higher than the Cisco QSFP to CX4 interface has

QSFP (Quad Small Form-factor Pluggable): four-channel SFP interface (QSFP), Cisco QSFP to CX4 born in order to meet the market demand for higher density of high-speed pluggable solutions.
The 4-channel pluggable interface transfer rate up to 40Gbps. A lot of the XFP mature key technologies are applied to the design.The QSFP can be as a fiber optic solutions, and the speed and density are better than a 4-channelCisco QSFP to CX4 interface. Support four channels of data transmission speed of 10Gbps per channel at the under XFP same port sizes, so the density of the QSFP can reach 4 times the XFP products, the SFP + product 3 times. Has 4 channels and the density is higher than the Cisco QSFP to CX4 interface has been adopted by the InfiniBand standard.

Cisco QSFP to CX4 interconnects offer the advantages of low-cost, low-latency, and low-power consumption at the expense of range. The length limitation for Cisco QSFP to CX4 is 15m (49ft) when using passive cable assemblies. Some novel solutions exist which use active signal boosters or fiber optics to achieve lengths beyond 15m, but these solutions negate the cost, latency, and power benefits inherent to Cisco QSFP to CX4 technology. Fortunately, lengths beyond 15m are rarely needed, since most switches reside in close proximity within a wiring closet.