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CFP vs QSFP28: Choosing the Right 100G Fiber Optic Module for Your Network

LINK-PP Official 　·

Sep 12,2025

Modern network infrastructures—especially data centers, metro backbones, and carrier networks—demand high bandwidth, energy efficiency, and flexibility. Both QSFP28 and 100 Gigabit CFP form factors are prominent options when deploying 100G+ links. But which is right for what scenario? This article delves deep: technical definitions, comparative metrics, and advice for choosing the best module type depending on your network requirements.

CFP vs QSFP28

1. Introduction: The 100G Revolution

The relentless growth of data traffic, driven by cloud computing, hyperscale data centers, and high-performance enterprise networks, has made 100 Gigabit Ethernet (100GbE) a fundamental standard. Two form factors dominate this landscape:

CFP (C Form-factor Pluggable): the first-generation 100G module, built for long-distance and telecom applications.
QSFP28 (Quad Small Form-factor Pluggable 28): a compact, energy-efficient module designed for modern high-density networks.

Selecting the wrong module can increase operational costs, reduce port density, and impact scalability. This guide helps network engineers, IT managers, and planners make informed choices based on real-world applications, technical performance, and cost-efficiency.

2. Understanding QSFP28 and CFP Modules

CFP: The Legacy Workhorse

Definition: CFP modules were designed to handle early 100G technology with multiple optical lanes (10×10 Gbps or 4×25 Gbps).
Size & Form Factor: Large, approximately 144.75 mm × 82 mm × 13.6 mm.
Power Consumption: High, often exceeding 24 W due to early-generation components.
Primary Applications: Long-haul DWDM networks, metro transport, legacy telecom switches, and high-bandwidth aggregation.

QSFP28: High-Density Efficiency

Definition: Quad Small Form-factor Pluggable 28, supporting four lanes at 28 Gbps for a total of 100 Gbps.
Size & Form Factor: Compact, around 72.5 mm × 18.35 mm × 8.5 mm, allowing more ports per switch.
Power Consumption: Low, typically 3.5–5 W for SR4/LR4 variants, ideal for energy-conscious deployments.
Primary Applications: High-density switches, data center interconnect (DCI), leaf-spine topologies, and cloud infrastructure.

3. Technical Comparison: CFP vs QSFP28

Feature	CFP	QSFP28	Winner 🏆
Form Factor Size	Large	Compact	QSFP28
Port Density	Low (1–2 ports per line card)	Very High (up to 36 ports per switch)	QSFP28
Power Consumption	High (>24 W)	Low (~3.5 W)	QSFP28
Primary Application	Long-Haul, Telecom	Data Centers, Cloud	Context-Specific
Thermal Management	Complex, high cooling needed	Simple, easy to cool	QSFP28
Cost	Higher, niche	Lower, economies of scale	QSFP28
Technology Generation	First	Second, Advanced	QSFP28

Insight: QSFP28 clearly leads in port density, energy efficiency, and cost-effectiveness, making it the preferred choice for modern deployments. CFP remains essential for specific long-range applications.

4. Application Scenarios

Short Reach (0–5 m)

Module: QSFP28 DAC (Direct Attach Copper)
Use Case: Rack-to-rack connections, high-density data center links, low-cost, low-latency setups.

Medium Reach (100 m–2 km)

Module: QSFP28 CLR4/CWDM4/PSM4
Use Case: Campus networks, metro interconnects using single-mode fiber (SMF) with MTP or LC connectors.

Extended Reach (10–80 km)

Module: QSFP28 LR4/ER4/ZR4 or CFP optical modules
Use Case: Inter-building links, long-distance metro networks, DWDM transport.

Metropolitan & Long-Haul Networks

Module: CFP / CFP2 / CFP4
Use Case: Dense wavelength-division multiplexing (DWDM), telecom aggregation, and legacy infrastructure requiring high optical link budgets.

5. Practical Deployment Guidelines

Distance Priority:
- <10 km → QSFP28
- 10 km → CFP
Port Density Requirement:
- High-density environments → QSFP28
- Fewer ports or legacy chassis → CFP
Energy Efficiency: QSFP28 consumes less power, reducing operational costs.
Future Scalability: QSFP28 can evolve to QSFP56 / QSFP-DD (200G–400G) for high-speed upgrades.
Cost Consideration: Evaluate TCO, including module cost, power, cooling, and cabling.

6. Commercial Value & Vendor Selection

At LINK-PP, we provide high-performance, MSA-compliant QSFP28 and CFP transceivers, ensuring:

100% Compliance: Guaranteed compatibility with leading switch brands.
Rigorous Testing: Modules verified for performance, latency, and BER.
Cost Efficiency: Significant savings versus OEM optics.
Lifetime Warranty: Confidence and reliability for enterprise and data center operations.

Recommended QSFP28 Module for Modern Networks:

LINK-PP QSFP-100G-LR4
Supports: 10 km SMF links, high-density DCI, leaf-spine architectures.
Compliance: MSA-certified for seamless interoperability.

7. FAQ: Common Questions

Q1: Can CFP and QSFP28 modules be used interchangeably?
No, they have different form factors and connector types. Always verify compatibility with your hardware.

Q2: Which module is better for energy-efficient networks?
QSFP28 is preferable due to lower power consumption.

Q3: Are CFP transceivers suitable for short-distance applications?
Typically not; CFP is optimized for long-range deployments.

Q4: How to decide between CFP and QSFP28?
Base your choice on distance, port density, energy efficiency, and existing network equipment. Mixed deployments are possible for hybrid networks.

Q5: Do QSFP28 modules support backward compatibility?
Yes, they are compatible with SFP, SFP+, and SFP28 interfaces in many modern deployments.

8. Conclusion & Recommendations

The evolution from CFP to QSFP28 reflects the industry trend: more efficiency, smaller size, lower power, and higher density. While CFP retains value for legacy and long-haul telecom networks, QSFP28 is the mainstream solution for next-generation data centers, cloud networks, and high-performance enterprise infrastructures.

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