Patent ID: 6262995
Filing Date: 2001-07-17
Classification: H04L,H04Q

Abstract:
An asynchronous transfer mode adaptation layer (AAL) processing method using a central processing unit in an asynchronous transfer mode (ATM) terminal, the ATM terminal including a system memory for temporarily storing the ATM cells, a software segmentation and reassembly interface device (SSID) connected with a physical layer to interface with the physical layer the ATM cells, a double port RAM connected with the SSID for storing and drawing the ATM cells, and a central processing unit connected with the SSID for interfacing control information and for controlling a transmission and a reception of the ATM cells, the method comprising the steps of:breaking down an area of the system memory into three AAL1's, AAL3/4's, and AAL5's user data area;determining whether or not the SSID is using the double port RAM when the ATM cells are transmitted from the physical layer, and analyzing the transmitted ATM cells and reading an application layer level when the SSID is using the double port RAM;temporarily storing the ATM cells transmitted to the user data with AAL1 if the user data read is for AAL1;extracting control information of the ATM cells temporarily stored in the system memory, generating an interrupt to the SSID to obtain the use of the double port RAM and storing the ATM cells of the system memory by using control information if there is a reply from the SSID;generating an interrupt to the SSID against the use of the double port when the SSID is not using the double port RAM and storing the ATM cells in the double port RAM if there is the reply from the SSID;reading the ATM cells stored in the double port RAM using the SSID based on control information of the ATM cells when transmitting the ATM cells; andformatting the ATM cells to be suitable for a UTOPIA interface and transmitting the ATM cells to the physical layer.