Towards IP-Optical Integration: Interconnecting Gigabit IP Routers Over Switched Optical Backbone

A re-configurable optical backbone provides a flexible transport infrastructure that eases many operational hurdles, such as fast provisioning, robust restoration and disaster recovery. It can also be shared with other service networks such as ATM, Frame Relay, and SONET/SDH. From that perspective, an agile transport infrastructure is definitely the architecture of choice. The IP-over-OTN solution is also more scalable since the core of the network in this architecture is based on more scalable optical switches rather than IP routers. But what about cost? Since the IP-over-OTN solution introduces a new network element, namely the optical switch, is it more expensive? In this talk, we address that question by comparing IP-over-WDM and IP-over-OTN architectures from an economic standpoint using real-life network data. We show that contrary to the common wisdom, IP-over-OTN architecture can lead to substantial reduction in capital expenditure through reduction of expensive transit IP router ports. The savings increases rapidly with the number of nodes in the network and traffic demand between nodes. The economies of scale for the IP-over-OTN backbone increases substantially when we move traffic restoration from the IP layer to the optical layer. We also compare the two architectures from the perspective of scalability, flexibility. and robustness.