JP2008294641A - Relay communication method in time division multiple access network system, and relay apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a relay communication method in a time division multiple access network system capable of reducing relay delay, evading collision in communication on a network, and raising the through-put of the network, and to obtain a relay apparatus. <P>SOLUTION: The relay communication method includes: a step for obtaining link information by the relay apparatus; a step for obtaining communication frame assignment information by communication equipment and the relay apparatus; a step for allowing the relay apparatus to determine a reception link and a transmission link by each communication time frame, based on the link information and the communication frame assignment information; a step for transmitting communication data by the communication equipment in the communication time frame assigned to the communication equipment; a step for allowing the relay apparatus to receive communication data from the reception link corresponding to the communication time frame, and to transmit the communication data to the transmission link corresponding to the communication time frame; and a step for receiving the communication data by the communication equipment in the communication time frame assigned to the communication equipment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a relay communication method and a relay apparatus in a time division multiple access network system, and more particularly to improvement of network throughput.

  In information communication in which communication is performed by time division multiple access (TDMA), a link where a data destination exists when communication devices cannot communicate directly and relay communication is performed via a third communication device. There is a switching hub as a relay device that sends data only to (communication line). Such methods include store-and-forward, cut-through, and fragment-free. In store-and-forward, after the relay device once receives and stores the entire communication data, the destination is included in the communication data, and the communication data is transmitted to the link that reaches the destination. In the cut-through, the repeater receives and accumulates communication data until a destination appears in the communication data, determines a link to be transmitted when the destination appears, and starts transmission of the communication data to the link from that point. In the fragment free, transmission of communication data to the link to the destination is started from the time when the control data which is important information in the communication data including the destination is received and stored, and the control data is completely received.

  Also, as a conventional switching hub, for example, “a switching hub having a plurality of ports and performing frame transfer between ports, the frame transfer method is set to either a cut-through method or a store and forward method. A switching hub characterized in that a setting unit is provided for each port so that the frame transfer method can be set individually for each port has been proposed (see, for example, Patent Document 1).

JP-A-9-162917 (Claim 1)

  However, even in relaying by cut-through, which has the smallest delay in relaying, the data frame cannot be transmitted until the destination address in the data frame is read, and a relay delay occurs even if it is slight. This delay is accumulated when the relay has multiple stages. In a communication system in which the communication timing is managed in time, such as a time division multiple access network system, the delayed communication is the communication that has occurred next. In some cases, a collision may occur or the communication time frame may end and reception may not be accepted. As a result, there is a problem that a communication error occurs and the throughput is reduced, or a necessary function cannot be realized.

  Therefore, in a time division multiple access network system, there is provided a relay communication method and relay apparatus in a time division multiple access network system capable of reducing relay delay, avoiding communication collisions on the network, and improving network throughput. It was desired.

  A relay communication method in a time division multiple access network system according to the present invention includes a plurality of communication devices and one or a plurality of relay devices connected to the communication devices via a communication line. A relay communication method in a time division multiple access network system that performs data communication by time division via the relay device, wherein the relay device uses link information that is identification information of the communication device corresponding to each communication line. Obtaining the communication frame assignment information that is identification information of the communication device assigned to each communication time frame by the communication device and the relay device, and the relay device comprising the link information and the link information Based on the communication frame allocation information, the communication line for receiving communication data and the communication data are transmitted for each communication time frame. Determining a transmission communication line to be transmitted, the communication device transmitting communication data in a communication time frame assigned to the communication device, and the relay device receiving the communication corresponding to the communication time frame Receiving communication data from the line and transmitting the communication data to the transmission communication line corresponding to the communication time frame; and the communication device receives the communication data in the communication time frame assigned to the communication device. And a step of performing.

  The relay device according to the present invention is a relay device that is connected to a plurality of communication devices via a communication line and performs communication in a time division manner, and the relay device is connected to each communication device corresponding to the communication line. Link information that is identification information and communication frame assignment information that is identification information of the communication device assigned to each communication time frame are acquired, and each communication time frame is obtained based on the link information and the communication frame assignment information. Each time, a reception communication line for receiving communication data and a transmission communication line for transmitting communication data are determined, communication data is received from the reception communication line corresponding to the communication time frame, and the communication time frame is supported. The communication data is transmitted to the transmission communication line.

