As data centers and enterprise networks continue to evolve toward higher speeds, achieving reliable high-bandwidth connectivity over medium-to-long distances remains a critical challenge. Among all 100G optical transceivers, QSFP28 LR4 stands out as one of the most popular and proven solutions for data center interconnects (DCI), campus backbone networks, and metro Ethernet applications.
Capable of delivering stable 100Gbps transmission over single-mode fiber up to 10 kilometers, QSFP28 LR4 offers an excellent balance of performance, reliability, and cost-effectiveness. Whether you are planning a network upgrade or designing new long-reach 100G links, this guide provides everything you need to know about QSFP28 LR4 — from technical fundamentals to practical deployment advice.
QSFP28 LR4 is a hot-pluggable 100G optical transceiver module designed for 100 Gigabit Ethernet (100GbE) applications. The name breaks down as follows: QSFP28 refers to the Quad Small Form-factor Pluggable 28 module form factor, while LR4 indicates Long Reach with 4 wavelength channels using LAN-WDM technology.
It is specifically engineered for medium-to-long distance transmission, supporting up to 10 kilometers over single-mode fiber (OS2). This makes it an ideal choice for connections that exceed the reach of short-range SR4 or cost-optimized CWDM4 modules.
QSFP28 LR4 employs LAN-WDM (Local Area Network Wavelength Division Multiplexing) technology. Its working process includes the following key steps:
This architecture enables efficient, high-performance 100G transmission over long distances while maintaining excellent signal integrity.
100GBase-LR4 QSFP28 transceiver module is compatible with other QSFP28 transceiver modules in the market. The compatibility of these modules enables users to mix and match various transceiver modules to meet different network requirements. The transceiver module is compatible with a broad range of switches and routers in the market, offering flexibility and ease of use. Users can easily configure the transceiver to support applications like Ethernet, SONET/SDH, and Fiber Channel.
The 100GBase-LR4 QSFP28 transceiver module complies with the Multi-Source Agreement (MSA) standard, a set of specifications governing the design and performance of pluggable optical transceiver modules. The MSA standard defines the transceiver modules’ mechanical, electrical, and optical specifications to enable vendor interoperability. The compliance with the MSA standard ensures that the 100GBase-LR4 QSFP28 transceiver module is compatible with other transceiver modules, offering more deployment options for network designers and administrators.
|
Parameter |
SR4 |
CWDM4 |
LR4 |
ER4 |
PSM4 |
|
Max Distance |
100m (OM4) |
2km |
10km |
40km |
500m–2km |
|
Fiber Type |
Multimode |
SMF （Single-mode Fiber） |
Single-mode |
Single-mode |
Single-mode |
|
Connector |
MTP/MPO-12 |
Duplex LC |
Duplex LC |
Duplex LC |
MTP/MPO-12 |
|
Wavelength |
850nm |
LAN-WDM 1310nm |
LAN-WDM 1310nm |
LAN-WDM 1310nm |
1310nm Parallel |
|
Power Consumption |
~3.5W |
~3.5W |
3.5–4.5W |
4.5–5.5W |
~3.5W |
|
Best For |
Intra-rack |
Short campus |
Medium-long DCI |
Long metro |
Parallel SMF |
For a broader view of 100G connectivity options, see our QSFP28 transceiver guide.
QSFP28 LR4 is one of the most widely deployed 100G single-mode optical transceivers in modern networks. Based on CWDM technology, it achieves 100G transmission through four 25G wavelength channels, providing an excellent balance between transmission distance, reliability, compatibility, and deployment cost.
Compared with short-reach multimode solutions, QSFP28 LR4 can deliver stable 100G connectivity over single-mode fiber for distances up to 10km without requiring signal repeaters or amplification. This makes it an ideal solution for medium- and long-distance network deployments in data centers, enterprise networks, and carrier infrastructures.
Designed for single-mode fiber (SMF), QSFP28 LR4 supports stable 100G transmission over distances up to 10 kilometers, making it suitable for inter-building, campus, and metro-area connectivity.
