What’s SFP and SFP+ MSA? Why is SFP/SFP+ MSA important?

A small form-factor pluggable (SFP) is a type of transceiver device that has been standardized by the MSA (multi-source agreement). The MSA will define the characteristics of the system and is typically an agreement between multiple manufacturers. The agreements guarantee that any SFP or SFP+ device from any vendor will function properly. This article will give you a more comprehensive introduction to the SFP MSA and SFP+ MSA.

An Overview of Pluggable Optical Transceiver MSA Standards

Both SFP and SFP+ optical transceivers are standardized by MSA. These documents strictly define sufficient characteristics of an optical transceiver so that system (like Ethernet switch, Router, and media converter) vendors may implement ports on their devices, therefore, MSA compliant pluggable optical transceivers (SFP or SFP+) from any vendor will function properly.

Pluggable optical transceivers are physically composed of a small printed circuit board (PCB) containing electronic circuity, with an electrical PCB “edge connector” at one end and, typically, a fiber optic connector (dual LC-type in the case of SFP/SFP+ modules) at the other, packaged in a metal housing including a release latch. The basic function of the device is to convert electrical transmit data from the host into an optical signal transmitted onto a connected fiber optic cable, and, in the other direction, convert a received optical signal into an electrical one to be sent to the host system over the edge connector.

SFP MSA transceiver

What is Defined by the SFP MSA or SFP+ MSA?

The main elements defined in the SFP/SFP+ MSA is listed as follows:

Mechanical Interface

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

Electrical Interface

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

Besides, the Digital Diagnostics Monitoring (DDM) feature common in many modern SFP/SFP+ transceivers as defined in SFF-8472 MSA specification. “D” in GLC-LH-SMD represents the DDM function according to the industry standard MSA SFF-8472. The SFF-8472 added DDM interface and outlined that DDM interface is an extension of the serial ID interface defined in GBIC specification, as well as the SFP MSA.

The Importance of SFP/SFP+ MSA

MSAs, like most standards efforts, are important primarily because they can give customers a choice in suppliers from which they purchase products. Freedom of choice is the foundation of the efficient operation of markets. Customers in the marketplace should have the benefit of multiple independent suppliers, each competing to gain a share of the market. This behavior forces suppliers to be as efficient and creative as possible, driving down costs and offering customers the widest array of options.

It is true that some system vendors have attempted to subvert the standardizing value of the SFP MSA or SFP+ MSA. The most common scheme is to write a unique code into some of the undefined memory in the EEPROM of each SFP/SFP+. When the transceiver is inserted into the host switch, its EEPROM is read, and, if the code is “incorrect” the module is rejected as “incompatible”. But Fiberstore can do it. At present, FS.COM offers a comprehensive brand’s compatible solution of the transceivers which can meet the demands for Cisco, HP, Juniper, NETGEAR, Brocade etc.

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Important Components for 40/100G Ethernet Migration

With the growth of bandwidth-intensive applications such as high-performance computing and business continuity, there emerge higher-speed networks of 40/100G Ethernet. And as products become less expensive and more available over time, 40/100G Ethernet will inevitably be commonplace in our daily life. Therefore, it is necessary to create a migration path by installing a structured cabling system that can support the future 40/100G networking needs. In this system, such fiber optic products as MTP/MPO assemblies, 40/100G transceivers and 40/100G direct attach cables (DACs) are important components. This article will discuss their roles in 40/100G Ethernet migration respectively.

