JP2005303900A - Communication control apparatus, program and recording medium for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a communication system wherein an End-to-End transmission data loss rate can be optimally adjusted when controlling transmission quality in real-time communication over one or more nodes. <P>SOLUTION: A communication control apparatus 100 monitors a transmission data loss rate between nodes and if a result of monitoring meets predetermined conditions, a transmission delay time allowable between the nodes is reset, thereby reducing an End-to-End transmission data loss rate. Thus, in the case of communication via a communication path over one or more nodes, a setting value of the transmission delay time allowable between the nodes can be changed and set based on the transmission data loss rate measured between the nodes, thereby decreasing the value of the End-to-End transmission data loss rate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication control apparatus for ensuring transmission quality on a network, a program for operating the communication control apparatus, and a recording medium on which the program is recorded.

In recent years, as various services are provided on an IP (Internet Protocol) network, a request for ensuring transmission quality on a transmission path in order to provide a higher quality service, so-called QoS (Quality Of Service). Requests are being made. In general, services on a network configured by IP are communicated via a plurality of nodes. Therefore, in order to ensure transmission quality on the transmission path, transmission quality control across a plurality of nodes is required. As a technique for ensuring transmission quality across a plurality of nodes, for example, there is a method as disclosed in Patent Document 1. In Patent Document 1, by monitoring the line usage rate between each node, by identifying the node causing the deterioration of the transmission quality in End To End, and increasing the bandwidth between the nodes. The transmission quality in End To End is going to be improved.
JP 2003-293917 (release date: September 26, 2003)

  Here, regarding services provided on an IP network, in recent years, so-called real-time communication such as video communication and VoIP (Voice over IP) has been provided. In real-time communication, unlike file transfer, there is a stronger demand for transmission delay time. Therefore, as transmission quality of real-time communication, it is required to secure a necessary transmission band and transmit data within a predetermined time while allowing a certain amount of transmission data loss.

  Furthermore, there is a trade-off relationship between transmission data loss and transmission delay time. In order to reduce the transmission delay time, there is a method of limiting the number of times of retransmission processing and the time when an error occurs on the physical medium, but as a result of the limitation, the loss rate of transmission data increases. Conversely, if the number of retransmission processes is increased in order to suppress the loss rate of transmission data, the transmission delay time increases.

  That is, in real-time communication, it is necessary to control transmission quality in consideration of this relationship. Further, in communication across a plurality of nodes, the total transmission delay time between the nodes becomes the transmission delay time of End To End, so that the transmission quality between the nodes satisfies the requirement so that the total between the nodes satisfies the request. It is necessary to control. As for transmission data loss, it is required to reduce occurrence as much as possible within a predetermined transmission delay time.

  However, in Patent Document 1, no consideration is given to requirements in real-time communication, and transmission quality in such communication cannot be ensured / improved. The present invention has been made to solve such a problem, and an object of the present invention is to realize transmission quality securing / improvement in real-time communication across a plurality of nodes.

  In order to solve the above problem, the communication control device according to the present invention provides data via a transmission path that passes through one or more specific nodes that can retransmit error data when a transmission error occurs within a preset transmission delay allowable time. A communication control apparatus for performing transmission control in communication, wherein among the nodes on the transmission path, the transmission delay allowable time is set for a plurality of nodes having the specific node as an end, and Transmission delay time control means for notifying the specific node at the end between the nodes, and monitoring for monitoring the transmission data loss rate between the nodes having at least the allowable transmission delay time among the nodes on the transmission path The transmission delay time control means resets a transmission delay allowable time between the nodes based on the monitoring result of the transmission data loss rate, and It is characterized by notifying the over de.

  In the above configuration, when data is transmitted via a transmission path that passes through at least one specific node, the transmission delay time control means of the communication control apparatus transmits a transmission delay between a plurality of nodes having the specific node as an end. Set the allowable time.

  Therefore, the transmission quality of communication across a plurality of nodes can be ensured / improved as compared with the configuration in which the transmission delay allowable time is controlled by simply focusing on one node. In particular, when performing real-time communication, it is desired that the transmission delay time be set to a predetermined value or less between the transmission device and the reception device. Therefore, the communication control device capable of ensuring / improving the quality of data transmission via the transmission path by setting the allowable transmission delay time between a plurality of nodes on the transmission path of the real-time communication can be particularly preferably used. .

  In the above configuration, the transmission data loss rate between the nodes is monitored, and the allowable transmission delay time between the nodes is reset based on the monitoring result of the transmission data loss rate. Accordingly, the transmission delay allowable time between the nodes can be determined (distributed) in accordance with the state of the transmission path (the state of the communication system). As a result, the allowable transmission delay time between the nodes can be determined more accurately, and the quality of data communication via the transmission path can be further improved.

  For example, by giving more transmission delay time between nodes with a high transmission data loss rate, nodes at both ends between the nodes can allocate more time for retransmission processing when an error occurs. Transmission data loss rate can be reduced. In addition, by providing a smaller allowable transmission delay time between nodes having a low transmission data loss rate, a larger allowable transmission delay time can be provided between nodes having a high transmission data loss rate.

  Note that the nodes for which the monitoring unit monitors the transmission data loss rate may not be between all the nodes on the transmission path as long as they are at least the nodes for which the transmission delay allowable time is set. If the interval is monitored, the transmission delay allowable time between the nodes can be determined more accurately, and the quality of data communication through the transmission path can be further improved.

  Further, the transmission delay time control means compares the transmission data loss rates between the plurality of nodes with each other if the transmission delay allowable time set between the plurality of nodes can be reset based on the monitoring result of the transmission data loss rate. Then, the transmission delay allowable time between the nodes may be set, or based on the predetermined transmission data loss rate and the transmission data loss rate between the nodes obtained by monitoring by the monitoring means, A transmission data loss rate between nodes may be set. However, by comparing the transmission data loss rates between a plurality of nodes and setting the allowable transmission delay time between the nodes, the allowable transmission delay time between the nodes can be set more accurately.

  Further, in addition to the above-described configuration, the transmission delay time control means may transmit the transmission path between the two devices so that the total transmission delay time between the transmission side device and the reception side device is a predetermined value or less. An allowable transmission delay time between the above nodes may be allocated.

  According to this configuration, the allowable transmission delay time between the nodes on the transmission path between the two devices so that the total transmission delay time between the transmitting device and the receiving device is equal to or less than a predetermined value. Therefore, the total transmission delay time between the transmission side apparatus and the reception side apparatus can be set to be equal to or less than the predetermined value. As a result, by using the communication control device, it is possible to realize a communication system that can guarantee that the total transmission delay time between the transmission side device and the reception side device is equal to or less than a predetermined value.

  In addition to the above configuration, the transmission delay time control means compares the transmission data loss rate between the nodes, and if the comparison result satisfies a predetermined condition, the transmission delay allowable time between the nodes. May be changed. The transmission delay time control means may change the allowable transmission delay time according to the transmission data loss rate when changing the allowable transmission delay time between the nodes.

  In the above configuration, when the transmission data loss rates between the nodes are compared and the comparison result satisfies a predetermined condition, the transmission delay allowable time between the nodes is changed. Therefore, for example, the relationship between the transmission data loss rates between the nodes such as the relationship in which the transmission data loss rates between the nodes are greatly different from each other does not become a relationship that deteriorates the quality of the data communication via the transmission path. The allowable transmission delay time between the nodes can be changed, and the quality of data communication through the transmission path can be ensured / improved.

  Further, in addition to the above configuration, the transmission delay time control means changes the allowable transmission delay time between the nodes when there is a difference greater than a preset value between the transmission data loss rates of the nodes. May be. The difference may be a difference between the absolute values of the transmission data loss rates, or may be a relative difference obtained after normalizing each transmission data loss rate with one value.

  In the said structure, when there exists a difference more than the preset value between the transmission data loss rates of each said node, the transmission delay allowable time between each said node is changed.

