JP4143881B2 - Network system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a network system in which the same isochronous channel number can be used in a plurality of nodes using an IEEE 1394 interface.
[0002]
[Prior art]
In the IEEE 1394 bus isochronous communication, regarding acquisition of a channel number and bandwidth, all nodes desiring to transmit isochronous data are nodes that manage isochronous resources using asynchronous communication {hereinafter referred to as IRM ( The channel number and the required bandwidth are obtained from the "isochronous resource manager".
This means the following. That is, a node that desires isochronous data transmission has acquired a different channel number from another node that desires isochronous data transmission, and each node has acquired a bandwidth that can be occupied for 125 μs. The total bandwidth that can be acquired by all nodes cannot exceed 125 μs.
[0003]
Each node wishing to transmit isochronous data has a maximum bandwidth to transmit in one cycle of its own node even if the isochronous data transmission interval is much slower than 125 μs and the communication accuracy does not require 125 μs. Must be acquired separately, and a finite number of channel numbers and a finite bandwidth were not used effectively.
[0004]
As for the case where the same data is transmitted to a plurality of nodes of the IEEE 1394 bus system, conventionally, asynchronous broadcast communication is used when the same data is transmitted to a plurality of nodes. However, this method causes the transmitted packet to be executed up to a transaction process of a node that is not necessary.
Therefore, it is said that asynchronous broadcast communication should not be transmitted as much as possible, and isochronous communication is performed separately for each node.
In this method of performing isochronous communication addressed to each node, processing time is required each time the number of destination nodes increases.
[0005]
FIG. 11 shows an example in which channel numbers and bandwidths are not effectively used when the same data is transmitted to a plurality of conventional nodes in such an IEEE 1394 bus system.
In FIG. 11, one cycle of a cycle start packet (Cycle Start Packet) CP is 125 μs, and is shown between the arrows in FIG. 11. However, in FIG. Shown.
The cycle start packet CP is a node that becomes a cycle master (Cycle Master, which is described as being the same node as the cycle master and IRM in FIG. 11) existing in a network that performs isochronous communication at every arrow interval. Sent from
[0006]
Further, data transmitted by a plurality of nodes B, C, and D (all of which are not shown in FIG. 11) existing in the network, that is, x in isochronous packet data Bx, Cx, and Dx is The numbers 1, 2, 3,... Are shown.
FIG. 11 shows the flow of data when the nodes B, C, and D are performing isochronous communication. The data Bx, Cx, and Dx use different channel numbers, and a total of three channels are used. Each node B, C, D is obtained from the IRM.
The reserved bandwidth is the total bandwidth of the data Bx, Cx, and Dx, that is, (Bx + Cx + Dx).
[0007]
[Problems to be solved by the invention]
As apparent from the above, in the conventional isochronous communication of the IEEE 1393 bus system, there is a problem that a node that desires isochronous data transmission does not effectively use a finite number of channel numbers and a finite bandwidth.
In addition, when the same data is transmitted to a plurality of nodes in the IEEE 1394 bus system, there is a problem that the transmission node takes a processing time each time the number of destination nodes increases.
[0008]
The present invention has been made to solve the above-described conventional problems, and enables sharing of isochronous resources among a plurality of nodes, enabling effective use of isochronous resources and transmitting the same data to a plurality of nodes. It is an object of the present invention to provide a network system that can be easily performed by isochronous communication without using asynchronous broadcast communication or multiple times of asynchronous communication.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a network system according to the present invention, in the isochronous communication of the IEEE 1394 bus system, is connected to the IEEE 1394 bus, has at least a cycle master function, and includes a cycle start data including cycle time data. A packet is transmitted to the cycle master to which the node ID is assigned, and to the IEEE 1394 bus connected to the IEEE 1394 bus and sharing the same isochronous channel number. Node I connected to acquire the bandwidth with the same isochronous channel number and the maximum bandwidth required in one cycle, and inform the plurality of nodes of the acquired isochronous channel number And a representative node that is allocated In addition, the cycle master also has a function of managing isochronous resources using asynchronous communication (cycle start packet). It is characterized by that.
