JP2007037014A - Contention control method and contention control program for polling signals - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably detect an establishing state of a session by the polling signals by avoiding the contention between the transmitted signal and the received polling signal. <P>SOLUTION: In the contention control method for the polling signals adopting the session control protocol with which communication nodes (a sender side communication node 1 and a receiver side communication node 2) are in compliance wherein the communication nodes detect an establishing state of a signal communication path by means of the polling signals and transmit the polling signals to each other through the signal communication path established between the communication nodes, the sender side communication node 1 for transmitting a polling signal transmits the polling signal at a prescribed polling interval through the signal communication path. The receiver side communication node 2 for receiving the polling signal calculates a time when the reception of the polling signal is estimated on the basis of the polling interval and suppresses transmission of the polling signal through the signal communication path in the vicinity of the calculated time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polling signal contention control method and a contention control program between communication nodes that perform polling periodically on a signal session between communication nodes.

  In a computer or network device connected via a network, when there is no communication from a communication partner for a long time, a method of detecting whether there is no communication because there is no data to be transmitted, or whether it is down or not There is no. In connection type communication that virtually establishes a communication path (session) to send and receive data, if the communication partner ends abnormally without a signal to end communication, the session cannot be closed forever. End up.

  For this reason, in many applications, a polling signal is transmitted to the partner device at regular intervals, and the partner device that receives this polling signal is used to inform the partner device that it is “alive”. Designed to send a response signal. This is called “keep alive”.

By the way, when a conflict between an operation performed by the operator and preset polling occurs in the same device, the priority of the operator's operation is increased, and during that time, the suspended polling is performed by the operator's operation. There has been proposed a mechanism for improving the certainty of polling by executing it upon completion (see, for example, Patent Document 1 (paragraphs 0009 to 0010, FIG. 1)).
JP-A-7-162426

  However, when performing polling set in advance in a network system capable of transmitting and receiving signals at any timing on a session between nodes as disclosed in Patent Document 1, a polling signal and the polling signal are received. Conflicts can occur when other signals transmitted by a node pass on the network or within its receiving node. In this case, an appropriate response to the polling signal cannot be transmitted, and as a result, the polling may fail as shown in FIG.

  The present invention has been made on the basis of the above circumstances, and avoids contention between a signal to be transmitted and a polling signal to be received at a communication node on the receiving side that receives the polling signal. It is an object of the present invention to provide a polling signal contention control method and contention control program that enable stable detection.

  In order to solve the above-described problem, the present invention provides a polling signal contention in a communication node that detects the establishment state of the signal communication path by a polling signal transmitted to the opposite communication node through a signal communication path established between the communication nodes. In the control method, a first communication node that transmits the polling signal transmits a polling signal through the signal communication path at a predetermined polling interval, and a second transmission node that receives the polling signal. A communication node calculates a time estimated to receive the polling signal based on the polling interval, and has a suppression step of suppressing signal transmission through the signal communication path in the vicinity of the calculated time. Is a competition control method characterized by

  According to the present invention, in the invention described above, the first transmission step includes information on the polling interval transmitted from the second communication node by the first communication node that transmits the polling signal. Receiving a signal, transmitting a polling signal through the signal communication path based on the polling interval included in the received signal, and the suppressing step includes: a second communication node that receives the polling signal includes the polling interval and A time estimated to receive the polling signal is calculated based on a time point when a signal including the polling interval information is transmitted to the first communication node, and a signal through the signal communication path is calculated from the calculated time. It is characterized by suppressing transmission.

  According to the present invention, in the invention described above, in the suppression step, the second communication node that receives the polling signal is transmitted from the first communication node and the polling interval and a signal transmitted by the second communication node. A time estimated to receive the polling signal is calculated based on a point in time when a conflict with the polling signal is detected, and signal transmission through the signal communication path is suppressed from the calculated time.

