According to the Cisco’s Visual Networking Index, the global IP traffic in 2015 was at 72.5 EB per month and will nearly triple by 2020, to reach 194.4 EB per month. Consumer IP traffic will reach 162.2 EB per month and business IP traffic will surpass 32.2 EB per month by 2020.

In 2017, 100G optical transceivers are slowly turning in the new standard for the data center market. However, as IP traffic is continuously expanding, 100G interconnects won’t be enough for data centers to support the pressure of an endless traffic growth generated by new technology.

For this reason, different MSA (Multi Source Agreement) for 400G interconnect has been created to face the constantly growing IP traffic and the future needs of data centers. This article will introduce the 400G QSFP-DD and 400G OSFP optical transceivers.


QSFP-DD stands for Quad Small Form Factor Pluggable Double Density. What Double Density means? What’s the difference with the QSFP and QSFP28?

The 400G QSFP-DD follows the same port densities system as the QSFP and QSFP28, but the QSFP-DD will support eight lanes instead of four lanes for the QSFP and QSFP28, which double the density.

Each of the eight lanes will operate a data rate up to 50Gb/s providing a 400Gb/s data speed and increasing the capacity of the QSFP28 by four. The 400G QSFP-DD published that the size of the optical transceivers enables to put 36 ports in one switch slot, accumulating 14.4 Tbp/s in one slot.

The great advantage of the new generation of QSFP is its backward compatibility with the QSFP and QSFP28. Indeed the QSFP-DD ports will also support 40G and 100G, which will facilitate and reduce the cost of the network migration toward the 400G.

400G OSFP 

OSFP stands for Octal Small Form factor Pluggable. As the QSFP-DD, the OSFP has 8 lanes supporting 50G each. The OSFP is a new pluggable form factor, which is slightly wider and deeper than the QSFP family. Its size won’t enable the backward compatibility with the QSFP and QSFP28. However the OSFP MSA group says that it will be possible to build an adaptor (OSFP to QSFP) that supports other QSFP transceivers. In addition, due to its larger size, it will only have 32 ports in one switch slot, giving up to 12.8 Tbp/s in one slot.

The OSFP MSA, founded by Google, hopes that they will be able to turn the OSFP in supporting 800G by increasing the capacity of each lane to 100G.


According to the market forecast, the QSFP-DD should be ready before the OSFP, which is an advantage in addition to its backward compatibility with QSFP and QSFP28. However, the two modules will have slightly different applications and are both smaller than the two first generation of 400G transceivers, the 400G CDFP and 400G CFP8.

While  400G Optical Transceivers are a great technology advance for the future application on this market, many data centers are still upgrading their network to a 100G data rate thanks to the cost-effective and high performance 100G QSFP28 optical transceivers and cables.

Optech 100G QSFP28 Transceivers
Optech Part Number Model Description
OPCW-MX1-85-CB QSFP28-SR4 100GBASE-SR4 QSFP28 850nm 100m Transceiver
OPCW-S02-113-CBS QSFP28-PSM4 100GBASE-PSM4 QSFP28 1310nm 2km Transceiver
OPCW-S02-13-CB4 QSFP28-CWDM4 100GBASE-CWDM4 QSFP28 1310nm 2km Transceiver
OPCW-S10-13-CB QSFP28-LR4 100GBASE-LR4 QSFP28 1294~1310nm 10km Transceiver


Optech 100G QSFP28 Cables
Optech Part Number Model Description
OPQS28-T-xx-PE Copper Cable Direct Attach Cable, QSFP28 to QSP28, up to 5meter
OPQS28-T-xx-P/SF28/4 Copper Cable Direct Attach Cable, QSFP28 to 4x25G SFP28, up to 100meter
OPQS28-F-xx-AK Optical Cable Active Optical Cable, QSFP28 to QSP28, up to 5meter
OPQS28-F-xx-AK/SF28/4 Optical Cable Active Optical Cable, QSFP28 to 4x25G SFP28, up to 100meter

All our products are compatible with major switches and servers brands on the market. You can check the compatibility of our products here. If you require further information, please visit our website or contact us at sales@optech.com.tw.