JPH0837530A - Time-out monitoring device - Google Patents

Abstract

PURPOSE:To monitor time-out with extremely efficient configuration. CONSTITUTION:This device is composed of one timer counter 4 to be up at fixed intervals, timer control part 3, and time-out value managing associated memory (TCAM) 2 for storing a time counter value (time-out value) showing time-out for each route information. The current timer counter value is compared with the time-out time for each route information while using the TCAM 2 so that time-out can be monitored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time-out monitoring device, for example, an AT in B (broadband) -ISDN.
It is applicable to the M communication system and the like.

[0002]

2. Description of the Related Art In recent years, technical development of B-ISDN has been actively conducted. In this B-ISDN, generally, when the maximum time from the first message to the last message is specified when transmitting / receiving an asynchronously input message, if the message is not input within the specified time, the message is input. Must be disabled.

In this way, "not entering a message within a specified time is called a timeout".

For example, ATM (Asynchronou)
s Transfer Mode: Asynchronous transfer mode)
The communication network handles multiple types of variable-length messages. Then, in the ATM communication network, the message is divided into fixed-length packets (cells). There are four types of cells as follows.

1. First cell (BOM): Cell worthy of the first message 2. Intermediate cell (COM): A cell that is worth the middle of the message. Last cell (EOM): last worthy cell of message 4. Single cell (SSM): A cell in which the message is only one cell And the same message is the route information (virtual path identifier VPI, virtual channel identifier VC) of the header part of the cell.
I, multiplex identifier MID) are equal. In this case also, since the maximum time from the first cell to the last cell is specified that is common to all messages, timeout monitoring becomes necessary.

The head cell (BO
Since the maximum time (Tm) from the input of (M) to the input of the final cell (EOM) is specified, the cells input over Tm must be treated as invalid.

[0007] Such a technique is explained in, for example, Minoru Akiyama, the editor of "B-ISDN picture and book," published by Ohmsha, pages 107-112.

FIG. 2 shows an example of a schematic functional configuration of a processing device for performing such processing. Further, an example of a schematic processing flowchart of this apparatus is shown in FIG.

As shown in FIG. 2, this device comprises timer counters 23 to 25 for each message, a control unit 22, and a passing discard processing unit 21. When a reset instruction is issued from the control unit 22, these timer counters 23 to 25 set the counter value to 0 and set the counter value to Tm + 1 for each unit time.
Increments up to. Cell output processing to the control unit 22 (processing to output an input cell as it is and convert the input cell to an idle cell according to a cell discard instruction and output)
There are two processes, that is, a counter reset instruction and a counter reset instruction.

The process will be described with reference to FIG. 3. First, when an input cell arrives, it is judged whether or not it is a valid cell (S3).
1) If it is not a valid cell, the input cell is output as it is. Then, if it is a valid cell, it is determined whether it is a single cell (SSM) (S32), and if it is a single cell (SSM), the input cell is output as it is. Next, it is determined whether or not it is the head cell (BOM) (S33), and if it is the head cell (BOM), a reset instruction is issued to the timer counter corresponding to the route information (S34). Then, the input cell is output as it is.

It is assumed that all the counters periodically count up and stop when the value of Tm + 1 is reached.

Further, in the above S33, the head cell (BOM)
If not, it is checked whether the counter value corresponding to the route information is equal to Tm + 1 (S35 to S3).
6). Then, if the values are equal, this cell has timed out and is discarded (S37). By this discard, the input cell is converted into an idle cell and output. T
If the value is smaller than m + 1, the input cell is output as it is.

The time-out is monitored as described above.

[0014]

However, when the time-out monitoring is performed by the above method, the number of counters corresponding to the number of routes is required, and when the number of routes increases, the hardware scale of the device becomes extremely large. However, it has become an obstacle to the realization of light, thin, short and small devices.

Therefore, it has been demanded to provide a mechanism capable of monitoring the timeout with a very efficient configuration.

[0016]

[Means for Solving the Problems]

(1) Therefore, the timeout monitoring device of the first invention is
It is a device that performs time-out monitoring of messages (including data) or signals (for example, control signals, status signals, etc.) for each monitoring target (for example, route, terminal device, host device, transmission line, virtual path, etc.). Then, a means for detecting the message or the signal, and a timer counter for counting while outputting a counter value while circulating every predetermined unit time are provided.

Further, means for fetching a counter value from the timer counter as a current timer counter value in accordance with the detected message or signal, and storage means for storing a time-out value for making a time-out judgment for the message or signal. , A means for comparing the current timer counter value and the timeout value for each monitored object for the message or signal using the storage means, and for performing timeout monitoring for the message or signal for each monitored object. The present invention solves the above problems.

