100G Direct Attach Cables (DAC) are cost effective interconnection media widely used in switch, server and data centers. Compared with optic transceiver modules, DAC consume less power, low latency and price cheaper. But it is limited for short range transmission. For 100G we have QSFP28 to QSFP28 form factor and QSFP28 to 4x25G SFP28 package.