cell monitoring device.

[0003] One purpose of the cell monitoring is to monitor traffic, and whether or not a user is transmitting cells at a high transmission rate exceeding contract conditions. For example, according to the contract conditions, user A (VPI number) does not transmit more than n cells within m cell time, and if it transmits beyond this, the carrier discards the cell transmitted by user A. In some cases, the telecommunications carrier monitors whether the cell transmitted by the user A exceeds the condition, and can discard the cell when the cell exceeds the condition. If the cells transmitted at the excessive rate are not properly discarded, the traffic temporarily increases inside the ATM communication network and the operation becomes inoperable.

[0004] With regard to such a cell monitoring device for monitoring traffic, the applicant of the present invention has disclosed in Japanese Patent Application No. Hei.
No. 4, Japanese Patent Application No. 2-319735 and many other patent applications.

[0005]

SUMMARY OF THE INVENTION The inventors who have tried to establish communication network management using the above-described cell monitoring apparatus have encountered a new problem. It is an OAM (operation and ma) that the user transmits to the ATM communication network.
management, operation control code, the same applies hereinafter). The OAM is a code for operation and control transmitted on the information area of the cell. In addition to being transmitted and received between nodes of the ATM communication network for the carrier to manage the communication network, the OAM is A specific OAM is set so that it can be transmitted and received between user terminals.

An OAM that can be transmitted and received between user terminals is, for example, an alarm of a terminal. When an error occurs in the receiving terminal and cell reception cannot be continued,
It is used to notify the transmitting terminal of a device error. For a carrier managing an ATM communication network, it is desirable that the OAM transmitted and received by the user is also an important management signal and transmitted reliably. Therefore OAM
Need to be managed separately from the above-mentioned traffic, and allow a margin for the traffic management by the OAM. The cell with the OAM can transmit even if it exceeds the contracted traffic. Management is performed such as not charging the listed cell.

[0007] Then, O is maliciously transmitted from the user terminal.
Cells may be transmitted using AM. For example, if it is found that the cell on which the OAM is placed is not discarded or billed, processing such as placing the OAM on the transmission cell and further placing information for the partner terminal may be performed. Furthermore, if the user can obtain information on the code construction and usage of a specific OAM transmitted and received for managing the communication network only between the nodes of the communication service provider for some reason, the purpose is to confuse the management of the communication network. It is also conceivable that OAM transmitted and received only between nodes is maliciously transmitted from the user terminal.

The present invention has been made in such a background, and a user uses a cell including an OAM to transmit information with traffic exceeding contract conditions, or confuses the management of a communication network due to malicious intent. So as not to let
It is an object of the present invention to provide a cell monitoring device for appropriately managing a cell including an OAM transmitted by a user.

[0009]

SUMMARY OF THE INVENTION A first point of the present invention is to perform simple management of a cell including an OAM transmitted by a user so that a cell including an excessive OAM is not transmitted from a user terminal. It is. That is, a delay holding circuit that temporarily holds a cell that the user transmits to the communication network, a determination circuit that monitors the cell and determines that the cell is not allowed to be transmitted to the communication network. ,
A discard processing circuit for discarding cells temporarily held in the delay holding circuit in accordance with the output of the judgment circuit, wherein the judgment circuit includes an OAM for the cell to be judged. It is characterized in that it comprises means for identifying, and means for counting that the transmission rate of the cell including the OAM identified by the identifying means exceeds a preset value.

The second point of the present invention is that the OA transmitted by the user
When the OAM for a cell including M is a network management OAM used only by a communication carrier, the cell is discarded regardless of other conditions. That is, the determination circuit includes means for identifying that the cell to be determined includes an OAM, and that the OAM includes a specific OAM set in advance for the cell including the OAM identified by the identification means. Identification means.

The devices described in the first and second points can be provided together in one cell management device.

[0012] The cell management device provided in addition to the above may further include a means for monitoring the traffic of the cell described as the prior art.

