The QSFP28 (Quad Small Form-factor Pluggable 28) is a standard for high-speed data communication, and it is defined by several industry standards bodies. The QSFP28 standard specifies a compact, hot-pluggable transceiver module with four channels, each capable of transmitting and receiving data at rates of up to 25 gigabits per second (Gbps). The total aggregate data rate for a QSFP28 module is 100 Gbps.

The key standards related to QSFP28 include:

1. IEEE 802.3bm:

• The IEEE 802.3bm standard specifies the physical layer specifications and management parameters for 100 Gigabit Ethernet (100GbE) over fiber optic cables, including the use of QSFP28 transceivers.

2. QSFP28 MSA (Multi-Source Agreement):

• The QSFP28 MSA is a cooperative effort among multiple vendors to establish common mechanical and electrical specifications for QSFP28 transceiver modules. The MSA defines the form factor, electrical interface, and various aspects of the module to ensure interoperability between different manufacturers' products.

3. SFF-8665 (Small Form-factor Pluggable):

• SFF-8665 is a specification within the QSFP28 MSA that specifically details the electrical and mechanical requirements of QSFP28 transceivers.

4. CWDM4 MSA:

• In addition to the standards mentioned above, there are specific MSA agreements for certain types of QSFP28 modules. For example, the CWDM4 MSA defines the specifications for QSFP28 transceivers that use Coarse Wavelength Division Multiplexing (CWDM) technology.

These standards ensure that QSFP28 modules from different manufacturers are compatible with networking equipment designed to support the QSFP28 standard. It's important to note that there are various types of QSFP28 modules, supporting different optical technologies (such as SR4 for short-range or LR4 for long-range), and each may have its own specific standards or agreements within the broader QSFP28 framework. Always refer to the documentation provided by the module manufacturer and ensure compatibility with your networking equipment.