Therefore, in the isochronous communication of the IEEE 1394 standard bus system, the same isochronous channel number is shared by a plurality of nodes using the information of the cycle time data included in the cycle start packet transmitted by the cycle master. As a result, resources such as the channel number and bandwidth of isochronous communication can be provided by a plurality of nodes, and the resources of isochronous can be used effectively.
Further, when the same data is transmitted to a plurality of nodes, it can be easily performed by isochronous communication without using asynchronous broadcast communication or multiple times of asynchronous communication.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a network system according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention, and shows an example of connection in a network of nodes A, B, C, D, and E which are devices capable of performing isochronous communication. These nodes A, B, C, D, and E are connected to an IEEE 1393 standard bus system.
The node A is connected to the nodes B, C, and D, and the node D and the node E are connected. Node IDs having values of “0” to “number of nodes−1” are individually assigned to the nodes A to E.
In the network, among these nodes A to E, there are one node that is effective as the cycle master and one node that is effective as the IRM.
[0011]
The cycle master and the IRM may be the same node (IEEE 1394 standard). Therefore, in the first embodiment, for the sake of explanation, the description will be made assuming that the function is effective with the node A as the cycle master and the function as the IRM is also effective. In other words, the node A has both the cycle master and IRM functions.
Further, the node B among the plurality of nodes B to E is assumed to be a representative node representing them.
[0012]
FIG. 3 shows a data format of a cycle start packet. A packet transmitted by the cycle master every broadcast at intervals of 125 μs, and each node B to E serves as a trigger for transmitting isochronous communication.
Also, “destination ID” in FIG. 3 is a destination node ID (FFFFh), “t1” is a transaction label (00b), “rt” is a retry code (00b), and “source ID” "Is the source node ID (Cycle Master node ID)," destination offset "is set to the standard address of the cycle master, and" header CRC "is the CRC of the packet.
[0013]
FIG. 2 shows an example in which the same isochronous channel number according to the present invention is shared by a plurality of nodes (corresponding to the nodes B to E in this first embodiment), so that the channel number and the bandwidth can be used effectively. Is shown.
Also in FIG. 2, as in FIG. 11, the generation interval length of the cycle start packet CP is shown differently for the sake of space.
The data Bx, Cx, and Dx (x indicates the data number as in FIG. 11) of the nodes B to D shown in FIG. 2 share the same isochronous channel number, and one channel is acquired. is doing.
Further, the bandwidth is acquired only for the largest bandwidth among the data Bx, Cx, Dx of the nodes B to D.
[0014]
Next, the first embodiment will be specifically described. Node B, which is a representative of a plurality of nodes B, C, and D that desire to share the same isochronous channel number, needs one channel number from IRM (node A) in one cycle using asynchronous communication. Get bandwidth with maximum bandwidth.
This bandwidth is the bandwidth that requires the most among the nodes that wish to share the same isochronous channel number.
Node B, which is a representative of a plurality of nodes, informs the plurality of nodes B, C, and D of the acquired channel number.
[0015]
Asynchronous communication can be used for determining the number of nodes B, C, D and their representatives who wish to share the same isochronous channel number, for determining the maximum bandwidth, and for notifying the acquired channel. It can be fixed in the system or any method.
Any node may have the cycle master or IRM function enabled.
[0016]
Each node B, C, D receives the cycle start packet CP transmitted from the node A as the cycle master, and extracts the cycle time data shown in FIG. 4 included in the cycle start packet CP.
FIG. 5 is a block diagram showing the internal configuration of each of the nodes B, C, and D. For example, when the representative node B is described as an example, when the node B receives the cycle start packet CP, The packet extraction unit 1 extracts the data packet, and transfers the extracted data packet to the data reception processing unit 3.
The data reception processing unit 3 performs, for example, data reception processing such as frequency conversion from a data packet, demodulation processing by a demodulation unit and decoding into an audio signal, and output of sound from a speaker or the like. .