[0013]

According to the apparatus described in the first aspect of the present invention, the upper limit of the traffic of the transmission cell is determined in advance by a contract with the user, and when the cell including the OAM is transmitted from the user terminal. Is to determine the upper limit of the traffic, and to separately monitor the traffic of the cell including the OAM so as to prevent the extra cell including the OAM from being transmitted. As an example, when the contract condition is that the transmission rate of a cell transmitted from one user terminal does not exceed 1 Mb / S,
A condition that the transmission rate of a cell including an AM does not exceed 64 kb / S is added.
And discards the cell when the transmission rate exceeds 64 kb / S.

In the apparatus described in the second aspect of the present invention, a cell including an OAM is identified for a cell transmitted from a user terminal, and further, it is identified that the content of the OAM is a specific code. When the code is the specific code, the cell is discarded. This particular code may be determined in any way, but here, it is set so that only the communication company that originally manages the communication network can transmit and receive between the nodes as communication network management information. Since such OAM should not be transmitted from the user terminal to the communication network, cells containing such OAM are discarded at the entrance of the communication network.

The cell monitoring device may be provided with a device for performing various monitoring for various purposes for each purpose. However, in general, it is inconvenient in terms of a system configuration. It is advantageous to provide a jointly implemented device in the determining means of the device.

[0016]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. In this device, a monitored signal arrives at a terminal 1. The monitored signal is supplied to the cell detection circuit 2 to detect a cell transmitted by the user to the communication network. The cell detected by the user and transmitted to the communication network is temporarily held by the delay holding circuit 3. The cells detected by the cell detection circuit 2 are provided to two determination circuits 10 and 20. The two determination circuits 10 and 20 are monitoring circuits that monitor a cell and determine that the cell is not allowed to transmit to the communication network. The apparatus further comprises a discard processing circuit 4 for discarding the cells temporarily held in the delay holding circuit 3 in accordance with the outputs of the judgment circuits 10 and 20. Sent to.

Referring to FIG. 2, the relationship between the embodiment of the present invention and a communication network will be described. FIG. 2 shows a configuration example of a communication network. In FIG. 2, a portion indicated as ATM / N / WORK is an ATM communication network. In this ATM communication network, a number of nodes distributed in each region and an ATM line for interconnecting the nodes are provided. , And a cell transmitted from the subscriber line termination SLT is asynchronously switched and connected according to the destination indicated in the cell. This ATM communication network is a known system. An embodiment of the present invention is a subscriber line termination SL.
UPC (usage parameter c) in T
(control). Each of the cell monitoring devices of the present invention is connected to a network terminating device BN via a line.
T (broadband network termi
user terminal TE (ter)
Minor equipment). In this example, the network terminator B-NT is an ISDN line terminator. The ATM communication network is an operating system (OP
S).

Returning to FIG. 1, the two decision circuits 10 and 20 will be described. For the cell to be determined detected by the cell detection circuit 2, the determination circuit 20 displays a VPI (virtual path id) indicating the source of the cell.
Identifier), and sorts the cells from 1 to N for each VPI and distributes the cells from distribution circuits 22-1 to 22-
N. Each of the distribution circuits 22-1 to 22-N includes a unit for identifying the OAM of the input cell. This is a circuit for outputting a cell having an effective OAM in a column of an OAM of an input cell (an information array in the cell will be described later in detail) and outputting a cell without an OAM to an upper stage.
For example, if the cell input to the distribution circuit 22-1 has an OAM, the cell is sent to the counting circuit 24-1. If there is no OAM, the cell is sent to the counting circuit 23-1.

The counting circuits 23-1 to 23-N are circuits for monitoring the traffic described in the above-mentioned prior art. In other words, this circuit counts whether or not a cell is transmitted from the user terminal at a transmission rate exceeding the contract condition for each continuous cell time. If it is determined that the transmission rate exceeds the contract condition, the cell is discarded. The judgment output for performing the judgment is sent. Since the contents of this circuit are not directly related to the present invention, the description is omitted here.

