Developers push for faster optical Ethernet speeds

Bandwidth demand shows no signs of peaking—and no part of the network has been untouched by users’ apparently infinite need for higher speeds.

Just a week after we reported on efforts to increase bandwidth over copper lines in the access network (CP: Calix launches high-density VDSL2 platform), new developments came to light this week in the network core and within data centers and campus backbone networks.

At the network core, TeliaSonera International Carrier and Infinera announced this week that they successfully completed optical transmission based on 500 Gb/s “superchannels” on an 1100-kilometer connection between Los Angeles and San Jose. Meanwhile, the IEEE is looking to address the needs of data center operators and high-capacity campus networks, launching a study group to explore standards for next-generation 100 Gb/s short-range optical Ethernet connectivity.

Getting to 500 Gb/s
The TeliaSonera/ Infinera trial was based on Infinera’s DTN-X platform and involved boosting the capacity on an existing production route. Infinera is promoting the idea of super-channels based on photonic integrated circuits (PICs) that combine multiple optical carriers into a single managed entity—an idea that sounds a bit like DSL bonding. By basing super-channels on PICs, Infinera said operators will be able to provision 500 Gb/s with a single operational maneuver.

That’s the sort of capability that can eliminate the need to break high-bandwidth transmissions into multiple lower-speed paths in the wide area network—and people involved in advanced networking have noted that significant efficiencies can be obtained when that capability is available (CP: Verizon expects better economics, lower latency with U.S. 100 G deployment).

100 Gb/s interfaces for data centers
The IEEE is looking at potentially three new 100 Gb/s relatively short-range optical Ethernet standards. These include an interface based on four multi-mode fibers, each operating at 25 Gb/s and an electrical interface between module and system integrated circuits that would also be based on four 25 Gb/s interfaces.

A third potential standard is the one that would be of greatest interest to communications service providers. That option, which would involve four single-mode interfaces operating at 25 Gb/s, would target data center and campus backbone applications.

The IEEE previously adopted a range of 100 Gb/s standards involving 10 multi-mode fibers or four wavelengths, also aimed at relatively short-range communications. Physical layer standards for longer-range high-speed Ethernet transport over a single wavelength have largely been the purview of the International Telecommunications Union—and those standards have been the most relevant for service provider networks.

The IEEE has favored multiple physical interfaces for it high-speed Ethernet standards as a cost saving measure. Sending 100 Gb/s over a single wavelength required the ITU to include costly forward error correction as part of its standards.

Another group within the IEEE is already looking at physical layer Ethernet standards above 100 Gb/s (CP: IEEE eyes next Ethernet speed standard).