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Introduction to 10GbE/25GbE/40GbE/100GbE Fiber Optic Cabling

Introduction to 10GbE/25GbE/40GbE/100GbE Fiber Optic Cabling

Technology is changing rapidly. Just when you got used to Gigabit Ethernet speeds being a fast & reliable system, someone unveiled 10GbE, 25GbE, 40GbE or even 100GbE systems a few years later. The newer and higher performing iterations are indeed the great breakthrough for telecommunication industry, but also pose difficulty in choosing network migration path—10G to 40G to 100G, or to 25G to 50G to 100G. We have described 10G, 25G, 40G and 100G Ethernet technology before, now in this blog, we’d like to introduce the four fiber optic cabling, and compare two 100G migration paths.

Cost-effective 10GbE Fiber Optic Cabling

10 Gigabit Ethernet technology defined by IEEE 802.3ae-2002 standard, is matured nowadays. Just like the “old” Gigabit Ethernet, 10Gb network can be terminated with either copper or fiber cabling. 1000BASE-T standard usually uses the Cat5e cables as the transmission media, while 10GbE bandwidth requires high grade copper cables like Cat6/Cat6a/Cat7 cables to support 10Gbps data rate. For instance, 10G SFP+ 10GBASE-T transceiver modules utilize Ethernet copper cables (Cat6a/Cat7) for a link length of 30m. SFP+ direct attach cables (DAC) and active optical cables (AOC) are also regarded as the cost-effective solutions for 10G short-reach applications. Besides 10G copper cables, there are single-mode (OS2) and multimode fiber patch cables (OM3/OM4) applied to different 10GbE IEEE standards. For the detailed information about the 10G cabling options, please see the following table.

10G fiber optic cable

As to the 10G fiber optic transceivers, there are a series of optical form factors including the XENPAK, X2, XFP, SFP+. The former three 10GbE optical transceivers were released earlier than smaller 10G form factor—SFP+ module. However, owing to their larger footprint, they are not successful on the 10G hardware market. Furthermore, SFP+ optics, compliant with several IEEE standards (SR, LR, LRM, ER, ZR and 10GBASE-T…) wins the heart of 10G end-users.

Singe-lane Design Makes 25GbE Shine

When 25G Ethernet was developed to support a single-lane 25Gbps standard in 2014, it was treated as the “new” 10GbE technology but delivers 2.5 times more data. Compared to 40GbE that was based on 10GbE, 25GbE with one lane obviously improves the port density and cost requirement. 25GbE network can support both copper and fiber optic cables, seen in the below table.Similar to 10GbE networks, 25G Ethernet physical interface specification supports several 25Gbps capable form factors, including CFP/CFP2/CFP4, SFP28 (1×25 Gbps) and QSFP28 (4×25 Gbps), which is also used for 100GbE. SFP28 25GBASE-SR and 25GBASE-LR SFP28 are two popular 25GbE optical transceiver modules available on the market, the former supports up to 100m link length while the latter allows a maximum transmission distance of 10 km.

25G optical modules

The available optical switches of the market do not support direct 25GbE connections using an SFP28 direct attach copper (DAC) cable. It is recommended to use a breakout cable that allows four 25GbE ports to connect to a 100GbE QFSFP28 switch port. FS.COM SFP28 DAC cable lengths are limited to four meters (1m, 2m, 3m, 5m) for 25GbE. And if you prefer a longer length, the 25GbE active optic cable (AOC) solutions are good recommendations.

25G Optics SFP28 Type
All 25G SFP28 Ports 25GBASE-SR 50µm MMF / 70m
25GBASE-LR 9µm SMF / 10km
25GBASE-AOC Pre-terminated in 3, 5, 7, 10, 15, 20, 25, 30m lengths
25G Copper SFP28 Type Media/Reach
All 25G SFP28 Ports 25GBASE-CR Twinax / ‘Direct Attach’ Pre-terminated in 1m, 2m, 3m, 5m lengths


Fast & Reliable 40GbE Fiber Optic Cabling

Like the 10GbE fiber optic cabling, there are several IEEE standards of 40GbE transceiver in the whole evolution. 40G QSFP+ optical transceivers are the most commonly used optics for 40G network. So how to choose fiber optic cables for 40G optical transceivers? The following table will help you out.

40G modules

Besides the QSFP+ fiber transceivers and fiber optic cables, 40G DAC cables available in QSFP+ DAC cables and AOC cables enable short-reach options. For 40G cabling, QSFP+ to QSFP+ (40G to 40G) and QSFP+ to 4SFP+ (40G to 10G) breakout cables satisfy customers for various fiber types and reach requirements.

