Detailed Breakdown of MPO Connectors and 40G QSFP+ Transceivers

As the speed and transfer rates of computer hardware continue to grow alongside demand for ever-more data, new cabling becomes a necessity to keep up. Backbones for 40G on multimode fiber generally use MPO connectors which work with QSFP+ transceivers to allow four simultaneous 10G or better connections. An upgrade to QSFP+ can mean a significant reduction in overall cabling, which brings better reliability and cost-effectiveness.

MPO can work at higher speeds as well, able to bundle hundreds of individual fiber lines at once into a single terminator. As this is a relatively new standard, MPO connectors are not well-understood by many people. However, they're necessary to deliver the speeds promised by today's top-line backbones.

Things You Need To Know About MPO Connectors

1. What Is MPO

MPO is short for the industry acronym—"multi-fiber push on". The MPO connector is a multi-fiber connector which is most commonly defined by two documents: IEC-61754-7 and EIA/TIA-604-5. Here is a MPO connector with parallel optics transceiver and pinouts for 40G and 100G. Generally, the backbone cable that is permanently installed will end in connectors with pins inside mating adapters, effectively creating a "socket" type connection. Patchcords will have no pins since they are subject to damage because they simply protrude from the connector. Transceivers will be set up as jacks also, with pins inside the transceiver socket.

2. MPO vs MTP

One of the biggest areas of confusion is in regards to naming, with the cabling in question sometimes being referred to as MPO or MTP.

MTP is a particular brand of MPO-compliant fiber cables from USConec. They incorporate a number of revisions to the overall design, such as removable connector housings, while still remaining 100% intercompatible with other MPO products.

Whether they're worth the extra money is largely a matter of opinion at this point, although they have their benefits. The key point is that MTP is simply one specific implementation of MPO whose creators, undoubtedly, would like to see become more standard in the future.

Things You Need To Know About 40G QSFP+ Transceivers

QSFP+ transceiver is a hot-swappable, parallel fiber-optical module with four independent optical transmit and receive channels. These channels can terminate in another 40-Gigabit QSFP transceiver, or the channels can be broken out to four separate 10-Gigabit SFP+ transceivers.

The QSFP+ transceiver link length for either 40 Gigabit Ethernet or high density 10 Gigabit Ethernet application is up to 100 m using OM3 fiber or 150 m using OM4 fiber. These modules are designed to operate over multimode fiber systems using a nominal wavelength of 850nm. The electrical interface uses a 38 contact edge type connector. The optical interface uses an 8 or 12 fiber MTP (MPO) connector. For example, both HP JG325B compatible QSFP + transceiver and Arista QSFP-40G-SR4 compatible QSFP + transceiver from Fiberstore can achieve distance of 100m over OM3 fiber and 150 m over OM4 fiber.

Fiberstore offers a wide range of MPO connectors and 40G QSFP+ transceivers which are 100% compatible with many famous brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com. Besides, we also provide high-quality and cost-effective cables such as MTP trunk cables, QSFP+ breakout cable, LC to MTP jumpers, etc.

What Is the SFP or SFP+ MSA?

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 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 direct, convert a received optical signal into an electrical one to be sent to the host system over the edge connector.

What is Defined by the MSA?

The main elements defined in the SFP/SFP+ MSAs are 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 MSAs

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 MSAs. 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, Fiberstore offers a comprehensive brands compatible solution of the transceivers which can meet the demands for Cisco, HP, Juniper, NETGEAR, Brocade etc.