Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
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Introduction
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Introduction to the N4891A Solution
N4891A 400G Multi-Port Tester
The N4891A is a compact Bit Error Rate (BER) and Forward Error Correction (FEC) test system. You
can use it to characterize and quantify, at line rate, the actual BER and FEC performance of silicon
communication devices, ASICs, fiber and copper interconnects, optical transceivers, and the port
electronics of switches, routers, and other networking equipment with 26.5625 Gbaud PAM4
interfaces. You can also use it to test the interconnection interoperability for all types of networking
devices and equipment.
It is available in two models: 2-port or 4-port. The 2-port model is field-upgradeable to 4 ports.
For both models, an optional RS-544 (KP4) FEC test capability is available that simplifies FEC lane
testing.
The N4891A is powered by IXIA's KiOS operating system, and includes Layer 1 BERT 400GE test
software. A browser-based user interface makes it easy to run tests and manage the N4891A
equipment. Keysight N4891A and Ixia A400GE-QDD offer the same capabilities and are
interchangeable.
The N4891A chassis can be mounted on a bench-top or in a rack. See
for more information.
N4891A 400GBASE FEC-aware Receiver Test Solution
When used in combination with the Keysight M8040A, the N4891A offers a unique 400GBASE
FEC-aware Receiver Test Solution. This solution enables measurement of frame loss ratio in 400G
Ethernet links using FEC by supplying one stressed lane, while maintaining the proper FEC striped
test pattern data. The test method is prescribed in the IEEE 802.3 standard clauses 121,122, 124 and
136, 137 and 138 (802.3bs and 802.3cd respectively). This solution provides unique insights to
understand how component and system design trade-offs are affected by Forward Error Correction
(FEC) requirements and to predict the system margin under realistic conditions.
For more information regarding the M8040A J-BERT system, refer to
