MAY 23, 2008 -- The Optical Internetworking Forum's (OIF's; search for OIF) Physical and Link Layer Working Group has opened a new work project to address 100G long-haul DWDM.
According to Ciena's Joe Berthold, former president of the OIF, the project will aim to speed implementation of the 100G specifications that the IEEE and ITU-T are expected to standardize. As Berthold put it, IEEE will set a 100 Gigabit Ethernet standard, ITU-T will create a way to frame it and issue an OTU-4 specification within its current Optical Transport Network framework, and the OIF project will figure out what else the industry needs to provide to implement 100G transmission over long-haul DWDM networks.
The result will be an OIF implantation agreement (IA). The agreement will focus on a single modulation format -- dual-polarized quadrature phase-shift keying (QPSK) paired with coherent receiver technology. Berthold acknowledged that there are other ways to support 100G transmission; however, the consensus among the participants in the IA development is that dual-polarized QPSK with coherent detection appears to be the most likely path the majority of suppliers will take to create 100G products.
The working group won't be idle while waiting for the IEEE and ITU-T to do their parts. Berthold says the ITU-T has asked for help in developing a forward-error correction approach robust enough for 100G requirements. The group also will examine coherent receiver signaling parameters. In addition, Berthold noted the success the OIF has had in developing interface specifications for chip-to-chip communications, and a look at the requirements to support 100G transmission at the board level would therefore make sense.
Berthold declined to set a timetable for completion of the IA.