Leveraging 25G CWDM Transceivers in 5G Fronthaul Networks

What is a 25G CWDM Transceiver?

The 25G CWDM transceiver plays a crucial role in modern telecommunications, particularly in 5G fronthaul networks. Operating at 25 Gbps, it utilizes CWDM technology to transmit multiple signals over one fibre, optimising bandwidth. Specifically designed for 5G fronthaul, it supports 25G Ethernet and CPRI/eCPRI, with impressive 10km link distances over single-mode fibre. Fully compliant with SFP28 MSA, CPRI, and eCPRI standards, it typically operates within the wavelengths of 1270nm-1370nm and 1470nm-1570nm.

If you want to know more about the differences between the 25G CWDM module and other 25G SFP28 modules, you can check out this article: 25G SFP28 Transceiver Module Overview.

 Figure 1: FS CWDM SFP28 Transceiver

What is the 5G Transport Network?

The 5G transport network encompasses fronthaul, midhaul, and backhaul, connecting cell sites with one another, then with the core network, and ultimately with data centres.


As 5G technology continues to evolve, the significance of “fronthaul” in the telecommunications industry is on the rise. This fiber-based link, integrated within the Radio Access Network (RAN) infrastructure, plays a pivotal role in achieving faster speeds and reduced latency. With the introduction of Distributed RAN (DRAN) and Centralized RAN (CRAN) approaches, base station components such as the Central Unit (CU), Distributed Unit (DU), and Active Antenna Unit (AAU) are undergoing substantial restructuring to meet evolving requirements. Fronthaul acts as the vital connection between the active antenna unit (AAU) and the distributed unit (DU), ensuring smooth communication and efficient data transmission. Innovations like the 25G CWDM SFP28 transceiver are essential for facilitating seamless communication and efficient data transfer across 5G fronthaul networks.


Midhaul is a vital element of the telecommunications network, acting as the intermediary between the fronthaul and backhaul segments. It encompasses the transmission path from the Distributed Unit (DU) to the Centralised Unit (CU). In the context of 5G networks, base stations are structured into a distributed architecture. Here, the DU oversees the transmission and reception of wireless signals, while the CU manages communication with the core network. Acting as a pivotal link between these two units, midhaul facilitates the transfer of data from the DU to the CU for further processing and dissemination across the network.


In addition to fronthaul and midhaul, the 5G transport network also includes the backhaul. This component consolidates access to traffic from the Radio Access Network (RAN) and utilises various technologies such as Ethernet, microwave, and optical fibre to transport it to the central office or data centre. The backhaul serves as a crucial link, connecting the fronthaul and midhaul to the core network, facilitating seamless data transmission across extensive distances.

Figure 2: 5G Transmission Networks Architecture

Utilisations of 25G CWDM Transceivers

In the initial stages of setting up 5G networks, fronthaul predominantly relies on direct fibre links, along with extensive coverage of both high-frequency and low-frequency spectrums for additional access points. To optimise the utilization of existing fibre resources, CWDM optical modules play a crucial role. The 25G CWDM solution allows for the selection of 6 or 12 wavelengths from the 18 specified in the ITU-T G.694.2 standard, spanning from 1271nm to 1611nm. Adhering to this standard enables optical transmission equipment from various vendors to operate harmoniously within the same network, ensuring network stability and reliability while mitigating issues stemming from equipment mismatches.

  • 25G CWDM SFP28 6-Wavelength Solution

The 6-wavelength 25G CWDM solution opts for the initial 6 shorter wavelengths (1271nm~1371nm) due to the maturity of the industry chain and the lesser impact of transmitter dispersion penalties (TDP). It’s widely agreed upon that the AAU side utilizes wavelengths of 1271nm, 1291nm, and 1311nm, while the DU side employs wavelengths of 1331nm, 1351nm, and 1371nm, as depicted in Fig.3. Additionally, the optical module on the AAU side requires cooled directly modulated lasers (DMLs) to meet industrial-grade standards.

Figure 3: 25G CWDM SFP28 6-Wavelength Solution
  • 25G CWDM SFP28 12-Wavelength Solution

The 12-wavelength 25G CWDM solution addresses a mixed transmission scenario involving both 4G and 5G networks. To enhance reliability and reduce component costs, the wavelengths ranging from 1271nm to 1371nm operate at a 25Gbit/s data rate for 5G fronthaul networks, while the wavelengths from 1471nm to 1571nm operate at a 10Gbit/s data rate for 4G fronthaul networks. This arrangement, illustrated in Fig. 4, facilitates the smooth transition from 4G to 5G base stations. However, in practice, the 25G SFP28 connector takes precedence due to its compatibility with both 4G and 5G networks, making the 12-wavelength solution less commonly used in real-world scenarios.