  According to the present invention, in the above-described invention, the second communication node cancels the suppression of signal transmission through the signal communication path after a predetermined time, holds the signal to be suppressed, and cancels the suppression. And a second transmission step of transmitting the suppressed signal to the first communication node when it is performed.

  According to the present invention, in the above-described invention, the computer of the second communication node detects the establishment state of the signal communication path by a polling signal transmitted to the opposite communication node through the signal communication path established between the communication nodes. Calculating a time estimated to receive the polling signal based on a predetermined polling interval at which the polling signal is transmitted by the first communication node of the polling signal, and the signal communication in the vicinity of the calculated time This is a contention control program for executing a procedure for suppressing signal transmission through a road.

  According to the present invention, a polling signal contention control method in a communication node that detects the establishment state of a signal communication path by a polling signal transmitted to an opposite communication node through a signal communication path established between the communication nodes includes: The first communication node to transmit transmits the polling signal through the signal communication path at a constant polling interval, and the second communication node that receives the polling signal receives the polling signal based on the polling interval. Calculating an estimated time, and suppressing signal transmission through the signal communication path in the vicinity of the calculated time. As a result, signal transmission by the second communication node is suppressed in the vicinity of the time estimated to receive the polling signal, and contention with the polling signal transmitted from the first communication node can be avoided. Become. As a result, the second communication node can reliably transmit a response to the polling signal received from the first communication node, and can stably detect the establishment state of the signal communication path.

  According to the present invention, the first communication node that transmits the polling signal receives the signal including the polling interval information transmitted from the second communication node, and sets the polling interval included in the received signal. A polling signal is transmitted based on the signal communication path, and the second communication node receives the polling signal based on the polling interval and a time point when the signal including the polling interval information is transmitted to the first communication node. The signal transmission through the signal communication path is suppressed from the calculated time. Thereby, it is possible to calculate the time estimated to receive the polling signal based on the polling interval and the time when the signal including the polling interval information is transmitted, and from the time estimated to receive the calculated polling signal. The terminating communication node can suppress signal transmission.

  Further, according to the present invention, the second communication node generates a polling signal based on a polling interval and a time point when a conflict between the signal transmitted by itself and the polling signal transmitted from the first communication node is detected. The time estimated to be received is calculated, and signal transmission through the signal communication path is suppressed from the calculated time. Thus, the time estimated to receive the polling signal can be calculated based on the polling interval and the time when the signal including the polling interval information is transmitted, and the time estimated to receive the calculated polling signal Thus, the second communication node can suppress signal transmission.

  Further, according to the present invention, the second communication node releases the suppression of signal transmission through the signal communication path after a predetermined time, holds the suppressed signal, and when the suppression is released, the first communication node And a step of transmitting the suppressed signal to one communication node. As a result, a signal whose transmission is suppressed by the second communication node is held, and after the processing of the polling signal is completed, the signal which has been suppressed is transmitted to the first communication node, thereby receiving a transmission request again. The necessary signal can be transmitted without any problem.

FIG. 1 is a block diagram showing an internal configuration of a communication node (network device) that executes a polling signal conflict control method according to an embodiment of the present invention.
Here, each network device includes a higher-level application unit 11 and a session control protocol unit 12. The upper application unit 11 issues a packet transmission / reception request to the session control protocol unit 12, and the session control protocol unit 12 realizes keep-alive and transmits / receives packets according to a protocol such as SIP (Session Initiation Protocol). Do.

The session control protocol unit 12 includes a time management unit 121, a suppression determination unit 122, and a polling execution unit 123.
The time management unit 121 monitors the polling interval by counting the time, and instructs the polling execution unit 123 to transmit a polling signal when a predetermined time is reached. In addition, the deterrence determining unit 122 calculates a time estimated to receive a polling signal to the polling execution unit 123 when the preset condition is met, and polling is performed when the calculated time is reached. The execution unit 123 starts suppression.

