How Much Do You Know About 100G DWDM Transceiver?

The pace of the development of network technology has never stopped, from Fast Ethernet to Gigabit Ethernet, 10G Ethernet, 40G Ethernet and 100G Ethernet. To keep up with the pace, many data centers has deployed 100G network. We know that there are many types of 100G transceivers, such as 100G CFP/CFP2/CFP4, CXP and 100G QSFP28. Recently, new 100G DWDM technology has been the choice for 100G network applications over long distance. There are two types of 100G DWDM transceivers—Coherent 100G DWDM transceiver and PAM-4 (Pulse Amplitude Modulation) 100G DWDM transceiver. How much do you know about them? This article is going to give an introduction to 100G DWDM transceiver.

Coherent 100G DWDM Transceiver

Coherent 100G DWDM transceiver refers to coherent CFP transceiver. DWDM CFP transceivers can achieve long-distance data transmission in applications, when previously only SR4/LR4 options were available. It is an important feature enhancement to provide DWDM connectivity in a CFP transceiver for transporting 100G traffic over long distances. What’s more, coherent DWDM transceivers cost less than ER4 and ZR4 CFP transceivers. Now on the market, there are two types: CFP DCO (Digital Coherent Optic) and CFP2 ACO (Analog Coherent Optic).

CFP DCO has a high speed DSP (digital signal processing) chip built in which makes the coherent CFP a real workhorse. The DSP provides the electronic dispersion compensation and this eliminates the need of separate DCMs (dispersion compensation modules) of CFP. As a result, coherent CFP is able to support transmission distance of more than 1000km between sites.

The available CFP2 coherent DWDM transceivers are analog. Judging from the size, CFP2 ACO is half the width of CFP. Apart from this, another difference between CFP2 ACO and CFP is that CFP2 ACO does not has a DSP. In order to take the full advantages of the coherent features, CFP2 ACO requires a separate DSP on the host board. Though the DSP increases the power consumption and cost, it means that there is no need to add DSPs to the board.

PAM-4 100G DWDM Transceiver

PAM-4, adopted by the IEEE, is expected to be the most cost-effective and efficient enabler of 100G and beyond in the data center. PAM-4 makes more efficient use of electronic and optical components by packing two bits for every symbol sent over the fiber. Single-lambda 100G PAM-4 offers the simplest architecture, lowest component count, the most streamlined data path, higher reliability and an easy upgrade path to 400G Ethernet and beyond. And it enables the lowest-cost 100G transceiver. The 100G DWDM transceiver utilizes PAM-4 solution in QSFP28 form factor. For those who want to build an embedded DWDM network, they can use this transceiver directly in the switch. It is a very simple and cost-effective solution, but there is one tradeoff: it needs amplification to get out of the blocks and dispersion compensation to go beyond 5-6km. As a result, a separate DWDM multiplexer with an amplification system and dispersion compensation is required to connect data canters together. In addition, there is one thing to note: before the QSFP28 PAM-4 transceiver is added to an existing DWDM network, the network must prepare right DCM (dispersion compensation module) and amplification system in place.


Utilizing DWDM technology in the transceiver offers a simple and cost-effective solution. For coherent 100G DWDM transceiver, it is suitable for applications which needs longer reach; while for PAM-4 100G DWDM transceiver, it meets the needs of data center operators, such as Microsoft, that intend to turn up 4Tb/s of transmission capacity in a point-to-point fashion between data centers in a 70km metro-distributed network. Which one to choose depends on the specific deployment requirements.


Introduction to Cisco Nexus 3232C Switch

It is undeniable that switch is the heart of the telecommunication network. Now is the time for 100G Ethernet network and 100G switch is widely deployed in data center. Cisco Unified Fabric family is able to get high-density, advanced programmability, low latency, workload isolation, and wire-rate layer 2 and 3 switching on a data-center-class, Cisco NX-OS operating system. This article is going to introduce one kind of this series—Cisco Nexus 3232C switch.