Figure 4: 25G CWDM SFP28 12-Wavelength Solution

Benefits of 25G CWDM Transceivers

  • Cost-effectiveness CWDM technology enables the transmission of multiple signal wavelengths over the same fibre optic cable, efficiently utilising fibre optic resources. With 25G CWDM optical modules, multiple data streams can be transmitted over a single fibre optic cable without the need for additional fibres, thus conserving fibre optic resources and reducing network construction costs.
  • Flexibility and Scalability Given the significant and ever-growing volumes of data typically associated with big data applications, networks must possess robust flexibility and scalability. By utilising 25G CWDM modules, users can dynamically select different wavelengths for data transmission, enhancing the adaptability and scalability of the network to meet the continuously expanding demands of big data processing.
  • Data Security In the realm of big data applications, the handling and processing of extensive volumes of sensitive data are routine, emphasising the critical importance of data security. 25G CWDM modules enhance data transmission security by segregating data streams of varying wavelengths into separate channels. This segregation reduces the risks of data leaks and interference, thereby enhancing the reliability and security of data transmission.


In brief, the 25G CWDM SFP28 is a critical optical transceiver that efficiently sends multiple signals down a single fibre optic cable using CWDM technology. It plays a pivotal role in providing effective data transmission solutions for 5G fronthaul networks. This technology not only optimizes how bandwidth is used but also meets the high-speed and low-latency demands of 5G networks. Moreover, it enhances data transmission security by segregating data streams into separate channels based on different wavelengths. Overall, its use ensures comprehensive protection for network performance, flexibility, and security, laying a solid foundation for the future of 5G communication.

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What Is 25GBASE-T?

Overview of Dual Rate 10/25G Transceiver Module

In the realm of network communications, the increasing demands for data processing have posed a challenging task for many enterprises: integrating high-speed, stable, and flexible data transmission solutions. This article will explore a solution that not only addresses the requirements of modern data centres but also considers cost efficiency—dual rate 10/25G transceiver module. With its versatility and economic viability, the dual rate module signifies a strategic amalgamation of performance and scalability ideally suited for the evolving landscape of network infrastructure.

What is Dual Rate 10/25G Transceiver Module?

The dual rate 10/25G transceiver module is a form of optical transceiver capable of accommodating two distinct data rate options: 10 gigabits per second (Gbps) and 25 Gbps. Its design allows seamless interoperability with network equipment, dynamically adjusting between these speeds based on the connected devices’ capabilities and the network’s requirements.

These dual rate modules provide a high level of flexibility for network infrastructure, eliminating the need for multiple types of transceivers. This significantly simplifies the management of network upgrades and inventory, as the same module can be employed across various network segments operating at either 10Gbps or 25Gbps speeds.

Practically, a dual rate module typically adopts a form factor like SFP28 (small form-factor pluggable 28), commonly utilized in 25Gbps networking but also compatible with 10Gbps, ensuring backward compatibility with older equipment. This empowers IT managers to future-proof their networks and facilitates an upgrade path from 10G Ethernet to 25G Ethernet without necessitating a complete overhaul of the existing cabling infrastructure.

The dual rate functionality proves particularly advantageous for data centres striving to optimize bandwidth, manage costs efficiently, and prepare for escalating data traffic demands, all while maintaining compatibility with existing 10G network equipment.

Applications of Dual Rate 10/25G Transceiver Module

The dual rate 10/25G transceiver module is an optical transceiver that can operate at two different data rates, 10 Gbps and 25 Gbps. This versatility allows the module to be used with a wide range of networking equipment and in various scenarios to meet the demands of modern data centres and enterprise networks. Here are some applications where a dual rate 10/25G transceiver module may be particularly beneficial:

Transitioning to 25G Network via Dual Rate 10/25G Transceiver Module

Businesses transitioning from 10G to 25G networks can employ dual rate modules to ensure seamless compatibility throughout the process, facilitating a gradual migration and minimising downtime. Data centres requiring high-bandwidth connections between servers, storage systems, and network switches can benefit from the increased data rates of 25G, while dual rate capability ensures compatibility with existing 10G equipment.