  Therefore, when the transmission data loss rate between one node and the transmission data loss rate between other nodes is not balanced, the transmission delay between the nodes is adjusted so that the transmission data loss rates are balanced. The allowable time can be changed, and the quality of data communication through the transmission path can be ensured / improved.

  In addition to the above configuration, the transmission delay time control means may set the allowable transmission delay time between the nodes so that the allowable transmission delay time between nodes having the maximum transmission data loss rate is increased. Good.

  In this configuration, the allowable transmission delay time between the nodes is set so that the allowable transmission delay time between nodes having the maximum transmission data loss rate is increased. Therefore, the transmission data loss rate between nodes having the maximum transmission data loss rate can be reduced, and the quality of data communication via the transmission path can be ensured / improved.

  Further, in addition to the above configuration, the transmission delay time control means may set the allowable transmission delay time between the nodes so that the allowable transmission delay time between the nodes having the smallest transmission data loss rate is reduced. Good.

  In this configuration, between nodes that have a minimum transmission data loss rate, that is, between nodes that are unlikely to degrade the quality of data communication via the transmission path even if the transmission delay allowable time is increased as compared with other nodes. The allowable transmission delay time between the nodes is set so that the allowable transmission delay time increases. Therefore, it is possible to increase the transmission delay allowable time between other nodes without significantly degrading the quality of data communication via the transmission path. As a result, the quality of data communication via the transmission path can be ensured / improved as a whole.

  In addition to the above-described configuration, the transmission delay time control means may be configured to allow the transmission data loss rate between the nodes for which the monitoring means is monitoring the transmission data loss rate to fall within a predetermined range. The allowable transmission delay time may be set.

  In this configuration, since the transmission delay allowable time between the nodes is set so that the total of the transmission data loss rates between the nodes monitoring the transmission data loss rate falls within a predetermined range, As a whole, the quality of data communication through the transmission path can be ensured / improved.

  Further, in addition to the above configuration, the transmission delay time control means may allow the transmission delay allowable time between the nodes when there is a change in the monitoring result of the transmission data loss rate between any nodes on the transmission path. May be reset to notify each node on the transmission path.

  According to this configuration, when there is a change in the monitoring result of the transmission data loss rate between any nodes on the transmission path, the allowable transmission delay time between the nodes is reset, so the transmission path state In addition, the allowable transmission delay time between the nodes can be determined. As a result, the allowable transmission delay time between the nodes can be determined more accurately, and the quality of data communication via the transmission path can be further ensured / improved.

  By the way, each means of the said communication control apparatus may be implement | achieved by hardware, and may be implement | achieved by making a computer run a program. Specifically, the program according to the present invention performs transmission control in data communication through a transmission path that passes through one or more specific nodes that can retransmit error data when a transmission error occurs within a preset transmission delay allowable time. A communication control program for setting a transmission delay allowable time between a plurality of nodes having the specific node as an end among the nodes on the transmission path. A transmission delay time control function for notifying the specific node at the end, and a monitoring function for monitoring a transmission data loss rate between nodes set with at least the allowable transmission delay time among the nodes on the transmission path. The transmission delay time control function is a program for realizing in a computer, and the transmission delay time control function is based on the monitoring result of the transmission data loss rate. Reconfigure the extension allowed time, it is characterized in that the function for notifying the particular node. The program is recorded on the recording medium according to the present invention.

  When these programs are executed by a computer, the computer operates as the communication control device. Therefore, similarly to the communication control apparatus, it is possible to realize a communication system capable of ensuring / improving transmission quality of communication across a plurality of nodes.

  According to the present invention, a communication system capable of ensuring / improving transmission quality of communication across a plurality of nodes can be realized. Therefore, as a communication control apparatus that controls transmission in data communication, including a communication control apparatus that controls real-time communication. Can be used widely and suitably.

〔Example〕
Embodiments of the communication control apparatus of the present invention will be described below. In the present embodiment, in real-time communication via one node, the transmission data loss rate at End To End is reduced while the request for transmission delay time at End To End is maintained at a predetermined value.

Here, the transmission data loss rate indicates the ratio of data transmitted from the transmitting device and data that could not be received by the receiving device. For example, if the number of transmitted bytes is n1 and the number of received bytes is n2, formula (n1-n2) / n1
Can be calculated.

  FIG. 1 is an example of a network system in which a communication control apparatus according to an embodiment of the present invention operates. For example, a system in which home devices such as a television and a hard disk recorder (hereinafter, HDR) are connected via a network. For communication between devices, for example, a network protocol such as IP is used.

  In FIG. 1, a communication control apparatus 100 is an apparatus that performs transmission quality control of real-time communication in order to reduce a transmission data loss rate at End To End, and corresponds to the communication control apparatus described in the claims. . In the present embodiment, the communication control device 100 is realized by a computer in which a program for performing the transmission quality control process is installed, and the program corresponds to the program described in the claims.

  The first device 101 is a data transmission device in real-time communication controlled by the communication control device 100. For example, an HDR or a video deck connected to a home network.

  The first relay device 102 is a blitching device for interconnecting network nodes of different communication media. In the present embodiment, the first relay device 102 is a wireless communication 802.11e capable of controlling transmission quality standardized by Power Line Data (PLC) and IEEE (American Institute of Electrical and Electronics Engineers). And three Ethernet (registered trademark) communication media that are generally used in the configuration of LAN, and can be connected to each other. In the present embodiment, a PLC is provided between the first device 101 and the first relay device 102 and between the first relay device 102 and the second relay device 105, and between the second device 103 and the first relay device 102. The communication control device 100 and the first device 101 are connected by Ethernet (registered trademark).

  The second device 103 is a data receiving device in real-time communication controlled by the communication control device 100. For example, a television connected to a home network. In this system, it is possible to output moving image data from the first device 101 to the second device 103 via the first relay device 102. For this output processing, for example, a protocol such as RTP (Real Time Protocol) is used. Also, by operating the second device 103, it is possible to send a command to the first device 101 and control the start and stop of playback. For this control process, for example, a protocol such as UPnP AV (Universal Plug And Play AV) is used. The other device 104 and the other device 106 are other components in the home network, and the second relay device 105 is a device for interconnecting them. For example, as an example of the other devices 104 and 105, a microwave oven, a refrigerator, a PC (personal computer), and the like can be considered. The second relay device 105 has a function similar to that of the first relay device 102.

  FIG. 2 is a diagram showing an internal configuration of communication control apparatus 100 in the embodiment of the present invention. The internal configuration is realized by a general-purpose computer configuration. A network connection unit 201 for connecting to a network, a RAM 202 used also as a work area, a recording unit 205 such as a hard disk, a ROM 206 and a CPU 207 as a nonvolatile memory. Are connected to the bus 204. In the present embodiment, the display device 203 and the input unit 208 are also connected to the bus 204, and the CPU 207 may receive a user operation on the input unit 208 or display a calculation result on the display device 203. it can. Since these are general-purpose computer configurations, detailed description of each part will not be given here. In this embodiment, the transmission quality control program is stored on the recording unit 205 such as a hard disk or the ROM 206. When the transmission quality control program is activated, it is loaded on the RAM 202 and executed by the CPU 207. Thus, the general-purpose computer functions as the communication control device 100. If necessary, the CPU 207 may control peripheral circuits such as the network connection unit 201 according to these programs. In the present embodiment, the network connection unit 201 is an Ethernet (registered trademark) connection interface.

  Next, the flow of control when executing real-time communication according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing an example of a control flow when executing real-time communication according to the embodiment of the present invention. Here, an example will be described in which the first and second devices 101 and 103 shown in FIG. 1 are an HDR and a television, respectively, and moving image content recorded on the HDR 101 is reproduced on the television 103 by real-time communication. In this case, the HDR 101 corresponds to the transmission side device described in the claims, and the television 103 corresponds to the reception side device. In this case, since the data transmission between the both devices 101 and 103 is performed via the first relay device 102, the first relay device 102 corresponds to a node and a specific node.

