Fiber Optic Tech

Introduction to CFP-40G-LR4 and CFP-100G-LR4

The C form-factor pluggable (CFP) is specified by a multi-source agreement (MSA) among many manufacturers for the transmission of high-speed digital signals. The CFP transceiver can both support 100 Gbit/s or OTU4, and 40Gbit/s OTU3 signals. The 40G and 100G CFP transceivers are hot-swappable input/output devices that can be plugged into the 40-Gigabit and 100-Gigabit Ethernet module ports. CFP-40G-LR4 has the same footprint as CFP-100G-LR4, and both of them terminate with duplex SC fiber connectors. Except that they support different transmission distance, what are the detailed information about them?

cfp-40g-lr4 vs. cfp-100g-lr4

40G CFP-40G-LR4

The Cisco CFP form factor can also operate over 40GbE, supporting both single-mode 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. 40GBASE CFP optical transceiver module supports 40GBASE Ethernet and OTU3 standards, which can be used in core and distribution layers of data center enterprises, and service provider networks. Cisco releases CFP-40G-LR4, CFP-40G-SR4, and CFP-40G-FR modules.


CFP-40G-LR4 Vs. QSFP-40G-LR4

CFP-40G-LR4, similar with QSFP-40G-LR4, is compatible with IEEE 40GBASE-LR4 standard and operates link length of up to 10km over standard single-mode fiber(OS2). However, CFP-40G-LR4 uses SC duplex connectors with a larger form factor, while QSFP-40G-LR4 utilizes LC duplex connector with a compact footprint ( as shown in the above image).


100G CFP modules use 10 x 10 Gbit/s lanes in each direction (RX, TX), the optical connection can support both 10 x 10 Gbit/s and 4 x 25 Gbit/s variants of 100 Gbit/s interconnects (typically referred to 100GBASE-SR10 in 100 m reach respectively and 100GBASE-LR4 in 10 km reach.)

Cisco 100GBASE-LR4 CFP is the 100G CFP type that was designed for long-reach 100GbE applications. CFP-100G-LR4 supports a link length of 10 km on standard SMF with duplex SC connectors. It is running at four optical wavelengths (1295.56 nm, 1300.05 nm, 1304.59 nm, 1309.14 nm) and muxing/demuxing of these wavelengths happening inside CFP module.

Comparison Between CFP-40G-LR4 and CFP-100G-LR4

CFP-40G-LR4 and CFP-100G-LR4 share many points in common, such as the wavelength, fiber type, max distance, fiber optic connector and DOM support. Nevertheless, CFP-40G-LR4 is used in 40GbE network, and CFP-100G-LR4 is in 100GbE.

Cisco CFP

To further understand the difference between CFP-40G-LR4 and CFP-100G-LR4, let’s have a look at the CFP architecture. According to the below image, the whole CFP diagram is composed of two parts—equipment Line card ASC or FPGA, line card interface and optical line interface. There are several “M-Lines” with 10Gbps speed between equipment line card and electrical interface.


If CFP is working 100GBase-LR4 mode, then it has 10 x 10Gbps M-Lines. As to 40GBase-LR4, it uses 4 x 10Gbps M-Lines. The “gear box” in the image is electrical 10:4 mux/demux module aggregating up to 10 M-Line interfaces in maximum 4 N-Line interfaces. Each N-Line is 25Gbps for 100GBase-LR4 and 10Gbps for 40GBase-LR4. So you may clearly understand the difference between CFP-40G-LR4 and CFP-100G-LR4.


The CFP MSA transceiver module defines hot-pluggable optical transceiver form factors to enable 40GbE and 100GbE applications. CFP-40G-LR4 and CFP-100G-LR4 are the CFP LR4 optics that are compatible with 40GBASE-LR4 and 100GBASE-LR4 standards. Other than the CFP form factor modules, pluggable CFP, CFP2 and CFP4 transceivers support the ultra-high bandwidth requirements of data communications and telecommunication networks that form the backbone of the internet. FS.COM offers a whole sale of CFP/CFP2/CFP4 optical transceivers that available in several standards. Please feel free to contact us if you need anything.

