With the price of 100G optics cutting down, 2017 witnesses the great expansion of `100G hardware market. QSFP28 and CFP 100G optical transceivers are becoming popular among customers. Not only Cisco, HPE, Brocade, and Huawei, but the third party vendors like FS.COM offer 100G devices including the 100G switches, MTP/MPO cables, QSFP28, CFP/CFP2/CFP4 and so on. In this blog, I will compare 100G QSFP28 SR4 with CFP SR10 modules, and analyze the electrical and optical diagram.

CFP 100GBASE-SR10 Module Outlook

CFP 100GBASE-SR10 is a MSA specified 100G C-form factor supporting link lengths of 100 m/150 m over laser-optimized OM3/OM4 cable, respectively. It is mainly used in 10 x 10 Gigabit Ethernet mode along with MTP Harness cables for connectivity to 10 10GBASE-SR optical interfaces. It usually enables high-bandwidth 100Gbps links over 24-fiber MPO/MTP ribbon cables.

100G QSFP28 100GBASE-SR4 Outlook

QSFP28 100GBASE-SR4 module is a parallel 100G optics designed with optical/electrical connection and digital diagnostic interface. It offers 4 independent transmit and receive channels, each capable of 25Gbps operation for an aggregated data rate of 100Gbps for 100m on 12-fiber MPO/MTP OM4 fiber cable. Figure 1 shows the CFP SR10 (left) and QSFP28 modules (right).


The QSFP28 SR4 transceiver (such as Cisco 100G-QSFP28-SR4) is compatible with 100G QSFP 100GBASE-SR4 standards that meets IEEE 802.3 and MSA requirements with power dissipation well under 3.5W. It supports both 100GBASE-SR4 as well as 4x25G breakout, 100G QSFP28 to QSFP28 DAC and 100G QSFP28 SR4 to 4SFP28 break-out cables.

Comparison Between CFP 100GBASE-SR10 and 100G QSFP28 100GBASE-SR4

  • Size Comparison

100GBASE CFP module is the old generation 100G transceivers. It is designed after SFP modules, but quite larger to support 100Gbps in 10 x 10Gbps lanes. QSFP28 is the newly released 100G form factor, which further increase port density and reduce footprint & power consumption. QSFP28 100GBASE-SR4 has the same form factor as the 40G QSFP optics, supporting 4x25Gbps mode.

size-comparison of CFP and QSFP28

The above image shows the size comparison between CFP 100GBASE-SR10 and 100GBASE SR4 QSFP transceiver. Obviously, QSFP28 is much smaller than CFP 100G modules, which just in time explains the reason that QSFP28 optics is more popular than CFP transceivers.

  • Working Principle

As noted before, QSFP28 SR4 modules work on 4x25G lanes and CFP SR10 operates over 10x10G lanes.



100GBASE-SR4 supports higher speed per channel (25Gbps) than 100GBASE-SR10 (10Gbps), so that QSFP28 can reduce port density with compact footprint.

  • Terminating Cables—12F Vs. 24F MTP/MPO MMF

Both CFP 100GBASE-SR10 and 100G QSFP28 100GBASE-SR4 terminates with MTP/MPO OM3/OM4 cables for 100G transmission. However, QSFP28 100GBASE-SR4 modules uses a 12 fibers MPO/MTP multimode cable for connectivity (4 Tx and 4 Rx, each lane providing 25 Gbps of throughput) while CFP 100GBASE-SR10 optics use a 2×12-fiber or 24-fiber strand MPO/MTP multimode cable for connectivity (10 Tx and 10 Rx, each lane providing 10 Gbps of throughput).

CFP 100GBASE-SR10, compared with QSFP28 SR4 optics uses two 12-fiber or one 24-fiber MPO/MTP cable. It is not a cost-effective solution in terms of the cable management.


100GBASE-SR10 CFP and 100GBASE-SR4 QSFP28 are the 100G multimode optics. QSFP28 SR4 transceivers, like 40GBASE-SR4, use a 12 fiber MPO cable with 4 strands for transmit and 4 for receive. While CFP 100GBase-SR10 optics uses a 24 strand MPO cable: 10 strands for transmit and 10 strands for receive. From the above article, we know that 100GBase-SR4 QSFP28 is more cost-effective than 100GBase-SR10 CFP in port density and cable management. FS.COM 100G QSFP28 price is lower than any other vendors. Our reliable 100G CFP modules are also with high quality and low price. If you have any interest, don’t forget to contact us.

