Deep analysis of 100G QSFP28 transceiver module

Deep analysis of 100G QSFP28 transceiver module

As we know, 100G Ethernet has been widely deployed and becomes a significant portion in data center. many data centers have already adopted QSFP28 transceiver for 100G migration. There are many products with QSFP28 form factor include SR4, LR4, PSM4, CWDM4 , Direct Attach Copper cables, Active Optical Cables and transceivers etc. The selection of the most suitable 100G QSFP28 product depends on a few factors, Do you know the difference between PSM4 and CWDM4? Which one is the best for 100GbE data center connectivity ?  this article will focus on deep analysis of 100G QSFP28 transceiver module.

QSFP28 PSM4

PSM4 is the standard defined by MSA for the point-to-point 100G link over eight single-mode fibers reaching the length of up to 500m with MTP/MPO interface, which uses four identical and independent lanes for each signal direction with each lane carrying a 25G optical transmission.

QSFP28 CWDM4

The CWDM4 provides a 100G Ethernet high-speed link with a maximum transmission distance of 2km with LC duplex interface,which uses Mux/Demux technologies with 4 lanes of 25Gbps optically multiplexed onto and demultiplexed from duplex single-mode fiber.

Comparison between QSFP28 PSM4 and CWDM4

The 100G PSM4 uses 8 parallel fibers (four transmits and four receivers), each transmit 25Gbps .100G PSM4 is a single mode parallel 4-channel optical transceiver, which is mainly applied to 500m distance in the data center but CWDM4 uses the retrocession multiplexer to reduce the number of optical fibers to 2 fibers, and the CWDM4 MSA goal is to run a generic specification of up to 2km of low-cost 100G optical interfaces in data center applications.

QSFP28 CWDM4 and QSFP28 PSM4 are designed to meet the requirement for intermediate or mid-reaches for data center applications. They both use WDM and parallel single mode fiber technologies and support transmission distance up to 2km. There are some tips we should know: PSM4 would be more cost-effective due to its lower costs of component However, PSM4 would be more expensive if there is a long link distance, it’s because PSM4 uses eight optical single-mode fibers while CWDM4 only uses two optical single-mode fibers.

100G cabling solutions

There are two options for 100G cabling with multimode fiber between switches. One option is to use QSFP28 SR4 transceiver with 12-fiber MTP OM3/OM4 cable, which can support distance up to 100m. The other option is to use use QSFP28 AOC which is the best suitable for 3-20 meters. Users could choose either SR4 transceiver with 12-fiber MTP cable or QSFP28 AOC if they want to use multimode fiber for connectivity.

QSFP28 DAC cables are ideal to use for distance within 5m and provide a cost-effective I/O solution for 100GbE connectivity. QSFP28 DAC cables offer a complete cable assembly for short distance connectivity . It is better for you to choose DAC within 5m intra racks.

PSM4 and CWDM4 can satisfy the intermediate or mid-reaches for a 100GbE solution connectivity in a cost-effective way, PSM4 transceivers can support up to 500m over 12-fiber MTP single-mode fiber cable and CWDM4 transceivers can support 2km over duplex LC single-mode fiber cable. 

For long span 100GbE cabling connectivity between two building, mostly up to 10km, 100G QSFP28 LR4 with duplex LC single-mode fiber cable is the best option.

Summary

QSFP28 transceiver is the most preferred module with smallest size and lowest power consumption for for upgrading the data center 100G network. Utoptical offers a full series of 100G products and professional service for you according to your demands.

 If you are interested in UTOPTICAL full range of optical transceivers & cables ,please visit :UTOPTICAL Online Store.