800G-to-8x100G Links for Switch-to-Switch Connectivity
Introduction
As data centers scale to support AI, HPC, and cloud workloads, high-bandwidth interconnects between switches become critical. One common scenario is connecting an 800G Ethernet switch (e.g., NVIDIA Spectrum-4) to multiple 100G Ethernet switches using breakout configurations. This article explores how OSFP-DR8-800G transceivers enable 800G-to-8x100G connectivity, optimizing network efficiency and cost.
1. Why Use 800G-to-8x100G Breakout?
Key Benefits
✔ Maximize Port Utilization – A single 800G port can replace eight 100G ports, reducing switch density requirements.
✔ Cost Efficiency – Fewer high-speed transceivers and cables compared to multiple 100G links.
✔ Future-Proofing – 800G switches (like Spectrum-4) can support legacy 100G devices while preparing for future upgrades.
Use Cases
- AI/ML Clusters – Connecting GPU nodes with mixed-speed networking.
- Cloud Data Centers – Aggregating multiple 100G leaf switches into an 800G spine.
- Storage Networks – High-throughput links between storage arrays and compute nodes.
2. Hardware Requirements
A. 800G Switch: NVIDIA Spectrum-4
- Port Speed: 800G (OSFP)
- Breakout Support: 8x100G (via OSFP-DR8)
- Key Features:
- Adaptive Routing & RoCEv2 support
- 25.6Tbps switching capacity
- Low-latency cut-through forwarding
B. Transceiver: OSFP-DR8-800G
| Parameter | Details |
|---|---|
| Form Factor | OSFP |
| Breakout Mode | 8x100G (DR8) |
| Max Distance | 500m (SMF) |
| Power Consumption | <14W |
| Compatibility | Spectrum-4, Spectrum-3 |
C. Cabling Options
- OSFP-DR8 to 8x100G DAC/AOC
- Short-reach (<5m), low-latency, cost-effective
- OSFP-DR8 to 8xLC Fiber Patch Panel
- Longer distances (up to 500m) using MTP-to-LC breakout cables
3. Performance Considerations
Latency
- 800G Native: ~300ns (Spectrum-4 cut-through mode)
- 8x100G Breakout: ~350ns (due to gearbox overhead)
Power Efficiency
| Configuration | Power per 800G Equivalent |
|---|---|
| 1x OSFP-DR8 | 14W |
| 8x 100G-SFP56 | 32W |
4. Comparison to Alternatives
| Approach | Pros | Cons |
|---|---|---|
| 800G-to-8x100G | Saves switch ports | Limited to 500m distance |
| Native 100G | Longer reach (>2km) | Higher cabling cost |
| 400G-to-4x100G | Wider compatibility | Half bandwidth density |
5. Troubleshooting Tips
❌ Link Flapping → Check fiber polarity (DR8 uses MPO-16)
❌ Low Throughput → Verify ethtool reports “8x100G” mode
❌ High BER → Replace faulty breakout cable
Conclusion
Deploying 800G-to-8x100G links with NVIDIA Spectrum-4 and OSFP-DR8 transceivers optimizes data center scalability. This approach balances:
- ✅ Bandwidth density (1:8 port consolidation)
- ✅ Power efficiency (56% lower power than 8x100G)
- ✅ Future readiness (Easy upgrade to native 800G)
About Optech
Optech Technology Co. Ltd was founded in 2001 in Taipei, Taiwan. The company was created with a sole purpose, to provide a wide and high quality portfolio of optical products to a very demanding and fast evolving market.
To respond to the permanent increase of IP traffic, Optech portfolio is constantly growing. Since the beginning, the company has always been up to date with the latest innovations on the market. Today, we are proud to deliver a large selection of 25G SFP28, 40G QSFP+, 100G QSFP28, 200G QSFP56, 400G QSFP-DD, 800G QSFP-DD and OSFP optical transceivers and cables.
Optech has a large portfolio of products which include optical transceivers, direct attach cables, active optical cables, loopback transceivers, media converters and fiber patch cords.
Through its large selection of optical products, that have a range of data speed from 155 Mbps to 800 Gbps and reach distances up to 120km, Optech products are suitable for various industries such as telecom, data centers as well as public and private networks.
| Part Number | Optech Part Number | Features | Note |
| 800G QSFP-DD DR8 | OPDM-SX5-13-CB | 800Gb/s QSFP-DD DR8 single mode mode, MPO, 1310nm, up to 500m | 800G QSFP-DD DR8: A Practical Powerhouse for High-Speed Data Center Interconnects |
| 800G QSFP-DD DR8+ | OPDM-S02-13-CBS | 800Gb/s QSFP-DD DR8+ single mode mode, MPO, 1310nm, up to 2km | |
| 100G QSFP-DR | OPCW-SX5-13-CB | 800Gb/s QSFP-DD 2xFR4 single mode mode, LC, 1310nm, up to 2km |
For additional information about the 800G-to-8x100G links, or price inquiry, please contact us at sales@optech.com.tw