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QSFP28 100GBASE-LR4 and 100GBASE-SR4 Optical Modules Overview

Without denying that the market for 100G data center optics is accelerating, and more and more telecommunication vendors are aiming to seize this opportunity to launch cost-effective 100G solutions. FS.COM also offers a series of 100G optical modules and cabling solutions that are compliant to the IEEE standards. Our 100G optical modules support different transmission distance from 100m, 10km and more reach options in CFP and QSFP28 form factors. Before introducing the FS.COM 100G optical modules, let’s firstly talk about the 100 Gigabit Ethernet standard.

IEEE 100GbE Standard Introduction

Defined by the IEEE 802.3ba-2010 standard, 100 Gigabit Ethernet (100GbE) technology was given birth to transmit Ethernet frames at the rates of 100 gigabits per second. The 100G optical modules are not standardized by any official standards body but are in multi-source agreements (MSAs). The major 100Gigabit Ethernet 100GBASE-R optical module standards are briefly listed in the below table.


According to the above table, the 100GBASE-CR4 and 100GBASE-CR10 standards were met by twinax copper cable with a link length of 7m. The 802.3bm standard was approved in 2015, which specifies a lower-cost optical 100GBASE-SR4 PHY for multimode fibers (MMF). The 100GBASE-SR4 standard can operate over OM3 MMF for a link length of 70m, and transmit over OM4 for a link length of 100m. QSFP28-100G-SR4 is one of the common types of the 100G modules, which can be used in 100 Gigabit Ethernet links on up to 100m of OM4 multimode fiber.

For those infrastructure who require a link length longer than 2 km, 100GBASE-LR4 and 100GBASE-ER4 standards were introduced. These two standards are specially designed for use in long haul applications. For example, QSFP28 100GBASE-LR4 optics can support a distance of 10km, and the CFP 100GBASE-ER4 operate over single-mode fiber for a distance of 40km.

As for the 100GBASE-SR10 or 100GBASE-CR10, the 10×10 MSA was intended as a lower cost alternative to 100GBASE-SR4 for applications, which defines an optical Physical Medium Dependent (PMD) sublayer and establish compatible sources of low-cost, low-power, pluggable optical transceivers based on 10 optical lanes at 10 Gbit/s each.

FS.COM 100G Optical Modules

FS.COM provides 100G QSFP28 optical modules, including 100G QSFP28 SR4, 100G QSFP28 LR4 as well as 100G CFP LR4 optical module. All these 100G transceivers are good choice for today’s high-density data center 100G interconnection and networking.

  • QSFP28 100GBASE-SR4

The QSFP28 100GBASE-SR4 transceiver, based on the QSFP28 from factors, is a parallel 100G optical module designed with optical/electrical connection and digital diagnostic interface. It offers 4 independent transmit and receive channels, each capable of 25Gbps operation for an aggregated data rate of 100Gbps for 100 m on 12-fiber MPO/MTP OM4 multimode fiber.


The QSFP28 SR4 module is a vertically integrated solution that meets IEEE 802.3 standards and MSA requirements with power dissipation well under 3.5W. It supports both 100GBASE-SR4 as well as 4x25G breakout applications, 100G QSFP28 to QSFP28 DAC and 100G QSFP28 SR4 to 4x25G SFP28 break-out cables, meeting the harshest external operating conditions including temperature, humidity and EMI interference.

  • QSFP28 100GBASE-LR4

The 100GBASE-LR4 QSFP28 transceiver, compliant to 100GBASE-LR4 of the IEEE P802.3ba standard, is also a 100Gbps transceiver module designed for long-reach communication applications. This module converts 4 input channels of 25Gbps electrical data to 4 channels of LAN WDM optical signals and then multiplexes them into a single channel for 100Gbps optical transmission. The high performance cooled LAN WDM EA-DFB transmitters and high sensitivity PIN receivers provide superior performance for 100GbE applications up to 10km links over single-mode fibers.


FS.COM 100G Optical Modules

According to the market researchers, the 100G optical transceivers market will be booming in the near future. So what are you waiting for? It is the ideal time for data center designers to prepare for the data center networking and architecture beforehand with 100G transceivers and cables. Contact us for the available 100G optical modules: 100G QSFP28 SR4, 100G QSFP28 LR4, 100G CFP, CFP2 and 100G CFP4 optics. Besides 100G optical modules, FS.COM also provides 100G cable solutions like 100G active optical cable (AOC) and 100G direct attach cable (DAC). You can have what you need here.