Each of the counting circuits 24-1 to 24-N is a counting circuit unique to the present invention.
This corresponds to a means for counting whether or not the transmission rate of a cell including M exceeds a preset value. That is, the number of cells input is counted for each of a plurality of continuous cell times, and an output is sent when the counted value exceeds a preset condition. These preset conditions are also set by contract. An example of this condition is that the transmission rate of the information cell does not exceed 1 Mb / S in one VPI, and the transmission rate of the cell including the OAM is 64 kb / S
Is not contracted. In the case of this example, the counting circuit 23-1 sends a judgment output for discarding the input cell when the input cell exceeds 1 Mb / S, and the counting circuit 24-1 outputs the input cell of 64 kb / S. When the value exceeds S, a determination output for discarding the cell is transmitted.

Counting circuits 23-1 to 23-N or counting circuit 24
The judgment outputs for discarding the cells transmitted from −1 to N are supplied to the discard processing circuit 4 via the OR circuit 25, respectively.

Another determination circuit 10 corresponds to a means for identifying that a cell to be determined includes a specific OAM set in advance. That is, the cell detection circuit 2
Are input to the comparison circuit 12. On the other hand, the memory 11 stores the specific OAM set in advance.
Are all accumulated. The specific OAM is an OAM that is used exclusively by a carrier to manage an ATM communication network, or an OAM that cannot be transmitted from a user terminal. When the comparison circuit 12 determines that the OAM of the input cell corresponds to any of the OAMs stored in the memory 11, it sends a determination output to the discard processing circuit 4 to discard the cell.

The specific OAM is, for example, a transfer of an alarm in the communication network, a transfer of fault information in the communication network, a control signal for blocking a part of routes in the communication network, and the like. Although this is not originally known to the user, if the user who knows it in some way uses this OAM in the cell transmitted from the user terminal, the operation of the communication network may be confused by malicious intent. Or to avoid billing,
To avoid these, a determination circuit 10 is provided.

Then, when VPI = 0 is identified by the VPI identification circuit 21 in the decision circuit 20, a decision output for discarding the cell is sent to the discard processing circuit 4 as it is. Since this is a VPI that is not originally assigned to a user but is used only for managing a communication network, it is a VPI that must not be included in a cell transmitted by a user terminal, and is therefore discarded.

When the discard processing circuit 4 receives the judgment output, the discard processing circuit discards the judgment target cell temporarily held in the delay holding circuit 3. In the discard processing circuit 4, a cell to which the judgment output is not inputted even after the time required for the judgments executed by the judgment circuits 10 and 20 has elapsed is regarded as a cell which can be transmitted to the ATM communication network from the terminal 5 through the ATM communication network. Send to.

FIG. 3 is a configuration diagram of a cell transmitted to the ATM communication network. The cell is composed of a 5-byte header and a 48-byte information part, and one byte is composed of 8 bits. In this figure, a digital signal transmitted in a time series is displayed with a line break so that it is easy to see. G in the header
FC (generic flow control),
VPI (virtual path identifier)
er, information of the transmitting terminal is displayed in this part), VC
I (virtual channel identifier)
ier, information of the destination terminal is displayed in this part), P
T (payload type), R (reserve
d, which is reserved for future use with undefined bits), C (cell loss pri
ity, priority or not) is displayed in bits), HEC
(Header error correction,
Here, a code for error correction in the header portion is inserted). In the information part, arbitrary transmission information is inserted. OAM
(Operation and managementmen
When t) is transmitted, OA is added to the head of the information part.
It is displayed that the M identification code is inserted and that the OAM column is provided in the information portion.

FIG. 4 is a block diagram of a device according to another embodiment of the present invention. This figure is for connecting the determination circuit 20 described in the above embodiment (FIG. 1) to one processor (CPU), one random access memory (RAM), one fixed memory (MEM), and another circuit. And an interface (I / O), and software is implemented in the processor to perform the same operation as in FIG.