  The reproduction of the moving image content is started when the user selects the moving image content by operating the remote controller of the television 103 or the like. That is, when the television 103 receives an instruction to display moving image content (S302), the television 103 determines values of various parameters necessary for the transmission quality request from the content (S304).

  As an example, when receiving a content list display instruction from the user, the television 103 issues a list acquisition request to the HDR 101, acquires a list of content data stored in the HDR 101, and displays the list on the screen. To prompt the user to select content. When receiving a content designation instruction from the user, the television 103 determines the values of various parameters necessary for the transmission quality request from the content of the selected content.

  For example, the required bandwidth: 24 Mbps, the required transmission delay time: 100 msec, and the required transmission data loss rate: 0.01% are determined. However, the request for the transmission data loss rate here is only a desired value, and is permitted even when the value is not satisfied.

  When the necessary value is determined in S304, the television 103 generates a message (hereinafter referred to as an inter-End QoS request) for making a transmission quality control request between the HDR 101 and the television 103, and sends it to the communication control apparatus 100. It transmits to (S306).

  Upon receiving the end-to-end QoS request from the television 103, the communication control apparatus 100 determines a permissible transmission delay time (transmission delay permissible time) set for each node (S308), and sends a transmission quality control request to each node. A message to be performed (hereinafter referred to as inter-node QoS request) is created, and the inter-node QoS request is transmitted to the node on the route (S310). The contents of the processing in S308 and S310 will be described in detail later using a flowchart and the like.

  After that, when receiving a response to the inter-Node QoS request from each node on the route, the communication control apparatus 100 notifies the television 103 of the result (S312). When the television 103 receives the notification of the result and a necessary transmission path is secured, the television 103 sends a generation command to the HDR 101 and starts reproducing the content (S314).

  When data reproduction is started, the communication control apparatus 100 starts monitoring the transmission data loss rate between the nodes. Then, according to the monitoring result, a message for requesting transmission quality change (hereinafter referred to as QoS change request) is sent to each node (S316). By this processing, the allowable value of the transmission delay time allocated between the nodes is reassigned, and the transmission data loss rate at End To End can be reduced. The contents of the process of S316 will be described in detail later using a flowchart and the like. The end of the reproduction is executed when the television 103 receives an end instruction from the user using a remote controller or the like, and notifies the HDR 101 or the communication control apparatus 100 of the instruction (S318).

  Next, detailed contents of processing executed by the communication control apparatus 100 in the embodiment of the present invention will be described.

  FIG. 4 is a block diagram showing an outline of functional blocks realized by the CPU 207 of the communication control apparatus 100 executing the above-described transmission quality control program. Specifically, the communication control apparatus 100 includes, as the functional blocks, an end-to-end QoS request reception processing unit 402, a transmission time determination processing unit 403, a transmission quality monitoring processing unit (monitoring means) 404, a transmission time change control execution determination. A processing unit 405 and a transmission time control processing unit (transmission delay time control means) 406 are provided.

  A program for realizing the end-to-end QoS request reception processing unit 402 is executed in conjunction with the activation of the transmission quality control program. The end-to-end QoS request reception processing unit 402 receives the inter-end QoS request transmitted in step S306, and can generate / transmit an inter-node QoS request to each node from the information.

  The message format of the end-to-end QoS request is shown in FIG. The inter-End QoS request includes an address (in this example, an IP address) for identifying a transmitting device and a receiving device as information for identifying an End between which a QoS request is issued, and an inter-End QoS request. The required transmission quality includes required bandwidth, transmission delay time, and transmission data loss rate (denoted as required loss rate in the figure). FIG. 14 is an example of an inter-node QoS request transmitted to each node. As illustrated in FIG. 14, the inter-Node QoS request according to the present embodiment includes an address (in the example of FIG. 14, the first device 101 in the example of FIG. 14) that specifies a node that is a start point and an end point between the nodes from which the QoS request is issued. And the IP address of the second device 103) and information indicating the transmission quality required between the nodes (in this example, necessary bandwidth and required transmission delay time) are included.

  Further, the inter-End QoS request acceptance processing unit 402 can determine to which node an inter-Node QoS request is issued from the network configuration management file 407 based on the information of the inter-End QoS request.

  As shown in FIG. 10, the network configuration management file 407 is a file for recording the device configuration and connection relationship of the network controlled by the communication control apparatus 100. The network configuration management file 407 includes, for example, device names and addresses from all nodes on the network when a member of the communication control device 100 (for example, the end-to-end QoS request reception processing unit 402 or the like) starts the transmission quality control program. It is generated by acquiring information and address information of directly connected devices. The network configuration management file 407 and other files 408 and 409 described later are stored in a recording medium that can be directly or indirectly accessed by the CPU 207, such as the recording unit 205 shown in FIG.

  Further, the inter-End QoS request reception processing unit 402 implements, for example, a transmission time determination processing unit 403 in order to determine an allowable value of the transmission delay time allocated between the nodes necessary for generating the inter-Node QoS request. The operation of the transmission time determination processing unit 403 can be started by causing the CPU 207 shown in FIG. Further, the end-to-end QoS request reception processing unit 402 can also perform input / output to the link management file 408 and the transmission quality setting management file 409 in order to acquire and record execution results and setting contents.

  Further, the inter-End QoS request reception processing unit 402 acquires the transmission data loss rate between the nodes when all the inter-Node QoS requests are successful, and allows the transmission delay time allocated between the nodes according to the situation. In order to reset the value, for example, the operation of the transmission quality monitoring processing unit 404 can be started by starting a program for realizing the transmission quality monitoring processing unit 404 as a separate process.

  When the inter-End QoS request reception processing unit 402 or a transmission time control processing unit 406 (to be described later) instructs the transmission time determination processing unit 403 to determine the allowable value of the transmission delay time allocated between the nodes, the transmission time determination processing unit 403 It is possible to determine the allowable value of the transmission delay time assigned to the nodes. Note that the end-to-end QoS request reception processing unit 402 or the transmission time control processing unit 406 described later, for example, causes the CPU 207 to execute a program for realizing the transmission time determination processing unit 403 to determine the allowable value. I can tell you.

  The transmission quality monitoring processing unit 404 can start an operation according to an instruction from the inter-End QoS request reception processing unit 402 or a transmission time control processing unit 406 described later, and from each node after a predetermined time from the start of the operation. By acquiring the transmission data loss rate of the transmission line managed by the node and operating the transmission time control processing unit 406 according to the content, the transmission delay time assigned to each node can be reset. . Whether or not to operate the transmission time control processing unit 406 is determined by the transmission time change control execution determination processing unit 405. In addition, the transmission quality monitoring processing unit 404 can write the acquired transmission data loss rate between the nodes in the transmission quality setting management file 409. The end-to-end QoS request reception processing unit 402 and the transmission time control processing unit 406 start the operation of the transmission quality monitoring processing unit 404 by, for example, starting a program for realizing the transmission quality monitoring processing unit 404. The transmission quality monitoring processing unit 404 can operate the transmission time control processing unit 406, for example, by starting a program for realizing the transmission time control processing unit 406. In addition, the transmission time change control execution determination processing unit 405 can control whether to operate the transmission time control processing unit 406 depending on, for example, whether to execute a program for realizing the transmission time control processing unit 406. .

  The transmission time change control execution determination processing unit 405 starts operation according to an instruction from the transmission quality monitoring processing unit 404, and can determine whether or not to operate a transmission time control processing unit 406 described later according to a predetermined algorithm. The transmission quality monitoring processing unit 404 can start the operation of the transmission time change control execution determination processing unit 405 by executing a program for realizing the transmission time change control execution determination processing unit 405, for example. it can.

  The transmission time control processing unit 406 is a processing unit for changing the transmission delay time. According to the algorithm for determining the transmission time, the transmission delay time allocated between the nodes can be recalculated, and a QoS change request can be sent to each node.