100GbE Fiber Optic Cabling For Future Proofing

With the price of 100G optics cutting down in 2017, 100GbE network is no longer out of customers’ reach. Telecom giants like Cisco, Arista, HPE launches series of 100G optical switches to meet the market demand. And for other 100G components like 100G optical transceivers, fiber patch cables, racks & enclosures, etc, those are ubiquitous on the market.

100G optical transceivers including the CFP, CFP2, CFP4, CXP and the most popular 100G QSFP28 optics in IEEE standards provide a great selection to the overall users.For 100G inter-rack connections, QSFP28 to QSF28 Direct Attach Copper (DAC) Cables and Active Optical Cables (AOC) as well as the QSFP28 to SFP28 breakout cables are the cost-effective solutions.

Path 1: 10G to 40G to 100G

Many of the largest data centers has already moved to 40GbE, which are constructed out of 4 parallel SerDes 10Gb/s links between the Ethernet chip and the QSFP pluggable. The short-reach QSFP interfaces (QSFP+ SR4 modules) use 4 pair of fiber between them, and the copper Direct Attach Cable (DAC) equivalent carry the same on several copper cables inside the big cable. Longer-reach QSFP interfaces (QSFP+ LR4 optics) put the 4 10Gb/t streams onto separate Wave Division Multiplexing (WDM) waves which can be carried over a single pair of fiber. This is part of the reason why QSFP optics are fairly expensive still, especially for longer distances.10GbE to 40GbE to 100GbESimilarly for the 100GbE interfaces that are available today, these are really constructed out of 10 parallel paths of 10Gb/t streams. 100G SR10 modules is the optical transceiver modules that support 10×10Gb/s modes. But neither the CXP SR10 modules or CFP 100G SR10 optics are not popular on the 100G hardware market owing to their larger form factors. Eventually, they need to utilize the smaller footprint 100G modules—QSFP28 transceiver, which is mentioned above as the optical transceivers that can be used in 25GbE and 100GbE.

Result: Although the migration path from 10G to 40G to 100G requires more ports and increases cost per bit, 40GbE between switches is expected to be remain and will not be affected in the near future.

Path 2: 25G to 100G—The Move From 10 Lanes to 4

The old transition path of Ethernet has increased by 10X in speed like the 10G to 40G to 100G. However, 25 Gbps over a single lane for server makes 100G migration be 4×25Gb/s mode.100-gbe-block-diagramUsing four-lane variants like QSFP28 is more economical in several ways:

  • The single-lane design makes four 25 Gbps lanes transceivers less expensive than ten 10Gbps lanes because the transceiver is simpler and less costly to manufacture.
  • The power required to run SFP28 transceivers is much less than required for a typical 10-lane transceiver, it is the same case as the cooling costs.
  • For fiber connections, moving from 10GbE to 40GbE may require an upgrade to four times the number of fibers (MPO), but a 25GbE connection does not because it is the same as 10GbE (single TX and single RX, not four each for TX and RX).
  • Moving from 10GbE to 40GbE typically requires a forklift upgrade to thicker, more expensive cables, but a 25GbE direct attach copper connection does not.

Result: There are few switches and NIC cards that directly support 25GbE. But the curve for 25GbE won’t fade away, rapid development and pre-standard 25GbE products coming soon!


This article introduces 10G/40G/100G fiber optic cabling, and make a clear comparison between the two paths to 100GbE. Customers prefer 4×25Gbps for the reasons: Less parallel paths, less fibers, less optics, less everything. For those who want to upgrade from 40G to 100G, appreciate the reliable performance of 40G with the potential to run across 2 parallel 25Ghz rather than 4 required today.

40GbE Parallel QSFP+ vs Duplex QSFP+ in 40G MMF Cabling

40GbE Parallel QSFP+ vs Duplex QSFP+ in 40G MMF Cabling

There two ways to deploy 40GbE multimode fiber (MMF) infrastructure. One is using the parallel transceivers with 12-fiber MTP cables. And the other one is to use the duplex transceivers with LC duplex cables (view transceiver options for 40GbE over duplex LC MMF cable). The former solution requires to add additional fiber to increase the number of 40GbE links. Thus, more fiber cost is taken in this solution. Conversely, the duplex transceiver solution allows for zero-cost fiber migration by reusing the current 10GbE fiber infrastructure for 40GbE connectivity. In this post, the typical cost difference for fiber infrastructure for parallel transceivers and duplex transceiver is introduced.