MTP/MPO Assemblies

Since 40/100G Ethernet uses parallel optics technology which requires data transmission across multiple fibers simultaneously, the multi-fiber connectors are needed. MTP/MPO is the designated interface for multi-mode 40/100G Ethernet, and its backward is compatible with legacy 1G/10G applications as well. 40G Ethernet uses a 12 position MTP/MPO connector interface that aligns 12 fibers in a single row. And the 4 leftmost fibers are used to transmit data, the middle 4 fibers are left unused, while the 4 rightmost fibers are used to receive data. 100G Ethernet uses a 24 position MTP/MPO connector with two rows of 12 fibers. And the outermost fibers on either end of the rows are vacant, while 10 fibers in the upper row for transmitting data and the remaining 10 fibers in the lower row for receiving data.

optical lane assignments

40/100G Transceivers

Together with MTP/MPO connectors, 40/100G transceivers are often used (as shown in the above figure). Through the use of plug-and-play, hot-swap transceiver miniaturization, fiber connectivity in higher-speed active equipment is being condensed and simplified. Transceivers used in 40/100G Ethernet migration include 40G QSFP+ transceivers, 100G CFP transceivers and so on. 40G QSFP+ transceivers can support 4x10G modes, which allow new parallel optics active equipment being compatible with existing 10G transceivers. And the electrical connection of a 100G CFP transceiver uses 10x10G lanes in RX (receive) and TX (transmit) direction, supporting both 10x10G and 4x25G variants of 100G interconnects.

40/100G DACs

To save cost, 40/100G DACs are often used in 40/100G Ethernet instead of optical transceivers. Applied to short reach applications, it is a fixed assembly supporting high speed data that uses a small form-factor connector module as an optical transceiver on each end of a length of cable. The modules on each end meet small form-factor standards and have some function of the optical transceivers, meaning that DAC inherits some advantages of the small form-factor module. Thus, sometime there is no need to upgrade the equipment by using a DAC.

To meet the future 40/100G networking needs, the cabling system shall include components that not only support future high-bandwidth applications but also be compliant to 1G and 10G applications and all current and anticipated industry standards. Meeting all these requirements, the above mentioned MTP/MPO connectors, 40/100G transceivers and 40/100G DACs play important roles in migration to 40/100G Ethernet. As a professional supplier of fiber connectivity network solutions, Fiberstore supplies all these fiber optic products and other kinds of products for 40/100G Ethernet migration.

XFP Transceiver Overview

Defined by an industry group in 2002, XFP is a standard for transceivers used in high-speed computer network and telecommunication links that employ optical fiber. XFP transceivers are hot-swappable transceivers designed for 10G network applications such as 10 Gigabit Ethernet, 10 Gbit/s Fibre Channel, synchronous optical networking (SONET) at OC-192 rates and so on. The followings are a few highlights that customers should know about XFP transceivers if they are in the market for them.

Specification of XFP Transceiver

Developed by the XFP multi-source agreement (MSA) group, the specification of XFP transceiver is an informal agreement of an industry group. In other words, it is recognized by many designers in the industry rather than “officially” endorsed by a standards body. There have been many updates to this specification since it was first introduced in 2002.

Interface of XFP Transceiver

XFP transceiver’s interface to other electrical components is often called XFI. Developed also by the XFP MSA group, the XFI electrical interface specification is a 10 Gbit/s chip-to-chip electrical interface specification defined as part of the XFP MSA.

Wavelengths of XFP Transceiver

XFP transceivers can operate at a variety of wavelengths including 850 nm, 1310 nm, and 1550 nm, etc. And at these near-infrared wavelengths, signals can be transmitted with high integrity and at longer distances. In addition, these transceivers also operate over a single wavelength and use dense wavelength multiplexing techniques.

Types of XFP Transceiver

XFP is available with a variety of transmitter and receiver types, and there are four main types XFP transceivers, which allows customers to select the type of XFP transceiver they need in their design. The most commonly used types of XFP transceivers are 10GBASE-SR XFP transceivers which have a wavelength of 850 nm and a maximum transmission distance of 300 m, and 10GBASE-LR XFP transceivers that have a wavelength of 1310 nm and a transmission distance up to 10 km. Both 10GBASE-ER XFP transceivers and 10GBASE-ZR XFP transceivers utilize 1550nm range, but they transmit different lengths of up to 40 km and up to 80 km respectively.

Size of XFP Transceiver

XFP transceivers are larger than SFP+ transceivers (as shown in the following figure), but they are by far among the smaller 10 Gbit/s interfaces suitable for dense wavelength division multiplexing (DWDM) transmission. Furthermore, several optical systems adopt XFP transceivers even when requiring long-haul transmission.


