Asynchronous transfer mode: solution for broadband ISDN
Asynchronous transfer mode: solution for broadband ISDN
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The present paper describes the AMDA integrated circuit (ATM Multiplexer/Demultiplexor ASIC). The circuit has two operation modes: in multiplexer mode an ATM low speed flow (up to 622 Mbits/s) is inserted in the empty slots of a high speed ATM flow (2.5 Gbits/s); in demultiplexer mode, the cells belonging to the low speed channels are extracted from the high speed ATM flow. An specific algorithm of distributed control has been developed, simulated and implemented, in order to guarantee an even bandwidth distribution independently of the network node position. The circuit is able to handle 8 K connections, with four different qualities of service; it manages a local queue of up to 16 K ATM cells using an external high speed SSRAM. The maximum clock frequency of the circuit is 155,52 MHz and it has been processed with the LSI-LOGIC's LCB5OOK technology (0,5 /spl mu/m CMOS). It contains 34800 equivalent gates, 48 Kbit of single port memory and 8,5 Kbit dual port memory, using an area of 6,7/spl times/6,7 mm and it is packaged in a 208 pins QFP.