[0017]
Further, when the cycle start packet CP is input at the node B, the cycle start packet extraction unit 2 extracts the cycle start packet CP.
The extracted cycle start packet CP is sent to the cycle time data extraction unit 4 and the normal isochronous data transmission unit 5 of the cycle time data utilization means 8.
The cycle time data extraction unit 4 extracts the cycle time data included in the cycle start packet CP and outputs it to the exclusive control processing unit 6 of the cycle time data utilization means 8.
The exclusive control processing unit 6 causes the shared isochronous data transmitting unit 7 of the cycle time data using means 8 to exclusively transmit isochronous data using this cycle time data.
[0018]
Further, by outputting the cycle time data extracted by the cycle start packet extraction unit 2 to the normal isochronous data transmission unit 5, the normal isochronous data transmission unit 5 transmits normal isochronous data.
In this way, each of the nodes B, C, and D receives the cycle start packet transmitted by the node A as the cycle master, and the cycle time shown in FIG. 4 included in the cycle start packet is shown in FIG. By extracting data and using this cycle time data, it is possible to perform exclusive control such that only one of the nodes A, B, C, and D transmits isochronous data.
[0019]
Here, a specific example of how to use cycle time data will be described. Each node B, C, and D extracts 13 bits (hereinafter referred to as Cycle Count) from bits 12 to 24 of the cycle time data shown in FIG.
Cycle Count is a counter that increases by one for each cycle start packet transmission.
[0020]
By using this Cycle Count and performing any one of the following processes (1) to (5), isochronous data transmission can be shared between the same cycle in which the cycle start packet CP is generated. Exclusive control in which only one of the nodes B, C, and D to be transmitted transmits isochronous data can be realized.
Instead of the Cycle Count, 7 bits (hereinafter referred to as Second Count) of bits 25 to 31 of the cycle time data shown in FIG. 4 may be used.
However, this Second Count is a counter that increases by 1 every 1 Sec.
[0021]
(1). A method of realizing exclusive control using the value of Cycle Count and the own node ID (in the case of FIG. 6).
The nodes B, C, and D that share isochronous data transmission use isochronous using the shared channel number when the lower 6 bits of the Cycle Count and the self-assigned node ID value are the same timing. Send data.
As a result, each of the nodes B, C, and D can transmit at an interval of (64 * 125 μs).
This exclusive control using the cycle count value and the own node ID will be described in more detail with reference to FIG. 6. FIG. 6 shows the configuration of the cycle time data utilization means in each of the nodes B, C, and D. Is a block corresponding to the cycle time data utilization means 8 shown in FIG.
[0022]
In FIG. 6, the nodes B, C, and D sharing the same isochronous channel number are connected to the cycle time data extracted from the cycle start packet by the cycle time data extraction unit as described in FIG. Data is detected by the lower 6 bits detection unit 9 of the cycle time and sent to the comparison unit 10.
A node ID value 11 automatically assigned to each of the nodes B, C, and D is also input to the comparison unit 10.
Therefore, the comparison unit 10 compares the lower 6 bits of the Cycle Count with this node ID value, and the isochronous data transmission trigger signal shared when the lower 6 bits of the Cycle Count and the node ID value are equal. 12 is output to perform isochronous data transmission.
[0023]
(2). A method of realizing by using the value of Cycle Count, the own node ID, and the number of connected nodes (FIG. 7).
Nodes B, C, and D that share the same isochronous channel number have the shared channel number when the remainder value obtained by dividing the Cycle Count value by the number of connected nodes is equal to the own node ID value. Use isochronous data transmission.
As a result, each of the nodes B, C, and D can transmit at {(64% number of connected nodes) * 125 μs} at an interval of one time.
Here, “%” is a multiplication operator.
[0024]
Here, with reference to FIG. 7, a method for realizing isochronous data transmission with the same isochronous channel number shared by using the value of Cycle Count, the own node ID, and the number of connected nodes will be described in detail.
In FIG. 7, the nodes B, C, and D that share isochronous data transmission with the same isochronous channel number are the cycles extracted from the cycle start packet by the cycle time data extraction unit as described in FIG. By inputting time data to the cycle time extraction unit 13 of the cycle time data utilization means 8, the value of Cycle Count is extracted and output to the calculation unit 14.
