1.25G SFP vs 100G QSFP28: Which One Will You Choose?

In recent years, as the demand for network bandwidth in various industries continues to increase, optical modules with different speeds have been fully used in different scenarios. YXFiber focuses on the production of 1-800G optical modules, which is very convenient for enterprises to choose appropriate optical transceivers.

1.What are 1.25G SFP and 100G QSFP28?

1.25G SFP is a small pluggable optical module that supports 1.25Gbps transmission rate. Its application is very mature and common. Common products include: 1000BASE-SX, 1000BASE-LX, BiDi SFP, CWDM SFP, DWDM SFP, etc. It is fully used in local area networks, campus networks, video surveillance, FTTx access networks, industrial Ethernet, power communications and other fields.

100G QSFP28 is an optical module package that supports 100Gbps rate transmission. Common models include QSFP28 SR4, QSFP28 LR4, QSFP28 CWDM4, QSFP28 PSM4, QSFP28 ER4, QSFP28 ZR4, QSFP28 Bidi, etc., are mainly used in data centers, cloud computing platforms, AI computing clusters, large enterprise core networks, operator backbone networks, etc.

2.What are the differences between 25G SFP and 100G QSFP28?

2.1 Transfer rate and core performance

The difference between them is the speed difference. The broadband of 1.25G SFP is 1.25Gbps, which is usually used for Gigabit-level Ethernet transmission. The bandwidth of 100G QSFP28 is 100Gbps, playing the role of a massive data highway.

2.2 Physical structure and working principle

1.25G SFP adopts a single-channel design, with only one transmission channel inside a module. The physical interface size of 100G QSFP28 will be larger than that of SFP. There are 4 transmission channels inside. These 4 signals are aggregated into 100G bandwidth through wavelength division multiplexing or optical fiber technology.

2.3 Actual deployment

1.25G SFP is active at the access layer, and can be used in application scenarios such as connecting desktop computers in offices, uploading backhaul to Wi-Fi access points, and campus security cameras. 100G QSFP28 is like the "heartland" of the network. It is responsible for processing data exchange between server clusters in the core switching layer of the data center, the metropolitan backbone network or the large interconnection nodes of the cloud service provider.

2.4 Transmission distance and fiber selection

Both can choose multi-mode optical fiber and single-mode optical fiber according to the transmission distance. The difference is that 1.25G optical fiber has lower cost for long-distance transmission. To achieve long-distance transmission, 100G QSFP28 needs to use coherent optical technology or high-precision modulation. In this way, the price of 100G long-distance will be several times higher than that of short-distance.

2.5 Flexibility and interoperability

In addition to being used as standard 100G ports, many switches also allow the QSFP28 interface to be connected to multiple 25G servers by splitting four independent 25G SFP28 interfaces. This is very practical in modern architectures, while 1.25G can only be used in a fixed pair and does not have this splitting function.

YXFiber is a professional optical module supplier that not only provides a rich product line, but also helps customers complete compatibility testing, project model selection, and OEM and ODM customized services. If you want to know more, please contact us online.