  Next, the contents of each process will be described in detail using a flowchart.

  FIG. 5 is a flowchart showing the control operation of the end-to-end QoS request acceptance processing unit 402. The end-to-end QoS request acceptance processing unit 402 basically operates constantly, and for example, the processing is started at the start of the transmission quality control program and stopped at the end of the transmission quality control program. Therefore, when the inter-End QoS request reception processing unit 402 has not received the inter-End QoS request, the inter-End QoS request reception processing unit 402 determines whether or not to end the following series of processes (S502). A determination is made as to whether or not a request has been received (S504), and if an inter-End QoS request has not been received, a series of processing of waiting for processing for a predetermined time t1 (S506) is repeated.

  If it is determined in S504 that the inter-End QoS request has been received, the inter-End QoS request acceptance processing unit 402 accesses the network configuration management file 407 recorded in the recording unit 205 in S508, and makes a request based on the inter-End QoS request. The communication path is determined when communication is performed with the transmitted transmitter and receiver.

  FIG. 10 shows an example of network configuration information recorded in the network configuration management file 407. FIG. 10 illustrates a case where the device configuration and connection relationship of the network illustrated in FIG. 1 are recorded. For example, the second line in FIG. 10 indicates that “the TV 103 is connected to the first relay device 102”, and the third line indicates that “the first relay device 102 is the TV 103, the HDR 101, The second relay device 105 and the communication control device 100 are connected to each other ”.

  Therefore, when an inter-end QoS request between the television 103 and the HDR 101 is received, from this table, the inter-end QoS request acceptance processing unit 402 indicates that “the television 103 is connected to the HDR 101 via the first relay device 102. The transmission path is determined.

  When the transmission path is determined in S508, the end-to-end QoS request reception processing unit 402 accesses the link management file 408 for managing the end to control the QoS, and acquires an unused link number (S510). ), The following necessary information is written in the record of the corresponding link number (S511).

  FIG. 11 is an example of management information stored in the link management file 408. The information to be written includes a transmission node and a reception node as information for identifying the end, a state between the end, a required bandwidth as a required required transmission quality, a required transmission delay time, and a required transmission data loss. Rate (required loss rate), and this information is stored in association with each End that controls QoS. In the example of FIG. 11, a record including a combination of these pieces of information and a link number for specifying each end is stored for each end. In the present embodiment, the number of hops is also stored as information related to the path between the ends in association with the ends that control QoS.

  The number of hops is determined by the end-to-end QoS request reception processing unit 402 based on the transmission path information determined in S508. For example, as described above, when an end-to-end QoS request between the television 103 and the HDR 101 is received, the number of end-hops related to the end-end QoS request is described in the record with the link number 1 in FIG. As shown in FIG. In addition, the status field is set to a “before connection” status by the inter-End QoS request reception processing unit 402. For other information, the inter-End QoS request reception processing unit 402 is set based on the information in the inter-End QoS request.

  When the writing to the link management file 408 is completed in S511, the inter-End QoS request reception processing unit 402 calls the program for realizing the transmission time determination processing unit 403, etc. The operation is started and the allowable value of the transmission delay time required between the nodes is determined (S512). Details of the operation of the transmission time determination processing unit 403 will be described later.

  When the transmission delay time for each node is determined in S512, the inter-End QoS request reception processing unit 402 generates an inter-Node QoS request to be requested to each node based on the transmission delay time to each node. Then, the inter-Node QoS request is transmitted to the nodes related between the nodes (S514).

  As described above, when an end-to-end QoS request between the television 103 and the HDR 101 is received, this request is transmitted to the HDR 101, the first relay device 102, and the television 103, and the HDR 101 is transmitted to the first relay device 102. To ensure the transmission quality when transmitting data to the first relay device 102, the first relay device 102 to ensure the transmission quality when transmitting data to the first relay device 102 and the television 103, and the television 103 to the first relay device 102. The transmission quality is ensured when data is transmitted.

  When the transmission of the inter-node QoS request is completed in step S514, the inter-end QoS request reception processing unit 402 performs the inter-node QoS request from each node for a predetermined time N1 in a series of processes of S516, S518, S520, and S522. Wait for a response to.

  More specifically, the end-to-end QoS request reception processing unit 402 sets, for example, a variable T1 indicating elapsed time to zero in S516, determines whether all responses have been received in S518, and uses the above variables in S520. It is determined whether or not the elapsed time stored in T1 is equal to or greater than N1, and in S522, a predetermined value t2 is added to T1, and the process is stopped for t2. After the elapse of t2, the process from S518 is repeated.

  If all responses are not obtained even after the time N1 has elapsed since the transmission of the inter-Node QoS request in S514 (NO in S520), the inter-End QoS request acceptance processing unit 402 Each node that receives the message is notified of the release of the secured transmission path, and the process returns to S502. In this case, the inter-End QoS request reception processing unit 402 may transmit a failure response to the transmission source of the inter-End QoS request, similarly to S530 described later.

  On the other hand, if all responses can be received within the time N1 after the transmission of the inter-Node QoS request is completed in S514 (YES in S518), it is determined whether or not all responses are successful (S526). ). If some of the responses fail (NO in S526), it means that the requested transmission quality has not been secured on the requested transmission path, and the inter-End QoS request acceptance processing unit 402 The node that has received success is notified of the release of the transmission path (S528), and a failure notification is transmitted to the requester of the inter-End QoS request (television 103) (S530).

  On the other hand, when successful responses are received from all nodes (YES in S526), the inter-End QoS request reception processing unit 402 accesses the transmission quality setting management file 409, and between which nodes, which It is written whether the allowable value of the transmission delay time is allocated (S532).

  FIG. 12 is an example illustrating an example of data recorded in the transmission quality setting management file 409. The transmission quality setting management file 409 is related to each end for which the communication control apparatus 100 manages the transmission quality, and an allowable value of a transmission delay time assigned to each node included in the end (in the figure, a setting) (Transmission delay time) and a current state of transmission quality of each node. In this embodiment, in relation to the link number, the following combinations, that is, between the end of the link number: Information for identifying the included nodes (for example, a name for identifying the transmitting side and the receiving side), the allowable transmission delay time allocated between the nodes, and the occurrence between the nodes A combination with the transmission data loss rate being stored is stored.

  In the initial state, that is, in response to the inter-end QoS request, the inter-end QoS request reception processing unit 402 determines the allowable value of the transmission delay time allocated to each node to the transmission time determination processing unit 403. In this state, since the transmission data loss rate that actually occurs is unknown, the inter-End QoS request acceptance processing unit 402 does not set the transmission data loss rate. The actually generated transmission data loss rate is written by the transmission quality monitoring processing unit 404 as will be described later.

  When the writing to the transmission quality setting management file 409 is completed in S532, the end-to-end QoS request reception processing unit 402 next accesses the link management file 408, and changes the status field from “Before connection” to “Connecting”. (S534). Next, the inter-End QoS request reception processing unit 402 starts the operation of the transmission quality monitoring processing unit 404 by starting a program for realizing the transmission quality monitoring processing unit 404 as another process, for example (S536). ), A success response is transmitted to the request source of the inter-End QoS request (television 103) (S538), and the process returns to S502. Details of the operation of the transmission quality monitoring processing unit 404 will be described later.

  FIG. 6 is a flowchart showing the control operation of the transmission quality monitoring processing unit 404. The transmission quality monitoring processing unit 404 starts its operation in response to an instruction from the above-mentioned end-to-end QoS request reception processing unit 402 or a transmission time control processing unit 406 described later. As an example, each of the members 402 and 406 activates a program for realizing the transmission quality monitoring processing unit 404 and instructs the transmission quality monitoring processing unit 404 to start operation.

