Quasi-dynamic intelligent optical networks: a proposal to solve essential scalability and cost issues in photonic core networks

摘要

This study proposes that a quasi-dynamic architecture is, in many cases, the best way to efficiently build and operate most of the photonic core. This is in contrast to the target architecture of other studies the evaluate enabling technology for truly dynamic photonic networking. A photonic core needs to provide three primary features: 1) fully, on-line managed connectivity between edge grooming devices and core routers; 2) cost efficient express traffic bypassing at intermediate network nodes; 3) re-configuration ability for grooming at 2.5Gb/s, 10Gb/s and 400b/s granularity for continuous optimization purposes. Truly dynamic networking features that enable traffic restoration and differentiated transport services are shown to be required for niche applications only. Formulas were derived to approximate the scaling of core network nodes. Additional formulas were derived to find the break-even point between two implementation alternatives of a photonic core network. One alternative is a strictly layered approach with photonic cross-connects (PXC) for dynamic switching purposes including traffic restoration. The second is a more synergetic approach with a quasi-dynamic, intelligent wavelength routing layer and client layer traffic protection. An ability to re-configure the wavelength routing layer on a monthly or quarterly basis is required for optimization purposes. Quasi-dynamic core grooming is about network configuration changes for continuous optimization. Based on assessments made with these formulas, next generation optical signal distribution technology is proposed to provide the required functionality. In summary, the paper proposes a unique approach to solve essential scalability and cost issues in photonic core networking, based on assessments of technology and cost structures of today and the near future.