CALIENT Technologies

Move the light, not the fiber

How CALIENT Optical Circuit Switching Can Drive Costs Down In Optical Transport Networks

Service provider optical transport networks have been migrating from SONET to WDM-based optical transport network (OTN) technology for the past several years as standards have evolved and as service providers have realized that muxing multiple signals across the fiber infrastructure can help them to get more value out of their fiber infrastructure.

But the explosion in data volumes has service providers looking to reduce network costs even more to improve profitability. Network technology is evolving as well with centralized software defined networking (SDN) controllers providing data flow control and packet forwarding. Evolving network infrastructure must be even more cost effective and flexible to accommodate these new network technologies.

One emerging solution is based on our S320 Optical Circuit Switch (OCS) combined with an IP aggregation router. The S320 Optical Circuit Switch is a 320-port, all-optical (OOO) switch that establishes, monitors and switches physical layer connections between single-mode optical fibers using Micro‑Electro‑Mechanical Systems (MEMS) based optical switching. Connections are made between fibers carrying signals with any data rate or protocol. Any input fiber on the S320 can be connected to any output fiber making a fully non-blocking switch fabric.

Optical Circuit Switching (OCS) offers networking functionality at a fraction of the cost of an OTN, including topology optimization, traffic balancing and protection / restoration. Furthermore, when client speeds equals network speeds, OCS provides circuit switching at a far lower cost compared to OTN.


The S320 can be paired with an IP router in place of an OTN mux. Router prices are coming down, and many devices can now support circuit switching functions including MPLS-TP, FRR and others. In addition, the OCS is able to provide the circuit switching functionality while the router provides both the service termination and the packet-by-packet forwarding. This solution can evolve with SDN with which many of the manual OCS operational procedures, such as circuit provisioning, bandwidth on demand, etc.) become networking functions.

With industry trend towards higher speeds (client = network), terminating on aggregation routers and SDN penetrating the physical layer, the OCS is an ideal solution as it offers maximum flexibility for a fraction of the cost of an OTN. For more information on this application, check out the CALIENT-ADARA SDN Transport Packet Optical Integration Solution page which shows how CALIENT is partnering with ADARA to deliver a complete OCS-IP/SDN solution.

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