Powering PoE Switch From A PoE Switch: Is It Possible?

PoE (Power Over Ethernet) technology supports power and data transmission over the same Ethernet cable, which makes the cabling easier and greatly saves the space. Characterized by this advantage, PoE switch gains the popularity among many users. In practical application, we may meet some emergency, such as power failure. At this time, is powering PoE switch from a PoE switch possible? This article will discuss this topic.

Working Principe of PoE Switch

Before we come to the answer of powering PoE switch from a PoE switch, let’s learn about working principle of PoE switch. A whole PoE system consists of Powering Sourcing Equipment (PSE) and Power Device (PD). PoE switch is a type of PSE device. The PSE device not only powers Ethernet client devices, but also manage the entire Power over Ethernet process. While the PD device is PSE load which receives power, or we can call it PoE system client. The working principle pf PoE switch can be divided into five steps.

Detection: PoE switch outputs very small voltage on the port, until it detects that the PD equipment connected to the cable end supports the IEEE802.3af standard.

PD Classification: After detecting the PD, PoE switch may classify PD equipment, and assess the power loss of PD equipment.

Begin to Supply Power: In a configurable time (usually less than 15μs) start-up period, PoE switch begin to power PD equipment with low voltage, until it provides 48V DC power supply.

Power Supply: PoE switch provide stable and reliable 48V DC power for PD equipment to meet the power consumption which is less than 15.4W.

Power Off: If the PD equipment is disconnected from the network, the PoE switch will stop powering the PD equipment quickly, generally within 300-400ms, and repeat to detect whether the end of the cable is connected to the PD equipment.

Powering PoE Device From A PoE Switch

PoE switch is self-adaptive. When the PSE has the power supply requirement, the PD will output the voltage to the PSE. This means the switch can be powered by PoE while simultaneously providing power by PoE to other devices such as IP phones or wireless access points. This provides great flexibility because it means that the switch can be deployed without the constraints of an AC power outlet. As for powering PoE switch from a PoE switch, Universal PoE (UPOE) technology will be required and the following part will talk about UPOE. The following figure shows the evolution of PoE technology.

Evolution of PoE Standard

Powering PoE Switch From A PoE Switch with UPOE Technology

UPOE technology is a new innovation from Cisco Systems which happens to the industry’s first 60-watt Power over Ethernet technology. It can offer twice the power per port of the switch—providing both power and network access to a greater range of devices through a single standard Ethernet cable. This can surely help to lower the total cost of IT operations. By using UPOE technology, powering PoE switch from a PoE switch is possible. Here is an example to help you have a better understanding of this.

Most major networking vendors provide PoE Passthru, but they all require using higher powered sources. It physically would be impossible otherwise. If X is the power provided to the switch and Y is the power the switch uses, then Z is the power available for PoE devices. Then X – Y = Z. If you want Z to meet the PoE specification, then X has to be at least: Z + Y which means your input power needs to be UPOE.


As the enterprise workspace evolves with more and more end devices for communication, collaboration, security, and productivity, the need of PoE is also evolving to support newer end devices with increased power requirements. Regarded as upgrade of PoE, UPOE technology doubles the power delivered per port over PoE+ to 60 Watts which can extend resilient network power to a broad range of devices. What’s more, it realizes powering PoE switch from a PoE switch.


Introduction to 48 Port Gigabit SFP Switch

As we all know, data center cabling system consists of multiple devices, such as fiber optic transceiver, fiber optic patch cable, fiber patch panel, cable manager, and so on. As the central nerve of the whole cabling system, gigabit switch has been a topic of discussion. To satisfy different sizes of networking deployment, there are various types of Ethernet switches. This article will introduce a kind of 48 port gigabit SFP switch.

