| 摘要 |
PURPOSE: A device for converting a transmitting ATM adaptive layer(AAL)2, is provided to process the device as a new ATM cell type including one subscriber per ATM cell, so that an AAL2'ATM cell may be recovered into an AAL2 ATM cell. CONSTITUTION: In a device composed of a cubit, 4:1 mux, an utopia(UT) unit, a TC_TX unit and a line interface unit(LIU), the TC_TX unit includes a cubit interfacing unit(10), cell processing unit(11), a virtual channel identifier(VCI), an AAL2 processing unit(15), a mux 25(16) and a physical layer interfacing unit(17). The cubit interfacing unit(10) interfaces with the cubit in a level 1, and has a FIFO structure to store four ATM cells. The cell processing unit(11) extracts data of an AAL5 and an AAL2' from an inputted ATM cell. The virtual channel identifier(VCI) unit(12) translates a VC value of an inputted cell header, to identify that an inputted cell is either an AAL2 or the AAL5. The demux25(14), if a received ATM cell is the AAL5, transmits the AAL5 to a mux25(16) straightly, and if the AAL2', recovers the AAL2' into the AAL2, and then transmits to the mux25. The mux25(16) transmits gathered AAL2/AAL5 ATM cells to a physical layer interfacing unit. The physical layer interfacing unit(17) is composed of a FIFO to store two cells in an UT-scale interfacing block and a PM7334 MPH. |
