A slightly larger sibling is the quad-way Quad Small Form-factor Pluggable (QSFP). The additional channels allow speeds equal to 4 times their corresponding SFP. In 2014, the QSFP28 version was released, enabling speeds of up to 100 Gbps.  In 2019, the very close QSFP56 was standardized, which doubled the maximum speeds to 200 Gbps, as the products were already sold by major vendors.  There are low-cost adapters that allow SFP receivers to be placed on a QSFP port. SFP+ also introduces Direct Attach for connecting two SFP+ ports without a dedicated transceiver. Direct attachment cables (DAC) are available in passive (up to 7 m), active (up to 15 m) and active optical (AOC, up to 100 m) variants. SFP receivers are available with a variety of transmitter and receiver specifications, allowing users to choose the appropriate transceiver for each connection in order to achieve the necessary optical range via the type of fiberglass available (for example. B multimode fiber or single mode fiber). Transceivers are also referred to by their transmission speed. SFP modules are usually available in different categories.
Modern SFP optical receivers support DDM (Digital Diagnostics Monitoring) functions.  This function is also known as digital optical surveillance (DOM). This function makes it possible to monitor SFP operating parameters in real time. Parameters include optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage.   The Enhanced Small Form Factor Pluggable (SFP+) is an enhanced version of the SFP that supports speeds of up to 16 Gbps. The SFP+ specification was first adopted on May 9, 2006 and version 4.1 on July 6, 2009.  SFP+ supports 8 Gbps Fibre Channel, 10 Gigabit Ethernet, and OTU2 for optical transport networks. It is a popular industry format, supported by many network component suppliers. Although the SFP+ standard does not mention 16 Gbps Fibre Channel, it can be used at this speed.  [a] The Multi-Source SFP-DD (Small Form Factor Pluggable Double Density) agreement is a new standard for doubling port density.
The SFD-DD MSA website says, “SFP-DD-based network devices support old SFP modules and cables as well as new dual-density products.”  The form factor and electrical interface are specified by a multi-source agreement (MSA) under the aegis of the Small Factors Committee.  In most applications, SFP has replaced the larger GBIC and has been referred to as a mini-GBIC by some providers.  The SFP transceiver is not standardized by an official standards body, but is specified by a multi-source agreement (MSA) between competing producers. . . .