Optical mesh network

Optical mesh networks are a type of telecommunications network.

Transport networks, the underlying optical fiber-based layer of telecommunications networks, have evolved from DCS (Digital Cross-connect system)-based mesh architectures in the 1980s, to SONET/SDH (Synchronous Optical Networking/Synchronous Digital Hierarchy) ring architectures in the 1990s. Technological advancements in optical transport equipment in the first decade of the 21st century, along with continuous deployment of DWDM (Dense Wavelength Division Multiplexing) systems, have led telecommunications service providers to replace their SONET ring architectures by mesh-based architectures. The new optical mesh networks support the same fast recovery previously available in ring networks while achieving better capacity efficiency and resulting in lower capital cost.

Optical mesh networks today not only provide trunking capacity to higher-layer networks, such as inter-router or inter-switch connectivity in an IP, MPLS, or Ethernet-centric infrastructure, but also support efficient routing and fast failure recovery of high-bandwidth services. This was made possible by the emergence of optical network elements that have the intelligence required to automatically control certain network functions, such as fault recovery.

Optical mesh networks enable Quality-of-Service protection and a variety of dynamic services such as bandwidth-on-demand, Just-In-Time bandwidth, bandwidth scheduling, bandwidth brokering, and optical virtual private networks that open up new opportunities for service providers and their customers alike.

Transport networks, the underlying optical fiber-based layer of telecommunications networks, have evolved from Digital cross connect system (DCS)-based mesh architectures in the 1980s, to SONET/SDH (Synchronous Optical Networking/Synchronous Digital Hierarchy) ring architectures in the 1990s. In DCS-based mesh architectures, telecommunications carriers deployed restoration systems for DS3 circuits such as at&t FASTAR (FAST Automatic Restoration) and MCI Real Time Restoration (RTR), restoring circuits in minutes after a network failure. In SONET/SDH rings, carriers implemented ring protection such as SONET Unidirectional Path Switched Ring (UPSR) (also called Sub-Network Connection Protection (SCNP) in SDH networks) or SONET Bidirectional Line Switched Ring (BLSR) (also called Multiplex Section - Shared Protection Ring (MS-SPRing) in SDH networks), protecting against and recovering from a network failure in 50 ms or less, a significant improvement over the recovery time supported in DCS-based mesh restoration, and a key driver for the deployment of SONET/SDH ring-based protection.

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