Combined COMBUS/APS/DXC in a single STM-4 Physical Layer Device expandable to a four device STM-16 configuration.
Original Publication Date: 2001-Jan-01
Included in the Prior Art Database: 2003-Jun-18
Combined COMBUS/APS/DXC in a single STM-4 Physical Layer Device expandable to a four device STM-16 configuration. The present disclosure relates to a physical layer device . A device can support an Add Drop Multiplex (ADM) feature for a STM-4 or 4 x STM-1 data stream in a single module configuration. It supports also the Add Drop Multiplex for a STM-16 or 4 x STM-4 data stream in a multiple module configuration.A4X4 digital-cross-connect (DXC) is also supported inside the device but there is no cross-connect possibilities between different devices. The Add or Drop STM-1 data streams are terminated at the Utopia Level 2 Bus. The device also supports TDM data streams connected to the 4 Telecombues. Automatic Protection Switching (APS) is supported for a single module (4 x STM-1) or for a four modules (16 x STM-1) configuration. The 1:n scheme uses addidional APS pins for n 4 16). This APS can only operate for a protection of a failing ATM or PPP 155 Mb/s data stream. A 622 Mb/s data stream or a TDM data stream protection is not supported. By moving the digital cross-connect out of the Utopia Handlers and combining them with the APS cross-connect located near the FIFOs, it is possible to cross-connect one or several 155/622 Mb/s data streams in a multi-module (STM-16 or OC-48) configuration independently of the type of data carried by the SDH/Sonet frame. With the new architecture shown in Fig. 1, it is now possible to protect an STM-16 data stream by installing 8 modules on the board to support a 1+1 APS scheme. By sharing the Telecombuses with the APS/DXC, no additional pins are needed even more the the 21 APS pins can be dropped, to offer a full 4x16 DXC and a complete APS feature.