JP6462230B2 - Simultaneous output method for information transmission, simultaneous output system for information transmission - Google Patents

Description

  The present invention relates to a method of simultaneous output in information transmission, and more particularly to one-to-many packet transmission.

  In general, in a LAN (Local Area Network) including a server and a plurality of clients, it is necessary to control data passing over the LAN. This is because data may collide on the LAN.

  For example, in a PON (Passive Optical Network) system such as that disclosed in Patent Document 1, data collision is monitored, and when a collision occurs, transmission is interrupted and re-transmission control is performed later. Therefore, in this related PON system, there may be a delay in the arrival of data between clients. Therefore, in Patent Document 1, the transmission device creates a correction value for the time information of the terminal device using the round-trip transmission delay time with the terminal device and the time information of the transmission device, and transmits the correction value to the terminal device. The terminal device is assumed to include the estimated arrival time information based on the time information of the terminal device and the correction value received from the transmission device in the frame transmitted to the transmission device.

JP 2009-65443 A

  However, in the method of retransmitting data when a collision occurs as in Patent Document 1, it is difficult to simultaneously transmit the same data between a plurality of clients.

  An object of the present invention is to realize one-to-many simultaneous packet output without competing with other signals.

  The method of simultaneous output in information transmission according to the present invention includes extracting time stamp information, which is a relative time difference from a reference signal related to downlink broadcast packet transmission, and information regarding the presence or absence of the time stamp information from the received packet, and outputting the time stamp information and output The packet is output until the sum of the delay adjustment time and the time when the reference signal is counted matches, and further, priority control is performed using information on presence / absence in packet output.

  The system for simultaneous output in information transmission of the present invention comprises a server for broadcasting information and a client for receiving information, and the client is time stamp information and time stamp information which are relative time differences from a reference signal related to information broadcast packet transmission. Information from the received packet is output, the packet is output until the sum of the time stamp information and the output delay adjustment time matches the time counted by the reference signal, and the packet is output. Perform priority control using information.

  According to the method of simultaneous output in information transmission and the system of simultaneous output in information transmission according to the present invention, simultaneous output of one to many packets can be realized without competing with other signals.

It is a figure explaining the timing of the packet output in the one-to-many information sending concerning embodiment of this invention. It is a block diagram of related one-to-many packet transmission using a layer 2 switch. It is a figure explaining the one-to-many packet sending method concerning embodiment of this invention. It is a storage example of the time stamp information in the packet header concerning embodiment of this invention. It is a flowchart which shows the process of the packet after reception of the client concerning embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the following description, components having the same function may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 1 is a view for explaining packet output timing in one-to-many information transmission according to an embodiment of the present invention.

  A timing supply device 1 (not shown) supplies a reference signal indicating a common timing to the server 2 and the client 3. After receiving the reference signal, the server 2 transmits a large number of information to be sent to the plurality of clients 3. The relative time difference between the transmission timing and the reference signal is stored in the header of the packet as time stamp information Ts. After receiving the packet from the server 2, the client 3 outputs information toward the terminal at the same timing using the time elapsed from the reference signal and the Ts extracted from the received packet. Ts is constantly changing and is given for each piece of information to be transmitted. Therefore, the output timing common to all clients is set according to the information to be transmitted.

  In the present embodiment, when information is collectively sent to a plurality of clients 3, for example, a common reference signal from a timing supply device 1, which is a transmission means other than packet transmission, is taken into the server 2 and the client 3. Thereby, a common timing is provided between the server 2 and the client 3. The relative time difference Ts determined based on this common timing is stored in the header of the transmission information and sent together. As a result, the time information elapsed from the reference signal is shared among all the clients 3. The fixed transmission line delay time until reaching the client 3 with the longest delay (for example, the client 3 located at the farthest end from the server) can be calculated, and this is common to all the clients 3 using Ts. Set the waiting time.

  FIG. 3 is a diagram for explaining a one-to-many packet sending method according to an embodiment of the present invention. A GPS satellite 8 is used as a timing generation device for supplying a reference timing to the server 2 and the client 3 by using a global positioning system (GPS). The timing supply device 1 supplies the reference signal received from the GPS satellite 8 to the server 2 and each client 3. The transmission device 6 is a transmission device responsible for packet transmission / reception. Server 2 is the source of the packet. The client 3 is a device that receives a packet broadcast from the server. Each client 3 outputs a packet received from the server to the terminal.

  The server 2 generates time stamp information Ts based on the timing signal received from the timing supply device 1. The server 2 adds the time stamp information Ts to the packet header and transmits the packet.

  The time stamp information Ts is generated using a counter included in the server 2. The counter operates with a clock (CLK) supplied from the timing supply device 1 using GPS. The reference clock signal used for the counter has a different phase (clock count timing) for each client. For this reason, the time error is one clock of the clock used in this counter. The accuracy of Ts can be adjusted by changing the clock frequency to be counted. Increasing the clock speed increases the accuracy of Ts, and decreasing the clock speed decreases the accuracy of Ts.

  FIG. 4 shows an example of storing time stamp information in the packet header according to the embodiment of the present invention. As shown in FIG. 4, in addition to the time stamp information Ts, information on the presence or absence of the time stamp information Ts is stored in the packet header in order to perform output priority control.

  FIG. 5 is a flowchart showing the processing of the packet after reception of the client according to the embodiment of the present invention.

  After receiving the packet, the client 3 detects time stamp information Ts and Ts presence / absence information indicating the validity of the Ts field (packet header analysis process, step S1).

