Solutions & Applications
Telecom Network Sync · 5G Infrastructure · Data Center Connectivity · Optical Networks · Critical Networks
Brownfield data centers running 400G QSFP56/QSFP-DD fabrics need a practical upgrade path — not a forklift. Backward-compatible 800G QSFP-DD optics, hybrid-speed topologies, zero-touch transceiver swaps.
50%Port Count Reduction
3Migration Phases
0Forklift Upgrades
1. The Challenge
QSFP-DD Cage Lock-In
Existing 400G switches use QSFP-DD cages. Replacing switches to support OSFP means a complete rip-and-replace.
Hybrid-Speed Instability
Mixing 400G and 800G optics in the same fabric can cause FEC mismatch, link flap, and unpredictable BER floors.
Budget Phasing
Operators can't upgrade every rack at once. They need a per-pod migration path that respects CapEx cycles.
Fiber & Cable Continuity
800G SR8 needs different MPO polarity than 400G SR4. Existing fiber plant must be validated before migration.
Core Insight: QSFP-DD cages support both 400G and 800G optics natively. The migration is not a hardware problem — it is a planning, qualification, and phasing problem.
2. Three-Phase Migration Plan
Phase 1: Spine-First Upgrade
Replace spine 400G transceivers with 800G QSFP-DD FR4/DR8. Spine ASICs support 800G natively. Leaves stay at 400G — spines auto-negotiate down per port. Zero leaf changes.
Phase 2: Leaf Pod Migration
Upgrade leaf switches pod-by-pod to 800G QSFP-DD. GPU racks get 800G SR8/DR8 first. General-compute racks stay at 400G until next budget cycle. Hybrid fabric runs stable.
Phase 3: Full 800G Fabric
All leaf and spine ports at 800G. Deploy 800G ZR+ coherent for DCI links. End state: 2× bandwidth density, 50% fewer ports, 30% lower per-bit power vs. all-400G baseline.
3. Product Selection Matrix
| Phase | Product | Form Factor | Reach | Typical Qty |
|---|---|---|---|---|
| 1 | 800G QSFP-DD FR4 | QSFP-DD | 2 km SMF | 32–64 |
| 1 | 800G QSFP-DD DR8 | QSFP-DD | 500 m SMF | 64–128 |
| 2 | 800G QSFP-DD SR8 | QSFP-DD | 100 m OM4 | 128–256 |
| 2 | 800G Active Optical Cable | QSFP-DD AOC | 3–30 m | 64–128 |
| 3 | 800G QSFP-DD ZR+ | QSFP-DD | 500–2,000+ km | 8–16 |
4. Key Benefits
0 switch replacements required — QSFP-DD backward compatible
18 kW interconnect power saved per 10K-GPU pod at full 800G
50% fewer ports vs. all-400G fabric at equivalent bandwidth
3-year typical phased migration timeline, pod by pod
5. Why Apex
| Capability | Why Apex |
|---|---|
| QSFP-DD backward compatible | Every Apex 800G QSFP-DD module auto-negotiates to 400G, 200G, and 100G lane speeds — plug into any QSFP-DD cage. |
| Pre-tested hybrid fabric | Apex validates 400G/800G mixed fabrics on Broadcom Tomahawk 5, Cisco Silicon One, and NVIDIA Spectrum-4 — no FEC mismatch. |
| Fiber audit tool | Free MPO polarity and insertion loss audit checklist for your existing fiber plant before migration. |
| Same-day swap inventory | All 800G modules ship from stock. Replace 400G optics in-place — no cage reconfiguration. |
Planning a 400G-to-800G migration?
Our migration engineers will audit your fabric topology, recommend a phased plan, and deliver a per-pod BOM with fiber compatibility checklist — typically within 48 hours.
Email: Info@apexallinone.com | WhatsApp/Phone: +852 9821 3834