As one of the most established 100G standards, QSFP28 LR4 is widely supported by leading vendors such as Cisco, Arista, Juniper, NVIDIA, and Huawei, ensuring excellent interoperability and deployment stability.
Compared with coherent optics or longer-distance transmission solutions, QSFP28 LR4 offers lower power consumption and reduced thermal requirements, making it well suited for high-density switch environments.
LR4 provides a strong balance between performance and cost, delivering long-distance 100G connectivity at a significantly lower deployment cost than more advanced long-haul optical solutions.
The standard QSFP28 form factor supports hot-swappable installation and seamless integration into existing 100G network infrastructure, simplifying upgrades and maintenance.
QSFP28 LR4 has a mature supply chain and ecosystem across switches, routers, and server platforms, making procurement and compatibility management much easier.
Data Center Interconnect (DCI)
QSFP28 LR4 is ideal for medium-distance data center interconnects, enabling high-bandwidth 100G links between buildings, campuses, or distributed data center facilities.
Campus Backbone Networks
In large enterprise campus environments, LR4 modules are commonly used for high-speed backbone connections between core switches, providing stable and low-latency transmission.
Metro Network Links
Telecom operators and ISPs frequently deploy QSFP28 LR4 in metro aggregation and edge networks to support high-bandwidth services within a 10km range.
Enterprise WAN Aggregation
For inter-office, inter-campus, or regional aggregation networks, QSFP28 LR4 provides reliable 100G WAN connectivity while reducing infrastructure complexity.
100G Switch-to-Switch Interconnects
In Spine-Leaf architectures, QSFP28 LR4 is widely used for medium-distance Leaf-to-Spine interconnects, especially in large-scale data centers and distributed network environments.
For detailed switch-specific guidance, see our QSFP28 compatible switches guide.
The 100GBase-LR4 QSFP28 Transceiver is a high-speed data transfer technology that has revolutionized data centers globally. In simple terms, the transceiver is a device that transmits and receives data from one point to another. However, its remarkable ability to transfer large amounts of data at lightning-fast speed sets it apart from other transceivers, ensuring optimal performance in data centers.
The 100GBase-LR4 QSFP28 Transceiver is engineered to support high-speed data transfer and meet the needs of today’s data-intensive applications. With data rates of up to 100Gbps, it provides the ideal solution for handling large volumes of data, making it an excellent choice for data centers that require maximum throughput capabilities. From cloud computing to data backup and virtualization, the transceiver ensures lightning-fast data transfer, enabling organizations to achieve increased productivity, better performance, and reduced operational costs.
Organizations are always looking for ways to reduce costs without compromising quality. The 100GBase-LR4 QSFP28 Transceiver is a cost-effective solution that performs better than traditional 10G or 40G transceivers. By utilizing the 100Gbps data rate, organizations can use fewer devices and cables, reducing power consumption and hardware costs.
The 100GBase-LR4 QSFP28 Transceiver is optimized for optical performance, reducing the attenuation of the optical signal during the data transfer process. Using LR4 (long-reach four lanes) technology, the transceiver can send data up to 10 kilometers, making it an excellent choice for long-distance data transmission. Additionally, the transceiver complies with industry standards, ensuring compatibility with various systems.
The 100GBase-LR4 QSFP28 Transceiver is easy to install and configure, making it a hassle-free solution for data centers. The hot-swappable design of the transceiver allows for easy installation and replacement, ensuring minimum disruption and maximum uptime. Additionally, since the transceiver is compatible with plug-and-play technologies, organizations can save time and resources on installation and configuration costs.
To ensure stable and reliable operation of QSFP28 LR4 modules in 100G networks, proper installation and deployment practices are essential. Good fiber management and environmental control can significantly improve link reliability while reducing maintenance complexity and long-term operational costs.
QSFP28 LR4 is designed for single-mode transmission and should be deployed with low-loss OS2 single-mode fiber and high-quality LC-LC duplex patch cables to ensure stable long-distance connectivity and optimal optical power budget performance.
Contaminated fiber connectors are one of the most common causes of optical link issues and power degradation. Use professional fiber cleaning tools to clean connectors and ports before insertion to avoid dust or oil contamination.
