This document will focus on QSFP, QSFP+ and QSFP28. Though they look very similar in physical appearance but the transmit data rates are quite different.
QSFP, QSFP+ and QSFP28 transceivers look very similar because they all share the same small form-factor. The QSFP has evolved to QSFP+ to meet 10 Gbps data rates. The standard is the SFF-8436. Further demand for higher data rates led to the introduction of QSFP28 which supports up to 100 Gbps of speed.
Related – 400 GE technology (QSFP-DD)
What is QSFP?
QSFP abbreviation stands for Quad Small Form Factor Pluggable.
QSFP is available for use in both single-mode and multimode and can to support 4 independent channels that can individually transmit at up to 1.25 Gbps per channel for a total speed of above 4 Gbps.
What Is QSFP+?
QSFP+ abbreviation stands for Quad Small Form Factor Pluggable Plus.
QSFP+ supports Ethernet, Fibre Channel and Infiniband at 10Gbp/s per channel up to a maximum of 4 channels for a total speed of 40Gbp/s.
What is QSFP28?
QSFP28 combines speeds of 28Gbps per channel for a total speed of 100Gbps. The QSFP28 interface is highly flexible and can be used in the following combinations.
- 100 Gbps
- 2 X 50 Gbps
- 4 X 25 Gbps
The comparison between 3 flavours is shared below –
|Abbreviated for||Quad Small Form-factor Pluggable||Quad Small Form-factor Pluggable Plus||Quad Small Form-factor Pluggable 28
|Philosophy||QSPF includes 4 channels carrying Gigabit Ethernet, 4G FiberChannel or DDR InfiniBand.||QSPF+ is an evolution of QSPF to support 4 * 10 G channels carrying 10 GB, 10 GB FiberChannel, or QDR InfiniBand.||QSPF28 is a high-density, high-speed product designed for 100 Gbps applications.
|Nominal Optical Output||4 * 2.5 Gbps||4 * 10 Gbps||4 * 28 Gbps
Download the difference table here.