Describing Cisco GLC 1000BASE SFP Transceiver Modules

Cisco SFP module, compatible with 1000BASE Gigabit Ethernet standard is a hot-swappable input/output device that can plug into a Gigabit Ethernet slot of Cisco switches and routers. Cisco, as a telecom giant supplies a whole series of fiber optic transceiver modules available in 1000BASE-T, 10/100/1000BASE-T, 1000BASE-SX, 1000BASE-LX, 1000BASE-EX, 1000BASE-ZX standards. It is truly dizzying to choose from a whole array of Cisco SFP transceivers, and each often has only minor differences between them. Thus, to help customers choose the suitable Cisco SFP modules, this article will clearly introduce several Cisco GLC modules.

Cisco Switch with SFP module

Figure 1 shows Cisco SFP plugging into the Cisco Nexus 9396 switches.


GLC-T is 1000BASE-T Cisco SFP copper 1g module, compliant to IEEE 802.3, operates over Cat5 copper wire for a distance of 100m. Cisco GLC-T fiber transceivers provide 1Gbps data transfer for full duplex Gigabit Ethernet connectivity.


Similar with GLC-T SFP modules, GLC-TE provides a link length of 100m over Cat5 copper wires. The only difference between these two SFP modules lies in the operating temperature range. GLC-T SFP is commercial temperature range (COM) from 0 to 70°C (32 to 158°F), while GLC-TE is Extended temperature range (EXT) from -5 to 85°C (23 to 185°F).

GLC-TE with RJ45 connector

Figure 2 displays GLC-TE SFP module with RJ45 connector.


GLC-SX-MMD resembles with GLC-SX-MM module. Both are the Cisco 1000BASE-SX SFP modules operating at the wavelength of 850nm. When connecting with OM2 multimode fibers, this optical transceivers can support up to 550m. However, GLC-SX-MMD allows data rate of 1000Mbps with digital optical monitoring (DOM) support, which performs transceiver monitoring and troubleshooting operation.


SFP-GE-S is compliant with 1000BASE-SX standard. It operates over multimode fibers with a wavelength of 850nm at 550m. Unlike GLC-SX-MM, SFP-GE-S support DOM performance and extended operating temperature range.


Compliant with 1000BASE-LX/LH standard, Cisco GLC-LH-SMD can support a large longer distance of 10km. The letter “D” also refers to the DOM support. It operates at longer wavelength of 1310nm over duplex LC single-mode fibers.

GLC-LH-SMD with LC connector

Figure 3 presents GLC-LH-SMD with LC connectors.


Cisco GLC-LH-SM-20 is the advanced version of GLC-LH-SM spec, which operate at 1310nm wavelength through LC connector with a transmitting distance of up to 20km.


GLC-EX-SMD is the Cisco 1.25Gbps SFP module that is compliant with 1000BASE-EX standard. It operates over 1310nm for distance up to 40km.


Compatible with 1000BASE-EX Gigabit Ethernet standard, this Cisco SFP also support a link length of 40km with DOM support. But unlike GLC-EX-SMD operating at 1310nm, this optical transceiver module works over 1550nm wavelength.


As the name implies, Cisco GLC-ZX-SM is compliant with 1000BASE-ZX standard for single-mode fibers. When used in Cisco 2960 switch, it can support a link length of up to 70km at 1550nm.


If the GLC-ZX-SM with a distance of 70km can not meet your network requirement, then you can use the GLC-EZX-SM-100 modules for 100km.


GLC-EZX-SM-120 with a operating wavelength of 1550nm can reach up to 120km over single-mode fibers.


This article lists several Cisco SFPs with detailed specification, such as the media type, supporting distance, wavelength, operating temperature range, etc. If you have Cisco switches and don’t know how to choose the suitable SFPs, you can have a look through this article or directly visit


10G SFP+ optical transceiver is considered as the mainstream form factor of the 2017 market due to its matured technology and lower price, even although 40G/100G optical modules are on the very top trend for enterprise and data center for the interconnection. 10G SFP+ modules come in several standards: SFP-10G-SR, SFP-10G-LR, 10GBASE-ER SFP+, and 10GBASE-LRM SFP+. This article will offer details about the difference between SFP-10G-SR and SFP-10G-LR.


