SFP28 25G SR vs. SFP28 25G LR: Which to Choose?
Feb 26, 20251 min read
With the growing demand for high-speed networks in data centers, the 25G SFP28 optical module has become a mainstream choice due to its high density, low power consumption, and cost-effectiveness. Among them, the 25GBASE SR and 25GBASE LR are the most commonly used models. This article will compare the differences between the two from multiple dimensions, including transmission distance, fiber type, technical specifications, and application scenarios, to help users make the best choice.
What are SFP28 25G SR and SFP28 25G LR?
SFP28 25G SR Definition
The SFP-25G-SR is a small form-factor pluggable optical transceiver that provides a high-speed solution for 25 Gigabit Ethernet and Infiniband Enhanced Data Rate applications.
It is designed to operate over multimode fiber (MMF) and uses an 850nm VCSEL for short-range optical transmission. This transceiver offers enhanced performance for environments requiring high bandwidth and low latency, making it ideal for data centers, telecom networks, and high-performance computing environments.
SFP28 25G LR Definition
SFP-25G-LR is an optical module designed for long-distance data transmission, supporting a data transfer rate of 25Gbps. It uses single-mode fiber (SMF) and transmits signals at a wavelength of 1310nm, with a maximum transmission distance of up to 10 kilometers.
The SFP-25G-LR optical module typically features a DFB (Distributed Feedback Laser) and PIN photodetector, offering low power consumption and high transmission performance. It is widely used in data centers, enterprise networks, and communication/interconnection applications that require long-distance transmission.
SFP28 25G SR vs. SFP28 25G LR: A Detailed Specification Comparison
Transmission Distance and Fiber Type
SFP28 25G SR
Transmission Distance: Supports up to 70 meters with OM3 multimode fiber, and up to 100 meters with OM4 multimode fiber.
Fiber Type: Uses multimode fiber (MMF) with a core diameter of 50/125µm, suitable for short-distance, high-bandwidth transmission.
Core Advantage: Multimode fiber is cost-effective and ideal for intra-rack connections.
SFP28 25G LR
Transmission Distance: Supports up to 10 kilometers with OS2 single-mode fiber.
Fiber Type: Uses single-mode fiber (SMF) with a smaller core diameter (9/125µm), offering lower attenuation and dispersion, making it ideal for long-distance transmission.
Core Advantage: Single-mode fiber offers higher signal stability over long distances.
Laser and Photodetector Technology
SFP28 25G SR: Uses a Vertical Cavity Surface Emitting Laser (VCSEL) with a working wavelength of 850nm, paired with a PIN photodetector. VCSEL technology is low-cost and low-power (<1W), suitable for short-range scenarios.
SFP28 25G LR: Uses a Distributed Feedback (DFB) laser with a working wavelength of 1310nm, paired with a PIN detector and built-in Clock Data Recovery (CDR) circuit. It has slightly higher power consumption (<1.5W) but ensures stable long-distance signal transmission.
Cost Analysis
SFP28 25G SR: The cost of multimode fiber is low, and the module manufacturing cost is also lower, making it suitable for projects with limited budgets.
SFP28 25G LR: Single-mode fiber and DFB laser technology increase costs, but long-distance transmission does not require additional repeater devices, which can result in a lower overall Total Cost of Ownership (TCO).
Performance Parameters Comparison
To better understand the practical impact of these technical differences, let's compare the detailed performance parameters of the 25GBASE SR and 25GBASE LR modules. The table below outlines their similarities and differences.
Product Specification | SFP28 25G SR | SFP28 25G LR | |
Similarities | Form Factor | SFP28 | SFP28 |
Connector | Duplex LC | Duplex LC | |
Commercial Temperature Range | 0 to 70°C (32 to 158°F) | 0 to 70°C (32 to 158°F) | |
DDM/DOM | Supported | Supported | |
FEC Function | Supported | Supported | |
Differences | Wavelength | 850nm | 1310nm |
Media | MMF | SMF | |
Power Consumption | ≤1W | <1.5W | |
Max Cable Distance | 100m@OM4/70m@OM3 | 10km | |
TX Power | -7.9~1.9dBm | -4~2dBm | |
CDR (Clock and Data Recovery) | TX & RX Built-in CDR | TX and RX | |
Protocols | SFF-8472, SFF-8024, SFF-8431, SFF-8432 | MSA Compliant, CPRI, eCPRI | |
Packaging Technology | COB Packaging | BOX Packaging | |
SFP28 25G SR vs. SFP28 25G LR: Comparing Application Scenarios
When selecting between SFP28 25G SR and SFP28 25G LR optical modules, understanding their respective application scenarios is crucial. Below is a detailed comparison of their typical use cases:
Typical Applications for SFP28 25G SR:
Intra-Data Center Connections: 25GBASE SR modules are ideal for short-distance links within data centers, such as connections between servers, switches, and storage devices. For instance, they are well-suited for interconnections within the same rack or between adjacent racks, providing high-bandwidth, low-latency connections that meet the data center's need for rapid data transmission.
