25G SFP28 Transceiver Module Overview
Updated at Mar 6th 20211 min read
With the evolution of 5G technology and pursuit for higher speeds in enterprise data centers, equipment providers are responding with 25Gbps edge devices that require more bandwidth than can be provided on a traditional 10Gbps interface. 25G SFP28 transceivers are the critical player among them. They come in various types that cover different transmission distances.
25G SFP28 Transceiver Type and Applications
Following are the main categories of 25G SFP28 transceivers: 25G SFP28 standard transceiver, 25G BiDi SFP28 transceiver, and 25G WDM SFP28 transceiver.
Category | Type | Reach | Cable Type | Application |
25G SR | 100m | OM4 MMF | 25GBASE-SR Ethernet | |
25G LR | 100m | SMF | Data Center Backbone; High-speed Servers | |
25G ER | 40km | SMF | High-speed storage area networks; CPRI 10 | |
25G BiDi | 10km | SMF | 25GE LR; eCPRI & CPRI | |
25G CWDM | 40km | SMF | 25G GE LR; eCPRI , CPRI; High-speed Servers; High-performance Computing Clusters | |
25G DWDM | 10km | SMF | 25G Ethernet Data Center Networks; CPRI/eCPRI 5G Fronthaul Networks | |
25G LWDM | 40km | SMF | 25GBASE-ER Ethernet Data Center Networks; CPRI/eCPRI 5G Fronthaul Networks |
25G Standard SFP28 Transceiver Module
The SFP28 transceiver modules are key components in high-speed optical networks, offering versatile solutions for various distances and applications:
SFP28 SR - "SR" refers to short range. It mainly uses OM4 multimode fiber and supports distances up to 100 meters. It is ideal for applications within data centers, such as server-to-switch connectivity, where short yet reliable connections are crucial.
SFP28 LR - "LR" refers to long range. This module utilizes OS2 single-mode fiber to achieve connectivity up to 10 kilometers. It is often employed in metro networks or connecting data centers to broader campus networks, providing consistent high-speed links over extended ranges.
SFP28 ER - "ER" refers to extended range. This module works with OS2 single-mode fiber to support transmission up to 40 kilometers. It is well-suited for service providers and enterprises with large-scale networking requirements across geographically dispersed locations.
All three variants of SFP28 transceivers can be plugged into switches and routers in data centers, campuses, and service provider environments. They ensure efficient, high-speed 25Gbps connectivity, supporting bandwidth-intensive tasks and enabling scalable network upgrades. With their compact size and hot-swappable design, SFP28 modules offer flexibility, ease of deployment, and reliable performance for modern network infrastructures.
25G BiDi SFP28 Transceiver Module
25G BiDi SFP28 transceiver is different from the common 25G SFP28 transceiver. It uses one port to transmit and receive signals over a single strand fiber and must be used in pairs. It adopts two optical signals of different center wavelengths, for example, 1270nm-TX/1330nm-RX at one end and 1330nm-TX/1270nm-RX on the other end. BiDi SFP28 transceivers realize bidirectional transmission of optical signals on one optical fiber, thus saving fiber resources and leading the next generation of 5G communication technology.
25G WDM SFP28 Transceiver Module
25G WDM SFP28 transceiver consists of 25G CWDM SFP28 transceiver, 25G DWDM SFP28 transceiver and 25G LWDM SFP28 transceiver, all of which are commonly used in 5G front-haul networks.
25G CWDM SFP28 transceiver is a single mode CWDM transceiver for duplex optical data communications at a nominal wavelength of CWDM (1271~1331nm). CWDM transceiver is designed for short-range communications and is mainly used for city and access networks. Moreover, 25G CWDM SFP28 solution can well solve the current 5G millimeter wave pre-transmission problem.
25G DWDM SFP28 transceiver is designed for 25G Ethernet and CPRI/eCPRI links over SMF where wavelengths are packed tightly together in order to increase bandwidth over existing fiber networks.
25G SFP28 LWDM transceiver presents as a low-cost solution among 25G WDM transceivers, for it adopts relatively cheap DML lasers to keep a stable transmission, making it an ideal and efficient solution in 5G front-haul transmission. The module can also save fiber resources by achieving the multi-channel signals transmission on one single fiber.
25G SFP28 Transceivers FAQs
Q1. What is the maximum supported distance for 25G SFP28 transceivers?
The maximum currently supported distance for 25G is 40km using SFP-25G-ER transceiver module. Additional optics may be released in the future to support longer distances.
Are 25G SFP28 transceivers of different brands interoperable with each other?
It depends on the SFP28 standards with which the 25G transceivers are compliant. As long as the 25G SFP28 transceivers meet the associated industry standard specifications,they are fully interoperable.
Q2. Can I use SFP28 transceivers in SFP+ ports?
Optical transceivers support the fixed speed as they are manufactured. The link could be down when using SFP28 transceiver for SFP+ link.
For some devices with 25G ports that are also 10G capable, FS recommends the 10/25GBASE-SR transceiver module with 25Gbps and 10Gbps dual rate, supporting connectivity options for 25G Ethernet, 10G Ethernet and data center. For more information, please refer to the 10/25GBASE-SR module.
Q3. Can I use SFP+ transceivers in SFP28 ports?
The SFP+ transceiver can be used on the SFP28 port, but will limit the connection speed to 10Gbps. The SFP28 port is designed for 25Gbps. In terms of compatibility, the SFP28 port can be backward compatible with SFP+ modules, which is a convenience factor for transitioning from 10Gbps to 25Gbps environments. However, to take full advantage of the 25Gbps capability of the SFP28 port and to avoid potential bottlenecks, it is recommended to upgrade to the SFP28 transceiver for long-term network upgrades.
Q4. Can I connect SFP28 ports with QSFP28 ports?
Yes, it is available by configuring the QSFP28 100G transceiver to work at 4*25G breakout mode, and use the supported hardware to connect SFP28 ports with QSFP28 ports, such as QSFP28 to SFP28 DAC/AOC breakout cable or MTP-LC breakout cable with one 100G QSFP28 optical module is used on one side and four 25G SFP28 optical modules used on the other side as the following figure shows.
Conclusion
25GbE transceiver is a critical carrier to implement 25G Ethernet technology in cloud and enterprise data center environments. As the enhanced version of SFP+, 25G SFP28 transceiver is able to handle 25Gbps per lane transceiver while ensuring backward compatibility to SFP and SFP+.