Do SFP MSA Benefits the Optical Transceiver?

When you purchase the 1000BASE-T SFPs for your switch, you may always see such description of them: This 1000BASE-T SFP transceiver is based on the SFP Multi Source Agreement (MSA). So, what's the SFP MSA? What's defined by the SFP MSA? Do SFP MSA benefits the optical Transceiver?

Multi-source Agreement(MSA)

A multi-source agreement (MSA) is an agreement between multiple manufacturers to make products which are compatible across vendors, acting as de facto standards, establishing a competitive market for interoperable products. Products created via multiple source agreements include SFPs and other network device interfaces.New MSA will define 1550nm silicon photonics based QSFP optical transceiver for 100G data center networks on single mode fiber (SMF) infrastructure.

SFP Multi-Source Agreement: This document establishesinternationally compatible sources of a pluggable fiber optic transceiver module in support of standards for fiber optic systems including Asynchronous Transfer Mode (ATM), FDDI, Fibre Channel, Fast Ethernet and Gigabit Ethernet, and Synchronous Optical Network (SONET) / Synchronous Digital Hierarchy (SDH) applications.

This MSA document strictly defines sufficient characteristics of a SFP transceiver so that system (e.g. Ethernet switch, Router, and media converter) vendors may Implement ports on their devices so MSA compliant pluggable optical transceivers SFP from any vendor will function properly. That is, transceivers could be purchased from any of the multiple sources in the open market, like Fiberstore. See Cisco GLC-T 1000BASE-T price on Fiberstore.

SFP transceivers also include a management (I2C) interface, an Electrically Erasable Programmable Read-Only Memory (EEPROM) and optional Digital Diagnostics Monitoring (DDM, Aka Digital Optical Monitoring or DOM). The EEPROM memory space is defined in the MSA and includes information describing the transceiver's capabilities, standard interfaces (e.g., SX, LX, EX, ZX), manufacturer and other data. This data makes available to the host system over the I2C interface, as is the status of the optional DDM functions.

What is defined by the SFP MSA?

The major elements or characteristics defined in the SFP MSAs are:

Mechanical Interface

• Transceiver edge connector to host PCB-mounted electrical connector mating
• Mechanical dimensions of the device (H: 8.5mm, W: 13.4mm, D: 56.5mm)
• Insertion, Extraction and Retention forces
• Host board mechanical layout (location/size of solder pads, etc.)
• Electrical connector mechanical aspects
• Bezel design considerations for host systems
• Cage assembly dimensions

Electrical Interface

• Timing requirements and Status I/O
• Pin definitions
• Module definition interface and data field description

Digital Diagnostics Monitoring (DDM) feature common in many modern SFP transceivers is defined by reference to the industry-standard SFF-8472.

Do SFP MSA benefits the optical Transceiver?

Optical transceiver form factors, defined through SFP multi-source agreements (MSAs), benefit equipment vendors by ensuring there are numerous suppliers to select from. No longer must a system vendor develop its own or be locked in with a supplier. Pluggables also decouple optics from the line card. A line card can address several applications simply by replacing the module. In contrast, with fixed optics the investment is tied to the line card. A system can also be upgraded by swapping the module with an enhanced specification version once it is available.

I propose that all such tries to undermine the value of these standards and subvert the free operation of the marketplace be vigorously resisted by consumers. Since there are many excellent choices, network operators should specifically avoid purchasing SFP modules directly from system vendors who attempt such coercive tactics. One reason should be to save money. System vendors primarily use these tactics to protect their grossly inflated prices. Second is to aid and encourage the creation and adherence to standards and, in addition, rebuke tries to undermine them. If you plan to buy the 3rd party or OEM transceivers (e.g. Cisco SFP compatible) for your switch, you had better to choose a vendor with high reputation. I recommend Fiberstore for you. Why? You may know the answer after you try.