KR100584355B1 - Cell transmission / reception method between AMT layer and physical layer - Google Patents

Abstract

The present invention proposes a method of using a supercell introduced at Utopia Level-3 when transmitting and receiving a cell between an ATM layer device and a physical (PHY) layer device. When the ATM layer device receives the cell, it is determined whether the cell is the user cell and the 'with the cell to send' state from the information included in the header in the supercell, and then transmits a read enable signal to the corresponding physical layer device and reads the cell. It will be. When the ATM layer device transmits a cell, it is determined from the information included in the header of the supercell to determine whether the physical layer device for cell transmission is in a 'cell space available' state and then writes a write enable signal to the corresponding physical layer device. Send the cell.

Description

Cell transmission / reception method between AMT layer and physical layer

The present invention relates to an ATM switching network, and more particularly, to a method for transmitting and receiving a cell between an ATM layer and a physical layer.

The Basic Reference Model (ATM), which is well known in Asynchronous Transfer Mode (ATM) switching networks, includes a physical layer (PHY) 11, an ATM layer 12, ATM Adaptation Layer (AAL) 13 and Higher Layers 14. In addition, a management and control block 10 for managing and controlling each layer is connected to each layer. In this basic reference model, matching between layers is required. For example, a universal test and operation physical interface for ATM (UTOPIA) refers to a protocol for interface between a physical layer and an ATM layer.

Conventionally, in UTOPIA level 2 for matching between an ATM layer and a physical layer, a cell of a 16-bit mode having a format as shown in FIG. 2 is used. According to the UTOPIA Level 2, when a cell is to be transmitted at a transmission rate of 622 Mbps, a direct status method, a multiplexed polling method, and the like are used to match an ATM layer and a plurality of physical layers. .

On the other hand, with the development of ATM switching technology, it is required to transmit cells at a higher transmission rate. In these days, it is required to transmit cells at a transmission rate of OC-48 / STM-16 (2.48Gbps) between the ATM layer and the physical layer. It is a trend. However, when using the cell format of the 16-bit mode as shown in Figure 2 there is a disadvantage that can not support the transmission rate of 2.48Gbps. In addition, the direct state method or multiplexing polling method has a disadvantage in that it cannot actively cope with varying transmission rates and matching methods.

Accordingly, an object of the present invention is to provide a cell transmission / reception method between an ATM layer and a physical layer in an ATM switching network.

Another object of the present invention is to provide a cell transmission / reception method between an ATM layer and a physical layer to support a transmission rate of 2.48 Gbps when transmitting a cell between an ATM layer and a physical layer.

It is still another object of the present invention to provide a cell transmission / reception method between an ATM layer and a physical layer that can actively cope with varying transmission rates and matching schemes.

The present invention for achieving the above object proposes a method of using a supercell introduced at Utopia Level-3 when transmitting and receiving a cell between an ATM layer device and a physical layer device. When the ATM layer device receives the cell, it is determined whether the cell is the user cell and the 'with the cell to send' state from the information included in the header in the supercell, and then transmits a read enable signal to the corresponding physical layer device and reads the cell. It will be. When the ATM layer device transmits a cell, it is determined from the information included in the header of the supercell to determine whether the physical layer device for cell transmission is in a 'cell space available' state and then writes a write enable signal to the corresponding physical layer device. Send the cell.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or chip designer, and the definitions should be made based on the contents throughout the present specification.

First, the present invention configures a header according to a cell format as shown in FIG. 3, and configures an in-band transmission connection between an ATM layer device and a physical layer device as shown in FIG. It is to be noted. The cell format shown in FIG. 3 is a cell format at UTOPIA level-3, which is scheduled to be presented in an ATM forum. Such a cell is called a 'super cell'.

Referring to FIG. 3, a supercell is structured with a header of 8 octets and a payload of 48 octets. The first 32 bits of the header are structured as VPI, GFC, PHY id [11: 0], CLAV [7: 0], type {3: 0}, and the second 32 bits are structured as UDF, VCI, VPI. . The type {3: 0} is 4 bits of data, and it is data that distinguishes whether the cell is an idle cell, a user cell, or a multicast cell. CLAV [7: 0] is 8-bit data that indicates whether or not a cell is available on a link of the corresponding physical layer device. The PHY id [11: 0] is 12 bits of data and identifies which physical layer device of the physical layer is connected. UDF (User Defined) is 8-bit data and consists of data such as payload type (PT), cell loss priority (CLP), and parity check. In the supercell, four bits (7 to 4) of GFC (Generic Flow Control), 8 bits (3 to 0, 31 to 28) of VPI (Virtual Path Identifier) and 20 bits (27 to 8) are well known. VCI (Virtual Channel Identifier) is included.