If there is time stamp information Ts in step S1, the client 3 extracts the time stamp information Ts from the packet (step S2) . Next, the client 3 counts the reference signal received from the timing supply device 1 to obtain a time count value (Time Counter, step S3). The above-mentioned “count reference signal” means that the client 3 obtains time information elapsed from the reference signal.

  The time count value is compared with the sum of the time stamp information Ts extracted from the received packet and the system delay value (the longest transmission line fixed delay in this embodiment) which is an output delay adjustment buffer (comparison, step S4).

  When the time count value matches the value of Ts + System delay, the client 3 enables reading of the packet buffer and outputs a packet. In this case, each client 3 performs output control at a common output timing, and as a result, simultaneous output is realized by all clients. (Read Timing gen, Step S5).

  If the time count value does not match the value of Ts + System delay, the client 3 performs the process of step S3 again.

  Further, priority control of packet output is performed by checking the presence or absence of time stamp information Ts. Specifically, for example, the signal level of the packet to which the time stamp information Ts is assigned is set to the High side, and the signal level of the packet not assigned is set to the Low side. Thus, by classifying the packets by dividing the signal level and storing the packets in different output queues, for example, an uplink transmission packet not assigned with the time stamp information Ts does not intersect with a delay adjustment waiting for downlink transmission. Output (output priority control, step S6).

  In addition, although the above-described embodiment is broadcast packet transmission in layer 2, also in layer 3, a packet multicasted using the information of the transmission path fixed delay time and time stamp information Ts is transmitted to the terminals between the destination clients. Can output simultaneously.

  In the above-described embodiment, a signal received from a GPS satellite is used at a timing common to all apparatuses. However, other methods for obtaining the reference timing include NTP (Network Time Protocol) or SNTP (Simple Network Time Protocol). It is also possible to use a time synchronization method such as

  In the above-described embodiment, the system delay is set by each client of the packet transmission destination. However, the server may define the system delay and store it in the packet header.

  In the above-described embodiment, any delay measurement method and setting method can be used. In the above-described embodiment, the resetting when the delay time is changed does not depend on a specific method.

(effect)
According to the present embodiment, one-to-many packet simultaneous output can be realized without competing with other signals in a single channel.

FIG. 2 is a block diagram of related one-to-many packet delivery using a layer 2 switch.
The server 2 is a packet sending device that broadcasts packet signals. L2SW4 is a packet sending relay device. The L2SW 4 relays the packet signal broadcast from the server and sends it to each client. The client 3 outputs a packet signal to the terminal.

  Here, consider a case where a packet signal is simultaneously output from the server 2 to each client 3. In this case, each client 3 receives a packet from the server 2 through a different transmission delay time. For this reason, the timing of packet output from the client 3 to the terminal differs for each client.

  Here, there are two causes for the sending delay, namely, the transmission path delay and the delay caused by the packet sending process in the L2SW4. The transmission line delay is caused by the distance of the transmission line 7 for each client.

  In the related packet sending apparatus, even if a delay adjusting buffer is provided and the same output delay adjusting time is set, the output timing of the client 3 varies due to the above-described difference in sending delay time.

  In the relay unit (L2SW4), a downlink packet signal broadcast from the server 2 to the client 3 and an uplink packet signal conveying a response from the client 3 to the server 2 are input to one client. There is. At this time, if they are placed in the same output queue, a delay occurs in packet transmission (contention due to L2SW4 queuing). As a result, the output timing of information from the client 3 to the terminal 5 varies. On the other hand, in the simultaneous output method in information transmission and the simultaneous output system in information transmission according to this embodiment, the output timing does not vary as described above.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.

1 Timing supply device 2 Server 3 Client 4 L2SW
5 Terminal 6 Transmission device 7 Transmission path 8 GPS satellite Ts Time stamp information

Claims (8)

Time stamp information that is a relative time difference between a timing at which a server transmits a broadcast packet to a client and a reference signal related to transmission of the broadcast packet , and information on the presence or absence of the time stamp information are extracted from the received packet;
The sum of the time stamp information and the output delay adjustment time, which is the delay time in the longest transmission path, set in the client that has received the time stamp information matches the elapsed time from the reference signal in the client. Wait until it outputs the packet,
Furthermore, in the output of the packet , a method of simultaneous output in information transmission for performing priority control using information on the presence / absence. 2. The method for simultaneous output in information transmission according to claim 1, wherein the priority control is control not to wait for output of the packet when the information on the presence / absence indicates that the time stamp information is not present. The packet not including the time stamp information is an upstream transmission packet
The method of simultaneous output in information transmission according to claim 2 . The method for simultaneous output in information transmission according to any one of claims 1 to 3 , wherein the reference signal is acquired from a transmission means other than the server and the client in the server and the client . 5. The method of simultaneous output in information transmission according to claim 4, wherein the transmission means is transmission using a global positioning system satellite. The downstream header of the received packet includes the time stamp information and the presence / absence information.
The method of simultaneous output in information transmission according to any one of claims 1 to 5 . The method for simultaneous output in information transmission according to claim 1 , wherein the time stamp information is provided for each transmission destination of the downstream packet for each transmission of the downstream packet . A server that broadcasts information;
A client receiving the information;
With
Information regarding the presence / absence of the time stamp information and the time stamp information, which is a relative time difference between the timing at which the server related to transmission of the broadcast packet of the information transmits the broadcast packet to the client and the reference signal related to transmission of the broadcast packet. From the received packet, the sum of the time stamp information and the output delay adjustment time, which is the delay time in the longest transmission path, set in the client that received the time stamp information and the elapsed time from the reference signal Wait until the time matches, and output the packet, and in the output of the packet, perform priority control using the information on the presence or absence
A system for simultaneous output in information transmission .

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