KR970002713B1 - Atm cell add/drop multiplexer in the ring structure for real-time communication - Google Patents

Abstract

None.

Description

[Name of invention].

ATM Cell Branching / Combination Multiplexer under Ring Structure for Real-Time Communication

[Brief Description of Drawings]

1 is a block diagram of an ATM cell branch / combined multiplexer according to the present invention;

2 is a block diagram of a ring connection node to which the present invention is applied;

3 is a block diagram of data transmitted and received on a ring,

4 is a timing diagram of an ATM cell branch / combined multiplexer when data is transmitted to buffer 1 from a local station;

5 is a timing diagram of an ATM cell branch / combined multiplexer when data is sent to buffer 2 from a local station;

5 is an arbitration timing diagram of an ATM cell branch / combined multiplexer when data is simultaneously transmitted to buffer 1 and buffer 2 in a local station.

* Explanation of symbols for main parts of the drawings

10: branch / combined multiplexer 11,12: buffer control unit

13: cell arbitration unit 14: multiplexer

15: physical layer transmission unit 20: cell determination unit

31 to 33: buffer 41: physical layer transmitter

42: physical layer receiving unit

Detailed description of the invention

The present invention relates to an ATM cell branch / complex multiplexer (Add / Drop Multiplexer, hereinafter referred to as ADM) under a ring structure for real time communication.

The future communication network will develop into a communication network capable of accommodating a variety of information such as voice and data as well as video. For this purpose, the broadband integrated information communication network (hereinafter referred to as B-ISDN) is being standardized by ATM. Therefore, in order to accommodate such various services, B-ISDN has to replace all existing subscriber networks with optical cables, unlike narrow-band integrated telecommunication networks, and the portion of the subscriber network accounts for 40-50% of the total investment of the network. Research in this area should also be actively conducted.

The subscriber network of B-ISDN can be configured by installing a separate cable for each subscriber and using one cable jointly by multiple subscribers, like the existing telephone network. The disadvantage is that it takes.

Using the latter method, there are protocols such as DQDB, FDDI-II, and ATMR, which not only accommodate information such as voice, data and video, but also provide services over large areas such as cities, Because of the common use of a single optical cable can be configured economically, there is an advantage that can efficiently accommodate the broadcast-type services expected to achieve the mainstream of the initial B-ISDN service.

Accordingly, the present invention is a ring structure for real-time communication required when connecting the subscriber node to the ring in order to configure the subscriber access network in the form of a ring sharing a plurality of users in consideration of the utilization efficiency of the optical cable It is an object of the present invention to provide an ATM cell branch / coupling multiplexer.

In order to achieve the above object, the present invention provides a cell discriminating unit for determining whether data received through a physical layer receiving unit should be delivered to a local station, a neighbor node on a ring, or broadcast type data, and the cell. The data received through the physical layer receiver is stored in the buffer 2 and the buffer 3 according to the determination of the discriminator, and the ATM layer cell stream applied from the outside is stored in the buffer 1 to transmit to the buffer 1 and the buffer 2 from the upper layer of the local station. A buffer mediator for controlling the buffer 1 and the buffer 2 according to a search result of the buffers 1 and 2, and a cell mediator for controlling the buffer mediator A multiplexer for multiplexing data read from buffer 1 and buffer 2 by the control unit 1 and buffer 2; / Drop multiplex comprising a physical layer transmitting unit for converting a format for transmitting the data to the physical layer is characterized by comprising a.

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

1 is a block diagram of an ATM cell branch / combined multiplexer according to the present invention, and FIG. 2 is a diagram illustrating an internal structure of a connection node connecting a subscriber to a subscriber access network. WCLK is a write clock signal and WEN * is It is a write enable signal, RCLK is a read clock signal, REN * is a read enable signal, and OE * is an output enable signal.

The ATM cell branching / combining multiplexer is a cell discriminating unit 20 that determines whether data received through the physical layer receiving unit 42 should be delivered to a local station, to an adjacent node on a ring, or broadcast type data, and the According to the determination of the cell discriminating unit 20, data received through the physical layer receiving unit 42 is stored in the buffers 2 and 3, 32 and 33, and an ATM layer cell stream applied from the outside is stored in the buffer 1 31. The buffer 1 and buffer 2 controllers 11 and 12 for searching whether the data to be transmitted in the upper layer of the local station are stored in the buffer 1 and the buffer 2 (31, 32), and the buffer 1 and buffer 2 controllers ( A cell arbitration unit 13 for controlling the buffers 1 and 2 (31, 32) according to the search results of 11, 12, and a buffer 1 and buffer 2 control unit 11 under the control of the cell arbitration unit 13; Multiplexing, where (12) multiplexes the data read from buffer 1 and buffer 2 (31, 32) And a 14 and the multiplexer 14 / drop multiplexer 10 including a physical layer transmission section 15 to be converted to a format for transmitting the multiplexed data to the physical layer via.

The physical layer receiver 42 is composed of a G-TAXI Rx chip, receives a signal transmitted at 1.25Gbps through an optical fiber, and transmits the signal to the cell discriminator 20.

That is, all the data on the ring are stored in the access node and transmitted to the upper layer if the node is the receiving node. If the node is not the receiving node, the data is transmitted to the neighbor node on the ring through the ADM. If the data is broadcast data, it is transmitted to the local station and the neighbor node.

As described above, the cell discriminating unit 20 performs a function of determining whether the data (cell) read through the ring is data to be transmitted to a local station or data to be transmitted to an adjacent node on the ring and storing the data in a buffer.