[0025]
The computing unit 14 also receives the number of connected nodes 15. As a result, the calculation unit 14 divides the value of Cycle Count by the number of connected nodes 15 and outputs a remainder value as a result of the calculation to the comparison unit 10.
The comparison unit 10 is also input with its own node ID value 11. Therefore, the comparison unit 10 compares the remainder value with the own node ID value 11 and transmits isochronous data in which the same isochronous channel number is shared at the same timing between the remainder value and the own node ID value 11. The trigger 12 is output and isochronous data is transmitted using the same isochronous channel number.
[0026]
(3). A method of realizing by using “ID for identifying a transmittable timing” not defined in the IEEE 1394 standard instead of the own node ID used in the above (1) (FIG. 8).
A transmission timing ID (hereinafter referred to as a transmission timing ID) for identifying a transmission timing having a different value from each of the nodes B, C, and D that share the same isochronous channel number and perform isochronous data transmission. Assign.
The transmission timing ID can be assigned by any method, such as using asynchronous communication, or setting specific to a node using ROM, hardware, software, or the like.
The nodes A, B, C, and D that perform sharing transmit isochronous data using the shared channel number when the value of the lower 6 bits of the Cycle Count is equal to the transmission timing ID value.
[0027]
Here, with reference to FIG. 8, a method for realizing isochronous data transmission using an ID for identifying a transmittable timing will be specifically described.
In FIG. 8, the nodes B, C, and D that share isochronous data transmission of the same isochronous channel number are extracted from the cycle start packet by the cycle time data extraction unit as described in FIG. By inputting the time data to the cycle time extraction unit 13 of the cycle time data utilization means 8, the lower 6 bits of the Cycle Count are extracted and output to the comparison unit 10.
[0028]
The comparison unit 10 is also input with a transmission timing value ID 16 for identifying a transmittable timing not defined by the IEEE 1394 standard.
The comparison unit 10 compares the lower 6-bit value of the Cycle Count with the transmission timing ID value 16, and when the lower 6-bit value of the Cycle Count and the transmission timing ID value 16 have the same timing, the same isochronou An isochronous data transmission trigger 12 having a shared channel number is output, and isochronous data is transmitted using the shared channel number.
[0029]
(4). Instead of the local node ID and the number of connected devices (number of connected nodes) used in the above item (2), an “ID for identifying a transmittable timing” and “basic interval of transmittable timing” not defined in the IEEE1394 standard Is realized by using “a predetermined value” (FIG. 9).
A transmission timing ID (hereinafter referred to as a transmission timing ID) for identifying transmission possible timings having mutually different values for each of the nodes B, C, and D to be shared, and a basic interval of transmission possible timings having the same values. Is set (hereinafter referred to as a transmission timing interval value).
[0030]
Note that the “transmission timing ID” can be assigned and the “transmission timing interval value” can be set by any method such as using asynchronous communication or setting specific to a node using ROM, hardware, software, or the like.
The nodes A, B, C, and D that perform sharing share the same isochronous when the remainder of the Cycle Count value divided by the “transmission timing interval value” and the “transmission timing ID” value are equal. Send isochronous data using the channel number.
[0031]
Here, with reference to FIG. 9, the same isochronous channel number is shared by using “ID for identifying a transmittable timing” and “a value for defining a basic interval of transmittable timing” which are not defined in the IEEE1394 standard. The method of realizing the isochronous data transmission that is being performed will be described more specifically.
In FIG. 9, the nodes B, C, and D that share isochronous data transmission sharing the same isochronous channel number are cycle start data extraction units as described in FIG. By inputting the cycle time data extracted from the packet to the cycle time extraction unit 13 of the cycle time data utilization means 8, the value of Cycle Count is extracted and output to the calculation unit 14.
[0032]
The calculation unit 14 also receives a transmission timing interval value 17. The calculation unit 14 divides the Cycle Count value by the transmission timing interval value 17 and outputs a remainder value obtained as a result of the division to the comparison unit 10.