When installing a QSFP28 LR4 module, make sure it is completely seated in the switch or router port. A distinct “click” sound usually indicates that the latch is securely locked in place, helping prevent poor contact or link instability.
Most mainstream networking platforms support DDM (Digital Diagnostic Monitoring), allowing real-time monitoring of Tx/Rx optical power, module temperature, voltage, and laser status for proactive troubleshooting and maintenance.
It is recommended to keep the operating environment within 0°C to 70°C and ensure sufficient airflow and cooling inside the rack to avoid thermal-related performance degradation.
During long-term operation, regular maintenance and proactive monitoring are critical to maintaining QSFP28 LR4 link stability. Routine inspection of fiber conditions and module parameters can help minimize network downtime and unexpected failures.
The following issues are among the most common causes of QSFP28 LR4 link failures:
Dust or debris on the fiber end face can significantly increase insertion loss and reduce received optical power.
Tight bend radii can increase optical attenuation and may even cause link interruption.
Different switch vendors may impose compatibility restrictions. Verifying EEPROM recognition and firmware support in advance is strongly recommended.
If DDM reports Tx/Rx optical power outside the normal range, it may indicate excessive link loss, dirty connectors, or potential module failure.
With proper deployment and routine maintenance, QSFP28 LR4 modules can provide stable and reliable 100G connectivity for data centers, campus backbone networks, and DCI applications over the long term. For detailed guidance, see our QSFP28 Troubleshooting: Link Down & No Light Guide.
QSFP28 LR4 remains one of the most reliable and widely deployed 100G optical transceivers for medium-to-long distance applications. With its mature LAN-WDM technology, excellent 10km reach, and strong compatibility, it continues to be the go-to solution for data center interconnects and enterprise networks where distance and reliability matter.
As 400G and 800G technologies advance, 100G links powered by QSFP28 LR4 will still serve as the backbone of many hybrid networks for years to come.
Ready to deploy QSFP28 LR4 in your network?
Explore Ascent Optics’ full range of QSFP28 LR4 transceivers or contact our engineers for expert compatibility verification and personalized recommendations.
Make your connections go further, faster, and more reliably — with the right QSFP28 LR4 solution.
A: 100GBase-LR4 is a standard optical transceiver module used in data centers to transmit data over long distances at up to 100Gbps. It uses a 1310nm wavelength over single-mode fiber (SMF) with a range of up to 10km.
A: Some key features of 100GBase-LR4 include its ability to transmit data at high speeds, 1310nm wavelength, and long-range transmission of up to 10km over a standard pair of LC SMF connectors. It is also hot-swappable, with a high-performance design, and compliant with IEEE 802.3ba 100GBase-LR4.
A: 100GBase-LR4 is commonly used in data centers for high-speed data transmission over long distances. It is ideal for video streaming, cloud computing, and high-speed server connectivity applications.
A: 100GBase-LR4 is designed to transmit data over long distances of up to 10km, while other 100G optical transceiver modules may be designed for shorter-distance transmissions. Additionally, 100GBase-LR4 uses the 1310nm wavelength over single-mode fiber, while other modules may use different wavelengths and fiber types.
A: Yes, 100GBase-LR4 is compatible with Cisco QSFP-100G-LR4-S. It is designed to comply with IEEE 802.3ba 100GBase-LR4, making it compatible with other QSFP28 optical transceiver modules.
A: 100GBase-LR4 can transmit data at speeds of up to 100Gbps, with a range of up to 10km over a standard pair of LC SMF connectors.
A: A datasheet for 100GBase-LR4 is a document that provides detailed technical information about the optical transceiver module, including its specifications, electrical characteristics, performance parameters, and application guidelines.
A: DOM, or digital optical monitoring, is a feature in 100GBase-LR4 that allows for real-time monitoring of the module’s operating conditions, such as output power, input power, and temperature.
A: 100GBase-LR4 is compatible with other QSFP28 optical transceiver modules compliant with IEEE 802.3ba 100GBase-LR4. This makes it easy to mix and match compatible transceivers to meet the needs of your data center.