Overview of Cisco Nexus 3232C Switch

The Cisco Nexus 3232C switch is a 1U fixed form-factor 100G switch with 32 qsfp28 ports. Each QSFP28 port can operate at 10, 25, 40, 50, and 100Gbps, up to a maximum of 128 x 25Gbps ports. It runs the industry leading Cisco NX-OS Software operating system which provides customers with comprehensive features and functions that are widely deployed. In addition, the QSFP28 transceiver, AOC cable and DAC cable can work on its QSFP28 ports. Here is a figure of Cisco Nexus 3232C switch for you.

Cisco Nexus 3232C switch
Advantages of Cisco Nexus 3232C Switch

There are many advantages of Cisco Nexus 3232C switch which will be introduced in this part.

High-density ports: It structured with 32 qsfp28 ports. Each QSFP28 port can be configured to work as 4 x 25Gbps ports, offering deployment flexibility, with up to a maximum of 128 x 25Gbps ports.

Flexibility: The switch can be used for fiber-based network deployment and copper-based network deployment. Both fiber and copper cabling solutions are available for 10G, 25G, 40G, 50G and 100G connectivity, including AOC cable and DAC cable.

High performance and scalability: With a four-core CPU, 8GB of DRAM and 16Mb of dynamic buffer allocation, the switch is suitable for massively scalable data centers and big data applications.

Comprehensive programmability: It enables data center managers to run today’s applications while also preparing them for demanding and changing application needs such as big data, cloud and virtualization.

Applications of Cisco Nexus 3232C Switch

This part will introduce two 100G to 100G cabling solutions for Cisco Nexus 3232C switch to you.

Direct Connection for 100G to 100G

As the following figure shows, two 100G QSFP28 transceivers are plugged into QSFP28 ports on Cisco Nexus 3232C switch set on two sides. The two 100G QSFP28 transceivers are designed with 12-fiber MTP connector interface. Therefore, they can be directly connected by 12-fiber MTP trunk cable. This is the simplest way to achieve 100G to 100G connectivity.

direct connection for 100G to 100G
Interconnection for 100G to 100G

We can also deploy fiber enclosure to get higher density and make the cabling procedure more flexible. Since 1RU rack mount fiber enclosure is able to hold up to 4 MTP fiber adapter panels or 4 HD 12 core MTP MPO fiber optic plug-n-play cassettes, here we take MTP fiber adapter panel for example. From the figure below we can see that, the two 100G QSFP28 transceivers are plugged into QSFP28 ports on Cisco Nexus 3232C switch on two sides. The the 100G QSFP28 transceiver is connected to the MTP adaptor on MTP fiber adapter panel by 12-fiber MTP trunk cable. Then the two MTP fiber adapter panels installed inside two fiber enclosures respectively are connected by 12-fiber MTP trunk cable.

interconnection for 100G to 100G

As a compact 1RU form factor switch for top-of-rack (ToR) data center deployments, Cisco Nexus 3232C switch allows a smooth transition from 40 to 100G Ethernet infrastructure in data centers. It is a high quality 100G switch. I hope after reading this article, you can have a better understanding of Cisco Nexus 3232C switch.

Introduction to Server Power Cord

The power cord is an indispensable unit to support the work of power supply. Connecting the servers and PDU (power distribution unit), server power cord plays an important role in ensuring good electricity supply. However, the standard for the connector type and voltage level of power cord are different in different countries. To make the network system work with high performance level, it is necessary to choose a suitable power cord. This article will give an introduction to server power cord to help you make the choice.