Referring to FIG. 4, each of the ATM layer device 40 and the plurality of physical layer devices (PHY 0 to PHY n) 41 to 43 connected to the ATM layer device 40 has an SOC [n: 0] terminal and an ENB [n: 0] terminal and a SUPER [31: 0] terminal. More specifically, the SOC [n: 0] terminals of the ATM layer device 40 and the physical layer devices (PHY 0 to PHY n) 41 to 43 are connected to each other through the L1 line, and the ENB [n: 0] terminal is connected to L2. The lines are connected to each other, and the SUPER [31: 0] terminals are connected to each other via the L3 line. In the devices, the ENB [n: 0] terminal is a terminal for transmitting and receiving the read enable signal RDenb and the write enable signal WRenb, and the SUPER [31: 0] terminal is a terminal for transmitting and receiving a supercell. At this time, the supercell is transmitted and received in units of 32 bits (4 octets).

The connection configuration between the ATM layer and the physical layer according to the present invention is different from the various polling methods at the UTOPIA level-2 such that the CLAV [7: 0] signal indicating whether the cell is valid is transmitted together with the data cells. do. That is, the super cell always flows through the L3 line as the data line. The ATM layer transmits a read enable signal RDenb to each physical layer device in a kind of round-robin manner, and reads the supercell coming up correspondingly.

5A and 5B illustrate a flow of processing a flow of a cell transmitted and received between an ATM layer and a physical (PHY) layer. 5A illustrates a flow of transmitting a cell from the PHY layer to the ATM layer, that is, a flow of receiving the cell by the ATM layer. 5B is a diagram illustrating a flow of transmitting a cell from an ATM layer to a PHY layer.

First, a process of receiving a cell at an ATM layer will be described with reference to FIG. 5A.

Now, assuming that a cell arrives at any one of the plurality of PHY layer devices in step 51 of FIG. 5A, the corresponding PHY layer device sets a user cell to a value of type in step 53, and CLAV. Set the link value corresponding to the value of and set the device value corresponding to the PHY id value. In contrast, if the cell does not arrive, the stuffed cell is set to the value of type in step 52, the link value corresponding to the CLAV value is set, and the device value corresponding to the PHY id value is set. Set it. This set value goes up. In this case, when it is determined in step 54 that the enable signal is received from the upper layer, the corresponding device places the supercell on the L3 line which is a superbus line in step 55.

In step 56, the ATM layer first reads the first 32-bit data from the supercell, and determines in step 57 whether it is a user cell or a stuffed cell. Next, when it is determined in step 58 that the CLAV signal indicates a 'cell to send' state, in step 59, the read enable signal RDenb is continuously transmitted to the corresponding PHY layer device for one cell time. Read

Next, a process of transmitting a cell in the ATM layer will be described with reference to FIG. 5B.

In the transmission, the supercell is used in the same manner as the operation in the reception. In step 61, the ATM layer checks the PHY id and the CLAV signal included in the header of the supercell. This is because the PHY id contains the id of the PHY layer device that will transmit the cell. Next, in step 62, the ATM layer transmits the write enable signal WRenb to the corresponding PHY layer device in step 63 when the CLAV state value most recently indicates a 'cell receiving space' state, and transmits the supercell data. do.

As described above, the present invention uses a supercell when transmitting and receiving a cell between an AT layer and a physical layer. This has the advantage of enabling the transmission of OC-48 / STM-16 (2.48Gbps) because of the 32-bit data path. In addition, the present invention can support a large number of ports, can be designed to support later OC-192 or more, parity check with control signals as well as payload, and can reduce the number of output of the pin It can be easily muxed to a large number of ports and has the advantage of simplifying the design.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a diagram illustrating a basic reference model used in an ATM switching network to which the present invention is applied.

FIG. 2 is a diagram illustrating a cell format of a 16-bit mode used in matching between an AT layer and a physical layer according to the related art. FIG.

3 is a diagram illustrating a super cell format to be used in matching between an AT layer and a physical layer according to the present invention.

4 is a diagram illustrating an in-band connection configuration between an AT layer and a physical layer using a supercell according to the present invention.

5A and 5B illustrate a cell transmission flow between an AT layer and a physical layer according to the present invention.

Claims (3)

In the method of receiving a cell from any one physical layer device of the AT layer device to which a plurality of physical layer devices are connected, A first process of setting a user cell, a corresponding link value, and a corresponding device value in a header within a super cell by the physical layer device receiving the cell and raising the set value to a higher level; A second process in which the physical layer device puts a supercell on a superbus line when an enable signal is received from the upper layer, A third step in which the AT layer device reads 32-bit header information from among the received supercells as the second process is performed, and determines whether the cell is a user cell and whether there is a cell to be sent; And a fourth process of transmitting a read enable signal to the physical layer device and reading a cell when it is determined that the user cell and the cell to be transmitted are present in the third process. The method of claim 1, wherein the read enable signal is transmitted for one cell time. A method of transmitting a cell to a physical layer device by an AT layer device to which a plurality of physical layer devices are connected, Determining a physical layer device for cell transmission from a physical layer device ID included in a header of the supercell; A second process of determining whether the physical layer device has a space to receive a cell; And a third process of transmitting a write enable signal and transmitting a cell when it is determined that the physical layer device has a space to receive a cell.