The Optical Internetworking Forum (OIF) has published a new Implementation Agreement (IA), OIF-EEI-112G-RTLR (Retimed Transmitter Linear Receiver), to address demand for high-speed, energy-efficient data center interconnects. This standard targets hyperscale data centers and AI architectures by improving power efficiency, interoperability, and system flexibility across optical networking equipment vendors.
According to OIF, the OIF-EEI-112G-RTLR IA specifies a 112 Gb/s chip-to-module electrical interface connecting retimed optical transmitters with linear optical receivers—often described as “half retimed optical links.” The interface supports both Ethernet chip-to-module connections at 100 Gb/s and Common Electrical I/O 112G Very Short Reach using 16 dB channels, operating in the 36 to 56 gigabaud per second range, ensuring full compatibility with Ethernet systems.
By removing the need for a digital signal processor (DSP) in the receive side of the optical module and shifting signal processing to the host device, this IA enables reduced power consumption, cost, and complexity, OIF claims. The group also states this approach maintains interoperability and performance—essential for multi-vendor AI environments in modern data centers.
Jeff Hutchins, OIF Physical and Link Layer Working Group Energy Efficient Interfaces Vice Chair (Ranovus), stated, “Across the ecosystem, OIF heard a clear message — the industry needs robust lower power links that are IEEE compliant,” adding, “This IA reflects that input, advancing energy efficiency without sacrificing link quality or compatibility. It reinforces that OIF is where collaboration and technical leadership deliver the interoperability specifications needed for AI-driven, high-performance networks.”
OIF recently demonstrated RTLR technology at the European Conference on Optical Communication (ECOC) 2025, showcasing interoperability across over 30 vendors using 400ZR, 800ZR, Multi-span Optics, Co-Packaging, and Common Electrical I/O technologies. The RTLR demo highlighted lower power and reduced complexity in real-world, multi-vendor settings, validating the framework specified in this new IA.
The EEI-112G-RTLR agreement builds on the CEI-112G-Pulse Amplitude Modulation 4-level (PAM4) foundation and aligns fully with IEEE 802.3 standards. The document covers general requirements, electrical and optical specifications, test methodologies, and parameter definitions.
Source: OIF