Overview of Power Cord

Although there are many different types of power cords used around the word, the structures of them are similar. In general, power cord consists of three parts: plug, cord and receptacle. The IEC60320 power cord and NEMA power cord are the most commonly seen types. The former one is commonly seen in US, while the latter one is widely used in North America and other countries that use the standards set by the NEMA. The following figure shows c13 to c14 power cord, nema 5 15p to c13 power cord, c14 to c15 power cord and nema 5 15p to c15 power cord, which are the most popular one power cable manufacturers like Dell, HP and IBM.

power cord
Applications in Different Cabling System
Low Density System

For low density system, it is very easy to install the power cord. The server needs to use a country-specific power cord for direct connection to a facility AC feed. However, server availability goals can require providing redundant AC power to the server in the form of a redundant AC bus or a UPS. As the following figure shows, server in figure A uses c13 to c14 power cord, and server in figure B uses nema 5 15p to c13 power cord.

power cord in low density system
Medium Density System

For medium density system, the installation of power cord is a little complex than that of low density system. To achieve an effective power connection, different types and other accessories are may be needed. As the following figure shows, power connections are achieved using modular PDH, extension bars and c13 to c14 power cord assemblies. For server which contains hot-pluggable fans accessible by sliding the chassis out on rails, the power cord connecting to the server must have adequate length and slack to allow chassis movement while staying connected and powered up.

power cord in medium density system
High Density System

For high density system, the length of power cord can be short since cable movement is less frequent. The following figure shows three kinds of methods to connect enclosures to AC power. The first one in the upper area shows that the c13 to c14 power cord is used to connect a single-supply server to a vertical mount PDU, which is suitable for lower-density installations. The second one in the central area shows the use of C13 x4-to-C20 fixed cord extension bars, which is a recommended method for extreme-density installations using redundant power supplies. The last one shows the use of a C13 x2-to-C20 Y-cable assembly, which is recommended for connecting a server with dual 1200-watt power supplies directly to a PDU core with C19 outlets.

power cord in high density system

Power cord serves as an important bridge in the network device power supply system. I hope after reading this article, you can have a better understanding of server power cord. FS.COM offers different types of IEC power cords, NEMA power cords, and jumper cords for server rack equipment with different colors and different lengths.

Deploy 40G/100G in Your Data Center

Due to the massive amount of storage is needed for high bandwidth, the demand for higher capacity of network deployment is rapidly increasing. Obviously, the conservative 2-fiber transmission is not enough to satisfied the need. And 12 or 24-fiber 40/100G Ethernet migration is quickly becoming a hot spot. This article will provide some cabling solutions for 40G/100G cost-effective and simplified migration path in data center.

10G to 40G

Take parallel optical transceiver 40GBASE-SR4 QSFP+ for example, it is structured with 12-fiber MTP connector, so it is used with 12-fiber MTP cable (only eight fibers are used, four for transmit and four for receive). The following figure shows the simplest way for migration from 10G to 40G. We can utilize 40G MTP/MPO breakout cable which has an MTP/MPO connector on one end and four duplex LC connectors on the other end. The MTP/MPO connector end is plugged into the MTP/MPO connector interface of 40GBASE-SR4 QSFP+ transceiver, while the other end is connected with four 10G SFP+ transceivers.

10G to 40G
10G to 100G

As for migration from 10G to 100G, we can utilize 100GBASE-SR10 CFP transceiver and 100G MTP/MPO breakout cable. The 100GBASE-SR10 CFP transceiver is structured with 24-fiber MTP/MPO connector interface. When using with MTP/MPO 24 fiber cable, the 100GBASE-SR10 transceiver only uses twenty fibers, ten for transmit and ten for receive. The following shows that one 100GBASE-SR10 CFP transceiver and ten 10G SFP+ transceivers are connected by MTP breakout cable which has 24-fiber MTP/MPO connector on one end and ten duplex LC connectors on the other end. This is the simplest cabling solution for 10G to 100G connectivity.

10G to 100G
40G to 40G

For 40G to 40G connectivity, we can use 12-fiber MTP trunk cable and MTP/MPO adapter panel to connect two 40GBASE-SR4 QSFP+ transceivers. We know that when deploying MTP link, we have to take polarity into consideration. Here are two cabling solutions for you. The first one uses Type A and Type B MTP trunk cable; the second one only uses Type B MTP trunk cable.

