In this paper, we consider the distribution of routing information for a large optical network consisting of metro and core sub-networks, all under the administrative control of a single carrier. In general, a connection starts in a metro sub-network, traverses a core sub-network, and terminates in another metro sub-network. An inter-sub-network routing protocol is needed to distribute the key information required to guide selection of the border nodes and links used to exit each sub-network when routing connections. We seek solutions that fit within the emerging GMPLS framework for distributed control of optical networks. This paper proposes two solutions. The first is based on a natural application of today's standard OSPF (Open Shortest Path First) protocol with the OSPF backbone area roughly coinciding with the core sub-network, and non-backbone areas coinciding with metro sub-networks. The second applies OSPF's reliable flooding mechanism to create routing policies where each sub-network (metro or core) summarizes just that information needed to choose appropriate border nodes and links.
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