quad small form factor pluggable (QSFP)
The QSFP+module(Quad Small Form Factor Pluggable) is a transceiver module for 40 Gigabit Ethernet and is intended to replace four SFP+modules. Supported data rates are 4 Gbps, 40 Gbps, 56 Gbps and 100 Gbps.
The compact QSFP module, measuring 18.3 mm x 8.5 mm x 52.4 mm, can be used for 40-Gigabit Ethernet, Fibre Channel and Infiniband.
In the various interface designs, data is transmitted via four lanes in each case in both directions for sending and receiving. In the case of the copper-based 40GBase-CR4interface, transmission takes place via the direct connection cable and over four channels at 10 Gbit/s each over a distance of up to 10 meters. Alternatively, transmission can take place optically via Active Optical Cable( AOC) with four lanes. Optical interfaces such as the 40GBase-SR4 and the 40GBase-LR4 use ribbon fiber with four parallel optical fibers. The SR4 variant uses single mode and bridges distances of 100 m, the LR4 variant even 10 km.
In addition to the standard version of QSFP with a channel bandwidth of 1 Gbit/s, there are more powerful versions with QSFP+ (10 Gbit/s), QSFP14 (14 Gbit/s) and QSFP28 (28 Gbit/s). Since the mentioned values are about the data rate of a single channel, the respective total data rate for four channels is many times higher. It should be noted that QSFP14s do not support Gigabit Ethernet or Fibre Channel. The latter is also not supported by QSFP28.