(2) Further, the time-out monitoring device of the second invention is a device for performing time-out monitoring of a message or a signal with respect to each monitoring target, and means for detecting the message or the signal, and a predetermined unit time. A timer counter for counting and outputting a counter value, and means for fetching the counter value from the timer counter as a current timer counter value in accordance with the detected message or signal. Up to this point, the configuration is the same as that of the first invention described above.

Further, characteristically, a table in which the time-out time for each monitoring target is respectively registered, a storage means for storing a time-out value obtained by combining the current timer counter value and the time-out time, and the current timer It is also possible to provide a means for comparing the counter value and the time-out value for each monitored object using the storage means, and for performing time-out monitoring for the message or signal from each monitored object at each time-out time for each monitored object. The above-mentioned problems can be solved even further.

In the configurations of (1) and (2) of the invention described above, it is considered practically preferable that the storage means is constituted by an associative memory. As this associative memory, for example, a content address memory (Content
t Addressable Memory (CAM),
Data Address Memory (Data Addressed)
Memory), search memory (Search Mem)
ory) is assumed.

[0021]

In the configuration (1) described above, the timer counter is, for example, one in which the maximum value of the counter becomes the time-out time and which counts cyclically. Then, the storage means has a timeout value (timer counter value) for determining a timeout for each monitoring target (for example, route information) for the message or signal.
Therefore, the time-out can be monitored for each monitoring target by comparing the current timer counter value with the time-out time for each monitoring target.

In other words, the maximum value of the timer counter is the time-out time, and the timer counter circulates and counts up. Therefore, when the counter reaches the same value next time, it can be determined that the time-out has occurred.

Because of such a mechanism, it is not necessary to provide a counter as many as the number of monitoring targets (for example, the number of routes) as in the conventional case, and a monitoring target of a message or a signal for time-out monitoring (for example, Even if the number of routes is increased, the hardware scale of the device does not become very large.

Further, in the above-mentioned configuration (2), the above-mentioned table registers the timeout time corresponding to the monitoring target (for example, route information). Then, the storage means reads the timeout value retrieved from the current timer counter value and the timeout time for each monitoring target (for example, route information).

Then, by comparing the current timer counter value with the time-out value for each monitoring target (for example, route information), the time-out is performed at a different time-out time for each monitoring target (for example, route). Can be monitored.

With such a mechanism, it is possible to monitor (manage) a different timeout time for each monitoring target (for example, route information), which is suitable for more detailed monitoring of the timeout. it is conceivable that. Further, unlike the conventional case, the number of counters corresponding to the number of monitoring targets (for example, the number of routes) is not required, and even if the number of monitoring targets (for example, the number of routes) of a message or signal to be time-out monitored increases. The hardware scale of the device does not become very large.

Moreover, it is considered convenient to solve the above-mentioned problems very easily by using the associative memory as the storage means.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to the drawings. "Basic configuration": Therefore, in this embodiment, "one timer counter that rises at a constant interval and an associative memory that stores a time counter value (timeout value) indicating a timeout for each route information, A time-out monitoring device capable of performing time-out monitoring with a small-scale hardware configuration by comparing the timer counter value and the time-out time for each route information using an associative memory.

In view of this, in this embodiment, "a time-out is monitored by a fixed time-out value".

(Configuration of Timeout Monitoring Device): FIG. 1 is a functional configuration diagram of the timeout monitoring device of this embodiment. In FIG. 1, the time-out monitoring device includes a passage discard processing unit 1, a time-out value management associative memory (TCAM) 2, a timer control unit 3, and a timer counter 4.

In FIG. 1, the passage discard processing unit 1 discriminates a single cell (SSM), a head cell (BOM), an intermediate cell (COM), a last cell (EOM), etc., and manages a timeout value according to this discrimination. Associative memory (TCA
M) 2 and the timer control unit 3 are instructed.

The time-out value management associative memory (TCAM) 2 can register and read data for an address and valid tag (validtag: indicating whether this data is valid now). Also, it has a function of searching whether the search data is registered in the timeout value management associative memory (TCAM) 2 and sending out the address of the part where the data is registered to the outside if there is a matching data. It is a thing.

Then, the timer control unit 3 sends out the current timer counter value according to an instruction from the passage discard processing unit 1 or causes the timeout value management associative memory (TCAM) 2 to be stored in the current timer counter value at regular intervals. If a match is found by searching, the timeout value management associative memory (TCA)
M) The discard bit (using the valid tag) of the memory data of the corresponding address of 2 is cleared. That is,
1 is registered in the valid tag.