  In the present invention, for each communication time frame, the relay device determines a reception communication line for receiving communication data and a transmission communication line for transmitting communication data, and communication data is received from the reception communication line corresponding to the communication time frame. By receiving and transmitting communication data to the transmission communication line corresponding to the communication time frame, it is possible to reduce relay delay, avoid communication collision on the network, and improve network throughput.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a time division multiple access network system according to the first embodiment. As shown in FIG. 1, a time division multiple access network system (hereinafter also referred to as “network”) includes a network management device 1, a communication device 2, a communication device 3, a communication device 4, a communication device 5, a relay device 6, and The relay device 7 is configured, and each device is connected by links a to f (hereinafter, also simply referred to as “links”) that are communication lines. The network management device 1 and the communication devices 2 to 5 (hereinafter collectively referred to simply as “communication devices”) have a function of transmitting and receiving predetermined communication data. The relay device 6 and the relay device 7 (hereinafter collectively referred to simply as “relay device”) are configured by, for example, a switching hub or the like and have a function of relaying communication data. The communication lines (links) between the apparatuses may be wired or wireless, and are connected to each other by a predetermined communication protocol.

  In FIG. 1, devices at both ends of each link can directly communicate with each other. For example, the network management device 1 and the relay device 6 can communicate directly using the link a. Further, the communication device 2 and the communication device 3 can perform relay communication using the link b and the link c via the relay device 6. Further, multi-stage relay is possible. For example, the network management device 1 and the communication device 5 can communicate with each other through the relay device 6 and the relay device 7 using the link a, the link d, and the link f. In the first embodiment, a case where there are four communication devices and two relay devices will be described. However, the present invention is not limited to this, and a network can be configured by an arbitrary number. Further, the function of the network management device 1 may be included in any one of the communication devices 2 to 5 so that the communication device also serves as the operation of the network management device 1.

  This network multiple access method uses time division multiple access (TDMA). That is, the communication apparatuses 2 to 5 are allowed to communicate only in a communication time frame assigned in advance. It is assumed that the network management device 1 has a function for assigning a communication time frame in this network. The network management device 1 notifies communication frame allocation information (described later) to the communication devices 2 to 5 and the relay devices 6 and 7 by broadcast transmission (broadcast) according to a certain standard or request. This communication frame allocation information will be described next with reference to FIG.

  FIG. 2 is a diagram illustrating an example of communication frame allocation information according to the first embodiment. The communication frame allocation information indicates identification information of a communication device allocated to each communication time frame in the time division multiple access method. In the example shown in FIG. 2, for example, communication from the communication device 2 to the communication device 3 is possible from the start time T1 to the communication time frame of the time frame length D1, that is, from the time T1 to the time (T1 + D1). It is a time frame. As a result, in this communication time frame, link b and link c are indispensable links for transmitting communication data (information). As described above, the communication devices 2 to 5 transmit and receive communication data based on the communication time frame allocation notification notified from the network management device 1. Next, the configuration of the communication data will be described with reference to FIG.

  FIG. 3 is a diagram illustrating a configuration example of communication data according to the first embodiment. As shown in FIG. 3, the communication data includes at least a header portion having information (identification information of the communication device) for identifying the communication device of the transmission source and the transmission destination, and a communication data body that is information to be transmitted and received. The In the example of FIG. 3, communication data from the communication device 2 (transmission source) to the communication device 3 (transmission destination) is shown. The communication devices 2 to 5 transmit and receive such communication data via the relay device 6 or 7. Next, the relay operation of the relay device according to the first embodiment will be described below with reference to FIGS.

First, acquisition of link information by the relay device will be described.
The relay device acquires link information, which is identification information of the communication device corresponding to each link, before performing a relay operation without capturing communication data by an operation described later, such as at the time of initial relay or a predetermined period after network construction. To do. The relay device reads communication data at the same time as relaying communication, and learns a link that reaches the transmission source.