Cisco SFP-10G-SR

SFP-10G-SR is compliant with 10GBASE-SR standard. The Cisco 10GBASE-SR module supports a link length of 26m on standard Fiber Distributed Data Interface (FDDI)-grade multimode fiber, up to 300m link lengths over OM3 and 400m link lengths over OM4 cables.

Cisco SFP-10G-SR transceiver is hot-swappable input/output device which allows a 10 Gigabit Ethernet port to link with a fiber optic network. Because it is hot-swappable and MSA compliant, the Cisco SFP-10G-SR transceiver can be plugged directly into any Cisco SFP+ based transceiver port, without the need to power down the host network system. This capability makes moves, add-ons and exchanges quick and painless. The data sheet of SFP-10G-SR is as follows:


The Cisco SFP-10G-SR series consists of two other modules: the Cisco SFP-10G-SR-S Module and the Cisco SFP-10G-SR-X Module.

The Cisco SFP-10G-SR-S module belongs to the Cisco S-class optics that possess the same performance with Cisco SFP-10G-SR module. For the detailed information about the difference between Cisco S-class and non S-class optics, you can review the previous article.

Cisco SFP-10G-LR

The Cisco 10GBASE-LR module supports a link length of 10 km on standard single-mode fiber. Compliant with 10GBase-LR standard, SFP-10G-LR can support up to 10km over single-mode fiber and uses 1310nm lasers. There is no minimum distance for LR, either, therefore it is suitable for short connections over single mode fiber, too. The following image shows a Cisco Compatible SFP-10G-LR SFP+.

Cisco SFP-10G-LR


10GBASE-LRM is the type of transceiver that customers may easily feel confused with 10GBASE-LR SFP+ optics. However, in short, 10GBASE-LRM SFP+ still uses the 1310nm lasers, but it can only reach up to 220 m over standard multimode fibers (OM3/OM4). The 10GBASE-LRM can be packaged in XFP and SFP+ form factors.

Besides the Cisco SFP-10G-LRM module, there are a new type of the 10G SFP+ module for multimode fibers—SFP-10G-LRM2. It is a type of SFP+ transceivers compatible with the 10GBASE-LRM standard. SFP-10G-LRM2 can reach up to 2km over standard multimode fiber.

Do You Need Cisco Original Brand or Compatible SFP+ Modules?

If you spend a large sum of money on the Cisco original brand switch, next you may think of buying the compatible optics. However, there comes the problem, do I need the Cisco original brand modules?

To tell the truth, not every SFP+ modules can work well on the Cisco switch SFP+ ports. You must make sure of the compatibility before plugging the SFP+ transceivers on it. Furthermore, SFP+ modules are the essential components of fiber optic network, usually, network installers need a bunch of them for your network deployment. Thus, select cost-effective 3rd party modules are necessary. You can also purchase more for back up.

FS.COM, as a reliable and qualified fiber optics supplier, supplies a full range of optical transceivers with a large quantity of products available in stock. Our compatible Cisco SFP-10G-SR and SFP-10G-LR modules are provided at really low price. Cisco SFP-10G-SR is $16, and SFP-10G-LR is $34.


SFP-10G-SR is mainly used for short-reach 10G application, while SFP-10G-LR, with a link length of 10 km is ideal for metro infrastructure. Customers can choose either reliable SFP-10G-SR or SFP-10G-LR, according to their own needs.

DAC Twinax for Top of Rack Switching

Top of rack switching as the basic data center architecture, requires one or two access switch installed on the top pf each sever rack, which provides easy cable management and maintenance. Additionally, it reduce the cable requirement as all sever connections are terminated to its own rack. Direct attach cables (DAC) twinax cable can achieve interconnection up to 15 m at 10 Gbps or 40 Gbps with low power. Most server gears come default with DAC twinax cables in-rack along with a couple of short-throw lasers back to core. This article will present the cabling solutions of the DAC cables for data center top of rack deployment.