Overview of 48 Port Gigabit SFP Switch

FS.COM S5800-48F4S switch is a 48 port gigabit switch with 10gb uplink. It has 48×1GbE SFP ports and 4×10GbE SFP+ ports in a compact 1RU form factor. The switching capacity of this 48 port switch is 176 Gbps and its non-blocking bandwidth is 88 Gbps. And this gigabit switch can provide 130.95 Mpps. Meanwhile, FS.COM S5800-48F4S switch has 2 (1+1 redundancy) hot-swap power supplies and 4 (N+1 redundancy) hot-swappable fans. It is also a low latency L2/L3 Ethernet switch with 2.3us latency. The price of this 48 port gigabit switch with 10gb uplink is US$ 1,699.00. Here is a figure for you which shows front and back panel overview of FS.COM S5800-48F4S 48 port gigabit SFP switch.

front and back panel overview of 48 port gigabit SFP switch

Highlights of 48 Port Gigabit SFP Switch

The S5800-48F4S 48 port gigabit SFP switch with 10GE SFP+ uplinks comes with the complete system software with comprehensive protocols and applications to facilitate the rapid service deployment and management for both traditional L2/L3/MPLS networks. With support for advanced features, including MLAG, SFLOW, SNMP etc, this switch is ideal for traditional or fully virtualized data center. The S5800-48F4S hardware also provides high-availability features, including pluggable redundant fans and using high quality electronic components, which ensures low power consumption.

Applications of 48 Port Gigabit SFP Switch

Designed with 48×1GbE SFP ports and 4×10GbE SFP+ ports, FS.COM S5800-48F4S 48 port gigabit SFP switch can accomplish N×1G to N×1G (N≤48) connection or N×10G to N×10G (N≤4) connection. For example, in 5G to 5G connection, on one side, five 1G SFP transceivers are plugged into SFP ports on S5800-48F4S switch; on the other side, another five 1G SFP transceiver modules are plugged into SFP ports on switch, too. Then, these five SFP optical transceivers are connected by five fiber optic cables. It should be noted that the transceivers and fiber patch cables used in the link are of the same type.

Supported Accessories for 48 Port Gigabit SFP Switch

In the above part, we mention that the S5800-48F4S 48 port gigabit SFP switch can be used with SFP transceiver, SFP+ module and fiber optic cable. This part will go on introducing some support accessories for this 48 port gigabit SFP switch.

Fiber Optic Transceiver
ID Type Wavelength Transmission Distance Interface DOM Support
29838 1000BASE-SX SFP 850 nm 550 m over OM2 MMF LC duplex, MMF Yes
20057 1000BASE-T SFP 100 m over Cat5 RJ45 No
29849 1000BASE-LX/LH SFP 1310 nm 10 km LC duplex, MMF/SMF Yes
11591 10GBASE-LR SFP+ 1310 nm 10 km LC duplex, SMF Yes
11589 10GBASE-SR SFP+ 850 nm 300 m over OM3 MMF LC duplex, MMF Yes
ID Cable Length Connector Type Fiber Count Polish Type Jacket Material
21278 2 m SFP+ to SFP+ Passive Copper Cable (DAC) PVC (OFNR)
35194 3 m SFP+ to SFP+ Passive Copper Cable (DAC) PVC (OFNR)
40191 1 m LC to LC OS2 Duplex UPC to UPC PVC
40192 2 m LC to LC OS2 Duplex UPC to UPC PVC
41730 1 m LC to LC OM3 Duplex UPC to UPC PVC
40180 1 m LC to LC OM4 Duplex UPC to UPC PVC
ID Wavelength Channel Spacing Channel Bandwidth Line Type Client Port Special Port
33489 18 channels 1270-1610nm 20 nm ±6.5nm Dual fiber Duplex LC/UPC Monitor Port
43099 8 Channels 1470-1610nm 20 nm ±6.5nm Dual fiber Duplex LC/UPC Expansion Port


As the size of data center becomes larger and larger, cable density increases, too. To simplify the cabling, many data center managers prefer network switch with high density ports. The above 48 port gigabit SFP switch with 10GE SFP+ uplinks is a suitable choice for high density cabling.

A Closer Look at 100G Switch Market

To keep up with growing enterprise networks, transmission speeds and expansions in data center capacities are constantly changing, from 1G, 10G, 40G to 100G. And obviously, 100G will become the mainstream. It is said that by 2019, 100G Ethernet will make up more than 50 percent of data center fiber optic transmissions. To smoothly migrate to 100G Ethernet, 100G switch plays an important role. This article will guide you to have a closer look at 100G switch market and introduce several 100G switches.

