Apr 21

100G QSFP28 and CFP Transceiver Cabling Solutions

By the end of 2016, 100G Ethernet has been widely deployed and becomes a significant portion in data center. Many network-equipment developers are motivated to introduce 100G devices like CFP and QSFP28 modules that consumes as little real estate and power as possible, while achieving necessary price points and delivering superior performance. This post is heading to talk about these two 100G modules and their cabling solutions.

CFP: Out With the Old

Specified by MSA among competing manufacturers, CFP is the first generation 100G transceiver which is designed after the SFP interface, but is significantly larger to support 100Gbps. As we all know, the original CFP has very large size, and in order to meet the need for higher performance and higher density in data center, there is the development of CFP2 and CFP4 specification, which specify a form-factor of 1/2 and 1/4 respectively in size of the original specification. Commonly used CFP/CFP2/CFP4 transceivers are available in 100GBase-SR10 and 100GBase-LR4.

100GBase-SR10 and 100GBase-LR4 CFP

QSFP28: In With the New

QSFP28 is the latest 100G form factor, which is a high-density, high-speed product solution designed for applications in the telecommunications, data center and networking markets. It utilizes four channels of respective signals with data rates up to 25Gbps to meet 100Gbps Ethernet requirement. 100GBase-SR4 and 100GBase-LR4 are two main types of QSFP28 module. The detailed specifications of these two QSFP28s are shown in the following table.

100GBase-SR4 and 100GBase-LR4 QSFP28

100GBase-SR10 Cabling Solution

100GBase-SR10 CFP uses a 24 strand MPO cable for connectivity (10 Tx and 10 Rx with each lane providing 10Gbps, leaving 4 channels unused). It can support maximum link length up to 100m and 150m respectively on OM3 and OM4 fiber cable. 100GBase-SR10 can also be used in 10×10 Gigabit Ethernet modes along with ribbon to duplex fiber breakout cables for connectivity to ten 10GBase-SR optical interface.

100GBase-SR10 CFP Cabling Solution

100GBase-SR4 Cabling Solution

Like 100GBase-SR10, 100GBase-SR4 QSFP28 also uses laser optimized OM3 and OM4 multimode fiber for indication. But 100GBase-SR4 QSFP28 utilizes 12f MPO trunk cable for connectivity (4 Tx and 4 Rx, leaving the middle four unused), which makes it possible to reuse 40GBase-SR4 fiber assemblies when upgrade from 40G to 100G.

100GBase-SR4 QSFP28 Cabling Solution

100GBase-LR4 Cabling Solution

Both 100GBase-LR4 CFP and QSFP28 are both interfaced with LC connector. They uses WDM technologies to achieve 100G transmission over single-mode duplex LC fiber patch cable supporting the link length up to 10km.

100GBase-LR4 Cabling Solution


As the need for high bandwidth is increasing, 100G Ethernet will widespread in data center quickly. Equipped with this basic information about 100G modules and their cabling solutions, we will have little worry upgrading to 100G Ethernet.

Mar 16

Overview of 40/100GbE Terminations

Today’s data centers growth is placing increasing demands on the networking infrastructure. For some enterprises, existing 1GbE connections can’t support the growing business requirements well very, not to say 100Mbps connections. In order to accommodate these demands, it’s imperative to upgrade the data center network architecture to 40 or 100 Gigabit Ethernet (GbE) connections. This 40/100GbE network design helps to support not only the current growth, but also the increasing demands in the future.

IEEE 802.3ba 40G and 100G Standard

The Institute of Electrical and Electronics Engineers (IEEE) 802.3 working group is concerned with the maintenance and extension of the Ethernet data communications standard. And 802.3ba is the designation given to the higher speed Ethernet task force to modify the 802.3 standard to support higher speeds than 10Gbit/s, that is 40/100G in 2010. This 802.3ba 40/100G standard encompasses a number of different Ethernet physical layer (PHY) specifications which are supported by means of pluggable modules, like Quad Small-Form-Factor Pluggable (QSFP) and C Form-Factor Pluggable (CFP). As for transmission medium, the transport speeds at 40/100Gbit/s use two methods: parallel optics and copper cables, with the fiber optics solutions allowing more flexibility and greater distance reach.

40GbE Terminations

In most cases, 40GbE connections use a QSFP+ transceiver terminated to receive the multi-fiber push-on/multiplex pass-through (MPO/MPT) trunk. That is, the short-range QSFP+ transceivers (eg. QFX-QSFP-40G-SR4) use multi-mode MPO trunks to establish 40G links. During this link establishment, polarity becomes a consideration when implementing 40GbE switch-to-switch interconnects over multi-strand multi-mode fiber (MMF). Method B polarity is recommended for the functional link.

QSFP+ transceivers are also able to run on single-mode fiber (SMF) for long reach. These links are Little Connector (LC) terminated and can run up to 40km, mainly used for 40GbE interbuilding connections. Take QSFP-40G-ER4 for example, this 40GBASE-ER4 transceiver supports link lengths up to 40km over SMF with duplex LC connectors.

