Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
2000-05-26
2004-02-03
Pham, Chi (Department: 2667)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S389000, C370S392000, C370S474000
Reexamination Certificate
active
06687250
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for ATM (Asynchronous Transfer Mode) cell transfer in ATM communication system using AAL5 (ATM Adaptation Layer Type 5), an LSI (Large Scale Integrated circuit) unit, and a method for ATM cell transfer using AAL5.
Description of the Prior Art
Formerly, in a reassembly & segmentation processing of AAL5 (ATM Adaptation Layer Type 5), generally, priority is determined according to CLP-bit (Cell-loss priority bit) of ATM (Asynchronous Transfer Mode) cell header which CLP-bit is the priority in the ATM layer. The frame which is judged as the frame whose priority is low is discarded.
When the above described method is employed in such the reassembly & segmentation processing of the conventional device, in some cases, the priority of the upper layer is not reflected to the CLP-bit. Even though the frame which is a frame whose priority is high in the upper layer exists, such the frame with high priority is discarded caused by congestion in the ATM layer.
Further, when it causes the priority in the upper layer to be attempted to be reflected to the CLP-bit, it is not always reflected the priority accurately to the CLP-bit in the ATM cell header, because the CLP-bit is 1 (one) bit, while the priority in the upper layer is 4 to 8 bits.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention, in order to overcome the above-mentioned problems, to provide reassembly and segmentation (SAR:segmentation and reassembly sublayer) function of AAL5 while causing the priority in the upper layer to be reflected in the reassembly & segmentation processing of the AAL5 in the ATM layer processing.
According to a first aspect of the present invention, in order to achieve the above mentioned object, there is provided a device with quality controllable SAR function according to upper layer instruction, which comprises a frame storage means for executing reassembly of a frame of AAL5 (ATM Adaptation Layer Type 5) from an ATM (Asynchronous Transfer Mode) cell, an identification addition means for receiving a cell stream through a cell reassembly processor, and for adding an identifier on a basis of cell header information in order to introduce the cell which the frame storage means receives therein into the frame storage means or on the basis of upper layer information within a cell payload, a cell reassembly means for assembling the cell received by the cell reassembly processor, a next processing decision means having a second priority part for deciding either sending or abolition of the frame concerned on the basis of the received header on the occasion of sending the frame obtained from the cell received according to the cell reassembly processor and/or on the basis of the upper layer information within the payload, a storage means for storing therein an inputted transmission frame, and a selector for selecting the transmission frame sent from the storage means.
According to a second aspect of the present invention, there is provided a device with quality controllable SAR function according to upper layer instruction, which comprises a frame storage means for executing reassembly of a frame of AAL5 (ATM Adaptation Layer Type 5) from an ATM (Asynchronous Transfer Mode) cell, an identification addition means for receiving a cell stream through a cell reassembly processor, and for adding an identifier on a basis of cell header information in order to introduce the cell which the frame storage means receives therein into the frame storage means or on the basis of upper layer information within a cell payload, a cell reassembly means for assembling the cell received by the cell reassembly processor, a next processing decision means having a second priority part for deciding either sending or abolition of the frame concerned on the basis of the received header on the occasion of sending the frame obtained from the cell received according to the cell reassembly processor and/or on the basis of the upper layer information within the payload, a storage means for storing therein an inputted transmission frame, a selector for selecting the transmission frame sent from said storage means, and a cell segmentation processing means for decomposing to be processed the frame selected from the selector into cell.
A third aspect of the present invention, in the first or second aspect, there is provided a device with quality controllable SAR function, wherein the identification addition means has a first priority part which discards low priority frame in order to perform congestion avoidance accompanied by prescribed quality due to reception of high priority frame while deciding processing condition from cell header information received and/or the information from upper layer within payload when the cell reassembly means is congested.
According to a fourth aspect of the present invention, there is provided a device with quality controllable SAR function according to upper layer instruction, which comprises a frame storage means for executing reassembly of a frame of AAL5 (ATM Adaptation Layer Type 5) from an ATM (Asynchronous Transfer Mode) cell, an identification addition means for receiving a cell stream through a cell reassembly processor, and for adding an identifier on a basis of cell header information in order to introduce the cell which the frame storage means receives therein into the frame storage means or on the basis of upper layer information within a cell payload, a cell reassembly means for assembling the cell received by the cell reassembly processor, a next processing decision means having a second priority part for deciding either sending or abolition of the frame concerned on the basis of the received header on the occasion of sending the frame obtained from the cell received according to the cell reassembly processor and/or on the basis of the upper layer information within the payload, a storage means for storing therein an inputted transmission frame, and a selector for selecting the transmission frame sent from the storage means, wherein it causes a third priority part to be constituted by the storage means and the selector.
According to a fifth aspect of the present invention, in the second or forth aspect, there is provided a device with quality controllable SAR function according to upper layer instruction, wherein it causes a third priority part to be constituted by said storage means and said selector.
According to a sixth aspect of the present invention, there is provided a device with quality controllable SAR function according to upper layer instruction, which comprises a frame storage means for executing reassembly of a frame of AAL5 (ATM Adaptation Layer Type 5) from an ATM (Asynchronous Transfer Mode) cell, an identification addition means for receiving a cell stream through a cell reassembly processor, and for adding an identifier on a basis of cell header information in order to introduce the cell which the frame storage means receives therein into the frame storage means or on the basis of upper layer information within a cell payload, a cell reassembly means for assembling the cell received by said cell reassembly processor, a next processing decision means having a second priority part for deciding either sending or abolition of the frame concerned on the basis of the received header on the occasion of sending the frame obtained from the cell received according to the cell reassembly processor and/or on the basis of the upper layer information within the payload, a storage means for storing therein an inputted transmission frame, a selector for selecting the transmission frame sent from the storage means, a frame processing part interface, and a host processor interface for performing communication to the host processor.
According to a seventh aspect of the present invention, there is provided a device with quality controllable SAR function according to upper layer instruction, which comprises a frame storage means for executing reassembly of a frame of AAL5 (ATM Adaptation Layer
Amagai Tatsuhiko
Suzuki Yuichi
NEC Corporation
Qureshi Afsar M
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