High-Density Cabling Environments: Due to the larger core diameter of multimode fibers (50/125µm), SFP-25G-SR are suitable for areas with dense wiring. Multimode fibers are cost-effective and occupy less space, facilitating high-density cabling in confined spaces.
Cost-Sensitive Projects: SFP-25G-SR are more affordable, making them suitable for projects with limited budgets. In environments requiring extensive deployments, SR modules can effectively reduce overall network construction costs.
Typical Applications for SFP28 25G LR:
Data Center Interconnection: 25GBASE LR modules are suitable for connections between data centers or between data centers and remote sites, such as metropolitan area networks. They provide high-bandwidth, low-latency connections that meet the demands of large-scale data transmission.
Long-Distance Communication Needs: SFP-25G-LR modules are suitable for scenarios requiring long-distance transmission, such as telecom operator backbones and enterprise campus networks. They support transmission distances up to 10 kilometers, meeting the needs of wide-area coverage.
High-Reliability Requirements: SFP-25G-LR modules use single-mode fibers, which have lower attenuation and dispersion, making them suitable for applications with high signal stability and reliability requirements. For example, in critical business transmissions, LR modules can provide higher resistance to interference, ensuring reliable data transmission.
In summary, SFP28 25G SR and SFP28 25G LR optical modules each have their unique application scenarios. SR modules are suitable for short-distance, high-density cabling, and cost-sensitive projects, while LR modules are suitable for long-distance, high-reliability applications. When selecting, decisions should be based on actual network requirements, transmission distances, fiber types, and budget considerations.
SFP28 25G SR vs. SFP28 25G LR: Which is the Best Choice for Your Network?
When selecting between SFP28 25G SR and SFP28 25G LR optical modules, it's essential to consider transmission distance, fiber type, and cost-performance balance. Here's an expanded guide to assist in making an informed decision:
Transmission Distance Considerations
≤100 Meters: For applications within data centers or short-range interconnections, the 25GBASE SR module is ideal. It supports up to 70 meters over OM3 multimode fiber and up to 100 meters over OM4 multimode fiber, making it suitable for high-density environments.
1 Kilometer to 10 Kilometers: For interconnecting different data centers or long-distance communication needs, the SFP-25G-LR module is appropriate. It supports up to 10 kilometers over OS2 single-mode fiber, ensuring reliable data transmission over extended distances.
Fiber Type Compatibility
Existing Multimode Fiber (OM3/OM4): If your infrastructure utilizes multimode fiber, the SFP28 25G SR module is compatible and cost-effective. It operates over OM3 and OM4 multimode fibers, providing flexibility in deployment.
Existing Single-Mode Fiber (OS2): For single-mode fiber installations, the 25GBASE LR module is the suitable choice. It operates over OS2 single-mode fiber, ensuring optimal performance over long distances.
Balancing Cost and Performance
Short-Distance Scenarios: The SFP-25G-SR module offers better cost-performance for short-distance applications. Its lower cost and power consumption make it ideal for high-density environments where budget constraints are a consideration.
Long-Distance Scenarios: The SFP-25G-LR module provides superior reliability for long-distance applications. Its higher cost is offset by its ability to support longer transmission distances without the need for additional repeaters, resulting in a lower total cost of ownership over time.
Application Examples
SFP28 25G SR:
Data Center Interconnects: Ideal for connections between servers, switches, and storage devices within the same data center or adjacent racks.
High-Density Cabling Environments: Suitable for areas with dense wiring requirements due to its compatibility with multimode fiber.
SFP28 25G LR:
Data Center Interconnection: Perfect for linking data centers across campuses or metropolitan areas.
Telecommunications Backbone: Suitable for telecom operator backbones and enterprise campus networks requiring long-distance communication.
By carefully evaluating these factors, you can select the optical module that best aligns with your network's specific requirements, ensuring optimal performance and cost-effectiveness.
Whether you focus on high-density interconnection for short distances or high-reliability communication for long distances, FS provides high-quality products and comprehensive services to ensure perfect compatibility with various mainstream devices. FS's SFP28 25G SR and SFP28 25G LR modules feature advanced Macom CDR chips and low-power designs, with a power consumption of ≤1.2W, offering better power efficiency than comparable products. This ensures network stability while reducing energy consumption.
All of our 25G optical modules undergo testing on over 200 real devices, ensuring compatibility and stability across various equipment and network environments, whether in high-density server interconnects or remote connections across data centers. Additionally, FS's optical modules not only meet international standards such as IEEE 802.3 but also pass stringent safety and compliance certifications, ensuring round-the-clock, uninterrupted reliability, which further enhances network performance and user experience.
By choosing FS, you gain a cost-effective solution along with outstanding compatibility, reliability, and support services, ensuring your network operates smoothly and efficiently.
Conclusion
There are significant differences between the SFP28 25G SR and LR optical modules in terms of transmission distance, technical implementation, and application scenarios. The SR module is suitable for short-distance, high-density applications, while the LR module excels in long-distance transmission. Users should make a comprehensive decision based on their actual network architecture, budget, and future scalability. FS provides high-performance modules and full support and advice throughout the process, making it the ideal choice for your network's future development.
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