100G Switch Market Option 1: FS.COM N8500-32C 100G Switch

The FS.COM N8500-32C switch is a 32 port 100G switch. It has 32 100GbE QSFP28 ports and can achieve 6.4 Tbps full-duplex switching capability. In addition, FS.COM N8500-32C 100G switch uses Broadcom ICOS as its operating system. Designed in a compact 1U form factor, it is ideally suited for high performance and programmable data center environments. As a 100G ToR switch, FS.COM N8500-32C 100G Ethernet switch provides line-rate, high-bandwidth switching, filtering, and traffic queuing without delaying data. Redundant power and fans along with numerous high availability features ensure that N8500-32C is always available for business-sensitive traffic. With support for advanced features, including MLAG, VxLAN, SFLOW, SNMP, MPLS etc, FS.COM N8500-32C switch is a good choice for traditional or fully virtualized data center. This 100G switch price is US$ 9,199.00.

FS.COM N8500-32C 100G switch

100G Switch Market Option 2: Dell S6100-ON 100G Switch

Dell Networking S6100-ON Switch is a 2RU high-density 10/25/40/50/100GbE fixed switch with choice of up to 32 ports of 100GbE (QSFP28), 64 ports of 50GbE (QSFP28), 64 ports of 40GbE (QSFP+), 128 ports of 25GbE (SFP28) or 128 ports of 10GbE (using breakout cable) and two fixed SFP+ ports of 10GbE/1GbE/100MbE. It provides up to 6.4 Tbps of switching I/O bandwidth (full duplex) and non-blocking switching fabric delivering line-rate performance under full load with sub usec latency. Dell Networking S6100-ON 100G switch supports Dell EMC Networking’s Open Automation Framework, providing enhanced network automation and virtualization capabilities for virtual data center environments. It is a 100G ToR switch which can provide high-density 10/25/40/50/100GbE ToR server aggregation in high-performance data center environments. This 100G switch price is US $4,717.65.

100G Switch Market Option 3: Broadcom StrataXGS Tomahawk II 100G Switch

Broadcom StrataXGS Tomahawk II switch was released on October, 2016. It supports up to 64 ports 100GE or 128 ports of 40GE/50GE with SDN-optimized packet switch engines operating at 6.4 Terabits per second. The StrataXGS Tomahawk II offers increased bandwidth capacity, scalability, and cost efficiency for mega data centers and high performance computing (HPC) environments. Manufactured in 16nm, Tomahawk II integrates 256 serdes running at over 25 Gbps, with large on-chip forwarding tables and packet buffer memory. With next generation BroadView instrumentation and control capabilities, Tomahawk II provides enhanced traffic load balancing, network visibility and control of traffic provisioning. Tomahawk II’s proven architecture and comprehensive feature-set will enable partners to develop and deploy solutions more quickly, accelerating the transition to high density 100GE interconnect.

100G Switch Market Option 4: HPE FlexFabric 5950 32QSFP28 Switch (JH321A)

The HPE FlexFabric 5950 32QSFP28 switch is a 32 port 100G switch whivh provides advanced features and high performance in a top-of-rack, data center switch architecture. It has 32 QSFP28 and 2 SFP+ ports, dual hot-pluggable power supplies and six fan trays. In addition, it can provide up to 3.2 Tbps switching capacity. This 100G ToR switch utilizes intelligent Resilient Fabric (IRF) technology which simplifies the architecture of server access networks. With ultra-low-latency, HPE FlexFabric 5950 32QSFP28 switch is ideally suited for deployment at the spine and server access layer in large enterprise data centers. This 100G switch price is US $17,037.99.


The telecom industry develops rapidly and higher bandwidth networking is a trend. The 100G Ethernet’s time will come soon and 100G switch market gradually receives much attention. This article introduce several kinds of 100G Ethernet switches and I hope it can help you choose a best network switch for your 100G networking.