Optimising High-Density Networks

In high-density network environments where rack space is limited, dual rate modules can optimise port density and reduce space requirements by allowing connection consolidation and gradual speed upgrades. Enterprises needing a mix of 10G for legacy devices and 25G for newer, high-throughput applications can utilise dual rate 10/25G transceiver modules for flexible connectivity options.

Enhancing Hybrid Cloud Environments

Organisations operating within hybrid cloud environments can employ dual rate transceivers to facilitate efficient data transfer between different network segments operating at varying speeds. This flexibility enables seamless integration between on-premises and cloud infrastructures.

Versatile Solutions for Telecom Networks

Telecom operators and service providers can leverage dual rate modules to offer customers a range of services operating at either 10G or 25G, providing adaptable solutions tailored to diverse requirements and network demands.
Essentially, dual rate 10/25G transceiver modules assist in offering flexibility, scalability, and investment protection for network infrastructure. They enable network managers to balance performance requirements with budget constraints, and they can be a strategic option for phased network upgrades, ensuring compatibility between different generations of networking equipment.

Introducing FS Dual Rate 10/25G Transceiver Module

FS dual rate modules have earned high acclaim in the market owing to their outstanding reliability, excellent compatibility, and effective cost management. These modules are distinguished as the preferred option for enhancing network performance and efficiency. Below is a parameter comparison of FS dual rate 10/25G transceiver module FS 10/25G dual rate module.


With the continuous evolution of network technology and the growing demand for flexibility in data centres, dual rate 10/25G transceiver modules are poised with immense potential. Offering a cost-effective solution, they address the challenges of rate adaptability and future compatibility, making them a wise choice for constructing advanced and dependable network infrastructure.

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25G SFP28 Transceivers for Data Center and Enterprise Applications

With the rapid expansion of data centers, faster speed and higher bandwidth are required for better experience. To meet the demands, data center operators are now turning to 25G Ethernet technology. 25G SFP28 transceivers, as high-bandwidth data switching fiber optics, play an important role in 25G fiber-optic communication systems. This article will reveal the 25G SFP28 transceivers for data center and enterprise applications.

What Is the Definition and Type of 25G SFP28 Transceiver?

25G SFP28 transceiver is the enhanced version of SFP+, which is designed for 25G signal transmission. It has the same physical structure as SFP and SFP+, but its electrical interface is upgraded to handle 25Gbps per lane. Therefore, the pinouts of SFP28 and SFP+ connectors are compatible. Compared to SFP+ optics, SFP28 has higher bandwidth, superior impedance control, and less crosstalk. 25G SFP28 transceiver module can be divided into Short-Range (SR) and Long-Range (LR) transceivers. The SR SFP28 is mainly used with OM3\OM4 multi-mode fibers to transfer data over a short distance (up to 100m), while the LR SFP28 is mainly used with OS2 single-mode fibers for long distance transmission (up to 10 km). 25G SFP 28 DAC/AOC cables are also popular on the market and both used for transmission distance below 30m.

alt 25G SFP28 Transceivers

25G SFP28 Transceivers for Data Center Applications

The data center architecture is undergoing tremendous changes. Previously, the data center mainly composed of 1/10G servers and 1/10/40G EOR-MOR-TOR (End-of-Row, Middle-of-Row, Top-of-Rack) switches. Today, data centers are built using high-performance 10/25G servers and 10/25/40/100G EOR-MOR-TOR switches. Moreover, many data center operators choose SFP28 transceivers with SMF/MMF (Single-Mode Fiber/Multi-Mode Fiber) over SFP28 DAC/AOC (Direct-Attach Cable/Active Optical Cable) cables for 25G cabling solutions. That’s because by using the pluggable modules and fibers, data center operators can easily replace transceivers or upgrade TOR, MOR and EOR switches, servers, and cables without changing the cabling infrastructure.

alt 25G SFP28 Transceivers for Data Center Applications

25G SFP28 Transceivers for Enterprise Applications

The traditional enterprise network includes workstations, desktop computers, access points or video walls, and local computer rooms. Generally, these networks consist of a building backbone cabling based on IEEE 802.3 MMF 10G-SR or SMF 10G-LR transceivers. Due to the increase in video conferencing and business applications, the enterprise campus traffic continues to grow, requiring faster speed than traditional 10G networks. In response to the needs, the enterprise campus is transforming from a backbone that was based on a 10G network to new high-performance 25G network. Since the 25G SFP28 transceivers are compatible with 10G equipment, it enables the 10G connectivity infrastructure to remain and achieve a seamlessly upgrading from 10G to 25G. The upgrading of the 25G network not only brings higher speed and bandwidth than 10G network but also saves money for the enterprise networks.