The comparison unit 10 is also input with a transmission timing ID 16 for identifying transmission possible timings having different values.
Thereby, the comparison unit 10 compares the remainder value from the calculation unit 14 with the transmission timing ID 16 and outputs an isochronous data transmission trigger 12 that is shared when the remainder value and the transmission timing ID 16 are equal. And isochronous data transmission using a shared channel number.
[0033]
(5). Using the method (4) above, by assigning a plurality of “transmission timing IDs” to one node, it is possible to arbitrarily set the transmission order and interval of isochronous communication of a shared channel ( FIG. 10).
This will be described more specifically with reference to FIG. In FIG. 10, the nodes B, C, D that share isochronous data transmission of the same isochronous channel number are extracted from the cycle start packet by the cycle time data extraction unit as described in FIG. By inputting time data to the cycle time extraction unit 13 of the cycle time data utilization means 8, the value of Cycle Count is extracted and output to the calculation unit 14.
[0034]
A transmission timing interval value 17 is also input to the calculation unit 14. The calculation unit 14 divides the Cycle Count value by the transmission timing interval value 17 and outputs a remainder value obtained as a result of the division to the comparison unit 10.
On the other hand, a plurality of transmission timing ID1 values 16a, 16b,..., Transmission timing IDn values 16n assigned to each of the nodes B, C, and D are input to the multiplex 18.
The multiplex 18 receives a plurality of transmission timing ID1 values 16a, 16b,..., And a transmission timing IDn value 16n so that the transmission order and interval of the isochronous communication of the shared channel can be arbitrarily set. The transmission timing ID1 values 16a, 16b,..., And the transmission timing IDn value 16n are input sequentially or arbitrarily, and output to the comparator 10.
[0035]
The comparison unit 10 compares any one of the transmission timing ID1 value 16a, the transmission timing ID2 value 16b,... The transmission timing IDn value 16n, which is switched and input by the multiplex 18, and the remainder value input from the calculation unit 14.
As a result of this comparison, an isochronous that is shared when the value of the remainder value and any one of the transmission timing ID1 value 16a, transmission timing ID2 value 16b,... By outputting the data transmission trigger 12, it is possible to arbitrarily set the transmission order and interval of the isochronous communication of the shared channel.
[0036]
【The invention's effect】
As described above, according to the present invention, in the isochronous communication of the IEEE 1394 standard bus system, the same isochronous channel is utilized by using the information of the cycle time data included in the cycle start packet transmitted by the cycle master. Since the number is shared by a plurality of nodes, resources such as the channel number and bandwidth of isochronous communication can be provided by the plurality of nodes, and the resources of isochronou can be effectively utilized.
In addition, when the same data is transmitted to a plurality of nodes, it is possible to easily perform isochronous communication without using asynchronous broadcast communication or multiple times of asynchronous communication.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first embodiment of a network system according to the present invention.
FIG. 2 shows that the same isochronous channel number applied to the first embodiment of the network system according to the present invention is shared by a plurality of nodes so that the plurality of nodes perform isochronous communication by effectively using the channel number and the bandwidth. It is explanatory drawing which shows the flow of data at the time.
FIG. 3 is an explanatory diagram showing a data format of a cycle start packet applied to the first embodiment of the network system according to the present invention.
FIG. 4 is an explanatory diagram showing a format of cycle time data included in a cycle start packet applied to the first embodiment of the network system according to the present invention.
FIG. 5 shows that only one node transmits isochronous data using a cycle time data value included in a cycle start packet transmitted by a cycle master applied to the first embodiment of the network system according to the present invention. It is a block diagram which shows the structure of the exclusive control process part in the case of enabling exclusive control so that it may do.
FIG. 6 shows the cycle time when exclusive control is enabled so that only one node transmits isochronous data using the cycle time data applied to the first embodiment of the network system according to the present invention; -It is a block diagram which shows the structure of a data utilization means.