  After the operation is started, the transmission quality monitoring processing unit 404 waits for processing for a predetermined time t3 (S602). During this time, the transmission data loss rate is measured between the nodes. In the present embodiment, during this time, each node measures a transmission data loss rate generated between the nodes.

  The transmission quality monitoring processing unit 404 generates / transmits a message for requesting the transmission data loss rate report to each node after the time t3 has elapsed (S604), and a series of processes of S606, S608, S618, and S620 Thus, a response to a request for reporting the transmission data loss rate from each node is waited for a predetermined time N2. These series of processes are the same as S516, S518, S520, and S522 shown in FIG. 5, except that a variable for storing the elapsed time after transmission, a waiting time to be added to the variable, and a threshold are T1, It is changed from t2 and N1 to T2, t4 and N2.

  If all the responses have not been received even after the predetermined time N2 has elapsed (NO in S618), the transmission quality monitoring processing unit 404 notifies each node of the QoS release on the already secured transmission path. Is transmitted (S622), a disconnection notice is transmitted to the request source of the inter-End QoS request (in the above example, the television 103) (S624), and the process is terminated.

  On the other hand, if a response is received (YES in S608), the transmission quality monitoring processing unit 404 accesses the transmission quality setting management file 409, and sets the transmission data loss rate between the nodes included in each response to the transmission quality setting. Write to the management file 409 (S610). When the writing is completed, the transmission quality monitoring processing unit 404 causes the transmission time change control execution determination processing unit 405 to start the operation and determines whether or not to operate the transmission time control processing unit 406 described later (S612). The execution result of the transmission time change control execution determination processing unit 405 is transmitted from the transmission time change control execution determination processing unit 405 to the transmission quality monitoring processing unit 404, for example, by being stored in the flag F1. The operation of the transmission time change control execution determination processing unit 405 will be described later.

  For example, when the transmission time change control execution determination processing unit 405 determines that the operation of the transmission time control processing unit 406 is necessary (YES in S614), such as when the flag F1 is true, the transmission quality monitoring processing unit 404 Then, the transmission time control processing unit 406 is operated as a separate process to activate the transmission time control processing unit 406, and the processing is terminated. On the contrary, for example, when it is determined that the operation of the transmission time control processing unit 406 is unnecessary (for example, when the flag F1 is false) (NO in S614), transmission data loss between the nodes on the transmission path It is determined that the rate satisfies the adaptation condition required by End To End, and the transmission quality monitoring processing unit 404 ends the processing without operating the transmission time control processing unit 406.

  FIG. 7 is a flowchart showing the control of the transmission time change control execution determination processing unit 405. The transmission time change control execution determination processing unit 405 starts an operation in response to an instruction from the transmission quality monitoring processing unit 404.

  After the activation, the transmission time change control execution determination processing unit 405 accesses the transmission quality setting management file 409 and determines whether or not the transmission delay time needs to be reset (whether the operation of the transmission time control processing unit 406 is necessary).

  As an example, a case where the necessity of resetting is determined according to whether the ratio between the maximum and minimum transmission data loss rates on the transmission path exceeds a preset value will be described. Transmission time change control execution determination processing unit 405 accesses the transmission quality setting management file 409, and acquires the maximum transmission data loss rate Lmax and the minimum data loss rate Lmin for the corresponding link (S702). More specifically, the transmission time change control execution determination processing unit 405 includes the transmission data loss rate between the nodes stored in the transmission quality setting management file 409 for each end and between each end. Among these nodes, the maximum transmission data loss rate Lmax and the minimum transmission data loss rate Lmin are extracted.

Next, the transmission time change control execution determination processing unit 405 executes the calculation (Lmax / Lmin) and stores the result in the variable C1 (S704). Next, the transmission time change control execution determination processing unit 405 compares the variable C1 with a predetermined value M1 (S706). M1 is a number that satisfies M1> 1, and for example, a numerical value of 10 is set. If it is determined that C1> M1, the transmission time change control execution determination processing unit 405 sets the flag F1 to true, for example,
The transmission delay time is reset (the operation of the transmission time control processing unit 406 is necessary) and transmitted to the transmission quality monitoring processing unit 404 (S708). If it is determined that C1 <= M1, for example, Then, the flag F1 is set to false to notify that the resetting of the transmission delay time is unnecessary (S710), and the process is terminated.

  In the above example, when the maximum and minimum transmission data loss rates on the transmission path are extracted and the ratio is equal to or higher than a preset value (for example, 10 times), the transmission time control processing unit 406 transmission time control processing unit If the operation of 406 is necessary and less than that, it is determined that the transmission time control processing unit 406 is unnecessary.

  FIG. 8 is a flowchart showing the control operation of the transmission time control processing unit 406. As described above, the transmission time control processing unit 406 starts the operation in response to an instruction from the transmission quality monitoring processing unit 404, and resets the allowable value of the transmission delay time between the nodes for the specified link. To do.

  Specifically, after activation, the transmission time control processing unit 406 operates a transmission time determination processing unit 403, which will be described later, to determine the allowable value of the transmission delay time between the nodes (S802). When the allowable value of the transmission delay time between the nodes is determined in the transmission time determination processing unit 403, the transmission time control processing unit 406 transmits a QoS change request to be transmitted to each node based on the allowable value of the transmission delay time. And the QoS change request is transmitted to each of them (S804).

  Next, the transmission time control processing unit 406 waits for a response to the QoS change request from each node for a certain time N3 by a series of processes of S806, S808, S816, and S818. These series of processes are the same as S516, S518, S520, and S522 shown in FIG. 5, except that a variable for storing the elapsed time after transmission, a waiting time to be added to the variable, and a threshold are T1, It is changed from t2 and N1 to T3, t5 and N3.

  If all the responses have not been received even after the time N3 has elapsed (NO in S816), the transmission time control processing unit 406 transmits a release notification to each node (S820), and an inter-End QoS request A disconnection notice is transmitted to the request source (the television 103 in the above example) (S822), and the process ends.

  On the other hand, if all responses have been received (YES in S808), the transmission time control processing unit 406 determines whether the response result is a success or a failure (S810). The success here means that the change is successful in response to the QoS change request in S806. If the change is successful (YES in S810), the transmission quality setting management file 409 is accessed, and the item (field) of the set transmission delay time is changed to a value requested for each node (S812).

  When the change of the transmission quality setting management file 409 is completed, the transmission time control processing unit 406 causes the transmission quality monitoring processing unit 404 to start a program for realizing the transmission quality monitoring processing unit 404 in another process, for example. A new monitoring operation is started and the process is terminated. If some of the response results are not successful (NO in S810), the transmission time control processing unit 406 executes a series of processes from S820 and ends the process.

  FIG. 9 is a flowchart showing the control operation of the transmission time determination processing unit 403. As described above, the transmission time determination processing unit 403 starts operation according to an instruction from the end-to-end QoS request reception processing unit 402 or the transmission time control processing unit 406, and transmits the specified link between the nodes. Determine the allowable delay time.

  Specifically, when the process is started, the transmission time determination processing unit 403 accesses the link management file 408, for example, whether the specified link is connected based on the value of the status field of the record of the specified link. Determine whether or not.

  If it is determined that the link is not connected (NO in S902), the transmission time determination processing unit 403 determines from the end To End requested transmission delay time D (msec) and the number of nodes included between the Ends. The initial value of the transmission delay time to be set between the nodes is determined. More specifically, the transmission time determination processing unit 403 further acquires the requested transmission delay time D (msec) and the number of hops n of End To End from the link management file 408, and the result of the calculation (D / n). Is stored in the variable d as an initial value of the transmission delay time. The variable d is a variable used when setting the same allowable value of the transmission delay time for all the nodes. The inter-End QoS request reception processing unit 402 uses each information in S514 based on this information. A node-to-node QoS request is generated.

