If you need real 40 Gigabit Ethernet port density on the Optixia platform — without CFP-era optics or adapter gymnastics — the Ixia Xcellon-FlexFE40G4Q is the card built for exactly that. It puts four native 40GE QSFP+ ports on a single-slot load module, scaling to 24 ports of 40GbE in a single XM12 chassis, with a rich Layer 2–7 feature set under IxNetwork and IxLoad. When it shipped, that was the industry’s leading 40GE QSFP+ port density — and on the refurbished market it remains one of the most economical ways to build a serious 40GbE test bed.
We currently have 15 refurbished Xcellon-FlexFE40G4Q modules in stock — every unit fully tested, shipped with a comprehensive test report, and backed by a one-year warranty. Here is what the card does, where it fits among Ixia’s other 40GbE options, and what to check before you order.
What the Xcellon-FlexFE40G4Q Is Built For
The FlexFE40G4Q is the 40GbE member of Ixia’s Xcellon-Flex family — the “Full Emulation” tier tuned for mid-range Layer 2–3 and Layer 4–7 protocol scalability at an affordable price per port. Ixia aimed it squarely at manufacturers of large-port-count, converged data-center switches, and that remains its sweet spot:
- High-density 40GE switch and router validation — four wire-speed ports per slot for throughput, latency, and forwarding-performance work on 40GE line cards and fabrics.
- Layer 2–7 protocol emulation and scale testing — driven by IxNetwork for routing/switching emulation and IxLoad for application-layer traffic, at the mid-range scale tier that covers most converged-switch test plans.
- IEEE 802.3ba compliance work — including PCS lane testing, the physical-coding-sublayer verification that 40GE silicon and optics vendors need and that generic traffic generators skip.
- Data-center bridging validation — DCB-ready for converged-fabric testing on 40GE links.
- Server and NIC aggregation testing — validating 40GE server uplinks, CNAs, and top-of-rack aggregation at line rate.
Native QSFP+ matters here: the card takes the same transceivers and direct-attach cables as the 40GE equipment it tests — no CFP adapters, no exotic optics budget.
Which Ixia 40GbE Card Do You Need?
Ixia built 40GbE test capability across three generations, and we stock all of them — the right choice depends on what you are testing:
- Xcellon-FlexFE40G4Q — the density play. Four native QSFP+ ports per slot, 24 per XM12 chassis, mid-range L2–7 scale. The most test ports per dollar of any 40GE option here; the card to buy for port-count-hungry switch validation and regression beds.
- Xcellon-Lava AP40/100GE 2P — the speed-flexibility play. Two CFP ports, each switchable between 40GE and 100GE, Accelerated Performance L2–7 tier. Buy the Lava when your roadmap includes 100GE; buy the Flex when it is 40GE density you need. (Full write-up in our Lava guide.)
- K2 HSE40GEQSFP1-01 — the budget single-port. Ixia’s first native-QSFP+ 40GE module: one port per slot, full K2 L1–7 measurement feature set. At a fraction of the multi-port cards’ price, it is the economical way to add a 40GE port or two to an existing bed — we stock these as well.
Chassis Fit — What to Check Before You Order
- The FlexFE40G4Q is a single-slot XM-form-factor module for Ixia’s 12-slot chassis. Per Ixia’s specification it scales to 24 ports — six modules — in a single XM12; plan the remaining slots for your other cards.
- We stock licensed XM12 and XG12 chassis ready to pair with it — tell us your target port count and we will spec the loadout.
- QSFP+ transceivers (40GBASE-SR4/LR4) and direct-attach copper are sold separately — ask us about bundling optics with your modules.
- Like all high-speed Xcellon cards these run warm; keep blanking panels in unused slots and give the chassis its specified airflow headroom.
- IxOS version support matters at 40GE — send us your chassis part number and IxOS revision and we will confirm compatibility before you buy.
Competitor Modules It Replaces or Competes With
Cross-shopping brands? On the secondary market the FlexFE40G4Q competes with the 40GbE generations from the other major test vendors — Spirent’s 40G TestCenter HyperMetrics modules and Xena Networks’ (now Teledyne LeCroy Xena) Loki/Thor-class 40G generators. Its differentiators are the same ones Ixia sold it on: four native QSFP+ ports per slot, PCS-lane compliance testing, and the IxNetwork/IxLoad software stack most validation labs already run. If your lab searched for any 40GE test module, fifteen matched, tested cards in one place is the practical answer.
Where It Fits Alongside Your 10GbE Test Bed
Most 40GE test beds are the uplink tier of a larger 10GbE lab, and the whole stack shares the same 12-slot chassis. The practical mixed build: Xdensity XDM10G32S cards for bulk 10GbE data-plane load, Xcellon-Flex 16-port 10GbE cards where per-port session scale matters, and FlexFE40G4Q cards on the 40GE uplinks — one chassis, one software stack, one vendor’s card ecosystem. Our NGY family guide covers the budget 10GbE tier of the same platform.
Why 40GbE Testing Still Matters in 2026
- The 40GE installed base is enormous. 40GE had a decade as the standard data-center uplink speed before 100G took over, and those switches, NICs, and fabrics remain deployed — and regression-tested — everywhere.
- 40G optics are cheap and everywhere. QSFP+ transceivers and DACs cost a fraction of their original price, which makes a refurbished 4-port 40GE test card the cheapest wire-speed high-speed-Ethernet test capacity you can buy, full stop.
- Compliance testing did not go away. Silicon and optics vendors still verify 802.3ba PCS behavior on every respin — exactly the capability this card carries.
- The Keysight connection keeps the platform alive. Keysight Technologies acquired Ixia in 2017, and the IxNetwork and IxLoad software that drives these cards continues under Keysight today.
In Stock Now: 15 Refurbished FlexFE40G4Q Modules — Test Report and 1-Year Warranty Included
We currently have 15 refurbished Ixia Xcellon-FlexFE40G4Q load modules in stock — a matched pool deep enough to populate a full 24-port XM12 build with spares, or to standardize 40GE capacity across several chassis.
Every refurbished unit we ship includes:
- A comprehensive test report — each module is fully tested before shipment, and the detailed report ships with the unit, so your lab has documented proof of functionality on day one.
- A full one-year warranty — every module is backed by 12 months of coverage for complete peace of mind.
- Significant savings versus new list price — four wire-speed 40GE test ports per slot for a fraction of the new-equipment budget.
View the refurbished Ixia FlexFE40G4Q product page and order now →
Or contact us directly for volume pricing on multiple units, a sample test report, or chassis-compatibility guidance: Contact Zombie Components
Zombie Components LLC · 13177 Foothill Blvd, Sylmar, CA 91342 · +1.909.747.9984 · ahall@zombiecomponents.com