The role of optical layer cross-connects in emerging network architectures

As long haul carriers begin to implement an optical layer, the optical cross-connect (OXCs) is emerging as the critical element. Whereas OXCs were originally envisioned (predominantly) as a vehicle for restoration, the importance of this role is arguably diminishing. This phenomenon is partially driven by the large amount of effort and progress made on IP restoration schemes. However, the ability for an OXC to enable a fast provisioning service is becoming one of paramount importance. The ability for a customer to obtain an OC-48 in seconds or minutes in contrast to the current weeks or months is indeed a viable service. We examine optical layer cross-connects (OLXCs) which may have either electronic or optical switching fabrics, their possible relationship (i.e., control plane) to routers, and their role in providing both restoration and possibly more importantly fast provisioning.