Introduction
In high-speed networking, transceiver connectors play a critical role in ensuring optimal performance, thermal management, and compatibility. Two primary types of connector shells exist: Finned Top and Flat Top Transceivers. Each is designed for specific networking devices, including switches, adapters, and DPUs (Data Processing Units). This article explains their differences, applications, and why matching the correct shell type to the right device is essential.
1. Finned Top Transceivers: Designed for Switches
Key Characteristics
- Heat Dissipation: The fins improve airflow and cooling, critical for high-power switch environments.
- Usage: Exclusively found in network switches, including:
- Quantum-2 InfiniBand switches
- Spectrum-4 Ethernet switches
- Why Switches Need Finned Top?
- Switches operate continuously at high throughput, generating significant heat.
- The finned design prevents thermal throttling and maintains signal integrity.
Compatibility Note
⚠️ Do not use finned top transceivers in non-switch devices (e.g., NICs or DPUs), as they may obstruct adjacent ports due to their larger profile.
2. Flat Top Transceivers: Optimized for Adapters & DPUs
Key Characteristics
- Low-Profile Design: Saves space in dense server and accelerator deployments.
- Usage: Found in network adapters and DPUs, including:
- ConnectX-7 InfiniBand adapter cards
- BlueField-3 DPUs
- Why Adapters/DPUs Use Flat Top?
- These devices prioritize compactness over active cooling.
- Flat tops allow tighter stacking in servers without blocking airflow.
Compatibility Note
⚠️ Avoid using flat top transceivers in switches, as they lack the cooling capacity for sustained high-power operation.
3. Comparison Table: Finned Top vs. Flat Top Transceivers
| Feature | Finned Top Transceivers | Flat Top Transceivers |
|---|---|---|
| Primary Use Case | Switches (e.g., Quantum-2) | Adapters/DPUs (e.g., ConnectX-7) |
| Cooling Method | Passive (fins enhance airflow) | Relies on system airflow |
| Form Factor | Taller (fins add height) | Ultra-low profile |
| Example Devices | NVIDIA Spectrum-4 switches | BlueField-3 DPUs |
| Thermal Tolerance | High (for 24/7 switch operation) | Moderate (for burst workloads) |
4. Why Does Shell Type Matter?
A. Mechanical Fit
- Finned tops may physically block adjacent ports in adapter/DPU configurations.
- Flat tops cannot dissipate heat effectively in high-power switches.
B. Signal Integrity
- Improper shell matching can cause thermal-induced signal degradation (especially at 400Gbps+ speeds).
C. Vendor Compliance
- Using non-recommended shells may void warranties (e.g., NVIDIA’s HCA and switch compatibility guidelines).
5. Industry Trends & Future Designs
- Emerging Unified Connectors: Some next-gen devices (e.g., NVIDIA Quantum-3) may support hybrid cooling shells.
- Liquid Cooling Adoption: May reduce reliance on finned designs in future switches.
6. Best Practices for Deployment
- Always check vendor documentation (e.g., NVIDIA’s InfiniBand and Ethernet compatibility guides).
- Do not mix shell types in the same chassis unless explicitly certified.
- Monitor thermals when deploying high-speed transceivers (≥200Gbps).
About Optech Technology Co. Ltd
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 |
| OSFP-800G-SR8 | OPQM-MT5-85-CBO | 800Gb/s OSFP SR8 Finned top, multimode mode, MPO, 850nm, up to 50m | Compatible with NVIDIA MMA4Z00-NS |
| OSFP-800G-SR8 | OPQM-MT5-85-CBO | 800Gb/s OSFP SR8 Finned top, multimode mode, MPO, 850nm, up to 50m | Compatible with NVIDIA MMA4Z00-NS-T |
| OSFP-800G-SR8-FLT | OPOM-MT5-85-CBN | 800Gb/s OSFP SR8 Flat top transceivers, multimode mode, MPO, 850nm, up to 50m | Compatible with NVIDIA MMA4Z00-NS-FLT |
| OSFP-800G-DR8 | OPQM-SX1-13-CBO | 800Gb/s OSFP DR8 Finned top, single mode mode, MPO, 1310nm, up to 100m | Compatible with NVIDIA MMS4X00-NS |
| OSFP-800G-DR8 | OPQM-SX1-13-CBO | 800Gb/s OSFP DR8 Finned top, single mode mode, MPO, 1310nm, up to 100m | Compatible with NVIDIA MMS4X00-NS-T |
| OSFP-800G-DR8 | OPQM-SX5-13-CBO | 800Gb/s OSFP DR8+ Finned top, single mode mode, MPO, 1310nm, up to 500m | Compatible with NVIDIA MMS4X00-NM |
| OSFP-800G-XDR8-FLT | OPOM-SX5-13-CBN | 800Gb/s OSFP DR8+ Flat top Transceivers, single mode mode, MPO, 1310nm, up to 500m | Compatible with NVIDIA MMS4X00-NM-FLT |
| OSFP-800G-2FR4 | OPOM-S02-13-CB2 | 800Gb/s OSFP 2xFR4 single mode mode, LC, 1310nm, up to 2km | Compatible with NVIDIA MMS4X50-NM |
For additional information about 800G Finned or Flat Top Transceivers, price inquiry, or custom OEM solutions, please contact us at sales@optech.com.tw
