Optical networking uses thin glass or plastic optical fiber to transmit information in the form of light pulses. It is far more reliable and offers greater transmission capacity than conventional copper-wire networks.
SONET and Synchronous Digital Hierarchy (SDH) are the most common optical transport protocol standards used in optical networking. They both meet the needs of traditional voice traffic, where all traffic is high-priority and patterns are generally predictable.
Extremely demanding enterprise networking solutions can use Dense Wavelength-Division Multiplexing (DWDM) platforms. These deliver high-speed Ethernet connectivity and carrier interconnect, in addition to managed Storage Area Network (SAN) extension services.
DWDM typically supports all point-to-point and ring topologies, along with a variety of transmission distances. Transparent and protocol-independent, DWDM can carry SONET, SDH, storage protocols, data, and video.
Using DWDM, multiple signals can be transmitted simultaneously on one optical fiber, with each signal on a different wavelength. This allows multiple traffic types to be aggregated on to a single wavelength and transmitted over long distances uninterrupted, to deliver different types of services.
One recent optical networking innovation is the Cisco Reconfigurable Optical Add/Drop Multiplexer (ROADM). It delivers uninterrupted high-speed, high-capacity services to customers on meshed and multi-ring networks. A ROADM can be configured remotely to add or drop capacity at each network node, so capacity can be managed as needed.
Each ROADM offers outstanding manageability and scalability for transport networks, and have proven to be vitally important for wavelength services delivery. A ROADM-enabled DWDM node can scale to 40 wavelengths. By using automated signal and power management, a ROADM can eliminate truck rolls to intermediate locations to support or redirect services.