The architecture of MAIN-ONU for FTTC-based access-network

This paper focuses on the functional architecture of the multi-service access integrated network-optical network unit (MAIN-ONU), which can provide diverse services via existing copper lines using very high bit rate digital subscriber line (VDSL) technology. The MAIN-ONU accommodates POTS/ISDN/VDSL interfaces in a system simultaneously and integrates heterogeneous traffic using ATM technology. We realize core functions in customized chips: ASAH-L4 for ATM layer processing, VLC-series for VDSL link control, and VTOA for circuit emulation. The requirements and configuration of the MAIN system are also discussed.