  The polling execution unit 123 selects a communication node to perform polling, transmits a polling signal according to an instruction from the time management unit 121, and transmits a response signal when the polling signal is received. In addition, when a signal requested from the upper application 11 is transmitted and a suppression instruction from the suppression determination unit 122 is received, a specific signal transmission request from the higher application 11 is suppressed.

FIG. 2 is a communication sequence diagram quoted for explaining the processing procedure of the embodiment of the present invention.
In FIG. 2, reference numerals 1 and 2 are both communication nodes, and for convenience, reference numeral 1 is an outgoing communication node 1 and reference numeral 2 is an incoming communication node 2, both of which are described in FIG. The originating communication node 1 includes an upper application unit 11 and a session control protocol unit 12, and the receiving communication node 2 includes an upper application unit 21 and a session control protocol unit 22. It is equipped with. In the session control protocol unit 22, the time management unit 221, the suppression determination unit, and the polling execution unit included in the session control protocol unit described with reference to FIG. The following description will be given with reference to the inhibition determination unit 222 and the polling execution unit 223.
In FIG. 2, it is assumed that the condition set in advance in the suppression determination unit 222 is a point in time when a response signal including information on “polling interval” described later and information indicating “which performs polling” is transmitted. .

First, the session control protocol unit 12 that has received a request signal request from the upper application unit 11 of the originating communication node 1 (step S21) transmits the request signal to the terminating communication node 2 that is the opposite node (step S22). The request signal is received by the session control protocol unit 22 of the receiving communication node 2, and is notified to the upper application unit 21 as a request signal notification (step S23).
The upper application unit 21 transmits a response signal request to the session control protocol unit 22 (step S24), and the session control protocol unit 22 that has received the request transmits a response signal to the originating communication node 1 that is the opposite node ( Step S25).

The terminating communication node 2 enters a session establishment state by transmitting a response signal. In the response signal, information on “polling interval” and information indicating “which communication node performs polling” are described. Here, a description will be given assuming that information for polling by the calling communication node 1 is set.
The session control protocol unit 12 of the originating communication node 1 that has received the response signal notifies the higher-level application unit 11 of a response signal notification (step S26). At the same time, the session control protocol unit 12 uses the time management unit 121 to measure the elapsed time from the time when the response signal is received or the time when the previous polling signal is transmitted, and polling is performed when the elapsed time matches the polling interval. The unit 123 is caused to generate a polling signal (polling request signal shown in FIG. 2), and transmit the generated polling signal to the receiving communication node 2 which is the opposite node (step S27).

  On the other hand, the deterrence determining unit 222 of the session control protocol unit 22 of the receiving communication node 2 is estimated to receive the polling signal based on the timing of transmitting the response signal and the polling interval included in the response signal. And when the calculated time comes, polling is issued to start suppression so that a predetermined signal from the upper application unit 21 is not transmitted to the originating communication node 1 which is the opposite node. To the unit 223.

  Here, the estimated time means that there is a time difference due to communication delay between the timing at which the terminating communication node transmits the response signal and the timing at which the originating communication node 1 receives the response signal. Even when the communication node 1 transmits a polling signal and the receiving communication node 2 receives it, a time difference due to communication delay exists. Therefore, a polling interval is added to the response signal transmission time, and the time difference is calculated. It's time.

  When the terminating communication node 2 receives a request signal request corresponding to a predetermined signal from the upper application unit 21 while the suppression is enabled (step S28), the terminating communication node 2 of the session control protocol unit 22 The polling execution unit 223 does not transmit the corresponding request signal to the transmission side communication node 1 that is the opposite node, but holds it in the internal storage area or the like (the hatched portion in FIG. 2 “block start”).

