100G CFP Application
CFP, one of the recommended 100G optical modules, is mainly applied in metro network and long-distance transmission (normally over 10 km).
To achieve high cabling density and long-distance transmission with CFP transceiver, the architecture mixed a 16-channel dual fiber DWDM Mux Demux by adding MTP harness cable and WDM SFP+ OEO converter to transfer the regular SR wavelength to DWDM wavelengths. Thus, a long-distance DWDM network with 100G coherent CFP module is achieved.
QSFP28 Application
Nowadays, QSFP28 is considered to be the mainstream form factor of 100G optical modules. There are many QSFP28 products on the market, including QSFP28 DAC/AOC cables and QSFP28 optical modules such as 100G SR4/LR4/PSM4/CWDM4 of different types. These products are mainly divided into the following four applications according to the transmission distance.
Copper DAC Used Inside Racks Within 5 Meters
QSFP28 DAC cables are ideal to use in short-range connections within 5 meters. They can offer a complete cable assembly in a cost-effective manner. Therefore, if your 100G network is deployed inside racks in 5 meters, you can use QSFP28 DAC cables instead of 100G optical modules.
QSFP28 AOC/SR4 Transceiver for 5-100 m
There are two options for 100G multimode fiber cabling between switches away from 5 to 100 meters. One is to use QSFP28 AOC which is the best fit for 3-20 meters, and the other is to use QSFP28 SR4 transceiver with 12-fiber MTP OM3/OM4 cable, which can support a transmission distance of up to 100 m.
QSFP28 PSM4/CWDM4/CLR4 Transceiver for 100 m-2 km
For mid-reach connectivity like 100 meters to 2 km, QSFP28 PSM4 and CWDM4/CLR4 transceivers can offer cost-effective solutions. They can support up to 500 meters over 12-fiber MTP single mode fiber and 2 km over duplex LC single mode fiber respectively.
QSFP28 LR4/ER4/ZR4 Transceiver for Long Span
For long-span 100GbE deployment, such as connectivity between two buildings (mostly up to 10 km), QSFP28-100G-LR4 with duplex LC single mode fiber is the preferred option defined by IEEE. For longer distances (up to 40 km and 80 km), 100G QSFP28 ER4 and 100G QSFP28 ZR4 transceivers are better.
Application: 100G CFP vs. QSFP28
As for 100G CFP vs. QSFP28, which to use for your network construction? Actually, it depends on two main aspects: the port type of your hardware device and application scenarios. CFP modules have a much larger size than QSFP28 modules. 100G QSFP28 appears to be the mainstream and is mostly used in shorter distances (0-10 km) between switches or sometimes in long distances (up to 40/80 km) with QSFP28 ER4/ZR4 and single mode fibers. While, although 100G CFP can be used in short distances as well, it is more common in metropolitan area networks (MANs) and long-haul WDM transmissions.