The timer counter 4 of FIG. 1 is an up counter which cyclically counts the maximum value of the counter as the timeout time.

FIG. 4 is an explanatory diagram of a memory map of the timeout value management associative memory (TCMA) 2. In FIG. 4, of the addresses 0 to ZZZ, for example, a pass or discard bit is set as data at address XXX using a valid tag. For example, when passing
1 is set, and 0 is set when discarding. Further, in the address XXX, a timeout value is set as data in addition to the pass or discard bit.

FIG. 5 is a cell processing flow chart for carrying out the passing / discarding processing of the flowing cells of this embodiment. FIG. 6 shows the time-up of the timer counter 4 of this embodiment.
6 is a flowchart of timer control processing for detecting timeout and performing discard registration.

(Cell processing operation): In FIG. 5, when a cell is first input into this device, a single cell (SS
M) or whether it is an idle cell or not (S51). Next, if it is a single cell (SSM) or an idle cell, it is not related to the time-out monitoring, and is passed as it is.

Next, it is determined whether or not it is the first cell (BOM) (S52). If it is the first cell (BOM), it issues a request to read the current timer counter value to the timer control unit 3. In the timer control unit 3, the timer counter 4
The current timer counter value is read from. Then, the read current timer counter value becomes the timeout value. This is because the maximum value of the timer counter 4 is the time-out time, and the timer counter 4 circulates and counts up, so that the next time the count reaches the same value, the timer counter 4 times out.

Next, the read current timer counter value is stored in the timeout value management associative memory (TCAM) 2 with the route information as an address and the data input as a valid tag (value is 1) and the current timer counter value. to register. That is, a timer is set (S53).

On the other hand, in S52, when it is not the head cell (BOM), that is, the intermediate cell (CO
M) or the last cell (EOM), the discard passage processing unit 1 reads data from the timeout value management associative memory (TCAM) 2 using the route information as an address (S).
54). Then, the discard bit (using the valid tag) in that is referred to.

It is confirmed whether this discard bit is 0 or 1 (S5
5) If the discard bit is 0, it is determined that a timeout has occurred, and the pass discard processing unit 1 discards the cell (S56).

The above processing is repeated each time a cell arrives.

(Timer control processing operation): In FIG. 6, the timer counter 4 is first incremented by 1 (S61). Next, the timer control unit 3 inputs data (search data) into the timeout value management associative memory (TCAM) 2.
The current timer counter value is input as, and it is searched whether the same value as the current timer counter is registered (the search request signal is used) (S62).

If it has been registered, the matching address of the registered portion is output from the timeout value management associative memory (TCAM) 2 and the timer control unit 3
Resets the discard bit in the data registered in the matching address in the timeout value management associative memory (TCAM) 2 to 0 (S63). That is, it is timed out.

The above-mentioned processing is repeated at regular time intervals.

Then, the time-out is monitored by performing the above two processes.

(Effect of One Embodiment): According to the time-out monitoring device of the above-mentioned one embodiment, one timer counter 3 which increases at a constant interval, the timer control unit 3, and a time-out for each route information are shown. A time-out value management associative memory (TCAM) 2 that stores a time counter value (time-out value). The time-out value management associative memory (TCAM) 2 is used to store the current timer counter value and the time-out time for each route information. By comparison, it is considered that timeout monitoring can be realized with a smaller hardware configuration than before. Further, this device is considered to be applicable to any configuration as long as it detects (monitors) a timeout from a certain time.

(Other Embodiments): (1) Further, the above-mentioned timer control unit 3 is configured as shown in the timer control unit 3A shown in FIG. That is, "the table 3A1 in which the time-out time corresponding to the route information is registered in the timer control unit 3A"
Is provided. Further, it is further preferable to further provide an arithmetic unit 3A2 for adding the current timer counter value and the timeout time. The timer counter 4 is configured so that the maximum counter value is sufficiently larger than the largest timeout time.

With this configuration, instead of the current timer counter value in the timeout value management associative memory (TCAM) 2 in step S53 of FIG. 5 of the above-described embodiment,
The value obtained by adding (adding) the current timer counter value and the timeout time drawn from the route information is registered.

By doing so, "it is possible to manage different timeout times for each route information, and it is considered that this is suitable for more detailed monitoring of timeouts. (2) Further, in the above embodiment, the two processes of the cell processing flow and the timer control processing can be performed in parallel, but it is also preferable to position them as processing to be performed in the cell processing. .

(3) Further, the target of the timeout monitoring is
The present invention can be applied not only to cells but also to packets and the like.

(4) Furthermore, the timeout value management associative memory (TCAM) 2 described above can realize the same function by using a content address memory, a data address memory, a search memory, or the like. it is conceivable that.