Typical MMF Cabling Cost Per 40GbE Link With Parallel Transceivers

In this scheme, a pairs of 40GbE parallel transceivers called 40GBASE-SR4 QSFP+ are used with the MTP patch cables and trunks. In addition, two MTP-MTP conversion modules are required. As shown in the picture below, there are two patch cables, two MTP-MTP conversion modules, and a 24-fiber trunk per link. Since the QSFP-40G-SR4 just uses 8 fibers in the trunk per link, total two MTP-MTP conversion modules can be used for 3 links.

40G parallel transceivers

The detailed cost for per 40GbE link with parallel transceivers are shown in the following table:

Item Unit Price Extended Price Per 40GbE Link
MTP patch cables (5 m, OM3) US$48.00 US$96.00
MTP-MTP conversion modules (OM3) US$400.00 US$267.00
24-fiber MTP trunk (90 m, OM3) US$367.00 US$123.00
Total US$486.00


Typical MMF Cabling Cost Per 40GbE Link With Duplex Transceivers

In the scheme using duplex transceivers, such as Juniper JNP-QSFP-40G-LX4 or Arista 40G QSFP-UNIV, two LC patch cables, two MTP-LC cassettes and a 24-fiber MTP trunks are used. As shown in the picture below, by deploying the duplex 40GbE transceivers, users can increase the number of 40G links by 4X without making any changes to their fiber infrastructure. In other word, the total two MTP-LC cassettes can be used for 12 links.

40G duplex transceivers

The detailed cost for per 40GbE link with duplex transceivers are shown in the following table:

Item Unit Price Extended Price Per 40GbE Link
Duplex LC patch cables (5 m, OM3) US$4.00 US$8.00
MTP-LC cassettes (OM3) US$120.00 US$20.00
24-fiber MTP trunk (90 m, OM3) US$367.00 US$30.00
Total US$58.00



The prices of product above are estimated according to FS.COM list prices (for reference only). Assume shipping costs are the same, as you see, a saving of over 90% on the cabling equipment alone is realized from the duplex transceivers. The project management costs to upgrade existing duplex systems are entirely avoided resulting in even more significant savings. In addition, the duplex transceivers mentioned above can also support running over single-mode fiber which is a cost-effective solution for migrating from multimode to single-mode fiber.

However, it is noted that the duplex 40GbE multimode transceiver is more expensive than the parallel one. For example, the 40GBASE-SR4 costs just 65 dollors while the LX4 costs about 400 dollors at FS.COM. Thus, the best option is just to choose the one you need, based on your network plan and future-proof upgrade.

Buyer Guides: At FS.COM, you can buy the above products at very affordable prices. In addition, you can buy both parallel and duplex 40GbE transceivers for many major brands compatible. For more information, please contact
How to Run 40GbE Over Duplex LC MMF Cabling

How to Run 40GbE Over Duplex LC MMF Cabling

The use of parallel optics in 40GbE multimode fiber cabling (MMF cabling) require more fiber strands than the 10GbE infrastructures. Thus, data center will require a cabling upgrade to meet the requirement of migration. In this case, cost is a big factor. To help user solve the fiber cost issue, many vendors developed a new transceiver alternative that allow zero-cost fiber migration by reusing the current 10Gbps multimode fiber-optic cabling plant for 40Gbps connectivity. This post will introduce three mainstream transceiver options for running 40GbE over duplex multimode fiber cable with LC connectors.

Option 1: Cisco QSFP 40G BiDi Transceiver (QSFP-40G-SR-BD)

The Cisco QSFP BiDi transceiver can transmit full-duplex 40Gbps traffic over one duplex OM3 or OM4 MMF cable with LC connector. It provides the capability to reuse 10Gbps fiber infrastructure, enabling data center operators to upgrade to 40Gbps connectivity without making any changes to the previous 10GbE infrastructures.

The working principle of Cisco QSFP BiDi transceiver is that it uses has two 20Gbps channels, each transmitted and received simultaneously over two wavelengths on a single MMF strand, as shown in the following.


Concept of QSFP BiDi transceiver

Cisco QSFP BiDi transceiver can be supported in most Cisco switching and routing products that support 40GbE interfaces. The connection distance can reach up to 100 meters over OM3 MMF or 150 meters over OM4 MMF, which is the same as 40GBASE-SR4 QSFP+.

Note: The other version of Cisco QSFP BiDi transceiver (QSFP-40G-BD-RX) is almost the same with the QSFP-40G-SR-BD, but with link monitor hardware, such as the Cisco Nexus® Data Broker.