  For example, when the relay device 6 relays communication data from the communication device 2 to the communication device 3, the identification information of the communication device 2 included in the communication data transmitted from the communication device 2 and the communication data are received. Based on the link b (communication line), the identification information of the communication device 2 corresponding to the link b is acquired. That is, it stores that the communication device 2 is ahead of the link b from the information of the transmission source (communication device 2) included in the communication data and the link (link b) where the communication data arrives. Note that this link information is not limited to the case where the relay apparatus acquires the communication data from the communication data as described above. For example, the information may be given to the relay apparatus from the outside (for example, by manual input) during network configuration.

  Next, the relay device receives a reception link (reception communication line) for receiving communication data for each communication time frame based on the link information acquired by the above operation and the communication frame allocation information notified from the network management device 1. ) And a transmission link (transmission communication line) for transmitting communication data. An example of the reception link and transmission link determination operation will be described with reference to FIG.

FIG. 4 is a diagram showing information held by the relay device 6 according to the first embodiment. As shown in FIG. 4, for example, it is assumed that the relay device 6 has learned that the communication device 2 is ahead of the link b and the communication device 3 is ahead of the link c as link information. According to the communication frame allocation information from the network management device 1, there is communication from the communication device 2 to the communication device 3 between the start time Ta and the time frame length Da, and communication between the start time Tb and the time frame length Db. Assume that the device 3 is notified that there is a broadcast communication. At this time, between the start time Ta and the time frame length Da, the relay device 6 determines the received link as the link b from the link information corresponding to the communication device 2 that is the transmission source, and the communication device that is the transmission destination. From the link information corresponding to 3, the transmission link is determined as the link c. Similarly, between the start time Tb and the time frame length Db, the reception link is determined as the link c from the link information corresponding to the communication device 3 that is the transmission source. At this time, since the transmission destination is a broadcast, all link information (links a to d) is determined as a transmission link.
Using the reception link and transmission link for each communication time frame determined in this way, a relay operation is performed without capturing communication data. In such a relay operation, determination of the relay method according to the transmission destination and the transmission source will be described below with reference to FIG.

  FIG. 5 is a diagram illustrating determination of a relay method of the relay device according to the first embodiment. As shown in FIG. 5, the relay apparatus determines the relay method for each communication time frame according to the transmission destination and the transmission source of the received communication frame allocation information as shown in (a) to (d) below. To do.

(A) When the transmission destination is a broadcast.
Regardless of the transmission source, it relays to all links other than the reception link without capturing the received communication data.
(B) When the transmission destination is a single communication device, the link information is known, and the transmission source is the same link as the transmission destination.
Do not relay. This is because communication via the relay device is not performed in this case. For example, it is a communication time frame in which communication from the communication device 4 to the communication device 5 is performed in the relay device 6.
(C) When the transmission destination is a single communication device and the link information is known, and the transmission source is a link different from the transmission destination.
It relays only to the transmission link without capturing the received communication data.
(D) When the transmission destination is a single communication device and the link information is unknown.
Regardless of the transmission source, it relays to all links other than the reception link without capturing the received data.

  Next, an example of the relay operation of the relay device 6 in the information example shown in FIG. 4 will be described with reference to FIGS.

  6 is a diagram illustrating a relay operation at Ta to Ta + Da of the relay device 6 according to the first embodiment, and FIG. 7 is a diagram illustrating a relay operation at Tb to Tb + Db of the relay device 6 according to the first embodiment.

  As shown in FIG. 6, during the period from the start time Ta to Ta + Da, the relay device 6 does not check (read) or accumulate the content of the communication data, and the communication data coming from the link b, which is the reception link, The data is sent to link c which is a transmission link. On the other hand, communication data is not sent to link a and link d. That is, the determination of the relay method at this time is (c) above.

