Cost Comparison of Alternative Architectures for IP-over-Optical Core Networks

We explore alternative architectures to reduce cost of IP-over-optical core networks. We conducted a detailed cost study of three architectures. We start with a Baseline architecture that captures present mode of operations with future traffic projections and utilizes technologies such as Ethernet line-cards and OTN sub-wavelength switching. The next architecture, Streamlined, replaces the hub-and-spoke topology of Baseline with a flat topology and is also more judicious in its restoration design. Our detailed study shows significant cost savings for the Streamlined architecture compared to the Baseline. We reduce the cost further in our third proposed architecture: Ethernet enabled IP core consisting of OTN switches (with and without packet switching) and without any backbone routers or MPLS switches. Our results also demonstrate that we can achieve significant reduction in switching costs but reducing cost of transport remains a significant challenge. This paper is an extended version of our previous work published in (11th international conference on the design of reliable communication networks (DRCN), pp 227---234, 2015).