Buyer Guide: FS.COM offers cost-effective and highly compatible QSFP BiDi transceivers which are tested to ensure 100% Cisco compatibility.
ID# Description More Details
48722 Cisco QSFP-40G-SR-BD Compatible 40GBASE-SR Bi-Directional Duplex LC Transceiver View
65231 Cisco QSFP-40G-BD-RX Compatible 40GBASE-SR Bi-Directional Duplex LC DOM Transceiver View


Option 2: Juniper 40Gbps QSFP+ LX4 (JNP-QSFP-40G-LX4)

Juniper 40Gbps QSFP+ LX4 module uses the same infrastructure as 10GbE. The LX4 technology represents a new way to deploy 40GbE that meets all of the performance criteria of today’s data centers by providing 40GbE on two MMF strands with duplex LC connectors. Thus, users can simply replace existing 10GbE transceiver modules with 40GbE LX4 modules without expensive 40GbE migration cassettes and additional fiber infrastructure.

As the following picture shown, QSFP+ LX4 transceiver uses four 10Gbps channels, each transmitted and received simultaneously over four wavelengths on a single MMF strand. Similar with the 40GBASE-SR4 modules, it can also support transmission distance up to 100 meters over OM3 MMF or 150 meters over OM4 MMF cable. Juniper 40Gbps QSFP+ LX4 can be supported in many Juniper devices that support 40GbE interface, such as QFX3000 QFabric system, QFX5100 switches, and so on.


Concept of QSFP+ LX4 transceiver

Note: The Juniper 40Gbps QSFP+ LX4 also support to run over single-mode fiber (SMF: OS1) and reach up to 2 kilometers.

Buyer Guide: FS.COM offers cost-effective and highly compatible QSFP+ LX4 transceiver which are tested to ensure 100% Juniper compatibility.
ID# Description More Details
36175 Juniper Networks JNP-QSFP-40G-LX4 Compatible 40GBASE-LX4 QSFP+ 1310nm 2km DOM Transceiver View


Option 3: Arista Networks QSFP-40G-UNIV Transceiver

The Arista networks QSFP-40G-UNIV is a 40GbE QSFP+ transceiver with a duplex LC connector that can be used with both MMF and SMF. Its working principle is similar with the Juniper LX4 mentioned above, having 4 channels of 10G multiplexed inside the module to transmit and receive an aggregate 40Gbps signal over 2 strands of fiber. UNIV is short for the word “universal” because of its ability to operate with both MMF and SMF without the need for any software/hardware changes to the module or any additional hardware in the network. The Arista networks QSFP-40G-UNIV can operates on OM3 or OM4 MMF for distance up to 100 meters or SMF (OS1) for distance up to 500 meters. It is noted that this QSFP module can interoperate with Cisco and other vendors standards based 40GbE LR4 optics.

Buyer Guide: FS.COM offers cost-effective and highly compatible QSFP-40G-UNIV transceiver which are tested to ensure 100% Arista Networks compatibility.
ID# Description More Details
36196 Arista Networks QSFP-40G-UNIV Compatible 40GBASE-UNIV QSFP+ 1310nm 500m DOM Transceiver View


For more details, please contact

Optics Use Cases for 40 Gigabit Ethernet Connectivity

Optics Use Cases for 40 Gigabit Ethernet Connectivity

The 40 Gigabit Ethernet (GbE), used in today’s networks as the preferred spine uplink technology, has become commonplace in data centers. With the rise of 40GbE QSFP+ optics market, various of optics solutions are available, which offer users a lot of flexibility in connectivity. Today, I am going to summarize some 40 Gigabit fiber optic connection use cases of several types of commonly used 40GbE QSFP+ optics.

Case One: QSFP+ to QSFP+ Direct Connectivity

For 40GbE to 40GbE connectivity, namely the interconnection between two QSFP+ ports, users can use different optics and cables options according to different transmission distances.

40GbE direct connectivity

  • For distances of up to 7 meters: QSFP+ to QSFP+ DAC (Direct Attach Copper) cables
  • For distances of up to 100 meters: QSFP+ to QSFP+ AOC (Active Optical Cable) or 40GBASE-SR4 QSFP+ transceiver with OM3 multimode fiber with MTP/MPO connectors or OM4 multimode fiber with MTP/MPO connectors (up to 150 meters)
  • For distances of up to 300 meters: 40GBASE-CSR4 QSFP+ transceiver with OM3 multimode fiber with MTP/MPO connectors or OM4 multimode fiber with MTP/MPO connectors (or up to 400 meters)
  • For distances of up to 1 kilometers: 40GBASE-PLRL4 QSFP+ transceiver can be used with single-mode fiber with MTP/MPO connectors
  • For distances of up to 10 kilometers: 40GBASE-LR4 QSFP+ transceiver can be used with single-mode fiber with LC connectors

Tips: The standard QSFP+ MTP/MPO connector is 12-fiber connector, but use 8 out of 12 fibers.