  As shown in FIG. 7, between the start time Tb and Tb + Db, the relay device 6 does not check (read) or accumulate the content of the communication data, and the communication data coming from the link c, which is the reception link, The data is transmitted to link a, link b, and link d, which are transmission links. That is, the determination of the relay method at this time is (a).

  Through the operation as described above, the transmission source communication device transmits communication data in the communication time frame assigned to the communication device, and the relay device receives communication data from the reception link corresponding to the communication time frame. Then, the communication data is transmitted to the transmission link corresponding to the communication time frame. Then, the communication data is relayed by receiving the communication data in the communication time frame assigned to the communication apparatus by the transmission destination communication apparatus.

As described above, in the first embodiment, the relay device determines the reception link and the transmission link for each communication time frame based on the link information and the communication frame allocation information, and each determined communication time frame. By using the reception link and the transmission link for each, and performing the relay operation without capturing the communication data, it is not necessary to confirm the destination every time the communication data is received, so that the relay delay can be reduced.
As a result, communication collisions on the network due to relay delay can be avoided and network throughput can be improved.

1 is a configuration diagram of a time division multiple access network system according to Embodiment 1. FIG. 6 is a diagram illustrating an example of communication frame allocation information according to Embodiment 1. FIG. 3 is a diagram illustrating a configuration example of communication data according to Embodiment 1. FIG. FIG. 6 is a diagram illustrating information held by the relay device 6 according to the first embodiment. 6 is a diagram illustrating determination of a relay method of the relay device according to the first embodiment. FIG. It is a figure which shows the relay operation | movement by Ta-Ta + Da of the relay apparatus 6 which concerns on Embodiment 1. FIG. It is a figure which shows the relay operation | movement by Tb-Tb + Db of the relay apparatus 6 which concerns on Embodiment 1. FIG.

Explanation of symbols

  1 network management device, 2 communication device, 3 communication device, 4 communication device, 5 communication device, 6 relay device, 7 relay device, a link, b link, c link, d link, e link, f link.

Claims (6)

Time-division multiplexing comprising a plurality of communication devices and one or a plurality of relay devices connected to the communication devices via communication lines, and performing data communication between the plurality of communication devices via the relay device by time division A relay communication method in an access network system,
The relay device acquiring link information that is identification information of the communication device corresponding to each communication line;
The communication device and the relay device acquiring communication frame allocation information which is identification information of the communication device allocated to each communication time frame;
The relay device determines, based on the link information and the communication frame allocation information, a reception communication line for receiving communication data and a transmission communication line for transmitting communication data for each communication time frame;
The communication device transmitting communication data in a communication time frame assigned to the communication device;
The relay device receives communication data from the reception communication line corresponding to the communication time frame, and transmits the communication data to the transmission communication line corresponding to the communication time frame;
The communication device includes a step of receiving communication data in a communication time frame assigned to the communication device. A relay communication method in a time division multiple access network system. The step of acquiring the link information includes:
Obtaining the identification information of the communication device corresponding to each communication line based on the identification information of the communication device included in the communication data transmitted from the communication device and the communication line that has received the communication data. The relay communication method in a time division multiple access network system according to claim 1. A relay device connected to a plurality of communication devices via a communication line and performing communication by time division,
The relay device acquires link information that is identification information of each communication device corresponding to the communication line, and communication frame allocation information that is identification information of the communication device assigned to each communication time frame,
Based on the link information and the communication frame allocation information, for each communication time frame, determine a reception communication line for receiving communication data and a transmission communication line for transmitting communication data,
A relay device that receives communication data from the reception communication line corresponding to the communication time frame and transmits the communication data to the transmission communication line corresponding to the communication time frame.   The relay device identifies the communication device corresponding to each communication line based on the identification information of the communication device included in the communication data transmitted from the communication device and the communication line that has received the communication data. The relay apparatus according to claim 3, wherein information is acquired and the link information is generated.   5. The relay device according to claim 3, wherein the relay device is connected to the communication device and a network management device that broadcasts the communication frame allocation information to the communication device and the relay device via a communication line.   The relay device according to claim 3, wherein the relay device is a switching hub.

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