| 摘要 |
PURPOSE: A circuit agency service system in an ATM exchange is provided to easily transfer CBR(Continuous Bit Rate) traffic through an ATM network by interfacing an old transmission circuit network, such as DS3, T1, E1, etc., and the ATM network. CONSTITUTION: A cell bus driver part(10) interfaces transmitting/receiving stream cell bus processing parts(20,30) with an upper layer of an ATM exchange and transmits and receives ATM cells. The transmitting stream cell bus processing parts(20) processes an ATM cell supplied from the cell bus driver part(10) and supplies it to an ATM adaptive layer part(110). The receiving stream cell bus processing parts(30) translates the header of a cell supplied from an SAR/channel part(100), adds a 3-byte header and outputs it to an upper layer. A control part(40), communicating with an upper layer processor through a DPRAM(60), controls the whole operation of the ATM exchange. A clock part(50) drives the ATM adaptive layer part(110) and a line interface part(120) normally and supplies clocks to each device according to the control of the control part(40). The DPRAM(60) stores and then outputs the data necessary for the control part(40) to communicate with an upper layer. An SRAM(70) stores and then outputs the data generated according to communication between the control part(40) and the ATM adaptive layer part(110). A buffer part(80) temporarily stores and outputs the data between the SRAM(70) and the ATM adaptive layer part(110). An SRTS(Synchronous Residual Time Stamp) processing part(90) generates synchronization information and supplies it to a clock oscillation part(130). The SAR/channel part(100) is provided with the ATM adaptive layer part(110), the line interface part(120) and the clock oscillation part(130). The transmitting stream cell bus processing parts(20) is comprised of a transmitting cell processing part(21), a transmitting HTT(Header Translation Table)(22), the first transmitting FIFO(23) and the second transmitting FIFO(24).
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