Industrial Electronics

Video: Solution enables PAM4-to-NRZ signal conversion for 400/100 GE data center testing

02 June 2020

Keysight Technologies Inc. has introduced a test platform that enables data center operators to leverage 400 Gigabit Ethernet (GE) capable test ports to link with and test legacy 100 GE network equipment.

The new test platform is comprised of Keysight’s Ixia AresONE 400 GE high performance layer 1 through 3 test system, based on the pulse amplitude modulation level-4 (PAM4) signaling protocol, interconnected to legacy 100 GE non-return-to-zero (NRZ) networking equipment ports using Credo’s HiWire Active Electrical Cable (AEC) technology. The collaborative solution provides speed-shifting of the signaling rates and forward error correction (FEC) conversion.

Data center operators have widely deployed mature 100 GE NRZ-based technologies. However, higher speeds, such as 400 GE, create a new mixed signaling, mixed FEC, multi-rate environment. This new environment Source: Keysight Technologies Inc.Source: Keysight Technologies Inc.produces unique challenges relating to the integration of PAM-4-based 400 GE and 100 GE-capable switch ports with existing 100 GE NRZ signaling-based switch port technology.

The combined Keysight and Credo test solution bridges the signaling gap between incompatible PAM4- and NRZ-encoded signaling. It removes potential compromises in testing configurations to improve overall performance validation and quality. The AEC cable technology performs the necessary conversions to allow a PAM4-encoded port to interoperate with an NRZ-encoded port. The solution provides support for testing four ports of 100 GE NRZ from a single port of 400 GE QSFP-DD PAM4 in four times 100 GE speed mode.

The Credo HiWire AEC allows flexibility in configuration of network rack equipment. Data center operators can install 400 GE-capable ports and connect them when and where needed to legacy 100 GE NRZ ports. Testing performed with the Ixia AresONE 400 GE combined with the Credo HiWire SERDES speed shift and PAM4-to-NRZ conversion technology is completed at a fraction of the cost of the equivalent configuration using optical transceiver technology. Keysight and Credo are members of the HiWire Consortium, a non-profit organization dedicated to accelerating the adoption of AECs in applications such as this.

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