Keysight Unveils 1.6T Testers. What It Changes for Teams Running 400G

On October 13, 2026, Keysight announced two 1.6T Ethernet testers, the SERT 1600GE and the AresONE Plus 1600GE, and demonstrated them at the OCP Global Summit in San Jose. For most engineers, the headline is not the speed. One such unit, via breakout, becomes 32 ports of 400GE or 64 ports of 200GE, and the methodology it was built for (RoCEv2, PFC/ECN, FEC statistics, AI workload emulation) applies in full to 400G and 800G test beds. A mid-sized operator or integrator does not need to buy one. What they need is to understand what it can do and order those checks from a lab.

What was announced

AresONE Plus 1600GE: 8 OSFP1600 ports in a 2U chassis, 12.8 Tbit/s of line-rate traffic at 64-byte packets. Signaling is PAM4 on 224G SerDes (212 Gbit/s per lane), backward compatible with 112G. Each port fans out as 1×1600GE, 2×800GE, 4×400GE or 8×200GE. There are two modes: an eight-port mode for data center switch qualification and a four-port mode for AI benchmarks.

SERT 1600GE: the same eight-port 2U form factor, but aimed at switching fabrics and edge routers, with PTP support for synchronizing large topologies. Both support BGP, ECMP, VXLAN and SONiC testing, and work with DAC, ACC, AEC, AOC and coherent optics; the product page states up to 40 W per port for high-power transceivers.

Software: IxNetwork for L2/L3 (RFC benchmarks, protocol emulation, REST API) and Keysight AI Data Center Builder for emulating collective operations, Mixture-of-Experts traffic, RoCEv2, PFC/ECN and Ultra Ethernet Consortium profiles. Keysight separately highlighted its work with NVIDIA: the platform is designed for load testing fabrics built on Spectrum-6. Pricing has not been published.

Why this matters to teams running 100G and 400G

The market is moving fast, but not evenly. According to Dell'Oro, 800G reached 20 million ports in roughly three years; 400G took 6–7 years to hit the same mark. Dell'Oro calls 2026 the first year of volume 1.6T shipments and expects more than 5 million ports within one to two years. That is hyperscalers and AI clusters. For enterprise data centers, operators and integrators, the working speeds are 100G and 400G, with 800G in the core in some cases. That is not falling behind; it is the normal lifecycle. Equipment bought for 400G will serve for years to come.

Test methodology, however, migrates to lower speeds faster than the hardware does. Three elements of the 1.6T test bed are worth adopting today.

First, throughput and latency at 64-byte packets. Keysight quotes 12.8 Tbit/s at 64 bytes for a reason: short packets are where buffers, ASIC tables and the lookup pipeline reach their limits. A classic RFC 2544 run at 400G across the full range of frame sizes remains the cheapest way to catch this before production.

Second, behavior under RoCEv2. The PFC and ECN mechanisms validated at 1.6T for AI fabrics affect NVMe-oF storage and GPU nodes at 100G/200G/400G in exactly the same way. A typical problem that only shows up on a test bed: PFC pauses on one port stall neighboring queues, or ECN marking triggers too late and the RoCE flow falls back to retransmissions. Collective-operation emulation (all-reduce and similar patterns) in KAI DC Builder works on 400GE breakout ports as well.

Third, the physical layer. FEC and PCS lane statistics, symbol error injection, BER and FLR measurement: things that used to require separate instruments. With the move to 212 Gbit/s PAM4 the error margin has shrunk, and this layer gets checked at any speed that uses PAM4, including 400G with 112G lanes. If a 3 m DAC intermittently loses link, the cause is usually found here.

What this means for the business

A 1.6T tester is a tool for hyperscalers and equipment vendors. For a mid-sized operator or integrator, buying one will not pay off: the workload is rare, the expertise to run it is expensive, and in a year or two the next version will be needed. Yet the risk it protects against is the same for you: new switch firmware, a new optics vendor, a storage migration to RoCE, and a network that meets the specification on paper starts dropping packets under real load. Fixing that in production costs more than a day on a test bed. The rational model is to rent lab time and expertise for a specific project rather than own equipment that sits idle for 11 months of the year.

What to do

Before a core upgrade, an optics vendor change or a RoCE storage rollout, put together a checklist: RFC 2544 at target speeds with 64-byte frames, PFC/ECN scenarios under RoCEv2, FEC/BER on real cables and transceivers, protocol regression (BGP/EVPN/VXLAN) on the new firmware. If this is on your roadmap, contact TEST4NET: we will discuss your scenario and propose a test program.

Sources

• Keysight Expands 1.6T Ethernet Validation... (Business Wire, 13.10.2026)
• Keysight AresONE 1600GE — product page
• Keysight launches 1.6T Ethernet test platforms for AI networks (engineering.com, 14.10.2026)
• Dell'Oro: Data Center Networking in 2025–2026 (17.12.2025)
• Broadcom at 2026 OCP Global Summit (08.10.2026)