Why Use DAC Twinax Instead of Cat5e or Cat6 Cables for Top of Rack Switching?

What media option would be the best to invest in for top of rack application? Category copper cable (Cat5e or Cat6) used to be the preferable options. Cat5e or Cat6 cables, standardized on 10GBASE-T, are overall cheap, backward compatible and much easier for cable management, especially for shorter cable runs. But these days, DAC twinax cables are more suitable for top of rack switching owing to the following reasons.

First, most of the hosts we are buying are not with RJ45 on board and all the switches and firewalls we’ve used for years were SFP+. Second, the extra power consumption for 10GBASE-T is higher than DAC cables. Additionally, DAC cables has lower latency hit. Last but not least, people often prefer DAC twinax owing to its flexibility. People can easy swap a DAC cable for a SFP+ transceiver and generally connect to anything I need to.

Note that the decision between Cat5e/Cat6 cables and DAC comes down to what your strategy for server hardware is, if you don’t run high density servers, or you use blade enclosures to reduce your server port count, Cat5e or Cat6 cables might be fine and should be much cheaper.

DAC Twinax Cables

For interconnection in top of racks, the direct attach cable assemblies are used to connect server to switch, storage to switch or switch to switch. Just as the following image shows, DAC twinax cables, available in direct attach passive or active copper cable, active optical cable or breakout direct attach cable assemblies, can cope with different interconnection applications.


Twinax copper cable with various length options, are popular on the market. For example, 10G SFP+ DACs are commonly used in interconnect application below 15 m, e.g. server to switch or storage to switch interconnection in the same rack. Cisco SFP-H10GB-CU2M is the 10G SFP+ passive direct attach copper cable used for short-reach direct connection. And for 40GbE, 40G QSFP+ DACs and AOCs are used, the former is usually used for short-interconnection below 15 m while the latter is used for longer interconnect application that over 15 m but less than 100 m. Of course, higher speed and more bandwidth are needed for spine switches. 100G DACs, like QSFP28 DACs are used in this case.

DAC Twinax Used in Top of Rack Switching

FS.COM offers a comprehensive solution for data center ToR deployment including cables, transceiver optics and direct attach cabling products to satisfy various demands on data rate. Depending on different layers, we offer the different solutions:

  • Use Case for Interconnecting Rack Servers and ToR Switch

For interconnection between rack servers and ToR switch within rack, the Category 6a (Cat 6a) Ethernet patch cables or SFP+ direct attach cables can be used. The cable length depends on the distance from the rack server to the ToR switch that is limited to the vertical height of the cabinet.

  • ToR Switch to Network Switch

When connecting the ToR switch to network switch, it requires increased transmission speeds and distances. For distances below 15 m, the SFP+ direct attach cable is still an ideal option. But if the distances are more than 15 m, we recommend you to use the multimode fiber with the corresponding optics. In addition, for distances less than 100 m, the SFP+ AOC (active optical cable) is a viable option.

  • Network to Core Switch

At the core of data center, direct attach cables designed with QSFP+ connectors can be used for short distance transmission of up to 15 m to support up to 40Gbps. To support distances above 15 m, the OM3 or OM4 fiber is recommended to use with the QSFP+ optics. In addition, for distances less than 100 m, the QSFP+ AOC is a viable option.


Twinax copper cables including the DAC and AOC cables are the mainly used cable type to support high transfer rates between servers, switches and storage devices intra rack or inter rack in a data center. This article has concluded the reasons why we should DAC cables and the cabling solution for top pf rack switching.

Gigabit Ethernet Transceivers Supported on Cisco Nexus 3500 Series Switches

Cisco Nexus 3500 Series switch are the comprehensive portfolio of 1, 10, and 40 Gigabit Ethernet switches to achieve exceptional layer 2 and 3 switching latencies of less than 200 ns. They are Cisco’s hot-selling switches that can support a series of Gigabit Ethernet transceivers like the SFP transceiver module, SFP+, and the QSFP+ modules. Cisco Nexus 3500 Series Switches include various models such as Cisco Nexus 3048 switch, Cisco Nexus 3100 platform switches, Cisco Nexus 3100-V platform switches and Cisco Nexus 3200 platform switches. Today’s article will provide a clear description of this switch type along with the available Gigabit Ethernet transceivers.