In conclusion, XFP transceivers are flexible and can offer customers a variety of options in terms of design. It is appreciated by customers who are searching for compact devices with flexibility and power. Nowadays, there are various kinds of XFP transceivers in the market. Among them, Cisco XFP transceivers are one of the best-selling XFP transceivers.

1000BASE SFP Transceiver for Gigabit Ethernet

Gigabit Ethernet, which is standardized by the IEEE as the 802.3z standard, is a term describing various technologies for transmitting Ethernet frames at a rate of a Gigabit per second. It is currently used as the backbone in many enterprise networks. The 1000BASE SFP transceiver is an important part in Gigabit Ethernet applications, which is a hot-pluggable input/output device that plugs into a Gigabit Ethernet port/slot, linking the port with the network. There are a number of 1000BASE SFP transceivers that are available in Gigabit Ethernet in accordance with the customer application and distance capability required.

Classification of Gigabit Ethernet

Depending on the cable material, Gigabit Ethernet can be classified into fiber-based Gigabit Ethernet and copper-based Gigabit Ethernet.

  • Fiber-based Gigabit Ethernet

In fiber-based Gigabit Ethernet, 1000BASE-X is used in industry to refer to Gigabit Ethernet transmission over fiber. 1000BASE-X is a group of standards for Ethernet physical layer standards. These standards include: 1000BASE-SX (A fiber optic Gigabit Ethernet standard for operation over multi-mode fiber), 1000BASE-LX (a fiber optic Gigabit Ethernet standard using a long wavelength laser and a maximum RMS spectral width of 4 nm), 1000BASE-LX10 (which is very similar to 1000BASE-LX, but achieves longer distances over a pair of single-mode fiber), 1000BASE-BX10 (which is capable of up to 10 km over a single strand of single-mode fiber) or the non-standard 1000BASE-EX ( a industry accepted term to refer to Gigabit Ethernet transmission) and 1000BASE-ZX (a multi-vendor term to refer to Gigabit Ethernet transmission) implementations.

  • Copper-based Gigabit Ethernet

In copper-based Gigabit Ethernet, 1000BASE-CX, 1000BASE-KX, 1000BASE-T and 1000BASE-TX are four standards for Gigabit Ethernet over copper wiring. 1000BASE-CX uses copper cables as a medium. 1000BASE-KX is part of the IEEE 802.3ap standard for Ethernet Operation over Electrical Backplanes. 1000Base-T uses four pairs of Category 5 unshielded twisted pair cables to achieve Gigabit data rates. 1000BASE-TX is similar to 1000BASE-T but uses two pairs of wires rather than four for data transmission.

1000BASE SFP Transceivers for Gigabit Ethernet

1000BASE SFP transceiver (Small form-factor pluggable) is a device that interfaces a network device motherboard to a fiber optic or copper networking cable. It is designed to support Gigabit Ethernet, Fibre Channel and other communications standards. Since Gigabit Ethernet can be classified into fiber-based Gigabit Ethernet and copper-based Gigabit Ethernet, there are 1000BASE SFP transceiver and 1000BASE copper SFP transceivers used in Gigabit Ethernet.

As there are different physical layer standards for fiber-based Gigabit Ethernet, Different 1000BASE SFP transceiver may be used for different standards of Gigabit Ethernet. These 1000BASE SFP transceiver can be used for single-mode and multi-mode fibers of different reaches. For example, the 1000BASE-LX SFP transceiver can operate on standard single-mode fiber-optic link spans of up to 10km and up to 550m on any multi-mode fibers. When it is used over legacy multi-mode fiber type, its transmitter should be coupled through a mode conditioning patch cable.

1000BASE SFP transceiver

1000BASE Copper SFP transceivers use copper lines for linking. In copper-based Gigabit Ethernet, the 1000BASE-T SFP module is the most commonly-used transceiver. Be compatible with the Gigabit Ethernet and 1000BASE-T standards, it operates on standard Category 5 unshielded twisted-pair copper cabling of link lengths up to 100m.