FIG. 5 shows a flowchart of the main part. That is, the fixed memory stores the traffic transmission rate and the OAM transmission rate according to the contract conditions for each VPI handled. The CPU is the VPI
And immediately sends a judgment output if VPI is zero. For other VPIs, a means for identifying that the cell to be determined includes an OAM for each VPI and a transmission rate for the cell including the OAM identified by the identifying means are set in advance for each VPI. Means for counting exceeding a given value. That is, the cell is held in the area set in the RAM,
The transmission rate of incoming cells is counted with reference to the contents of the fixed memory for the VPI. Further, for the cell including the OAM, an area is separately set and held in the RAM, and the transmission rate of the incoming cell including the OAM is counted.
If the transmission rate exceeds a preset value, a judgment output is sent out via the interface. It should be noted that the process of performing traffic determination for a cell that does not include the OAM can be similarly understood, and is a matter described in the prior application and is not directly related to the present invention.

The configuration shown in FIG. 4 is a device programmed to perform the same operation as that of FIG. 1, and each circuit means is built in by software. This configuration can reduce the size of the hardware of the entire apparatus and is a realistic configuration suitable for mass production.

The determination circuit 10 shown in FIG. 1 can be realized similarly by being constituted by a processor and a memory and by mounting appropriate software. FIG.
As for the determination circuit 20 and the determination circuit 10 shown in (1), two functions can be configured using one processor.

[0031]

As described above, according to the present invention,
The user transmits the information in such a manner that the user does not use the cell containing the OAM to transmit information with traffic exceeding the contract conditions, does not confuse the management of the communication network by malicious intention, and does not escape charging. A cell monitoring device for appropriately managing cells including OAM is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of the configuration of a communication network for explaining where the apparatus according to the embodiment of the present invention is located in the overall configuration of the communication network;

FIG. 3 is a bit configuration diagram of a cell transmitted to an ATM communication network.

FIG. 4 is a block diagram of another embodiment of the present invention.

FIG. 5 is a flowchart showing a main part of a portion of a device according to another embodiment of the present invention which is configured by a processor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Terminal to which signal to be monitored is input 2 Cell detection circuit 3 Delay holding circuit 4 Discard processing circuit 5 Terminal to which cells not discarded are transmitted 10 Judgment circuit 11 Memory 12 Comparison circuit 20 Judgment circuit 21 VPI identification circuit 22- Distribution circuits provided for each of 1 to N VPIs 23-1 to Counter circuits provided for each of the N VPIs 24-1 Counter circuits provided for each of the N VPIs 25 OR circuits

Continuation of the front page (56) References JP-A-4-25255 (JP, A) Naoki YAMANAKA et al., "Performance Evalution of an ATM Connection with Seven-Cell Electronic Components International Communications Company, ICON Information and Communication Society, May 1996, VOL. E79-B, No. 5, p. 716-718 (58) Fields surveyed (Int.Cl. ⁶ , DB name) H04L 12/24-12/28 H04L 12/56

Claims (4)

(57) [Claims] 1. A delay holding circuit for temporarily holding a cell transmitted by a user to a communication network, and monitoring the cell to determine that the cell is not allowed to be transmitted to the communication network. A cell monitoring device comprising: a judgment circuit; and a discard processing circuit for discarding cells temporarily held in the delay holding circuit according to an output of the judgment circuit. (Op
means for identifying an operation and management (hereinafter, the same).
Means for counting that the transmission rate of the cell including the OAM identified by the identifying means exceeds a preset value. 2. A delay holding circuit for temporarily holding a cell transmitted by a user to a communication network, and monitoring the cell to determine that the cell is not allowed to be transmitted to the communication network. A cell monitoring device comprising: a judgment circuit; and a discard processing circuit for discarding cells temporarily held in the delay holding circuit according to an output of the judgment circuit. A means for identifying that a specific OAM is included in advance. 3. A delay holding circuit for temporarily holding a cell transmitted by a user to a communication network, and monitoring the cell to determine that the cell is not allowed to be transmitted to the communication network. A cell monitoring device comprising: a judgment circuit; and a discard processing circuit for discarding cells temporarily held in the delay holding circuit according to an output of the judgment circuit. Means for identifying that the cell includes the OAM identified by the identifying means, and means for counting that the transmission rate of the cell including the OAM exceeds a preset value. Specific OA
Means for determining that M is included. 4. The cell monitoring device according to claim 3, wherein
A cell monitoring apparatus, wherein the determination circuit includes means for identifying that traffic for each user exceeds a preset value.