alt 25G SFP28 Transceivers for Enterprise Applications


25G SFP28 transceivers enable data centers and enterprises to reach a higher speed, scalability and performance level. To meet your interconnection needs, FS provides a variety of 25G SFP28 transceivers include 25GBASE-SR, 25GBASE-LR, CWDM SFP28 transceivers, 25G DAC/AOC Cables, and 100G QSFP28 to 4x25G SFP28 DAC/AOC cables. For all the transceivers, FS provides a lifetime warranty to ensure product quality and they are all compatible with major brand companies.

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How Far Can 25G Ethernet Go?

Seeing from the evolution of data transmission speed and size of data centers, it is not difficult to find that the pressure on the data centers to manage data quality and transmission speed continues to grow, which leads to the need for faster data transmission over the network. Ethernet industry has laid a path to higher networking speeds like 100GbE, and 25G Ethernet has been developed to provide a simpler path to future Ethernet speeds of 50 Gbps, 100 Gbps and beyond. The release of the 25GbE specification provides cost-effective solution for server-to-switch connectivity. However, network will not stop the pace of development. How far can 25G Ethernet go? This article is going to focus on the question.

Overview of 25G Ethernet

25G Ethernet is a standard for Ethernet connectivity in a datacenter environment, developed by IEEE 802.3 task force P802.3by. The IEEE 802.3by standard uses technology defined for 100 Gigabit Ethernet implemented as four 25 Gbps lanes (IEEE 802.3bj). In 2016, 25G Ethernet equipment was available on the market, such as 25G SFP28 transceiver and DAC cable. In addition, 25G Ethernet supports for 100G using QSFP ports that can be converted to 4 lanes of 25 Gbps, like 100G QSFP28 transceiver. Here is a table of 25G Ethernet specification for you.

25G Ethernet specification

Advantages of 25G Ethernet

For 10G ToR to 10G Server connectivity, the simplest cabling solution is to use two 10G SFP+ transceivers and one fiber optic cable. When the network has to be upgraded to 25G Ethernet, the data center manager only needs to replace 10G SFP+ transceivers with 25G SFP28 transceivers. In the same way, we know that in 40G ToR to 10G Server connectivity, one 40G QSFP+ transceiver, four 10G SFP+ transceivers and one MTP to LC breakout cable are utilized. When this network deployment is upgraded to 100G ToR to 25G Server connectivity, the work can be quickly finished by replacing 40G QSFP+ transceiver with 100G QSFP28 transceiver, four 10G SFP+ transceivers with four 25G SFP28 transceivers. It can be easily found that there are some advantages when upgrading from 10G to 25G or 40G to 100G:

  • It can offer both CapEx and OpEx savings through backward compatibility, for investment protection and seamless migrations with consistent rack-design and reuse of the existing cabling infrastructure, avoiding costly and complex changes.
  • The technology utilized in 100G to 25G connectivity is similar to that in 40G to 10G connectivity, but the performance is increased by 2.5 times, thus reducing the power and cost per gigabit significantly.
  • 25G Ethernet provides higher port and system density than a comparable 40G solution.
  • Both power savings and higher density results in lower cooling requirements and operational expenditure for data center operators.

advantages of 25G Ethernet

How Far Can 25G Ethernet Go?

Considering the significant benefits and compelling economics of 25G Ethernet, it is no surprise that the move to 25G is accelerating—a recent five-year forecast by industry analysts at the Dell’Oro Group predicts 25G Ethernet will be the dominant Server port speed for new systems by 2018. You can learn about it from the following figure.

forecast for 25G Ethernet

However, never underestimate the need for industry consensus building. At present, 25G is mainly used for switch-to-server applications. If it can realize switch-to-switch application, 25G Ethernet may go further.


To be frank, 25G Ethernet indeed gains ground in some aspects compared to 10G and 40G Ethernet. If you plan to deploy 25GbE network, you can visit FS.COM which provides quality 25G SFP28 transceiver and various fiber optic cables.

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