Towards more practical LCAS for VCAT in MSTP ASIC
Peng Wang, Jishi Li, Depeng Jin, Lieguang Zeng · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
Link Capacity Adjustment Scheme (LCAS) is a protocol to provide hitless bandwidth adjustment of virtual concatenated (VCAT) signal under the control of network management system (NMS). It has much larger flexibility to dynamically assign resources and becomes an important feature for multi-service transport platform (MSTP) systems. However, the scheme is a two-way handshake signalling with status messages exchanged continuously, which can hardly be implemented within a single chip. Aiming at an easier implementation in ASIC, we revise the LCAS protocol to have a shorter handshaking procedure by adding MST bits in the reserved K4 bits and remove the complex mappings between TU12s and theirs SQs. Simulation results show that the revised LCAS shortens the period of handshaking procedure and synthesis results show that the size of logic is greatly reduced. We believe the new scheme will be accepted and applied in future.