A number of important multi-source agreements for optical transceurs are presented in the table below: the SFP transceiver is not standardized by an official standards body, but is established by a multi-source agreement (MSA) between competing manufacturers. The SFP was developed according to the GBIC interface and allows a higher port density (number of transceivers per given surface) than GBIC, which is why the SFP is also known as Mini-GBIC. MSAs indicate the parameters of system components and their indicative values, such as mechanical dimensions, electrical and optical interfaces, and electromagnetic values. Device manufacturers are attacking MMAs to develop their systems. This ensures interoperability and interchangeability between interface modules. Products that comply with multi-source agreements include: optical transceurs such as SFP, SFP, XENPAK, QSFP, XFP, CFP, etc.; fibre optic cables and other network devices. Optical transponder devices are both “standardized” by multi-resource agreements (MSA) and a Small Form Pluggable, Enhanced (SFP) form factor. These documents define the characteristics of an optical transceiver to enable system providers (for example. B ethernet, router and media converter) to implement ports on their devices so that MSA-compliant optical transceivers (SFPs) can function properly by each supplier. This means that transceivers can be purchased from one of the various sources on the open market, such as FluxLight. The multi-resource agreement with a small Pluggable Form Double Density (SFP-DD) is a new standard for doubling port density. The SFD-DD MSA website states that “network devices based on SFP-DD will support older SFP modules and cables, as well as new dual-density products.”  A small form factor pluggable (SFP) is a kind of transceiver device standardized by the MSA (multi-source agreement).
The MSA defines the characteristics of the system and is generally an agreement between several manufacturers. The agreements ensure that any SFP or SFP device from any manufacturer works properly. This article gives you a more complete introduction to the SFP MSA and SFP MSA. A multi-source agreement, commonly known as MSA, is an agreement between several manufacturers to manufacture products with the same basic functionality and ease of use between different suppliers. Member States act as de facto standards and create and promote a competitive market for interoperable products instead of a monopoly structure. The form factor and the electrical interface are defined by a multi-source agreement (MSA) under the aegis of the Small Factors Committee.  The SFP has replaced the largest GBIC in most applications and has been called mini-GBIC by some vendors.  Because life is not always so simple. Over the years, device manufacturers have tried to lock up the customer by making the transceivers proprietary for commercial reasons.
This result is usually achieved by using specific codes in defined or undefined memory positions in the MSA. This means that after inserting the compatible, the user will identify the “unsupported transceiver” or display a similar message. However, most of the compatible transceivers providers in place have understood this and are able to write the corresponding codes for the appropriate supplier for the transceivers. In this regard, it is obviously important to choose a supplier that has the means to test the transceiver in the right network device in order to ensure interoperability. Really excellent intro to the SFP/SFP modules and the INF-8074 and SFF-8472 specifications! Thank you very much! Modern SFP optical transqueurs support standard DDM (Digital Diagnostic Monitoring) functions.  This function is also called Digital Optical Surveillance (DOM).