Gigabit Switch Review: Ethernet Switches Recommendations

Ethernet switches, also known as network switches, serve as the brain of the whole network, especially for data center. On the market, there are various types of Ethernet switches which are designed for different requirements, such as port number, speed, managed or unmanaged. Faced with so many choices, you may get confused about which one is the best switch. In fact, not just you, there are a lot of people who don’t know how to make the choice. In the year 2017, Gigabit switch has been the hot topic at several big forums, and the question “Can you recommend a Gigabit switch for me?” frequently occurred. This article will focus on Gigabit switch review and recommend several Ethernet switches for you.

Gigabit Switch Review 1: D-Link DGS-1008G Gigabit Switch

D-Link DGS-1008G Gigabit switch has eight gigabit ports and boasts data transfer speeds of up to 2000 Mbps. It comes with QoS features, which automatically organize and prioritize important and time-sensitive data packets, ensuring efficient delivery. This feature helps enable smoother media streaming, VoIP calling and online gaming features. In addition, it utilizes D-Link’s Green Technology which allows the switch to reduce heat and use less energy. D-Link DGS-1008G Gigabit switch is a solid choice if you are looking for a fast, easy-to-use and reliable network switch.

Gigabit Switch Review 2: FS S5800-8TF12S Managed Switch

FS S5800-8TF12S switch is a 12 port smart managed switch. It is designed with twelve 10G SFP+ ports and eight 1000BASE-T/ SFP combo ports. The 1000BASE-T copper RJ45 ports support Gigabit speeds over Cat6 cable up to 100 meters, and the 1G SFP fiber ports can be connected to other devices via SFP transceivers over fiber optic cable. FS S5800-8TF12S 12 port smart managed switch is designed to support a demanding and dynamic environment of SMB networks. It is a good choice for 10G access Layer switch for hyper-converged infrastructure.

Gigabit Switch Review FS-S5800-8TF12S 12-port smart managed switch

Gigabit Switch Review 3: UniFi US-24-500W PoE Switch

UniFi US-24-500W switch is a 24 port PoE switch which comes with 24 Gigabit RJ45 ports and 2 SFP ports. Its non-blocking throughput is up to 26 Gbps and the switching capacity is up to 52 Gbps. UniFi US-24-500W PoE switchh is a fully managed Gigabit switch which can deliver robust performance and intelligent switching for networks. Besides, it offers the forwarding capacity to simultaneously process traffic on all ports at line rate without any packet loss. It is really a cost-effective PoE switch at $399.00.

Gigabit Switch Review 4: FS S5850-48T4Q 10GBASE-T Switch

FS S5850-48T4Q 10GBASE-T copper switch is a 1U managed L2/L3 Ethernet switch. It has forty-eight 10GBASE-T RJ45 ports and four 40G QSFP+ ports. And it can provide 1.28Tbps switching capacity. FS S5850-48T4Q switch is designed to meet next generation Metro, Data Center and Enterprise network requirements. For example, it can be used for Spine-Leaf network which is a popular architecture design for data center. For 1GBASE-T copper switch at lower cost, FS S5850-48T4Q switch is a great option to help you migrate to 10GbE network.


The above content Gigabit switch review has recommend 8 port unmanaged Gigabit switch, 12 port 10G smart managed switch, 24 port PoE switch and 48 port 10GBASE-T copper switch. All of them are good choices when compared with the same type of Ethernet switches. I hope this article can help you choose the best switch when you feel confused.


High speed data transmission is the prerequisite for enterprise network deployment. For big data centers, 40G is still the mainstream. For 40G network, 40 gbps transceiver and 40gb ethernet cable are important components, and they can be classified according to transmission distance. For long transmission distance, there are 40G LR4 QSFP+ transceiver and singlemode fiber cable; for short transmission distance, there are 40G SR4 QSFP+ transmission and multimode fiber cable. In addition, for 40G short link, there is QSFP+ DAC cable. Two types of QSFP+ DAC cables are available on the market: 56G QSFP+ DAC vs. 40G QSFP+ DAC, what’s the difference between them? This article will make a comparison.

56G QSFP+ DAC Vs. 40G QSFP+ DAC: Same construction

We know that DAC cable is a kind of high speed passive copper cable with one connector on each end. The connectors are not real optical transceiver modules but in the form of optical transceiver module. DAC twinax cable Therefore, QSFP+ DAC consists of two QSFP+ transceiver style connectors and one twinax copper cable. With the same construction, the operation of 56G QSFP+ DAC and 40G QSFP+ DAC in 40G network deployment is the same, too. Just plug the connector into 40G QSFP+ port on the switch on both sides, and then you can get 40G link. Here is a figure of QSFP+ DAC cable for you.