FIG. 7 shows a configuration of cycle time data utilization means when only one node transmits isochronous data using the node IID and the number of connected nodes applied to the first embodiment of the network system according to the present invention; It is a block diagram.
FIG. 8 is a block diagram showing a configuration of cycle time data utilization means when only one node using transmission timing ID applied to the first embodiment of the network system according to the present invention transmits isochronous data; .
FIG. 9 shows the structure of cycle time data utilization means when only one node transmits isochronous data using the transmission timing ID and transmission timing interval value applied to the first embodiment of the network system according to the present invention; FIG.
FIG. 10 is a block diagram showing the configuration of cycle time data utilization means applied to the first embodiment of the network system according to the present invention when only one node transmits isochronous data using a plurality of transmission timing ID values; It is.
FIG. 11 is an explanatory diagram showing a data flow when a channel number and a bandwidth are not effectively used when a plurality of nodes in a conventional communication network are performing isochronous communication.
[Explanation of symbols]
A to E: Node, 1 ... Data packet extraction unit, 2 ... Cycle start packet, 3 ... Data reception processing unit, 4 ... Cycle time data, 5 ... Normal isochronous data transmission unit , 6... Exclusive control processing unit, 7... Shared isochronous data transmission unit, 8... Cycle time data utilization means, 9... Lower 6 bit extraction unit of cycle time, 10. ... Node ID value, 12... Shared isochronous data transmission trigger, 13... Cycle time extraction unit, 14... Arithmetic unit, 15 .. number of connected nodes, 16. ˜16n... Transmission timing ID1 value to transmission timing IDn value, 17... Transmission timing interval value, 18.

Claims (14)

In isochronous communication of the IEEE 1394 bus system, the cycle start function is connected to the IEEE 1394 bus and has at least the cycle master function of the cycle master function and the isochronous resource manager function, and includes cycle time data. A cycle master that sends a packet and is assigned a node ID;
A plurality of nodes connected to the IEEE 1394 bus, wishing to share the same isochronous channel number, and each assigned a node ID;
A representative node that is connected to the IEEE 1394 bus, obtains a bandwidth with the same isochronous channel number and the maximum bandwidth required in one cycle, and is assigned a node ID that informs the plurality of nodes of the obtained isochronous channel number When,
With
The cycle master has a function of managing isochronous resources using asynchronous communication (cycle start packet).   The node includes a cycle time data extraction unit that extracts a 13-bit cycle count of bits 12 to 24 of cycle time data included in the cycle start packet, and the cycle time data extraction unit. A data transmission unit shared by a plurality of nodes so that only one node among a plurality of nodes to be shared between the same cycle in which the cycle start packet is generated based on the cycle count extracted in step 1 transmits isochronous data. 2. The network system according to claim 1, further comprising a cycle time data utilization unit including an exclusive control processing unit that performs exclusive control on the network. 3. The network system according to claim 2 , wherein the cycle count is replaced with a 7-bit second count of bits 25 to 31 of the cycle time data. The cycle time data utilization means is configured such that each of the plurality of nodes desiring to share the same isochronous channel number has 13 to 13 of bits 12 to 24 of cycle time data included in the cycle start packet. The isochronous data transmission is performed using a shared channel number to a plurality of nodes at a timing when the value of the lower 6 bits of the cycle count of the bit and the automatically assigned automatic node ID value are equal. 2. The network system according to 2 . The cycle time data utilization means includes a cycle time lower 6-bit extraction unit that extracts lower 6 bits of a 13-bit cycle count from bits 12 to 24 of the cycle time data, and the cycle time When the value of the lower 6 bits of the cycle count extracted by the lower 6-bit extracting unit is compared with the value of the node ID automatically assigned to each of the plurality of nodes, and when both values are equal The network system according to claim 2, further comprising: a comparison unit that outputs a trigger for isochronous transmission of the same isochronous channel number shared by the plurality of nodes. The cycle time data utilization means is configured such that each of the plurality of nodes desiring to share the same isochronous channel number has 13 to 13 of bits 12 to 24 of cycle time data included in the cycle start packet. Isochronous using the same isochronous channel number shared by the plurality of nodes at the same timing as the remainder when dividing the value of the cycle count of the bit by the number of connected nodes and the value of the