  After that, the session control protocol unit 22 of the receiving communication node 2 that has received the polling signal processes the polling signal at the polling execution unit 223 and sends a response signal corresponding to the polling signal (the polling response signal shown in FIG. 2). After transmitting to the originating communication node 1 which is the opposite node, the suppression is canceled (step S29). Then, the session control protocol unit 22 detects the presence of the request signal request whose transmission is suppressed after the suppression is canceled, and if there is, the session control protocol unit 22 sends the corresponding request signal to the session control protocol unit of the originating communication node 1. 12 (step S30). On the other hand, if it does not exist, the process ends. The request signal to be transmitted is received by the session control protocol unit 12, and is notified from the session control protocol unit 12 to the upper application synthesizing unit 11 (step S31).

  In the above processing, as a condition set in advance in the suppression determination unit 222, it is a time point when a response signal including information on “polling interval” described later and information indicating “which performs polling” is transmitted. However, in addition to the above conditions, for example, the time when an error response signal to be transmitted to the opposite communication node when contention occurs may be set as the condition. Further, the suppression may not be canceled after the polling response signal is transmitted, but may be canceled after a predetermined time has elapsed.

FIG. 3 is a diagram showing a specific communication sequence of the session control protocol when SIP is used as the session control protocol.
In FIG. 3, first, the session control protocol unit 12 that has received the INVITE transmission request (S21: request signal request) from the upper application unit 11 of the originating communication node 1 sends the INVITE transmission request (S22: request signal) to the opposite node. It transmits to a certain incoming communication node 2. The INVITE is notified to the upper application unit 21 as an INVITE reception notification (S23: request signal notification) received by the session control protocol unit 22 of the receiving communication node 2 (step S301).

The host application unit 21 transmits a 200 response transmission request (S24: response signal request) to INVITE to the session control protocol unit 22, and the session control protocol unit 22 that has received this transmits a 200 response to INVITE (S25: response signal). Is transmitted to the caller communication node 1 which is the opposite node (step S302).
As described above, by transmitting a 200 response to INVITE, the receiving communication node 2 enters a session established state. In the Session-Expires header of the 200 response to INVITE, information on “polling interval” and information indicating which communication node performs polling are described. Here, it is assumed that polling is performed by the originating communication node.

The session control protocol unit 12 of the originating communication node 1 that has received the 200 response to INVITE notifies the upper application unit 11 of a 200 response reception notification (S26: response signal notification) to INVITE.
At the time when the polling interval is reached, the session control protocol unit 12 of the caller communication node 1 sends a session refresh re-INVITE or UPDATE (S27: polling request signal) to the callee communication node 2 that is the opposite node. Transmit (step S303).

The session control protocol unit 22 of the receiving communication node 2 receives re-INVITE and UPDATE (predetermined signal) from the upper application unit 21 for a certain period of time at the opposite node when the polling interval is reached. Suppression is started so as not to transmit to a certain originating communication node 1.
Note that SIP has a function of recognizing the passing of polling signals by returning a specific response, so that the suppression starts upon receipt of the error response and the polling signal is retransmitted during that time. You may make it make it the node 1.

When the receiving side communication node 2 receives the re-INVITE and UPDATE transmission request (S28: request signal request) from the higher-order application unit 21 while the suppression is valid, the receiving side communication node 2 faces the re-INVITE and UPDATE transmission request. Without being transmitted to the originating communication node 1, which is a node, it is held internally.
Upon receiving the session refresh re-INVITE or UPDATE, the session control protocol unit 22 of the callee side communication node 2 sends a 200 response (S29: polling response signal) to the session refresh re-INVITE or UPDATE as the opposite node. It transmits to the node 1 and cancels the inhibition (step S304).

  After the suppression is canceled by the receiving communication node 2, the presence of the re-INVITE and UPDATE transmission request received from the upper application unit 21 is detected, and if there is, the re-INVITE and UPDATE are transmitted (step S305).

