Agilent / Keysight N4891A 400GBASE FEC-aware Receiver Test Solution

The Keysight N4891A 400GBASE FEC-aware Receiver Test Solution is a physical layer bit error rate tester engineered for characterization and compliance validation of 400 Gigabit Ethernet receivers. Purpose-built to evaluate receiver performance under Forward Error Correction (FEC) conditions—a mandatory requirement for 400GbE system reliability—this instrument measures critical performance indicators including frame loss ratio and system margin under realistic stressed conditions. It delivers actionable insights into component and system design trade-offs driven by FEC requirements.

– Technical Specifications

• Data Rate: 400GbE interfaces at 26.5625 GBaud PAM4
• FEC Support: RS-544 (KP4) FEC mode with symbol-striped physical layer BER testing
• Frame Loss Measurement: Quantifies FLR in 400G Ethernet links employing FEC
• Standards Compliance: IEEE 802.3 clauses 121, 122, 124, 136, 137, 138 (802.3bs and 802.3cd); 400GAUI-8 and 400GBASE-LR8/-FR8/-SR8 interface specifications

– Key Features

• FEC-aware physical layer BER measurement with symbol striping
• FEC margin and compliance testing aligned with IEEE and OIF recommendations
• Layer 1 channel stress and impairment testing with optical receiver stress testing (ORST) capability
• Adjustable jitter injection, eye diagram analysis, and error characterization
• Layer 1 BERT 400GE test software with browser-based user interface
• KiOS operating system integration for streamlined test automation

– Typical Applications

• Silicon communication device receiver characterization
• 400GbE compliance validation under FEC-stressed conditions
• System margin prediction in production and design environments
• Layer 1 physical layer stress testing and channel impairment analysis

– Compatibility & Integration

The N4891A integrates with the Keysight M8040A High Performance BERT (64 GBaud) to generate correct striped FEC test patterns on single lanes under test. Combines with the A400GE-QDD 400GE layer 1 BERT and KP4 FEC multiport test system to deliver aligned striped FEC traffic across remaining lanes. Compatible with Keysight FlexDCA Oscilloscopes via the M809256PB OIF CEI-56G Rx Test Automation Application for extended measurement capability.