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Why Choose QSFP28 Transceivers for 100G Transmission?

Over the years, there has been an unprecedented increase in network connectivity and bandwidth needed to accommodate workload requirements of cloud computing, and high-performance web services. The rapid advancements in fiber optic technology has enabled easy upgrading from 10GbE to 40/100GbE within the data centers. With the emergence of 100GbE technologies, the creation of data center network architectures free from bandwidth constraints has been made possible. Among 100G interconnect components, QSFP28 transceiver is the predominant form factor for 100G switching and routing connectivity, a key enabler as 100G begins to ramp in data centers.

QSFP28 Brief Introduction

QSFP28 is the exact same footprint as the 40G QSFP+ module, “Q” for “Quad”. Just as the 40G QSFP+ is implemented using four 10-Gbps lanes, the 100G QSFP28 is implemented with four 25-Gbps lanes. In all QSFP versions, both the electrical lanes and the optical lanes operate at the same speed, eliminating the costly gearbox found in CFP, CFP2, and the CPAK. The QSFP28 module has an upgraded electrical interface to support signaling up to 28Gbps signals, yet keeps all of the physical dimensions of its predecessor. As QSFP28 technology becomes even maturer, QSFP28 transceivers become more and more popular in 100G optics market.

QSFP28 transceiver

There are mainly two 100G QSFP28 transceiver versions: 100GBASE-SR4 QSFP28 transceiver and 100GBASE-LR4 QSFP28 transceiver. The former is specified to operate over multi-mode fiber (MMF) with the maximum link length of 70m on OM3 and 100m on OM4, while QSFP28 100GBASE-LR4 is standardized to work through single-mode fiber (SMF), able to realize 10km link length. The image below shows the working principles of 100GBASE-SR4 QSFP28 (left) and 100GBASE-LR4 QSFP28(right).

QSFP28 100GBASE-SR4 vs. 100GBASE-LR4

Why Choose QSFP28 Transceiver?

Since its surge, the QSFP28 transceiver has gained increasing popularity among enterprises or organizations, as it increases density and decreases power and price per bit. 100G QSFP28 makes it as easy to deploy 100G networks as 10G networks. Listed below are specific reasons why choose QSFP28 for 100G transmission?

  • At the first point, QSFP28 increases front-panel density by 250% over QSFP+. Although QSFP28 has the same form factor and the maximum number of ports as QSFP+ module, the lane speeds are increased from 10Gbps to 25Gbps.
  • Next, QSFP28 breaks some limitations found in other 100G optics. For instance, in the first generation of 100G switches and routers, the smaller CXP form factor was used for cabling and the CFP or CFP2 was used for transceivers. This forced the equipment designer to make huge sacrifices. Besides, a switch with CXP port could not be used in any data center with SMF, and a router with CFP2 or CPAK ports was limited in bandwidth by the 8-10 ports that could fit on the front panel. Well, as for QSFP28, it’s designed to support both cables and transceivers. Within QSFP28, a 1 rack-unit (RU) switch can accommodate up to 36 QSFP ports on the front face plate. Many varieties of either transceivers or cables can plug into these ports. The cables can be either direct attach cables (DACs), commonly referred to as direct attach copper cables, or active optical cables (AOCs).
  • Finally, QSFP28 transceivers can use either VCSELs (for shorter distances on MMF) or silicon photonics (for longer distances on SMF). The advent of silicon photonics enables QSFP28 transceivers to support any data center reach up to 2km or more. Silicon photonics provides a high degree of integration; the CMOS chips are small enough to fit within a QSFP package. Silicon photonics is low-power; even WDM designs can fit within the 3.5W maximum of QSFP.

With the fiber optic technology becoming maturer and more available, the choice of high-bandwidth switches, routers, and adapters which feature QSFP28 will be diversified, ensuring data centers to scale to 100G networks with the simplicity as 10G networks. Fiberstore supplies a large number of QSFP28 transceivers available in QSFP28 100GBASE-SR4 and QSFP28 100GBASE-LR4 types. If you want to know more information about QSFP28 transceivers, you can visit Fiberstore.

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