40G to 40G
100G to 100G

For 100G to 100G connectivity, here are three cabling solutions. The first one uses two 24fiber MTP-LC fanout cables, two 12-fiber MTP trunk cables and two MTP adapter panels; the second one uses three 24-fiber MTP trunk cables and two MTP adapter panel; the third one uses two duplex LC patch cables, two MTP cassettes and one 24-fiber MTP trunk cable. However, the third cabling solution does not use 100GBASE-SR10 CFP transceiver. It deploys ten 10G SFP+ transceivers on both sides to achieve 100G to 100G data transmission.

100G to 100G

With the rapid development for data communication, the migration from 10G to 40G or 100G is inevitable. Then how to deploy 40G or 100G in data enter becomes the primary concern. All the transceivers and cabling assemblies presented in 40/100G connectivity solution are available in FS.COM.

Decoding 25G SFP28 Transceiver

The 25G Ethernet is proposed standard for Ethernet connectivity in a data center environment, developed by IEEE 802.3 task force P802.3by. According to the IEEE standards, 25G Ethernet is now defined for both single-lane and four-lane versions of 25G, such as SFP28 25G transceivers (1×25 Gbps) and QSFP 28 100G transceivers (4×25 Gbps). This article will focus on 25G SFP28 transceiver.

Overview of 25G SFP28 Transceiver

The 25G SFP28 transceiver is a high performance module which supports 25G data rate for data communication applications. It has two types: SFP-25G-SR and SFP-25G-LR. The former one is designed to use a nominal wavelength of 850nm and can operate over OM3 fiber up to 70 meters and OM4 fiber up to 100 meters. It is suitable for short-range data communication and interconnect applications. While the latter one features a highly reliable 1310nm DFB transmitter and PIN photo-detector into duplex LC connector, providing links up to 10 kilometers over single mode fiber. It is designed for long-reach applications. Here is a figure of SFP-25G-SR for you.


Cabling Solutions of 25G SFP28 Transceiver

Generally speaking, 25G SFP28 transceiver is usually used for 25G to 100G connectivity. This part will take 25G SFP28 SR transceiver for example.

Cabling Solution 1. From the figure below we can see that one 100G QSFP28 transceiver can be connected with four 25G SFP28 transceivers via the MTP LC fanout cable. This is the simplest cabling solution for 25G to 100G connectivity.

25G to 100G connectivity with MTP LC fanout cable

Cabling Solution 2. We can deploy the MTP/MPO breakout cassette to accomplish the optical link. As the following figure shows, one end of MTP trunk cable is plugged into the MTP/MPO mm connector interface of 100G QSFP28 transceiver, while the other end is plugged into the MTP port at the rear of the MTP/MPO breakout cassette. Then the LC ports in the front of the MTP cassette and four 25G SFP28 transceivers are connected by four duplex LC patch cables.

25G to 100G connectivity with MTP MPO breakout cassette

Cabling Solution 3. In addition to deploy MTP modular cassette, we can also use fiber enclosure containing MTP fiber adapter panel. In this way, the cabling can be flexible. Since the fiber enclosure can hold up to four MTP fiber adapter panels, the fiber density can be greatly improved. The cabling solution is shown in the following figure. From the left to the right, the 100G QSFP28 transceiver is connected with MPO adaptor on the MTP fiber adapter panel by MTP trunk cable. The MTP fiber adapter panel will be installed in the fiber enclosure. Then another MTP trunk cable connect the MPO adaptor on both MTP adapter panel and at the rear of the MTP cassette. Finally, the whole 25G to 100G connectivity is completed by the connection between duplex LC ports in the front of the MTP cassette and four 25G SFP28 transceivers, using four duplex LC patch cables.

