| 摘要 |
PURPOSE: A data transmission device in accordance with ATM(Asynchronous Transfer Mode) adaptation layer(AAL)2 protocol is provided to reduce hardware load in AAL2 process layer by transmitting in a certain time period or in a certain length when sending source data having changeable length. CONSTITUTION: A selection multiplexer(55) selects among an ATM cell header generator(51), a start field(STF) generator(52), a common part sublayer packet header(CPS-PH)(53), and a charged load of a certain length by control signal. A common part sublayer packet header(CPS-PH) is read from a packet received from upper layer and sent to the common part sublayer packet header(CPS-PH) generator(53). A channel identifier(CID) is read from the common part sublayer packet header(CPS-PH) and sent to the conversion table(57). A virtual path identifier and virtual channel identifier(VPI/VCI) correspond to the channel identifier(CID) is received and sent to the ATM cell header generator(51). A control block(56) sends out a control signal to the selection multiplexer(55) to select transmission order as the ATM cell header generator(51), the start field(STF) generator(52), the common part sublayer packet header(CPS-PH)(53), and a charged load of a certain length by control signal.
|
