Converge IP and DWDM Layers in the Core Network

One recent core network trend is the consolidation of multiple Layer 2/3 networks into a single IP/Multiprotocol Label Switching (IP/MPLS) infrastructure. In spite of this Layer 2/3 convergence, however, the underlying transport layer (Layer 1) of many service provider core networks has continued to use SONET/SDH, an infrastructure that was introduced in the early 1990s to support traditional time-division multiplexing (TDM)-based data and voice services. This SONET/SDH infrastructure was implemented to support three critical functions: grooming; protection and restoration; and thorough operational support (such as alarming and performance monitoring).

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