Convergence of Terrestrial and Undersea Networks
By Adam Hotchkiss and Richard Romagnino
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Traditionally, submarine optical system design and development have been largely separated from its terrestrial counterpart. Undersea networks typically rely on optical technologies promoting lengthy unregenerated reach in ideal conditions without frequent physical layer reconfiguration. On the other hand, terrestrial networks largely promote optical technologies allowing for a wide variety of distances with less than ideal fiber conditions. Additionally, in the past, the consortium model that dominated the deployment of submarine systems dictated that the submarine network would be operated as separate entity, independent of the terrestrial network. Since the negotiation of the technical content of the submarine network was carried out by a group of diverse companies with often conflicting commercial interests, innovations that would lead to optimization of the network for any given carrier’s model were difficult to implement. The effect was a “lowest common denominator” from the service perspective and a “known risk-free approach” for bandwidth management and restoration. Innovations were generally centered on addressing technical issues such as propagation delay and transmission distances, rather than innovation in services. As a result, the network architectures that emerged from the consortium developments were optimized for partitioned reliable services, but were dissociated from the end-to-end services they were intended to carry. The end result was an equipment configuration at cable-stations intended to facilitate opaque demarcation, with often wasteful equipment planning practices.