25G to 100G connectivity with MTP MPO breakout cassette and MTP fiber adapter panel

Cabling Solution 4. We can replace the MTP cassette and four duplex LC patch cables with one MTP LC fanout cable. As the following figure shows, the MTP connect interface of the harness cable is plugged into the MPO adaptor on the MTP fiber adapter panel while the other end four duplex LC connector interfaces are plugged into four 25G SFP28 transceivers.

25G to 100G connectivity with MTP fiber adapter panel


By using MTP components, 25G to 100G connectivity can be accomplished with high cost effectiveness. I hope after reading this article, you can have a better understanding of 25G SFP28 transceiver as well as 25G to 100G connectivity.

Know More About 100GBASE-PSM4 QSFP28 Transceiver

There is an interesting phenomenon that multimode fibers are more expensive than single-mode fibers but the transceivers are the reverse. That is because the multimode core diameter is large and easy to align with VCSEL lasers and detectors while the single mode fiber cable is very hard to build and align transceiver components with and requires very expensive alignment equipment. Therefore, multi-mode transceivers are less expensive than single-mode transceivers. Now the 100G Ethernet network has been widely applied in data centers and there are various types of 100G fiber optic transceivers available on the market. Is there a type of 100G single-mode transceiver which can provide a low-cost solution for long-reach data center optical interconnects? The answer is Yes. The 100GBASE-PSM4 (parallel single-mode 4-lane) QSFP28 transceiver can do that.

Overview of 100GBASE-PSM4 QSFP28 Transceiver

The 100GBASE-PSM4 QSFP28 transceiver supports 100G link over eight single-mode fibers (four fibers for transmit and four fibers for receive) with data transmission distance up to 500 meters. It uses four parallel lanes for each signal direction and each lane carries 25G optical signal. In addition, the 100GBASE-PSM4 QSFP28 transceiver is structured with MTP/MPO interface, so it is usually used with single-mode fiber ribbon cable with MTP/MPO connector.

100GBASE-PSM4 QSFP28 transceiver
Working Principle of 100GBASE-PSM4 QSFP28 Transceiver

The figure below shows the working principle of the 100GBASE-PSM4 QSFP28 transceiver. The transmitter side accepts electrical input signals compatible with common mode logic (CML) levels, wile the receiver side converts parallel optical input signals via a photo detector array into parallel electrical output signals. The receiver module outputs electrical signals are also voltage compatible with CML levels. All data signals are differential and support a data rate up to 25Gbps per channel.

working principle of 100GBASE-PSM4 QSFP28 transceiver
Applications of 100GBASE-PSM4 QSFP28 Transceiver

The 100GBASE-PSM4 QSFP28 transceiver can be used for 100G to 100G connection. As the following figure shows, two 100GBASE-PSM4 QSFP28 transceivers are plugged into Host IC, then these two transceivers are connected by MTP/MPO patch cord and MTP/MPO patch panel.

100G to 100G connection with 100GBASE-PSM4 QSFP28 transceiver

From an optical transceiver module structure viewpoint, PSM uses a single uncooled CW laser which splits its output power into four integrated silicon modulators. Therefore, the 100GBASE-PSM4 QSFP28 transceiver can be used for 100G to 4x25G connection. As the following figure shows, the 100GBASE-PSM4 QSFP28 transceiver and four 25G-LR SFP28 transceivers are connected by MTP-LC breakout cable.

100G to 4×25G connection with 100GBASE-PSM4 QSFP28 transceiver

The 100GBASE-PSM4 QSFP28 transceiver meets the requirement for low-cost 100G connections at reaches of 500 meters in applications that fall in between the IEEE multi-wavelength 10 kilometers 100GBASE-LR4 single-mode fiber approach and its multimode-fiber based 100GBASE-SR10 short reach specifications. It can support a link length of 500 meters over single mode fiber cable, which is sufficient for data center interconnect applications.