Cisco Nexus 3500 Platform

Cisco Nexus 3500 series further extends the leadership of the Cisco Nexus 3000 series and uses the Cisco Algo Boost technology to achieve excellent Layer 2 and 3 switching. In addition, Algo boost technology offers several innovations in latency forwarding and performance visibility capabilities:

  • Hitless Network Address Translation (NAT)—In many financial trading environments, trade orders must be sourced from the IP space of the provider, requiring NAT at the border between networks. But Cisco Nexus 3500 platform can perform NAT for IPv4 unicast routed packets without incurring any additional latency.
  • Latency monitoring—The Cisco Nexus 3548x and 3524x enable users to finely control their environments to increase network performance. Customers can identify latency on a specific egress port through the command-line interface (CLI) and export this information to a file. The programmability of the Cisco Nexus 3548x allows users to use this information in real time.
  • Active buffer monitoring—Even on the lowest-latency switches, data packets can incur a millisecond or more of latency during periods of congestion. In contrast, Algo Boost accelerates the collection of buffer utilization data in hardware, allowing sampling intervals of 10 ns or less.
  • Cisco Nexus Data Broker—The Cisco Nexus 3500 platform switches with Cisco Nexus Data Broker can be used to build a scalable and cost-effective traffic monitoring infrastructure using network taps and SPAN. In addition, you can distribute these sources and traffic monitoring and analysis tools across multiple Cisco Nexus switches.

Cisco Nexus 3548 and 3524 Switches

Cisco Nexus 3548 and 3524 Switches are the two commonly used Cisco Nexus 3500 series switches. Cisco Nexus 3524 has 24 ports, while the 3548 enables the use of 48 ports. As seen in the below image, Cisco 3548 switch with 48 fixed SFP+ ports for 1, 10 Gigabit Ethernet enables the total switching capacity of 960 Gbqs. As part of the Unified Fabric Family, the Cisco Nexus 3548/3548-X Switch is well suited for mainstream top-of-rack, (ToR) data center deployments. It comes in a compact, 1-rack-unit (1RU) form factor.


Similarly, Cisco Nexus 3524 has the identical hardware as Cisco Nexus 3548. However, its software license is different from Cisco Nexus 3548 which only allows the operating of 24 ports. And its switching capacity is only 480 Gbps. If you want to active all the 48 ports of Cisco Nexus 3524, another license is required to enable the rest 24 ports.

Cisco Nexus 3548x and 3524x are the next generation switches. They keep the basic hardware structure as the previous generation, but consume 25 percent less power. They also introduce powerful hardware-based multicast NAT and latency monitoring capabilities and a second USB port for easier manageability.

Gigabit Ethernet Transceivers for Cisco 3500 Switches

Cisco Nexus 3500 series switches can support up to 40G Ethernet. For in-rack or adjacent-rack cabling, the Cisco Nexus 3500 platform supports SFP+ DAC copper cabling that combines the 10G twinax cables into an energy-efficient and low-cost solution. And for longer cable runs, multimode and single-mode optical SFP+ transceivers are supported.

  • SFP+ Direct attach copper cables on Cisco Nexus 3500 switch

Cisco has listed several 10G SFP+ copper cables that can be used on Cisco Nexus 3500 series switches: SFP-H10GB-CU1M, SFP-H10GB-CU3M, SFP-H10GB-CU5M, SFP-H10GB-ACU7M, and SFP-H10GB-ACU10M. But if you think the original Cisco switches are too expensive, you can have a look at the compatible SFP+ twinax copper cables from FS.COM. Their 10g SFP direct attach copper cables are about US $10. Here provides a table of FS.COM compatible Cisco twinax DAC cable.