  The first communication node described in the appended claims corresponds to the originating communication node that transmits the request signal in the above embodiment, and the second communication node receives the communication on the receiving side that receives the request signal. Added to correspond to nodes. However, in this embodiment, whether or not the communication node becomes the polling signal transmission side is determined based on the information indicating “which is polling” in the response signal in step S25 of FIG. In some cases, the node transmits a polling signal. At this time, the incoming communication node becomes the first communication node, and the outgoing communication node becomes the second communication node.

As described above, according to the present invention, in the session control protocol for detecting the session establishment state by the polling signal transmitted to the opposite communication node, the terminating communication node 2 that receives the polling signal transmitted from the originating communication node 1. However, by suppressing the transmission of the signal in the vicinity of the time estimated to receive the polling signal, the incoming communication node 2 is surely connected to the outgoing communication node 1. It is possible to transmit a response to the polling signal received from the terminal, and to detect the session establishment state, that is, keep alive stably.
In addition, a signal whose transmission is suppressed in the receiving communication node 2 is held, and after the processing of the polling signal is completed, the suppressed signal is transmitted to the communication node 1 on the transmission side, thereby receiving a transmission request again. The necessary signal can be transmitted without any problem.

  The procedure executed by each of the time management unit, the suppression determination unit, and the polling execution unit constituting the upper application unit and the session control protocol unit shown in FIG. 1 is recorded on a computer-readable recording medium. The present invention can be realized by causing a computer system to read and execute the program recorded in the above. The computer system here includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW (World Wide Web) system is used.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes designs and the like that do not depart from the gist of the present invention.

It is a block diagram which shows the internal structure of the communication node which performs the competition control method of the polling signal which concerns on this invention embodiment. It is the communication sequence diagram quoted in order to demonstrate the process sequence of the computer program which concerns on this invention embodiment. It is a figure which shows the specific communication sequence in the case of implement | achieving this invention using SIP. It is a figure which shows the conventional communication sequence.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Originating side communication node, 2 ... Incoming side communication node, 11, 21 ... Upper application part, 12, 22 ... Session control protocol part

Claims (5)

A polling signal contention control method in a communication node for detecting an established state of the signal communication path by a polling signal transmitted to a facing communication node through a signal communication path established between communication nodes,
A first transmission step in which the first communication node that transmits the polling signal transmits the polling signal through the signal communication path at a constant polling interval;
The second communication node that receives the polling signal calculates a time estimated to receive the polling signal based on the polling interval, and transmits a signal through the signal communication path in the vicinity of the calculated time. A deterrence step to deter,
The contention control method characterized by having. The first transmission step includes:
A first communication node that transmits the polling signal receives a signal including information on the polling interval transmitted from the second communication node, and a polling signal based on the polling interval included in the received signal Is transmitted through the signal communication path,
The inhibiting step includes
It is estimated that the second communication node that receives the polling signal receives the polling signal based on the polling interval and a time point at which a signal including the polling interval information is transmitted to the first communication node. The contention control method according to claim 1, wherein a signal transmission time is calculated, and signal transmission through the signal communication path is suppressed from the calculated time. The inhibiting step includes
The polling signal based on the polling interval and a time point when the second communication node that receives the polling signal detects a conflict between the polling signal and the signal transmitted by itself and the polling signal transmitted from the first communication node. 3. The contention control method according to claim 1, wherein a time estimated to be received is calculated, and signal transmission through the signal communication path is suppressed from the calculated time. The second communication node is
A release step of releasing the suppression of signal transmission through the signal communication path after a predetermined time;
A second transmission step of holding a signal to be suppressed and transmitting the signal to be suppressed to the first communication node when the suppression is released;
The contention control method according to any one of claims 1 to 3, wherein A computer of the second communication node that detects the establishment state of the signal communication path by a polling signal transmitted to the opposite communication node through the signal communication path established between the communication nodes.
A time estimated to receive the polling signal is calculated based on a fixed polling interval at which the polling signal is transmitted by the first communication node of the polling signal, and the signal communication path near the calculated time The procedure of deterring signal transmission through
A contention control program that executes

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