JPH01188058A - Routing information generating system - Google Patents

Abstract

PURPOSE:To decrease operating speed and to attain small scale and low power consumption by adopting the constitution so that a memory in a storage circuit is read once per one time slot and the storage circuit has only to store the information by (N-1) words with respect to address N-word. CONSTITUTION:The address is stored in a memory 3 in the unit of words based on an address counter 5 operated at sub-frame period. A 1st word of the address stored based on the address counter 5 is read out in the succeeding sub-frame and supplied to a table circuit 2 to generate routing information and a 2nd word of the address on a transmission frame is supplied to the table circuit 2 at the same time. The table circuit 2 generates the routing information based on the 2-word address information. Thus, the memory 3 in the storage circuit 1 has only to read once per one time slot. Moreover, the storage circuit 1 has only to store the information by (N-1) words with respect to the address N words.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a routing information generation method, and more particularly to a routing information generation method for a communication system in which addresses are added to user information and communication is performed by converting the user information into cells.

[Conventional technology]

Various methods have been studied for accessing the inside of the network in units of cells in which user information is divided into short information units and addresses are added thereto. One of them is a frame-by-frame cell multiplexing system shown in FIG. FIG. 3 is a diagram showing an example of the structure of a transmission frame used in this method. In this method, the cell shown in Figure 3(a) is divided into time slots (one time slot's worth of information is called a word), and the first subframe of the cell is placed in the allocated time slot of the first subframe of the frame. This is a method in which a word, in this case a first word of address information, is placed, and thereafter divided words of this cell are placed in the same time slot position as that given in the first subframe. Figure 3 (
b) shows a state in which cells are divided and multiplexed in the second time slot of each subframe. Therefore, cells as many as the timeslot multiplexing number of subframes are multiplexed within the frame. In such a system, as in other cell-type communication systems, it is necessary to generate routing information for intra-network access from address information. As in this example, when an address is transmitted using a plurality of words, in this case two words, the routing information is generated using the generation method shown in FIG.

FIG. 4 is a block diagram showing an example of a conventional routing information generation method, in which all address information of a transmission frame is stored in a storage circuit 1'. In FIG. 3, information on the first two subframes of the frame is stored. The stored address information is stored in the storage circuit 1 in which two words of corresponding address information are stored in each time slot of the third subframe.
’ is read out. The first word of address information read out is held in the latch circuit 4, and is supplied to the table circuit 2 which generates routing information together with the address information of another word read out next, and the routing information of this cell is generated. be done.

It is an object of the invention to operate at lower speeds and to operate at lower speeds. - 3. To provide a routing information generation circuit with low capacity.

[Problem that the invention seeks to solve]

In the conventional example described above, it is necessary to read two words of address information from the memory circuit 1' during one time slot, and a high-speed memory circuit is required. Another disadvantage is that the storage circuit needs to store information for two subframes.

[Means for solving problems]

The routing information generation method of the present invention divides one frame into multiple subframes, and further divides each frame into multiple time slots.
The multiple subframes in 1) are used for address information for providing routing, and the remaining subframes are used for user information,
Divide a cell consisting of address information and user 1'IW'l into time slot units, and multiplex this cell into the remaining subframe at the same time slot position as that multiplexed into the first subframe. In a communication system that performs communication, a storage circuit that stores the first (N-1) subframes and a memory circuit that stores the first (N-1) subframes and a memory circuit that stores the (N-1>timeslots) of cells multiplexed in each time slot of the Nth subframe The routing address information for (
N-1) Routing information is generated from address information for time slots and Nth time slot information.

〔Example〕

Next, the present invention will be explained with reference to FIGS. 1 to 3.

FIG. 1 is a method block diagram showing an embodiment of the routing information generation method of the present invention, and FIG. 2 is a circuit block diagram showing a detailed example of FIG. 1. The length of address information for each cell will be explained using two words as shown in FIG. 3 as an example. The present embodiment includes a memory circuit] and a table circuit 2, and the memory circuit 1 includes a memory 3 and an address counter 5. The information of the first subframe of the transmission frame is stored in the storage circuit 1. In FIG. 2, data is stored in the memory 3 word by word based on the address counter 5 which operates in subframe cycles. In the next subframe, the first word of the address stored on the basis of the address counter 5 is read out and supplied to the table circuit 2 which generates the routing information. At the same time, the second word of the address on the transmission frame is supplied to the table circuit 2.

The table circuit 2 generates routing information based on two words of address information.

With such a configuration, the memory 3 in the storage circuit 1 only needs to be read once in one time slot. Furthermore, the memory circuit 1 only needs to store information for N-1) words for N words of address.

〔Effect of the invention〕

As explained above, according to the present invention, the memory in the storage circuit only needs to be read once per time slot, so the operating speed can be reduced. Further, the memory circuit only needs to store information for N-1) words for N words of addresses, and is effective in reducing the size and power consumption.

[Brief explanation of the drawing]

FIG. 1 is a method block diagram showing an embodiment of the routing information generation method of the present invention, FIG. 2 is a circuit block diagram showing a detailed example of FIG. 1, and FIG. 3 is a diagram of a transmission frame used in the routing information generation method. FIG. 4 is a block diagram showing an example of a conventional routing information generation method. 1.1'...Memory circuit, 2...Table circuit, 3.
...Memory, 4...Latch circuit, 5...Address counter.

Claims (1)

[Claims] One frame is divided into multiple subframes, each frame is further divided into multiple time slots, and the first N (N>1) subframes at the beginning of the frame are used for address information that provides routing, and the remaining subframes are is used as user information, cells consisting of address information and user information are divided into time slot units, and such cells are multiplexed into the remaining subframe at the same time slot position as that multiplexed into the first subframe. In a communication system that performs communication, a memory circuit that stores the first (N-1) subframes, and (N-1) time slots of cells multiplexed in each time slot of the Nth subframe. 1. A method for generating routing information, characterized in that routing information is generated from address information for (N-1) time slots obtained by reading out routing address information for timeslots from the storage circuit and information for an N-th time slot.