  If it is determined that the link is connected (YES in S903), the transmission time determination processing unit 403 refers to the transmission quality setting management file 409 and resets the allowable value of the transmission delay time between the nodes. Determine the information to do. In this embodiment, as an example, the transmission delay time after reconfiguration between nodes whose transmission delay time is changed by reconfiguration (between nodes with the largest transmission data loss rate and between nodes with the smallest transmission data loss rate) The allowable value is transmitted to the transmission time control processing unit 406.

  More specifically, the transmission time determination processing unit 403 sets the setting time d1 (msec) between the nodes with the maximum transmission data loss rate and the setting time d2 (msec) between the nodes with the minimum transmission data loss rate into the transmission quality setting. Obtained from the management file 409, performs operations d1-1 and d2 + 1 to increase or decrease the allowable value, and stores the results in variables dmax and dmin, respectively. In the above, 1 (msec) is selected as an example of a value when the set times d1 and d2 between the nodes are increased or decreased by a predetermined value. The variables dmax and dmin are variables respectively representing the allowable value of the transmission delay time after the change between the nodes having the maximum and minimum transmission data loss rates, and the transmission time control processing unit 406 is based on this information. The process of S804 described above is executed to create a QoS change request.

  In the above, as an example, the transmission time determination processing unit 403 determines whether or not the link is connected, and stores the value in the variable d to notify the inter-End QoS request reception processing unit 402 of the determination result. Or selecting whether to notify the determination result to the transmission time control processing unit 406 by storing values in the variables dmax and dmin, but is not limited thereto. As an example, the transmission time determination processing unit 403 may determine a member to which a determination result is to be transmitted depending on which of the above-described members 402 and 406 is the member that has received the instruction. Alternatively, for example, by providing each program separately, a member for instructing the operation from each member 402, 406 is provided, and the member is determined as the corresponding one of the members 402, 406. The result may be returned. Further, the way of transmitting the determination result is not limited to a method of separately preparing a variable for returning a value to each of the members 402 and 406. For example, the determination result may be transmitted as a return value of a function. In any case, the transmission time determination processing unit 403 can notify the inter-End QoS request reception processing unit 402 of the initial value of the allowable value of the transmission delay time between the nodes, and the transmission time control processing unit 406. The same effect can be obtained if information for resetting the allowable value of the transmission delay time between the nodes can be transmitted.

  As described above, the communication control apparatus 100 according to the present embodiment allows the transmission delay time set for each node to be less than or equal to the transmission delay time required from the end to end from the request source. After calculating the value and allocating and setting it to each node as an inter-node QoS request, the transmission data loss rate between each node is checked after a predetermined time has passed, and the transmission data loss rate between each node is calculated. If there is a difference greater than a predetermined ratio, the allowable value of the transmission delay time requested between the nodes is recalculated and increased or decreased. This makes it possible to change the occurrence of the transmission data loss rate between the nodes, and to reduce the transmission data loss rate while keeping the total transmission delay time at End To End below a predetermined value. To do.

  As described above, the communication control apparatus 100 according to the present embodiment gives more transmission delay allowable time between nodes with a high transmission data loss rate, that is, between nodes with many errors, By assigning a small allowable transmission delay time, it is possible to allocate a balanced allowable transmission delay within the allowable range of the entire delay time between the transmitting device and the receiving device (between the ends), and moreover between the ends. To do. Therefore, it is possible to minimize the occurrence of errors by suppressing the overall delay time within a predetermined range.

  In the present embodiment, an example is shown in which the data transmitter and the data receiver function on different devices. For example, the data transmission function and the data reception function on the same device such as a videophone device. And may be realized.

  Further, in the present embodiment, in the process of determining the allowable value of the transmission delay time between the nodes, an example in which the nodes are allocated equally to each node at the time of the first allocation is shown, but past control contents are recorded. In addition, an initial value may be assigned according to the contents.

  For example, a past communication record between the same transmitter and receiver may be held, and the finally assigned transmission delay time allowable value may be used as an initial value from the recorded content. Further, regarding the method for determining the transmission delay time when changing the allowable value of the transmission delay time, in this embodiment, the time between the nodes with the largest transmission data loss rate is increased by 1 msec, and the time between the smallest nodes is increased. However, if the increase / decrease width is changed according to the ratio of the transmission data loss rate, or the next transmission delay time is determined based on the relationship between the past transmission data loss rate and the transmission delay time. Good. As an example, the larger the ratio, the more the transmission delay time may be changed. Moreover, as an example of a method of changing the increase / decrease width depending on the ratio, there is a method of controlling so that nodes other than the node between the maximum and minimum transmission data loss rates are also changed simultaneously.

  Further, in this embodiment, the transmission quality monitoring processing unit 404 actively requests the transmission data loss rate from each node. For example, each node may change the transmission data loss rate. If there is a means for notifying the communication control device 100 of the change contents only when there is, the reception of the notification is monitored by the transmission quality monitoring processing unit 404, and a transmission time control process is performed in response to the notification. A control method for executing the above is also conceivable. In any case, the same effect can be obtained if the transmission quality monitoring processing unit 404 can acquire the transmission data loss rate between the nodes.

  Furthermore, in the present embodiment, the communication control apparatus 100 has been described as an example of a device different from the device that transmits and receives data, but an example in which the communication control device 100 is integrated with a transmission device and a reception device is also conceivable.

  Furthermore, in this embodiment, the criterion for determining whether or not the transmission time change control execution determination processing unit 405 operates the transmission time control processing unit 406 is that the ratio between the maximum transmission data loss rate and the minimum transmission data loss rate is Although an example is shown in which the transmission time control process is executed when the value is equal to or greater than the predetermined value, the present invention is not limited to this.

For example, the transmission time change control execution determination processing unit 405 calculates the total transmission data loss rate at End To End 1−Π (1-Ei) Ei is the transmission error occurrence rate between i-th nodes
Π represents a product.
The transmission time control processing unit 406 may be operated when is equal to or greater than a predetermined value so that the total transmission data loss rate falls within a predetermined range. Further, as the predetermined value at this time, for example, a requested transmission data loss rate included in the inter-End QoS request may be set as a threshold value.

  As described above, when the transmission time change control execution determination processing unit 405 determines whether to instruct the transmission time control processing unit 406 to change the transmission delay time, as shown in FIG. ) It may be determined by “whether the ratio between the maximum data loss rate and the minimum data loss rate is equal to or greater than a predetermined value”, or (1-2) “total transmission data loss rate at End To End” It may be determined by whether or not “is greater than or equal to a predetermined value”. Alternatively, another determination method may be adopted. In any case, if the determination is made according to the transmission data loss rate between the nodes, the setting of the transmission delay time can be changed according to the situation of the communication system, so that substantially the same effect can be obtained.

  However, the optimum method is the model to be adapted (network configuration, communication medium to be used), or what request is made on the transmission path (what request is required for the communication control apparatus 100). It depends on what). Accordingly, an appropriate method is selected in advance or the transmission time change control execution determination processing unit 405 prepares in advance according to what request is made on the transmission path and at least one of the models to be applied. The transmission control according to the request depends on at least one of the request made to the communication control apparatus 100 and the model applied to the requested transmission path among the plurality of methods. A determination method may be selected.

  For example, comparing the determination methods (1-1) and (1-2), the determination method of (1-1) can bring the transmission data loss rate of End To End closer to the minimum value. Moreover, the amount of calculation required for determination can also be suppressed. On the other hand, the determination method (1-2) makes it easier to set the transmission data loss rate of End To End to a desired numerical range.

  Therefore, when a transmission data loss rate condition of End To End is requested from the member (for example, an application of the television 103) that transmits an inter-End QoS request to the communication control apparatus 100, (1-2 ) Is preferable, and when a request is made to reduce the transmission data loss rate between the ends as much as possible, or when it is strongly required to reduce the amount of calculation, it is preferable to determine according to (1-1).