(5) Further, in the above-mentioned embodiment, the message by the cell is monitored and the time-out is monitored. However, in a system in which a plurality of terminals are connected to the host device, the host device is accessed. In this state, if data transmission by key input from the terminal is not performed for a certain period of time, the host device judges that it has timed out and automatically disconnects from the terminal, that is, a system that releases from the access state. Can also be applied to the realization of.

(6) In addition to monitoring messages (including data), simple control signals such as ON / OFF control signals and status signals are transmitted from the terminal to the host device. It is also possible to monitor the status and monitor the timeout.

[0055]

As described above, the time-out monitoring device of the first invention comprises means for detecting a message or a signal,
A timer counter that counts and outputs a counter value while patroling every predetermined unit time, a means for fetching the counter value as the current timer counter value from the timer counter according to the detected message or signal, and a timeout for the message or signal The storage means that stores the time-out value for making the determination of the current timer counter value and the time-out value for each monitored object for the message or signal are compared using the storage means, and the message for each monitored object is compared. Alternatively, it is configured by including means for performing time-out monitoring for a signal.

With such a configuration, it is not necessary to have the number of counters corresponding to the number of monitoring targets as in the conventional case.
Even if the number of messages or signals to be time-out monitored is increased, the hardware scale of the device does not become very large, and time-out monitoring can be performed with a very efficient configuration.

The time-out monitoring device according to the second aspect of the present invention includes means for detecting a message or a signal, a timer counter for counting and outputting a counter value for each predetermined unit time, and a device for detecting the message or signal according to the detected message or signal. Means for fetching a counter value from the timer counter as a current timer counter value, a table for registering a timeout time for each monitored object, and a storage means for storing a timeout value obtained by combining the current timer counter value and the timeout time And a means for comparing the current timer counter value with the timeout value for each monitored object using the storage means, and for performing timeout monitoring for the message or signal from each monitored object at each timeout time for each monitored object. Be prepared.

With such a configuration, it is possible to monitor with different timeout times for each monitoring target, and it is considered that it is suitable for more detailed monitoring of timeout.

Further, unlike the conventional case, the number of counters corresponding to the number of monitoring targets is not required, and even if the number of monitoring targets of the message or signal for which the time-out is monitored increases, the hardware scale of the apparatus becomes very large. Without timeout, timeout monitoring can be done with a very efficient configuration.

[Brief description of drawings]

FIG. 1 is a functional configuration diagram of a timeout monitoring device according to an embodiment of the present invention.

FIG. 2 is a functional configuration diagram of a processing device of a conventional example.

FIG. 3 is a processing flowchart of a conventional example.

FIG. 4 is a timeout value management associative memory (T
It is an explanatory view of a memory map of (CMA).

FIG. 5 is a flowchart of cell processing according to an embodiment.

FIG. 6 is a flowchart of a time control process according to an embodiment.

FIG. 7 is a functional configuration diagram of a timeout monitoring device according to another embodiment.

[Explanation of symbols]

1 ... Passage discard processing unit, 2 ... Timeout value management associative memory (TCAM), 3 ... Timer control unit, 4 ... Timer counter.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H04Q 3/00 (72) Inventor Noriaki Kishino 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. Incorporated (72) Inventor Ken Tanaka 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Shigehiko Ushijima 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation In-house (72) Inventor Katsura Noritake 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. A device for monitoring a time-out of a message or a signal for each monitoring target, a means for detecting the message or the signal, and a timer counter for counting while outputting a counter value for each predetermined unit time. A means for fetching a counter value from the timer counter as a current timer counter value in accordance with the detected message or signal, a storage means for storing a timeout value for judging a timeout for the message or signal, A timer counter value and a timeout value for each monitored object with respect to the message or signal are compared using the storage means, and means for performing timeout monitoring with respect to the message or signal for each monitored object is provided. Timeout monitoring device. 2. A device for performing timeout monitoring of a message or a signal for each monitoring target, a means for detecting the message or the signal, a timer counter for counting every predetermined unit time and outputting a counter value, A means for fetching a counter value from the timer counter as a current timer counter value in accordance with the message or signal described above, a table in which a timeout time for each monitored object is registered, and the current timer counter value and the timeout time are combined. The storage means for storing the time-out value and the current timer counter value and the time-out value for each monitored object are compared using the above-mentioned storage means, and the message from each monitored object at each time-out time for each monitored object is compared. Or a means for performing time-out monitoring for signals A timeout monitoring device characterized by the above. 3. The time-out monitoring device according to claim 1 or 2, wherein the storage means comprises an associative memory.