JPH10135990A - Time division multiplex data transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect further more communication control LSIs by changing the allocation of a channel to the respective communication control LSIs for using a shared bus in a time division manner and mutually transferring data and allocating the channel only to the communication control LSI for transferring the data. SOLUTION: An 'Etherenet(R)' control part 30, for allocating the channel to 'Ethernet(R)' communication control LSIs 1-5 for using the shared bus 20 in a time division multiplex manner and mutually transferring the data, is provided. At the time of receiving the data from a network, the LSIs 1-5 request data transfer to a control part 30, and the control part 30 allocates the channel only to the communication control LSI requesting the data transfer. The communication control LSI transfers the data by the allocated channel. When it is ended, informs the control part 30 of that effect and opens the channel allocated by the control part 30. Thus, further more communication control LSIs are connected to the bus 20 without increasing hardware quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a plurality of communication controls L
The present invention relates to a time division multiplex data transfer method for allocating channels to SIs, and more particularly to a time division multiplex data transfer method that enables more communication control LSIs to transfer data without increasing the amount of hardware.

[0002]

2. Description of the Related Art As shown in FIG. 3, a switching hub used in a network is a communication device having a plurality of ports to which terminals can be connected and capable of simultaneous communication between a plurality of sets of ports. is there. As one of the configuration methods of the switching hub, there is a shared bus method in which a communication control LSI is provided for each port, and a plurality of communication control LSIs use a shared bus in a time-sharing manner.

FIG. 4 schematically shows a configuration of a data transfer circuit in a switching hub of a shared bus system.
Here, the data transfer circuit includes n communication control LSIs 11-
And communication control LSIs 11-1 to 11-n.
−n are mutually connected via the shared bus 20. The communication control LSIs 11-1 to 11-n mutually transfer data via the shared bus 20. A time region in which each communication control LSI is permitted to use the shared bus 20 is called a channel. Each communication control LSI performs data transfer using the assigned channel.

As shown in FIG. 5, when the data transfer capacity of the shared bus 20 per unit time is 40 Mbps, four 10M Ethernet (registered trademark) communication control L
A switching hub in which the SIs 1 to 4 are connected to the shared bus 20 can be configured. Each 10M Ethernet communication control LS
Channel assignments for I1 to I4 are as shown in FIG. That is, from time 0 to time t, the 10M Ethernet communication control LSI 1 performs data transfer. Similarly, the 10M Ethernet communication control LSI 2 performs data transfer from time t to time 2t, the 10M Ethernet communication control LSI 3 performs data transfer from time 2t to time 3t, and the 10M Ethernet communication control from time 3t to time 4t. The control LSI 4 performs data transfer. 10M
After the Ethernet communication control LSI 4, the 10M Ethernet communication control LSI 1 performs data transfer, and the operation is repeated.

[0005]

In the conventional time-division multiplex data transfer method, the channels to which each communication control LSI can transfer data are fixed. Therefore, there are the following problems.

The number of communication control LSIs that can be connected is limited by the transmission capacity of the shared bus. For example, when the data transfer capacity of the shared bus is NMbps, 10
The M Ethernet communication control LSI is limited to N / 10. In order to connect more communication control LSIs, it is necessary to increase the data transfer capacity by increasing the bus width of the shared bus. However, in this case, the amount of hardware increases and the cost increases.

It is an object of the present invention to solve the above-mentioned problems and to provide a time-division multiplexed data transfer method which enables more communication control LSIs to transfer data without increasing the amount of hardware.

[0008]

In order to achieve the above object, the present invention provides a method in which a plurality of communication control LSIs mutually transfer data using a shared bus in a time-division manner. The assignment can be changed, and a channel is assigned only to a communication control LSI that performs data transfer.

A vacant channel may be allocated in response to a data transfer request from a communication control LSI that performs data transfer, and the channel may be released in response to a data transfer completion notification from the communication control LSI that has completed data transfer.

[0010] Priorities may be determined in advance for the communication control LSIs, and when a data transfer request is issued from a communication control LSI exceeding the number of channels, channels may be allocated according to the priorities.

[0011]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

According to the present invention, a channel which has been fixedly allocated to each communication control LSI is dynamically allocated, and the channel allocation to each communication control LSI can be changed to perform data transfer. Communication control L
Channels are allocated only to SIs. Specifically, a free channel is allocated in response to a data transfer request from a communication control LSI that performs data transfer, and the channel is released in response to a data transfer completion notification from the communication control LSI that has completed data transfer.

Thus, even when the sum of the maximum data transfer amount per unit time of each communication control LSI exceeds the data transfer capacity per unit time of the shared bus, the channel assignment is changed according to the data transfer request. More communication control LSI without increasing the amount of hardware
Can be data transferable. For example, a plurality of communication controls LS having the same data transfer capacity per unit time
I shall be used. When the data transfer capacity of the shared bus per unit time is divided by the channel obtained by dividing the data transfer capacity per unit time of the communication control LSI, and the number of communication control LSIs is larger than the number of channels by this time division , Communication control L requesting data transfer
Channels are allocated only to SIs, and even if the number of channels is limited, more communication control LSIs than the number can be connected.

As shown in FIG. 1, a data transfer circuit to which the time-division multiplexed data transfer method of the present invention is applied comprises five Ethernet communication control LSIs 1 to 5, and these Ethernet communication control LSIs 1 to 5 are interconnected. And a control unit 30 that allocates channels to the Ethernet communication control LSIs 1 to 5.

