Patent ID: 7769290

Claim:
An optical system comprising: a first network tier including a plurality of nodes optically interconnected by at least one optical communications path; a second network tier including a plurality of nodes disposed along the at least one optical communications path interconnecting the nodes in the first network tier, wherein: the nodes in the second network tier are connected to at least one of the nodes in the first network tier via the at least one optical communications path interconnecting the nodes in the first network tier, at least some traffic between the nodes in the first network tier travels through the at least one optical communications path and through at least one of the nodes in the second network tier without undergoing an optical-electrical-optical conversion, the nodes in the second network tier are configured to transmit all traffic to an adjacent node in the first network tier via the at least one optical communications path interconnecting the nodes in the first network tier, wherein the adjacent node in the first network tier is part of a working path for the traffic from the nodes in the second network tier, and the nodes in the first network tier are configured to transmit traffic to and receive traffic from other nodes in the first network tier and the nodes in the second network tier on the at least one optical communications path interconnecting the nodes in the first network tier.