node ID of the local node The network system according to claim 2, wherein data transmission is performed. The cycle time data utilization means includes a cycle time extraction unit that extracts a 13-bit cycle count value from the cycle time data to bits 12 to 24 of the cycle time data, and the cycle time extraction. The computation unit that outputs the remainder value when the cycle count value extracted by the division is divided by the number of connected nodes is compared with the remainder value output by the computation unit and its own node ID value, and both values 3. The network system according to claim 2, further comprising: a comparison unit that outputs a trigger for performing isochronous data transmission of the same isochronous channel number shared by a plurality of nodes at the same timing. The cycle time data utilization means is defined by a cycle time extraction unit for extracting a 13-bit cycle count value from the cycle time data to bits 12 to 24 of the cycle time data and an IEEE 1394 standard. The ID value that identifies the timing at which transmission is not possible is compared with the lower 6 bits of the cycle count value extracted by the cycle time extraction unit, and is shared by a plurality of nodes when both values are equal. The network system according to claim 2, further comprising: a comparison unit that outputs a trigger for isochronous data transmission of the same isochronous channel number. 9. The network system according to claim 8 , wherein the ID value for identifying the transmittable timing is assigned to each of the plurality of nodes that share isochronous resources. The plurality of nodes that share the isochronous channel number perform isochronous transmission using the shared channel number when the lower 6 bits of the cycle count and the transmission timing ID value are equal in timing. The network system according to claim 8 . The cycle time data utilization means is a basic interface of transmission timings having 13-bit cycle count values from 12 to 24 of the cycle time data extracted from the cycle time data having the same value. A remainder value obtained by dividing by the bar value and a transmission timing ID for identifying the transmission possible timings having different values not defined in the IEEE 1394 standard for the plurality of nodes sharing the isochronous channel number. 3. The network system according to claim 2, wherein the plurality of nodes perform isochronous transmission using the same isochronous channel number shared at the same timing. The cycle time data utilization means includes a cycle time extraction unit that extracts a 13-bit cycle count value of bits 12 to 24 of the cycle time data extracted from the cycle time data, and the cycle time data An arithmetic unit that outputs a remainder value obtained by dividing the cycle count value extracted by the time extraction unit by a basic interval value at a transmittable timing having the same value, and the residual value output by the arithmetic unit And the same isochronous shared by the plurality of nodes when the values are equal to each other when compared to the transmission timing ID for identifying the transmission possible timing having different values and not defined in the IEEE 1394 standard. Send isochronous using channel number Network system according to claim 2, characterized in that it comprises a comparing section for outputting the trigger fit. The cycle time data utilization means is a basic interface of transmission timings having 13-bit cycle count values from 12 to 24 of the cycle time data extracted from the cycle time data having the same value. transmission of burls value divided by the remainder value and isochronous communication either with isochronous channel number the same value is shared at the timing when the coincidence of the transmission timing ID value their respective assigned to the plurality of nodes when 3. The network system according to claim 2 , wherein a trigger is output so that the order and interval to be set can be arbitrarily set. The cycle time data utilization means includes a cycle time extraction unit that extracts a 13-bit cycle count value of bits 12 to 24 of the cycle time data extracted from the cycle time data, and the cycle time data A calculation unit that outputs a remainder value when the cycle count value extracted by the time extraction unit is divided by a basic interval value at a transmittable timing having the same value, and a plurality of values are assigned to each of the plurality of nodes. A multiplex that switches and outputs these transmission timing ID values so that the transmission order or interval of isochronous communication of the shared channel can be arbitrarily set by inputting the transmission timing ID values, and the above calculation unit Output from the above-mentioned remainder value and the above multiplex Is so as to the be arbitrarily set an order or interval for transmitting the isochronous communication channel that is shared at the timing of the transmission timing ID values match, claims, characterized in that it comprises a comparing section for outputting a trigger 2. The network system according to 2 .

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