Advantages
It has the advantages of small size, large port density, and low power consumption.
1. small volume. Compared with CFP and CFP4 optical modules, the QSFP28 optical module has a smaller volume;
2. The port density is high. Compared to other 100G optical modules, QSFP28 optical modules have a higher port density on the switch. Generally, 36 QSFP28 optical modules can be installed on a 1RU switch;
3．Low power consumption. Compared with other 100G optical modules, the power consumption of QSFP28 optical modules is low, and generally does not exceed 3.5W.
Application selection
In a 100G network, how to choose a suitable QSFP28 optical module can be considered from the following three aspects:
1. Multi-mode fiber cabling between switches: 5-100m
The QSFP28 SR4 optical module can be selected. It uses MTP interface (8 cores). The transmission distance when used with OM3 multimode fiber is 70m. The transmission distance when used with OM4 multimode fiber is 100m, which is suitable for short-distance transmission ( Distance less than 100 meters).
2. Single-mode fiber wiring between switches:> 100m-2km
You can choose QSFP28 PSM4 optical module or QSFP28 CWDM4 optical module, they are both suitable for short and medium distance 100G networks. QSFP28 PSM4 optical module uses 8 parallel single-mode fibers together, and the transmission distance is about 500 meters; QSFP28 CWDM4 optical module is used with single-mode fiber, and the transmission distance can reach 2 km.
3．Long-mode single-mode fiber: ≤10km
The QSFP28 LR4 optical module can be selected. It uses a duplex LC interface. When used with single-mode fiber, the transmission distance can reach 10km. It is suitable for 100G networks with long distances (more than 2 kilometers and less than 10 kilometers).