In the case where the data received through the physical layer receiver 42 is data to be transmitted to the local station according to the determination of the cell discriminating unit 20, the data is sequentially stored in the buffer 3 33 and transmitted to the adjacent node on the ring. In the case of data, it is stored in the buffer 2 (32). In the case of broadcast data, the buffer 2 is simultaneously stored in the buffer 2 (32) and the buffer 3 (33).

On the other hand, the present invention uses a combination of two methods, the transmission side removal and the reception side removal in order to maximize the characteristics of the ring-shaped network, Liang's data transmission efficiency and ring utilization, general point-to-point data transmission In this case, the receiver receiving the data (cell) uses the receiver-side elimination technique to remove the data from the ring, and for the broadcast type data or the abnormal data, the transmitting node removes the data from the ring. use. That is, in the case of broadcast type data, all the access nodes on the ring copy and transfer to the upper layer of the own station, and when the data transmitted by the own node returns to the transmitting node, the transmitting node removes it from the ring.

Therefore, the cell determination unit 20 performs a function of discarding the received data if it is data originally transmitted by the cell.

3 shows a format of general data transmitted and received on a ring.

4 illustrates an ADM timing diagram when data is transmitted from a local station. If there is data to be transmitted to the buffer 1 31, the buffer 1 controller 11 transmits a cell arbitration unit (PAE * -1 signal (Active HIGH)). 13) indicates that there is data to be transmitted to buffer 1 (31). Accordingly, the cell arbitration unit 13 transmits the BI-START command to the buffer 1 control unit 11 so that the buffer 1 control unit 11 continuously stores data stored in the buffer 1 31 for one cell (53 octets). Control to read.

On the other hand, if there is data to be transmitted to the buffer 2 32, the buffer 2 controller 12 notifies the cell arbitration unit 13 that there is data to be transmitted to the buffer 2 32 through the PAE * -2 signal (Active HIGH), Accordingly, the cell arbitration unit 13 transmits the B2-START command to the buffer 2 control unit 12 so that the buffer 2 control unit 12 continuously performs buffer 2 (53 octets) for the same time as the buffer 1 control unit 11. Control to read the data saved in 32).

As described above, the data read from the buffer 1 (31) and the buffer 2 (32) is multiplexed in units of 4 octets through the multiplexing unit 14 and transferred to the physical layer transmitting unit 15, and thus the physical layer transmitting unit ( 15) converts the multiplexed data into an appropriate format so that the multiplexed data can be transmitted through an optical fiber and delivers the data to the physical layer transmitter 41. The actual timing at this time is equal to the fifth degree.

6 is a diagram illustrating a conventional arbitration timing diagram of an ATM cell branching / combining multiplexer when data is simultaneously transmitted to buffer 1 and buffer 2 at a local station. The data and buffer 2 of buffer 1 31 are mediated in ADM. Figure 32 shows the multiplexing of the data.

As shown in FIGS. 4 and 5, when data to be transmitted is stored in only one buffer, there is no problem in transmission through multiplexing. However, at a moment, data to be transmitted is stored in both buffer 1 and buffer 2 (31, 32). If so, there must be mediation between them. In other words, when data to be transmitted to the buffer 1 and the buffer 2 (31, 32) are stored at any moment, only data in a specific buffer must be transmitted through an algorithm.

In the present invention, 1: 1 arbitration is performed for each ATM cell. That is, when PAE * -2, which is a signal indicating that there is data to be transmitted to buffer 2 (32), is transmitted to cell arbitration unit 13 when data stored in buffer 1 (31) is transmitted, among the data in buffer 1 (31). Only one cell (53 octets) is transmitted, and one cell is extracted from the data in buffer 2 (32) and transmitted. In this case, even if there is data to be transmitted, the buffer 1 31 waits until one cell is transmitted from the buffer 2 32 and starts transmission again. In the case of the buffer 2 (32), the multiplexing is performed in the same manner. Therefore, when data is stored in the buffer 1 and the buffer 2 (31, 32), 1: 1 multiplexing is performed. Otherwise, hub-polling multiplexing is performed.

As described above, the present invention is a ring node access controller that can be commonly used in an ATM terminal device, a network access node, and a B-NT system in a B-ISDN environment, while minimizing losses in an ATM-based B-ISDN network. It can be efficiently used in a system of multiplexing cells at high speed.

Claims (1)

A cell discriminating unit 20 that determines whether data received through the physical layer receiving unit 42 should be delivered to a local station, to an adjacent node on a ring, or broadcast type data; And an ATM layer cell stream stored in buffers 2 and 3 (32, 33) stored in buffers 2 and 3 (32, 33) according to the determination of the cell discriminating unit 20, and applied from the outside to buffer 1 (31). Buffer 1 and buffer 2 controllers (11, 12) for retrieving whether data to be transmitted from a higher layer of a local station is stored in the buffers 1 and 2 (31, 32); The buffer 1 and buffer 2 controllers 11, under the control of the cell arbitration unit 13 controlling the buffers 1 and 2, 31 and 32, according to the search results of the buffer 1 and buffer 2 controllers 11 and 12; A multiplexer 14 for multiplexing the data read from the buffers 2 (31, 32) by 12; Real-time communication, characterized in that it comprises a branch / combined multiplexer 10 including a physical layer transmitter 15 for converting the data multiplexed through the multiplexer 14 into a format for transmitting to the physical layer. ATM cell branching / coupling multiplexer under the ring structure.