Sycamore Networks is doubling the capacity of its biggest optical switch to 2.5 terabits per second.

The hardware of the SN 16000 MC-1024 optical switch--six chassis filling three bays--was designed to be able to carry that much traffic back in 2000. But the higher capacity will finally be available through a software upgrade near the end of this year.

“We chose not to deploy that capacity back then because there was no demand for it,” said Kevin Oye, Sycamore’s vice president of systems and technology. “Now our customers are saying their [1.25 Tb/s] systems are getting tapped out, and they could use additional capacity.”

The new software upgrade gives Sycamore’s switch 40 Gb/s per slot, demand for which is now starting to emerge, the vendor said. The switch fabric, designed to enable optical mesh networks, can interface with a mix of Sonet and Ethernet traffic.

The new 1.25 Tb/s capacity is “full duplex,” meaning simultaneous in both directions. Some router vendors add the total ingress and egress capacities of their gear to report its total capacity, such as the 1.6 Tb/s capacity of Juniper’s half-rack T1600 core router or the 640 Gb/s of Cisco’s CRS-1.