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In the Ethernet optical transceiver datasheet, we often see the following description:
Standards
- Compliant with SFP MSA
- Compliant with SFF-8472
- Compatible with IEEE802.3ah 2004
What are these three standards, what do they specify for Ethernet optical transceiver, and what products are involved in them? Yingda will analyze and clarify for you one by one below:
SFP MSA, SFF-8472, and IEEE802.3ah 2004 each have their own responsibilities, defining the Ethernet optical transceiver’ physical appearance and basic functions, intelligent management and monitoring capabilities, and a specific network access technology.
SFP MSA: Defining “Appearance” and “Handshake Rules”
SFP MSA (Multi Source Agreement) is an industry “contract” whose core goal is to ensure that Ethernet optical transceivers produced by different manufacturers are compatible with each other.
What is specified: It mainly defines the physical details and basic electrical signal protocol of SFP modules to ensure that the modules can be smoothly inserted into any standard SFP port and establish basic connections, such as:
- Physical dimensions: Height 8.5mm, Width 13.4mm, Depth 56.5mm.
- Electrical interface: Defined the pin definition and timing requirements for the 20 pin gold finger.
Products involved: All SFP/SFP+/SFP28 fiber optic transceivers, direct copper cables (DAC) and active optical cables (AOC), as well as corresponding SFP port slots on switches and routers.
SFF-8472: Empowering Modules with the Ability to Think
If SFP MSA defines the “body” of a module, SFF-8472 endows it with a digital “brain“, which is an important extension of SFP MSA and a unified standard for digital diagnostic monitoring (DDM) functions of SFP (and subsequent SFP+/SFP28, etc.) Ethernet optical transceivers.
What is specified:
- DDM function: The module is required to monitor and report key parameters such as temperature, voltage, bias current, and transmit/receive optical power in real-time.
- Information Storage: Standardizes the information storage structure of the internal EEPROM of the module, which is used to store information such as manufacturer name, serial number, and speed for the switch to read and identify.
Products involved: All SFP/SFP+/SFP28 fiber optic transceivers with digital diagnostic monitoring (DDM) functionality.
✅The Evolution from MSA to SFF-8472
The standard for SFP was originally named INF-8074i. Later, the SFF committee incorporated and expanded it, adding digital diagnostic functions, thus giving birth to SFF-8472. This also explains why people commonly use SFF series numbering to refer to related technologies.
IEEE 802.3ah 2004: Defining a gameplay for “access networks”
Unlike the previous two, IEEE 802.3ah-2004 is an international official standard that focuses on addressing the access issues of Ethernet in the First Mile (EFM).
What is specified:
- Ethernet Passive Optical Network (EPON): defines point to multipoint (P2MP) fiber optic access technology.
- New physical layer standards: such as 1000BASE-PX10/PX20, designed specifically for optical access networks.
- Operations, Administration, and Maintenance (OAM): Defined Ethernet OAM mechanisms to help administrators discover, locate, and repair link issues.
Products involved: mainly used in fiber optic access networks, such as optical line terminals (OLT) and optical network units (ONU) equipment in EPON systems, as well as related EPON SFP optical modules.
Conclusion
The relationship between these three standards can be understood as different levels of specifications: MSA defines physical connections, SFF-8472 defines managing the “brain,” and IEEE 802.3ah defines the “game rules” for network access.
| Standard/Protocol | Definition and main functions | Main products involved |
| SFP MSA | External dimensions, electrical interfaces, and basic functional standards | SFP/SFP+ Ethernet optical transceivers and direct copper cables |
| SFF-8472 | Extended digital diagnostic monitoring interface standard | Ethernet optical transceivers with DDM/DOM functionality |
| IEEE 802.3ah | Ethernet access network standards, including EPON and OAM | EPON OLT/ONU equipment and corresponding fiber optic transceivers |
- SFP MSA is the cornerstone, ensuring the “physical universality” of modules.
- SFF-8472 is an “intelligent enhancement package” based on SFP MSA, providing a unified “digital brain” for SFP modules.
- IEEE 802.3ah is a “communication rule” defined at the network layer and application layer, which defines how to use Ethernet technology (including SFP optical modules) to build access networks.
Yingda provide Ethernet optical transceivers design with above standards at various speeds, including: Gigabit, 1.25G, 2.5G, 10G, 25G, 40G, 56G, 100G, 200G, 400, till 800G or 1.6T. Send Inquires to Yingda.
