XFP vs SFP: Key Differences in Optical Transceivers
In October 2024, a purchasing manager from a mid-size German systems integrator sent us an RFQ for 387 pieces of XFP-10G-LR. We asked what chassis they were going into. Cisco ASR 1004s - all scheduled for decommission within 14 months. Nobody on the project had flagged that the replacement ASR 9000 chassis would not accept XFP at all.
That RFQ became 420 SFP+ 10G-LR modules coded for ASR 9000, plus a 50-unit XFP maintenance buffer for one legacy ring staying live until 2026. Total savings against the original BOM: €31,200, with an additional €18,000 in projected energy cost reduction over the equipment lifecycle. Their technical lead told us afterward that the real value was simpler than the spreadsheet - one spare inventory instead of two, one coding spec instead of three.
This is what the "XFP vs SFP+" question actually looks like when it reaches a purchase order.
The Architecture Split
XFP and SFP+ both move 10G over fiber. Same LC connectors, same wavelengths, same signal on the glass. A 10G-LR link with XFP on one end and SFP+ on the other works fine. So why does it matter which one you buy?
Because the form factor determines everything downstream: your chassis selection, your power budget, your port density, your spare parts strategy, and increasingly, whether you can even source replacement modules at all.
XFP (MSA published 2005) puts CDR, EDC, and signal conditioning inside the module. SFP+ (ratified July 2009) strips all of that out and pushes it onto the host motherboard. Smaller package: 56.5 × 13.4 mm versus 71 × 18.35 mm. Lower power: 0.8–1.0 W versus 3.5 W. Different cage. No physical adapter between the two exists. When you commit to a form factor, you commit to a platform ecosystem.
Cisco ended all XFP production last year. Final order date: July 27, 2024 (cisco.com).
What a 1,247-Port Migration Actually Costs
Most XFP-vs-SFP+ comparisons show you a specification table and leave the math to you. That is not useful for a budget review. Here is a real scenario we helped scope.
Regional ISP. 26 PoP sites. 1,247 active 10G-LR ports on Cisco 7600 chassis, migrating to ASR 9000 with SFP+ line cards. All single-mode, 1310 nm.
| 5-Year Optics-Only TCO | XFP Path | SFP+ Path |
|---|---|---|
| Modules + 12% spares (1,397 units) | $57,277 | $23,749 |
| Energy (PUE 1.45, $0.094/kWh EIA avg) | $26,191 | $7,549 |
| Field replacement at 8% failure rate | $4,582 | $1,900 |
| Five-year subtotal | $88,050 | $33,198 |
62% lower on optics alone. Not including chassis, line cards, or the rack density gains from consolidating 52 chassis locations down to 31.
Why PUE 1.45 and not the industry average 1.58? Because this was a measured value from the customer's facilities. Your number will be different. If your PUE is 1.8, the energy gap gets significantly wider. If you are a European operator paying €0.21/kWh instead of $0.094, the five-year energy delta alone exceeds €41,000. We build these models for customers during the quoting process - it takes one email with your site specs.
The number most procurement teams overlook entirely is rack density. XFP line cards: 4 to 8 ports per slot. Current SFP+ line cards: 16 to 36. At $800/month per half-rack in colocation, every freed rack unit compounds fast.
When You Should Still Order XFP
We manufacture both. We would rather sell you the right module for your network than the one with the higher margin.
If you are running OC-192 on a metro SONET ring that is still carrying revenue traffic, replacing the transport layer is a seven-figure conversation that involves regulatory timelines, not a module swap. Third-party XFP at $38–45 each extends the life of that infrastructure at a fraction of the alternative cost. We keep XFP inventory in stock specifically for these maintenance cycles.
If your outdoor plant runs XFP-only ruggedized enclosures rated for -40°C to +85°C, a form-factor change means replacing the enclosure, not just the optics. The business case for that rarely works when the equipment has three or more years left.
If you need tunable DWDM on legacy ROADM systems, XFP tunables across the 50 GHz ITU-T grid are still the more proven option. SFP+ tunables exist but are not yet at parity for every architecture.
Outside those three situations, new XFP procurement is hard to justify. Lead times for uncommon XFP variants have stretched from two weeks to six. Wavelength availability is narrowing quarter over quarter. The supply window is closing. If you need a maintenance stock, build it now - not after your next module failure.
Choosing a Supplier Is Not About the Module Spec
Every 10G-LR on the market is built to the same MSA standard. The TOSA and ROSA sub-assemblies come from the same handful of component houses. A $15 module and a $600 module use the same Lumentum laser diode. So what are you actually choosing when you choose a supplier?
Three things.
Coding accuracy. Cisco, Juniper, Arista, and most other vendors run EEPROM validation on every module inserted. Wrong vendor code means "Unsupported transceiver" on the console and an engineer wasting time. We maintain coding libraries for over 200 platforms, tested against specific software versions. Some suppliers ship generic modules and tell you to figure out the coding. On the Juniper NSP mailing list, an architect documented brand-new QFX3500 switches blocking third-party optics entirely despite the supplier's compatibility claims (narkive.com). This is a solvable problem - but only if your supplier solves it before the module ships.
Quality control. A 2–3% DOA rate on a 500-piece order means 10 to 15 modules that need RMA processing. At $50 of loaded labor per incident, the cheapest unit price can produce the highest total cost. We publish our DOA data. Ask your other suppliers if they will do the same. Ask if they perform 72-hour burn-in before shipment, or if they are shipping untested inventory from a distribution warehouse.
Ongoing support. The DOM telemetry conversation - TX Bias Current trending, RX Power degradation monitoring, temperature threshold alerting - is something we help customers configure during onboarding. Modules that report degradation six months before failure give procurement the lead time to source replacements on normal timelines instead of emergency orders. This matters even more for XFP, where replacement stock is getting scarce. We include DOM configuration guidance with every order of 100+ units. Not every supplier does.
The Broader Migration Context
Both XFP and SFP+ are 10G form factors in a market accelerating toward 400G and 800G. IEEE 802.3df ratified 800GbE in February 2024. The 1.6T standard (802.3dj) is expected in 2026. The growth is in QSFP-DD and OSFP, which share no physical compatibility with either XFP or SFP+.
What this means for your next chassis purchase: SFP+ for current 10G needs, but confirm the platform has QSFP-DD or OSFP uplink slots. When access-layer speeds move to 25G, your aggregation layer should already handle 400G without another forklift upgrade. We can walk you through the specific platform options during the quoting process.
Getting Started
Send your equipment list to focc@focc-fiber.com. We will return coded module recommendations, volume pricing, and a five-year TCO estimate within 48 hours. If you need compatibility samples before committing to a volume order, we ship those at no charge.
FOCC Fiber Co., Ltd. manufactures MSA-compliant optical transceivers and passive fiber components from our facility in Shenzhen, China. SFP, SFP+, XFP, QSFP+, QSFP28 - DOM support, multi-vendor coding, burn-in tested.