The QSFP+ transceiver can also be used for 40GbE to 4x10GbE partitioned applications, that is QSFP+ to 4SFP+ fan-out cabling assemblies. One end of the connection is terminated using a MPO/MPT configuration with four individual pairs terminated with LC connectors at the other end. The image below just shows the QSFP+ to 4SFP+ Active Optic Cable (AOC) assembly.

QSFP+ to 4SFP+ AOC, 40GbE to 4x10GbE partitioned application

100GbE Terminations

100GbE connections use a CFP transceiver. Two CFP options are dominant in the industry: CFP2 and CFP4. The primary differences between the two are physical density and transmit/receive lane configurations. More specifically, CFP2 supports 100GBASE-SR10, 100BASE-LR4, and 100GBASE-ER4 optical interfaces, while CFP4 doubles the port density on the line card and supports 100GBASE-SR4, 100GBASE-LR4, and 100GBASE-ER4 optical interfaces.

CFP options, for 100G transmission

40/100GbE Termination Benefits

The 40/100GbE network infrastructure provides the following benefits:

  • Reduced data center complexity: As virtualization increases, the use of fewer physical servers and switches has been made possible by 40/100GbE network infrastructure.
  • Reduced total cost: Since 40/100GbE network system simplifies the local area network (LAN) and cable infrastructures, the potential cost reduction in virtualization environment is also accessible. Besides, the 40/100GbE network infrastructure requires fewer data center space, power, and cooling resources.
  • Increased Productivity: Faster connections and reduced network latency provide network designers with faster workload completion times and improved productivity.

Upgrading network architecture to support speeds greater than 10GbE, that is 40/100GbE, is essential in optimizing data center infrastructure, giving a hand in moving quickly in respond to business needs. At the same time, the services and value brought by information technology itself can also be enhanced.


The high-performance 40/100GbE network architecture simplifies the cabling infrastructure and reduces per-server total cost of ownership, capable of allowing high speeds at 40/100Gbit/s. Fiberstore offers a large selection of 40/100G optical modules, as well as 40/100G fiber optic-based cables and copper cables. For more information about 40/100GbE solutions, you can visit Fiberstore.

Jan 25

40G Transceivers: CFP, QSFP and CXP

In fiber optic communication, 40GbE transceivers are being developed along several standard form factors, such as CFP (C form-factor pluggable) transceiver, QSFP/QSFP+ (quad small-form-factor pluggable) transceiver and CXP optical transceiver. This article will introduce the three types of optical transceivers to further your understanding of 40G optics.

CFP Transceiver

CFP, short for C form-factor pluggable, is compliant with multi-source agreement (MSA) to produce a common form-factor for the transmission of high-speed digital signals. The C in the acronym “CFP” stands for the Latin letter C, which refers to the number 100 (centum), since the standard was primarily designed for 100 Gigabit Ethernet systems. In fact, CFP also supports the 40GbE. When talking about CFP, we always define it as multipurpose CFP.


The CFP form factor, defined in the MSA, supports both singlemode and multimode fiber and a variety of data rates, protocols, and link lengths, including all the physical media-dependent (PMD) interfaces contained in the IEEE 802.3ba Task Force. At 40GbE, target optical interfaces include the 40GBase-SR4 for 100 m and the 40GBase-LR4 for 10 km. There are three PMDs for 100 GbE: 100GBase-SR10 for 100 m, 100GBase-LR4 for 10 km, and 100GBase-ER4 for 40 km.

QSFP/QSFP+ Transceiver

QSFP/QSFP+ transceiver (Quad Small Form-factor Pluggable Plus) is a wildly used transceiver interfaces in data communications, connecting a network device motherboard (e.g. a switch, router, media converter and the like) with a fiber optic cable. It is a industry format that is jointly developed and supported by many network component vendors, such as Dell QSFP+, Juniper QSFP+, Mellanox QSFP+ and HP QSFP+. Additionally, QSFP supports both copper and optical cabling solutions.

Compared with the CXP, the QSFP (quad small-form-factor pluggable) is similar in size (shown as the following picture). It provides four transmitting and four receiving lanes to support 40GbE applications for multimode fiber and copper today and may serve single-mode in the future. Another future role for the QSFP may be to serve 100GE when lane rates increase to 25Gb/s.


CXP Transceiver

“C” in the acronym CXP represents for 12 in hex, and the Roman number “X” means that each channel has a transmission rate of 10 Gbps. “P” refers to pluggable that supports the hot swap. Thus, CXP is a hot-pluggable transceiver with data rate up to 12×10 Gbps.

CXP is developed for the clustering and high-speed computing markets, so we also call it high-density CXP. the CFP is able to work with multimode fiber for short-reach applications, but it is not really optimized in size for the multimode fiber market, most notably because the multimode fiber market requires high faceplate density. The CXP was created to satisfy the high-density requirements of the data center. It is featured with the parallel interconnections for 12x QDR InfiniBand (120 Gbps), 100 GbE, and proprietary links between systems collocated in the same facility.

As stated above, these 40G optics have been very popular in the market, and they are able to keep the momentum in the future for 100G transmission.