  In addition, the transmission time control processing unit 406 (2) “between nodes whose transmission delay time is changed (control target)”, as described above, (2-1) “between nodes having the maximum data loss rate” Or a transmission delay time between nodes having a minimum data loss rate ”or (2-2)“ between three or more nodes including other nodes. ” It may be. In any case, substantially the same effect can be obtained if the transmission time control processing unit 406 can set transmission delay times between a plurality of nodes.

  Here, when comparing the above two examples of control objects, when the control object (2-1) is selected, since it is a simple comparison between the two nodes, compared to the control object (2-2), The algorithm can be simplified and the amount of calculation can be reduced. On the other hand, when the control target (2-2) is selected, the transmission delay time between three or more nodes is controlled, so that the transmission delay time can be controlled more accurately. Here, even if the transmission delay time is set, if the transmission quality between the ends does not satisfy the desired condition, the communication control apparatus 100 can repeat the resetting of the transmission delay time to further improve the transmission quality. Therefore, when the control target (2-1) is selected, it is possible to reduce the need to repeatedly set the transmission delay time. The control target may be selected in advance as in the determination method, or the communication control apparatus 100 may be in a situation (for example, the QoS request between ends, the transmission data loss rate, the number of resets, or the communication control apparatus 100 It may be changed according to the calculation amount and the demand for power consumption.

  In addition, (3) “Transmission delay time changing method” by the transmission time control processing unit 406 is as described above. (3-1) “Constant transmission delay time between nodes having the maximum data loss rate” It may be a method of increasing the value and decreasing the transmission delay time between nodes with the minimum data loss rate. (3-2) “Maximum data loss rate and minimum data loss rate Depending on the ratio, the method of changing the constant value of (3-1) above may be used.

  Further, (3) “Transmission delay time changing method” is (3-3) “Transmission delay time determination method based on the relationship between estimated data loss rate and transmission delay time”. Also good. As an example, the communication control device 100 (more specifically, the transmission time control processing unit 406 or the transmission time determination processing unit 403) generates a transmission delay time request (QoS change request) in each node. The transmission data loss rate is graphed. Further, the communication control apparatus 100 estimates, based on the graph, what characteristics the transmission data loss rate of the communication path (between nodes) changes when a transmission delay time is given. Furthermore, the communication control apparatus 100 determines the allocation of the transmission delay time that minimizes the transmission data loss rate in the entire system (between the ends) based on the graph of each path (between nodes).

  In addition, the above (3) “transmission delay time changing method” may be (3-4) “a method of controlling the total transmission data loss rate in End To End to be within a predetermined range”. In this case, for example, the communication control apparatus 100 may repeat the setting of the transmission delay time, estimate the total transmission data loss rate, determine the transmission delay time that falls within a predetermined range, and set it to each node. It may be set in between.

  Alternatively, (3) “Transmission delay time changing method” may be a method other than the above (3-1) to (3-4), or may be changed by combining these methods. As an example, the methods can be combined by weighting and combining the transmission delay times determined by the methods.

  In any case, if the communication control apparatus 100 can change the transmission delay time between the nodes according to the transmission data loss rate between the nodes, the setting of the transmission delay time is changed according to the situation of the communication system. Since this is possible, substantially the same effect can be obtained.

  Note that the above control method (3-4) is combined with the control methods (3-1) to (3-3) until the total transmission data loss rate in End To End falls within a predetermined range. By repeating (3-1) to (3-3), the transmission quality between the ends can be secured / improved. Further, as the estimation method, for example, a history of past transmission delay time and data loss rate may be accumulated and estimated from the history, or a calculation method predetermined according to the above-described model It may be estimated by. As an example, the control method at the physical layer (MAC layer) level differs depending on the medium of the communication path, but if the medium is determined, what kind of delay is caused by a predetermined function (derived from calculation or LUT). It is possible to give an estimate of how much loss rate will occur when the request is made.

  Here, comparing the above-described transmission delay time changing methods, the changing method (3-1) can simplify the algorithm, and thus can reduce the amount of calculation. On the other hand, the change method (3-2) can be controlled more finely than the change method (3-1) while the amount of calculation is slightly increased. In addition, since the change method (3-3), for example, collects past data and estimates from the data in order to estimate, the calculation amount of the communication control apparatus 100 tends to increase. Compared with (3-1) and (3-2), the transmission delay time can be set more accurately. Therefore, in order to improve / secure the transmission quality between the ends, even if the resetting is repeated, the number of repetitions of the transmission delay time request process can be reduced.

  Furthermore, in the above description, the case where the communication control apparatus 100 can set the transmission delay time between all the nodes constituting the end (in the case where each node can set the transmission delay time) has been described as an example. It is not a thing. Any of the nodes between the ends may not be able to set the transmission delay time. In any case, the communication control apparatus 100 performs transmission in data communication through a transmission path that passes through one or more specific nodes that can retransmit error data when a transmission error occurs within a preset transmission delay allowable time. In addition, among the nodes on the transmission path, the transmission delay allowable time is set for a plurality of nodes having the specific node at the end, and the end between the nodes is set. If a specific node can be notified, the same effect can be obtained.

  Further, the transmission quality control program in the present embodiment can be stored in a recording medium as indicated by 1504 in FIG. 1500 is an example of the communication control apparatus 100 according to the embodiment of the present invention, and is a general general-purpose computer. By inserting the recording medium 1504 on which the transmission quality control program is recorded from the external recording medium insertion unit 1502 and starting the control program, it becomes possible to perform transmission quality control using a general general-purpose computer. As the recording medium, for example, a CD-ROM, a DVD, a floppy (registered trademark) disk, or the like can be used. However, it is not limited to them.

  In the above description, the members 402 to 409 constituting the communication control apparatus 100 are “functional blocks realized by a calculation means such as a CPU executing a program code stored in a recording medium such as a ROM or a RAM. Although the case of “some” has been described as an example, it may be realized by hardware that performs the same processing. Further, it can also be realized by combining hardware that performs a part of the processing and the above-described calculation means that executes the program code for controlling the hardware and the remaining processing. Further, even among the members described above as hardware, the hardware for performing a part of the processing and the arithmetic means for executing the program code for performing the control of the hardware and the remaining processing It can also be realized by combining them. The arithmetic means may be a single unit, or a plurality of arithmetic means connected via a bus inside the apparatus or various communication paths may execute the program code jointly. Further, the storage means for storing the file among the above members may be a storage device such as a memory as in the recording unit 205 described above, or may be a functional block similar to the above.

  The program code itself that can be directly executed by the computing means, or a program as data that can be generated by a process such as decompression described later, stores the program (program code or the data) in a recording medium, A recording medium is distributed, or the program is distributed by being transmitted by a communication means for transmitting via a wired or wireless communication path, and is executed by the arithmetic means.

  In the case of transmission via a communication path, each transmission medium constituting the communication path propagates a signal sequence indicating a program, whereby the program is transmitted via the communication path. Further, when transmitting the signal sequence, the transmission device may superimpose the signal sequence on the carrier by modulating the carrier with the signal sequence indicating the program. In this case, the signal sequence is restored by the receiving apparatus demodulating the carrier wave. On the other hand, when transmitting the signal sequence, the transmission device may divide and transmit the signal sequence as a digital data sequence. In this case, the receiving apparatus concatenates the received packet groups and restores the signal sequence. Further, when transmitting a signal sequence, the transmission device may multiplex and transmit the signal sequence with another signal sequence by a method such as time division / frequency division / code division. In this case, the receiving apparatus extracts and restores individual signal sequences from the multiplexed signal sequence. In any case, the same effect can be obtained if the program can be transmitted via the communication path.

  Here, it is preferable that the recording medium for distributing the program is removable, but it does not matter whether the recording medium after distributing the program is removable. In addition, the recording medium can be rewritten (written), volatile, or the recording method and shape as long as a program is stored. Examples of recording media include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks and hard disks, CD-ROMs, magneto-optical disks (MO), mini-discs (MD) and digital A disk such as a video disk (DVD) may be mentioned. The recording medium may be a card such as an IC card or an optical card, or a semiconductor memory such as a mask ROM, EPROM, EEPROM, or flash ROM. Or the memory formed in calculating means, such as CPU, may be sufficient.