As Gigabit Ethernet has been demonstrated to be a viable solution for increased bandwidth requirements for growing networks, the market is flooded with various 1000BASE SFP transceiver. Fiberstore supplies many kinds of 1000BASE SFP transceivers including the aforesaid 1000BASE-LX SFP transceiver and 1000BASE-T copper transceiver.

QSFP Transceiver – a Hot-pluggable Transceiver With High Density

As a new Multi-Source Agreement (MSA) for high speed applications such as 40G-BASE, QSFP transceiver, which is one kind of 40G transceiver, can provide four channels of data in one pluggable interface. Each channel is capable of transferring data at 10Gbps and supports a total of 40Gbps. Compared with standard SFP+ modules, QSFP transceiver is with higher density and lower cost. It is designed to enable extremely high-density applications with stacked and ganged configurations.

Advantages of QSFP Transceiver

Since the QSFP transceiver integrates four ultra-high capacity, independent fiber transmit and receive channels, its port density is increased and the total system cost is declined. Actually, its port density is of three times higher than the traditional SFP transceiver, enabling the QSFP to be used to replace four standard SFP modules in space that is only 30 percent larger than a single SFP. In addition, the QSFP transceiver can support Ethernet, Fibre Channel, InfiniBand and SONET/SDH standards with data rates up to 5Gb/s per channel. Thus the QSFP platform demonstrates potential for aggregated higher volumes and improved economics realized from several protocols/applications using the same transceiver.

Classifications of QSFP Transceiver

There are various kinds of QSFP transceivers for different distance requirements and fiber types. According to various criteria, QSFP transceivers can be classified into different categories.

  • Classified by Transport Media

Copper, single mode fiber (SMF) and multimode fiber (MMF) are three kinds of transport media used in 40 Gigabit Ethernet. Different QSFP transceivers may adopt different transport media. According to IEEE Ethernet standard, the followings are commonly used 40 Gigabit Ethernet media system:

QSFP-40G-CR4—40 Gigabit Ethernet over four short-range twinaxial copper cables bundled as a single cable.

QSFP-40G-SR4—40 Gigabit Ethernet over four short-range multimode fiber optical cables.

QSFP-40G-LR4—40 Gigabit Ethernet over four wavelengths carried by a single long-distance single mode fiber optical cable.


QSFP transceiver

  • Classified by Connector Type

Different QSFP transceivers may have different connector interfaces. Through various technologies, many kinds of connectors could be applied into 40 Gigabit Ethernet. And the commonly-used are Duplex LC, MPO and MPO/MTP. MPO and MTP are often used interchangeably. For example, the aforesaid QSFP-40G-SR4 and QSFP-40G-LR4 are transceivers with Duplex LC connectors. While the Cisco QSFP-40G-CSR4 is with MPO/MTP connector.

  • Classified by Transmission Distance

According to transmission distance, QSFP transceivers can be divided into short-range QSFP transceiver and long-range QSFP transceiver. QSFP-40GBD-SR is among the various short-range QSFP transceivers. It supports link lengths of 100 meters and 150 meters over laser-optimized OM3 and OM4 multi-mode fibers respectively. As a long-range QSFP transceiver, QSFP-40G-ER4 has a transmission distance of 40 km.

  • Classified by Wavelength

In a QSFP transceiver, the wavelength of each channel can either be of the same or differs from each other. For instance, The wavelengths of Cisco QSFP-40G-SR4 and Cisco QSFP-40G-CSR4 transceivers are 4×850nm. While the four lanes of QSFP-40G-ER4 are 1271nm, 1291nm, 1311nm and 1331nm respectively.

40 Gigabit Ethernet is really a hot topic in recent years. Accordingly, different kinds of QSFP transceivers are springing up all over the world. As a leading optical network products supplier, Fiberstore supports a full range of both direct attach cables and optical transceivers for 40 Gigabit Ethernet.