Cisco SFP+ DAC cables

  • Reliable 10g SFP+ transceiver

10G SFP+ single-mode or multimode transceivers are often used to support longer-reach applications. SFP-10G-SR (up to 300m) and SFP-10G-LR optics (up to 10km) are the two common types. For longer distance than 10km, you can also use the Cisco Cisco SFP-10G-ER and Cisco SFP-10G-ZR Modules.

  • Compatible gigabit SFP optical transceiver

You can also realize the Gigabit Ethernet connectivity on Cisco Nexus 3500 switches by using the compatible gigabit SFP optical transceivers like Cisco GLC optics.


This article outlines the fiber cabling solutions for the Cisco Nexus 3500 series switches. Gigabit Ethernet transceivers as the SFP optical transceivers, SFP+ DAC cables and SFP+ transceivers from are fully compatible with the Cisco original devices. Please feel free to contact us.

Compatible Test of Cisco QSFP-40G-SR4 Optics

When purchasing the third party optics, customers usually suffer from the poor quality and compatibility issue, which is the major obstacle of OEM market. Just as a saying goes, what is good is not cheap. However, this article will prove that the cost-effective OEM optics from FS.COM are well worth the penny.

FS.COM, as a professional and reliable manufacturer and supplier of compatible optical transceiver, provides a series of self-developed products which can be highly compatible with many major brands, such as Cisco, HPE, Juniper, Brocade, Arista, etc. In this blog, we are going to present a compatibility testing of our hot-selling Cisco compatible QSFP-40G-SR4 optics on Cisco Nexus 9396PX.

Cisco QSFP-40G-SR4 Optics

Before we come to the major part, let’s have a brief overview of the 40G QSFP-40G-SR4 and the Cisco Nexus 9396PX switch. Cisco QSFP-40G-SR4 Compatible 40GBASE-SR4 QSFP+ transceiver is a short-range transceiver for 40 Gigabit Ethernet. It supports link lengths of 100m and 150m on laser-optimized OM3 and OM4 multimode fiber, respectively. Cisco QSFP-40G-SR4 enables high bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber connectors, which is also optimized to guarantee interoperability with any IEEE 40GBase-SR4 and 10GBase-SR.

Our Cisco compatible QSFP-40G-SR4 optics is fully tested with most Cisco platforms to ensure compatibility and compliance. Thus, it can be supported on a wide range of Cisco equipment, such as Cisco ASR 9000 series, Nexus 9000 series, Nexus 6000 series, and so on.

Cisco Nexus 9396PX Switch

Cisco Nexus 9396PX belongs to the Cisco Nexus 9000 series. It delivers a comprehensive line-rate layer 2 and layer 3 featuring in a two-rack-unit form factor. It can support 1/10/40 Gbps of switching capacity with forty-eight 1/10 Gigabit Ethernet SFP+ port and twelve 40 GE QSFP+ nonblocking ports. The main advantage of this switch is that you can reuse the existing 10 Gigabit Ethernet multimode cabling for 40 Gigabit Ethernet by connecting the 40Gb bidirectional transceiver. Figure 1 shows the Cisco Nexus 9396PX switch.


The Testing Procedure of the Cisco QSFP-40G-SR4 on Cisco Nexus 9396PX Switch

In FS.COM’s test center, we care of every detail from staff to facilities to ensure our customers to receive the optics with superior quality. Just take our hot-selling Cisco QSFP-40G-SR4 optics as an example, the procedure can be quite simple that can be concluded in three steps:

1. Plug the Cisco QSFP-40G-SR4 compatible QSFP+ into the 40-Gbps ports of the Nexus 9396PX

2. Plug the cleaned MTP patch cord into the optical ports of the transceivers

3. View the state of LED light and more information in the CLI.

Besides the above procedures, we also have a testing demo of QSFP-40G-SR4 Cisco compatible module testing on Nexus 9396PX.


At the end of the article, you must know the reason why FS.COM is the number one choice of compatible optical transceivers. Not only the Cisco QSFP-40G-SR4 optics, but other reliable compatible fiber optic transceivers from FS.COM are the best-seller products over the past years. If you are the major brand user like Cisco, HPE or Juniper, and want to cut down your budget this time, you might want to have a look at our cost-effective compatible fiber optic transceiver.

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