  The program code may be a code for instructing the arithmetic means of all the procedures of the processes, or a basic program capable of executing a part or all of the processes by calling according to a predetermined procedure. If (for example, an operating system or a library) already exists, a part or all of the entire procedure may be replaced with a code or a pointer that instructs the arithmetic means to call the basic program.

  The format for storing the program in the recording medium may be a storage format that can be accessed and executed by the arithmetic means, for example, as in a state where the program is stored in the real memory, or is stored in the real memory. Installed in the local recording medium from the storage format after being installed in a local recording medium (for example, real memory or hard disk) that is always accessible by the computing means, or from a network or a transportable recording medium The previous storage format may be used. Further, the program is not limited to the compiled object code, but may be stored as source code or intermediate code generated during interpretation or compilation. In any case, the above calculation is performed by a process such as decompression of compressed information, decoding of encoded information, interpretation, compilation, linking, allocation to real memory, or a combination of processes. If the means can be converted into an executable format, the same effect can be obtained regardless of the format in which the program is stored in the recording medium.

  It should be understood that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

As described above, the communication control device according to the present invention provides a means for monitoring the data loss rate between the nodes, and the allowable value of the transmission delay time between the nodes based on the monitoring result of the data loss rate. Further, according to one aspect of the present invention, there is included means for controlling the transmission delay time so that the total transmission delay time between the nodes is equal to or less than a predetermined value.

  Further, according to one aspect of the present invention, when the comparison result of the transmission data loss rate monitoring results between the nodes satisfies a predetermined condition, the means for changing the allowable value of the transmission delay time between the nodes according to the contents including.

  Further, according to one aspect of the present invention, there is included means for controlling the transmission delay time between the nodes when there is a change in the transmission data loss rate between the nodes.

  According to the present invention, in real-time communication across a plurality of nodes, it becomes possible to set an allowable value of transmission delay time between nodes based on a result of a transmission data loss rate between the nodes. As a result, the allowable value of the transmission delay time can be determined and notified according to the transmission data loss rate between the nodes, so that the transmission quality is controlled according to the communication medium and communication status between the nodes. It becomes possible.

  It is also possible to set the transmission delay time between the nodes while keeping the total transmission delay time between the nodes, that is, the transmission delay time of End To End, below a predetermined value. This makes it possible to control the transmission quality by associating the transmission data loss rate with the transmission delay time within the range of the transmission delay time requested by End To End.

  In addition, when the comparison result of the measured values of the transmission loss rate between a plurality of nodes satisfies a predetermined condition, the allowable value of the transmission delay time between each node is recalculated, and the recalculated value is notified to each node. Thus, the total transmission loss rate of End To End can be adjusted. As a result, transmission quality control can be performed so as to satisfy the condition obtained by End To End.

  Further, it is possible to dynamically control transmission delay time between nodes in response to changes in the transmission data loss rate. As a result, even when the communication state between some nodes changes during communication, it becomes possible to change the allowable value of the transmission delay between the nodes, and End To End even under the changed conditions. Thus, transmission quality control can be performed so as to satisfy the conditions required in the above.

  According to the present invention, a communication system capable of ensuring / improving transmission quality of communication across a plurality of nodes can be realized. Therefore, as a communication control apparatus that controls transmission in data communication, including a communication control apparatus that controls real-time communication. Can be used widely and suitably.

It is drawing which shows the structural example of the network system which a communication control apparatus operate | moves in embodiment of this invention. It is drawing which shows the internal structure of the communication control apparatus in embodiment of this invention. It is a flowchart showing the control flow of the real-time communication controlled by the communication control apparatus in embodiment of this invention. It is drawing showing the outline | summary of the control structure of the communication control apparatus in embodiment of this invention. It is a flowchart showing the control operation | movement of the QoS request reception process part between Ends in embodiment of this invention. The flowchart showing the control operation of the transmission quality monitoring processing unit in the embodiment of the present invention. It is a flowchart showing control of the transmission time change control execution determination process part in embodiment of this invention. It is a flowchart showing the control operation of the transmission time control process part in embodiment of this invention. It is a flowchart showing the control operation | movement of the transmission time determination process part in embodiment of this invention. It is drawing showing the data of the network configuration management file in an embodiment of the present invention. It is drawing showing the data of the link management file in embodiment of this invention. It is drawing showing the data of the transmission quality setting management file in embodiment of this invention. It is a figure showing the example of the frame format of the QoS request message between ends in embodiment of this invention. It is drawing which shows the example of the frame format of the QoS request message between Nodes in embodiment of this invention. It is drawing which shows the example of the external appearance of a communication control apparatus, and an external recording medium in embodiment of this invention.

Explanation of symbols

100 communication control device 101 first device (hard disk recorder; transmitting device)
102 1st relay apparatus (node; specific node)
103 Second device (TV; receiving device)
404 Transmission quality monitoring processor (monitoring means)
406 Transmission time control processing unit (transmission delay time control means)

Claims (10)

A communication control device that performs transmission control in data communication via a transmission path that passes through one or more specific nodes that can retransmit error data when a transmission error occurs within a preset transmission delay allowable time,
A transmission that sets the allowable transmission delay time between a plurality of nodes having the specific node as an end among the nodes on the transmission path, and notifies the specific node that is an end between the nodes. A delay time control means;
Monitoring means for monitoring a transmission data loss rate between nodes set at least the transmission delay allowable time among the nodes on the transmission path;
The transmission delay time control means resets a transmission delay allowable time between the nodes based on the monitoring result of the transmission data loss rate, and notifies the specific node of the communication control device. .   The transmission delay time control means is a transmission delay between the nodes on the transmission path between the two devices so that the total transmission delay time between the transmission side device and the reception side device is not more than a predetermined value. 2. The communication control apparatus according to claim 1, wherein an allowable time is allocated.   The transmission delay time control means compares the transmission data loss rate between the nodes, and changes the allowable transmission delay time between the nodes when the comparison result satisfies a predetermined condition. The communication control device according to claim 1, 2 or 3.   The transmission delay time control means changes the allowable transmission delay time between the nodes when there is a difference greater than a preset value between transmission data loss rates of the nodes. The communication control device described.   5. The transmission delay time control means sets the allowable transmission delay time between the nodes so that the allowable transmission delay time between the nodes having the maximum transmission data loss rate is increased. The communication control apparatus according to any one of the above.   6. The transmission delay time control means sets the allowable transmission delay time between the nodes so that the allowable transmission delay time between nodes having a minimum transmission data loss rate is reduced. The communication control apparatus according to any one of the above.   The transmission delay time control means sets the allowable transmission delay time between the nodes so that the total transmission data loss rate between the nodes for which the monitoring means is monitoring the transmission data loss rate falls within a predetermined range. The communication control device according to any one of claims 1 to 6, wherein:   The transmission delay time control means resets a transmission delay allowable time between the nodes when there is a change in a transmission data loss rate monitoring result between arbitrary nodes on the transmission path, and The communication control apparatus according to claim 1, which notifies each node on the transmission path. A communication control program for performing transmission control in data communication via a transmission path passing through one or more specific nodes capable of retransmitting error data when a transmission error occurs within a preset transmission delay allowable time,
A transmission that sets the allowable transmission delay time between a plurality of nodes having the specific node as an end among the nodes on the transmission path, and notifies the specific node that is an end between the nodes. Delay time control function,
A program for realizing in a computer a monitoring function for monitoring a transmission data loss rate between nodes that set at least the transmission delay allowable time among the nodes on the transmission path,
The transmission delay time control function is a function of resetting a transmission delay allowable time between the nodes based on a monitoring result of the transmission data loss rate and notifying the specific node. program.   A computer-readable recording medium on which the program according to claim 9 is recorded.

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