Differences between QSFP28, QSFP56, QSFP112, QSFP-DD and OSFP

QSFP-DD Wiki

QSFP-DD is a Double-Density QSFP. It is similar to current QSFP but a new module with an additional row of contacts providing eight lane electrical interface.

QSFP-DD MSA

QSFP-DD is being developed by QSFP-DD MSA. QSFP-DD MSA defined all physical features such as electrical specifications, mechanical dimensions, cage and receptacle.

The advantages of QSFP-DD form factor are as follows:

1. QSFP-DD has the same front size with QSFP, which allow the switches match the lates ASIC capacities while maintaining optimized port density.
2. QSFP-DD series include QSFP-DD400/ QSFP-DD800/ QSFP-DD1600, continuous support the increasing bandwidth requirement driven by datacenter and AI.
3. QSFP-DD system is backwards compatible with QSFP, it is easy for user to choose QSFP/ QSFP-DD according to business requirements.

What Is OSFP Transceiver?

OSFP is a new pluggable form factor module providing eight lane electrical interface that will support 400Gbps(8X50G), 800Gbps(8X100G) and future 1.6Tbps(8X200G). It is a little wider and deeper than the QSFP and QSFP-DD but still supports 36 ports on 1U front panel.

QSFP-DD vs QSFP+/QSFP28/QSFP56/QSFP112

Structure

QSFP+/QSFP28/QSFP56/QSFP112 have the same structure and backwards compatible. QSFP-DD is a little deeper than QSFP+ with an additional row of contacts.

Bandwidth & Application

From QSFP+ to QSFP112, the bandwidth is from 40Gbps to 400Gbps.The suffix number means the bandwidth of one electrical interface.

QSFP-DD include QSFP-DD400/ QSFP-DD800/ QSFP-DD1600 also, but the suffix number means the whole module bandwidth.

Backward Compatibility

The high bandwidth QSFP/ QSFP-DD are backward compatibility with the low bandwidth, and the QSFP-DD system is backward compatible with QSFP module.

QSFP-DD vs OSFP/CFP8/COBO

QSFP-DD vs OSFP

OSFP is a little wider and deeper than the QSFP-DD and can’t compatible with each other.

QSFP-DD and OSFP have eight lane electrical interface with the max. bandwidth up to 1600Gbps.

QSFP-DD vs CFP8

CFP8 is a much wider and deeper than the QSFP-DD and can’t compatible with each other.

CFP8 and OSFP have eight lane electrical interface with the max. bandwidth up to 1600Gbps.

 QSFP-DD vs COBO

COBO is an un-packaged and un-pluggable module providing the highest port density on system front panel. It supports the minimal distance to ASIC to get the highest signal loss and bandwidth in the future.

Will OSFP/QSFP/QSFP-DD Be Popular in 800G Ethernet?

Of course. With the explosive growth of network data exchange volume, the requirements for optical modules package are getting smaller and the speed is getting higher, OSFP/QSFP/QSFP-DD are good choice in 800G Ethernet.

Conclusion

QSFP/QSFP-DD/OSFP/CFP8 are different and not compatible with each other, just QSFP-DD system support back compatible with QSFP. They are all supporting 400G or 800G application, will dominate in the AI and datacenter market.