When the Ethernet communication control LSIs 1 to 5 receive data from the network, they first make a data transfer request to the control unit 30. The control unit 30 allocates a channel only to the Ethernet communication control LSI that has issued the data transfer request. The Ethernet communication control LSI to which the channel is assigned performs data transfer using the shared bus 20 using the assigned channel. The Ethernet communication control LSIs 1 to 5 notify the control unit 30 of the end of the data transfer when the data transfer ends and there is no need to use the shared bus 20. Upon receiving this notification, the control unit 30 releases the channel allocated to the Ethernet communication control LSI, and allocates this channel to the Ethernet communication control LSI making another data transfer request.

By allocating a channel only to a communication control LSI that performs data transfer in this way, a larger number of communication control LSIs than in the conventional time-division multiplexed data transfer method.
Can be connected to a shared bus.

For example, in the data transfer circuit of FIG.
The data transfer capacity of the shared bus 20 per unit time is 40
When the transmission rate is Mbps, the number of 10M Ethernet communication control LSIs to which a channel is simultaneously allocated is four. Here, first, the Ethernet communication control LSIs 1 to
4 receives data from the network, and
When a data transfer request is made to the Ethernet communication control LSIs as shown in the upper part of FIG.
Channels are assigned to 1-4. That is, a channel from time 0 to time t is assigned to the Ethernet communication control LSI 1, a channel from time t to time 2t is assigned to the Ethernet communication control LSI 2, and a time from time 2t to time 3t to the Ethernet communication control LSI 3. Channel is assigned and the Ethernet communication control LS
The channel from time 3t to time 4t is allocated to I4. Next, assuming that the Ethernet communication control LSI 2 completes the data transfer and notifies the control unit 30 of that fact, the control unit 30 releases the channel allocated to the Ethernet communication control LSI 2, If the LSI 5 has made a data transfer request, as shown in the lower part of FIG.
The channel assigned to SI2 is assigned to Ethernet communication control LSI5.

In the data transfer circuit shown in FIG. 1, when the five Ethernet communication control LSIs 1 to 5 make a data transfer request to the control unit 30 at the same time, the data transfer request is arbitrated and the channel is assigned to the Ethernet communication control LSI. Determine the LSI. The arbitration of the data transfer request is performed by the arbitration circuit 40 in the control unit 30. In the arbitration circuit 40, the priority of the data transfer request of each of the Ethernet communication control LSIs 1 to 5 is set, and a channel is assigned to the Ethernet communication control LSI having a higher priority. For example, when the priority of the data transfer request of each of the Ethernet communication control LSIs 1 to 5 set in the arbitration circuit 40 is LSI1>LSI2>LSI3>LSI4> LSI5, the five Ethernet communication control LSIs 1 to 5
In the case where 5 makes a data transfer request to the control unit 30 at the same time, channels are assigned to the Ethernet communication control LSIs 1 to 4. Thus, when there is a data transfer request from communication control LSIs equal to or less than the number of channels, channels are allocated to all of the communication control LSIs,
When there is a data transfer request from the communication control LSI exceeding the number of channels, the channels are allocated according to the priority.

The present invention is applicable not only to the data transfer circuit shown in FIG. That is, when there is a data transfer request from communication control LSIs less than or equal to the number to which channels can be allocated, channels are allocated to all of these communication control LSIs, and data transfer from more than the number of communication control LSIs to which channels can be allocated. When there is a request, if a channel is assigned to a communication control LSI having a higher priority, a larger number of communication control LSIs than in the related art can be obtained regardless of the type of communication control LSI, the number of channels, and the data transfer rate. Can be connected.

[0020]

The present invention exhibits the following excellent effects.

(1) Since more communication control LSIs than the number of channels can use the shared bus in a time-sharing manner, more communication control LSIs can be used without increasing the amount of hardware.
Can be connected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a data transfer circuit to which a time division multiplex data transfer method of the present invention is applied.

FIG. 2 is a diagram illustrating channel assignment in an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a switching hub.

FIG. 4 is a schematic configuration diagram of a data transfer circuit in a switching hub of a shared bus system.

FIG. 5 is a schematic configuration diagram of a data transfer circuit having four 10M Ethernet communication control LSIs.

FIG. 6 is a diagram illustrating channel assignment according to the prior art.

[Explanation of symbols]

 1 to 5 Ethernet communication control LSI 20 shared bus 30 control unit 40 arbitration circuit

Claims (3)

[Claims] In a method in which a plurality of communication control LSIs mutually transfer data using a shared bus in a time-sharing manner, it is possible to change the assignment of a channel to each communication control LSI and only to a communication control LSI that performs data transfer. A time-division multiplexed data transfer method, wherein channels are allocated. 2. A method according to claim 1, wherein a vacant channel is allocated in response to a data transfer request from a communication control LSI that performs data transfer, and the channel is released in response to a data transfer completion notification from the communication control LSI that has completed data transfer. 2. The time division multiplexed data transfer method according to claim 1, wherein 3. A communication control LSI in which priorities are determined in advance, and when a data transfer request is received from a communication control LSI exceeding the number of channels, a channel is allocated in accordance with the priority. Division multiplex data transfer method.