Case Two: 40GbE to 10GbE Ports Breakout

As we know, 40GbE ports can be used either as a single port or turned into four 10GbE ports. Thus, you can use so-called QSFP+ breakout or fan-out cables with QSFP+ on one side and four SFP+ on the other side to increase the number of available 10GbE ports.

In general, according to different distance requirements, the basic three types of solutions are available:

40GbE breakout connectivity

  • For distance of up to 5 meters: QSFP+ to SFP+ DAC Breakout Cables
  • For distance of up to 100 meters: QSFP+ Breakout AOCs
  • For distance of up to 300 meters: MTP/MPO to 4xLC Duplex OM3/OM4 multimode fiber breakout cables (mpo to lc duplex breakout cable) with the 40GBASE-CSR4 transceiver

Tips: When connect to networking switches or to server adapters which support SFP+ fiber optic connectivity, the QSFP+ DAC breakout cables are always the preferred option.

Case Three: Deploy 40GbE With Existing 10GbE Cabling Using LC Connectors

In today’s server networks, 10GbE has become commonplace. 10GbE multimode cabling with LC duplex connectors is the main infrastructure of 10GbE network. To leverage existing 10GbE cabling using LC connectors, the 40GBASE-SR QSFP+ Bi-Directional (BiDi) transceiver is an ideal choice for you. Used with WDM (Wavelength Division Multiplexing) technology, the 40GBASE-SR QSFP+ BiDi transceiver can support up to 100 meters with OM3 multimode fiber and up to 150 meters with OM4 multimode fiber cables with LC duplex connectors, allowing reuse of existing 10-Gbps fiber infrastructure for 40-Gbps connections so that helps reduce overall costs and installation time.

40GbE bidi


According to the above contents, we learned that the optics market for 40GbE connectivity is now relatively mature. Users can choose the most proper solution according to their network plan, requirements, and budget.

Modular Fiber Patch Panel Solution – an Ideal Path for Today’s & Tomorrow’s Network Upgrade

Modular Fiber Patch Panel Solution – an Ideal Path for Today’s & Tomorrow’s Network Upgrade

As 40/100G fiber network becomes a popular option in data centers, how to connect 40/100G devices with existing 10G devices in a cost-effective manner becomes a primary challenge for most of the data center operators. Breakout cables and modular patch panels two main solutions to address this challenge. However, the breakout cabling solution is limited to use in high-density data center because of its cable congestion, higher cost of maintenance etc. Modular patch panel solutions solve this issues of breakout cabling solutions, offering users a more cost-effective path for today’s and tomorrow’s network upgrade.

What’s Modular Patch Panel?
Modular patch panel is integrated a range of modular, removable fiber assemblies in a rack-mount panels. Based on the same working principle with breakout cables, modular patch panel provides a mature and highly scalable alternative to breakout cables since it allows users to seamlessly and conveniently integrate equipment with different network speeds for today’s and even tomorrow’s connectivity needs. With a compact and easy maintenance design, it can support a variety of fiber network standards. Moreover, it is easy to mix, match, add, and replace so that it can satisfy all kinds of connectivity needs in data centers.

How Modular Patch Panel Work?
The modular fiber panels and cassettes are the key to this solution. Just by an easy plug-and-play step, you can easily complete the connectivity between two standard ports, eliminating the complicated cable management segment.

modular patch panel

Benefits & Challenges
There are more advantages of modular patch panel solution over the breakout cabling solution. The modular patch panel solution provides flexibility and scalability for your network upgrade, allowing users to connect diverse network cabling standard seamlessly, without the costly, labor-intensive hassle of replacing channels end-to-end. Designed with standard patch cables, it offers a reliable and readily available option for users. Moreover, with its compact size, it can help save more space and reduce cable congestion.

The biggest challenge of using modular patch panel solution is how to select the right one to meet your current needs, as well as adapting to and growing with your future needs, because it involves the cost, supported network standard, and the whole network plan concerns.

The above contents show us the details about modular patch panel solutions. It seems to be a better choice for network migration. But users should choose the right one according to their current and future plan to ensure a maximum return on investment. FS.COM offers a full range of breakout cables and modular patch panels with competitive prices and high quality, such as MTP harness cables, 40GBASE-SR4 breakout patch panel, high-density 144 ports patch panel, and so on. For more information, please contact us over or call 1 718 577 1006.

Source: Tutorial of FS.COM