The Optical Internetworking Forum (OIF) began technology advancement for 56 Gbps networking in 2012 by developing a Next Generation Framework white paper documenting the multiple challenges including: increasing power consumption, higher losses and advanced modulation schemes that all had to be successfully addressed. The formal development projects began in 2013, when the diverse OIF membership made of component suppliers, subassembly suppliers, equipment suppliers and Network Operator members, began the process of sharing detailed technical analysis, measured data and use case inputs with the members.
The OIF is now announcing the next round and level of CEI technology for the data center, networking and telecoms industries. The OIF announced today the publication of the “Common Electrical (I/O) CEI 4.0” with a focus on Serdes standards for 56 Gbps. This is the first completion of Serdes standards for the CEI generation of 56 Gbps I/O devices and adds PAM-4 and Ensemble NRZ as additional advanced modulation schemes to NRZ.
Preliminary testing of 56 Gbps work has also been demonstrated by OIF members for the past two years at OFC where chip designers, connector vendors and test equipment suppliers showed the viability of the electrical channel parameters. CEI 4.0 represents the eighth generation of OIF electrical interfaces over an 18-year span. “The industry continues to face challenges for diverging requirements regarding link latency and concerns with power consumption at the higher data rates,” said Klaus-Holger Otto of Nokia and the OIF Technical Committee Chair.
He added, “Documenting channel definitions in more granular reaches and multiple modulation schemes allows for the optimization of silicon chip designs, channel architectures and network operator use cases. These parameters for 56 Gbps will be used as building blocks for protocol specifications written by other organizations across the industry so the forum wanted to provide definitions that met their unique needs.”
The result is a number of carefully optimized channel definitions that will enable the industry to benefit from a range of interoperable solutions at 56 Gbps data rates. Key to this effort was aiming for the lowest possible power dissipation for each application while balancing link budget and latency. At this time the OIF is releasing CEI 4.0 with the following new clauses:
• CEI-56G-USR-NRZ: Ultra Short Reach, die-to-die inside muti-chip-modules, NRZ modulation
• CEI-56G-XSR-NRZ: Extra Short Reach, chip-to-driver, NRZ modulation
• CEI-56G-VSR-PAM4: Very Short Reach, chip-to-module, PAM-4 modulation
• CEI-56G-MR-PAM4: Medium Reach, chip-to-chip, one connector, PAM-4 modulation
• CEI-56G-LR-PAM4: Long Reach, chip-to-chip, two connectors over backplane, PAM-4 modulation
• CEI-56G-LR-ENRZ: Long Reach, chip-to-chip, two connectors over backplane, ENRZ modulation
The CEI 4.0 can be found here: http://www.oiforum.com/wp-content/uploads/OIF-CEI-04.0.pdf.
Further clauses with additional modulation variants of the above reaches will be added in a future CEI 4.1 release.