56G QSFP+ DAC Vs. 40G QSFP+ DAC: Different protocols

As qsfp+ passive copper cable, both 56G QSFP+ DAC and 40G QSFP+ DAC are QSFP MSA compliant. But 40G QSFP+ DAC supports 40G InfiniBand 8x DDR, 4x QDR, 10G/40Gigabit Ethernet, Fibre Channel, while 56G QSFP+ DAC supports 40G InfiniBand 4x FDR, 56Gigabit Ethernet, Fibre Channel. What’s the different between InfiniBand DDR, QDR and FDR? InfiniBand (abbreviated IB) is a computer-networking communications standard used in high-performance computing that features very high throughput and very low latency. It is used for data interconnect both among and within computers. InfiniBand is also used as either a direct or switched interconnect between servers and storage systems, as well as an interconnect between storage systems. And the following figure shows InfiniBand specification. We know that QSFP+ DAC cable uses four channels for data transmission. And for 40G QSFP+ DAC, it supports 40G InfiniBand 8x DDR, 4x QDR, so each channel can achieve 10G data rate; for 56G QSFP+ DAC, it supports 40G InfiniBand 4x FDR, so the maximum data rate of each channel is 14G.

InfiniBand Specification


Characterized by low Insertion loss and power consumption, qsfp+ passive copper cable is a cost-effective option for 40G data transmission over short distance. As for 56G QSFP+ DAC vs. 40G QSFP+ DAC, the only different is that the former can operate high bandwidth than the latter one. Therefore, if your network needs 40G data transmission, then 40G QSFP+ DAC cable; if you need more than 40G bandwidth, then choose 56G QSFP+ DAC.

Practical Use of PoE Technology

Now power over Ethernet switch gains great popularity among many users which utilizes PoE technology. But still some people know little about PoE technology. This article will focus on practical use of PoE technology.

Practical Use of PoE Technology: PoE switch and PoE-compatible Devices

When connected with other network devices, PoE switch will detect whether they are PoE-compatible devices and enable power automatically. Therefore, it is the simplest solution to add PoE to your network by using PoE switch and PoE-compatible devices.

Practical Use of PoE Technology: Non-PoE switch and PoE-compatible Devices

Non-PoE switch can support PoE function when connected to PoE injector by a network cable. Then PoE-compatible devices are connected to PoE injector. The whole cabling solution is completed. It is not hard to see PoE injector can be used to upgrade existing LAN installations to PoE, especially when fewer PoE ports are required.

Practical Use of PoE Technology: PoE switch and Non-PoE Devices

In this cabling solution, PoE switch has to be connected to PoE splitter which separates the data and power transmission. The PoE splitter has two output lines, one is the power output line and the other is network data signal output line. For example, you need one cat5e ethernet cable to connect PoE switch with PoE splitter, another one cat5e ethernet cable to connect PoE splitter with non-PoE device. In addition, you have to add power cable between PoE splitter and non-PoE device. Finally, the whole deployment will work.

Practical Use of PoE Technology: Non-PoE switch and Non-PoE Devices

Both PoE injector and PoE splitter are used in this cabling solution. PoE switch connects to the PoE injector, then the PoE splitter, and finally transmits to non-PoE devices. In fact, this solution makes cabling more complicated. But if you need, you can do it.

Note: To help you have a better understanding of practical use of PoE technology, the above four cabling solutions are shown in the following figure.

Practical Use of PoE Technology


PoE technology can support data and power transmission over one network cable at the same time, which simplifies the cabling process. I hope after reading this article, you can know more about practical use of PoE technology. What’s more, before you plan to use PoE, choosing quality and cheap PoE switch and network cable is important, or you may get poor network performance.

8 Port PoE Switch Recommendations

As more and more network devices are deployed in networking, the cabling becomes complicated. PoE technology, which support power and data transmission over an Ethernet cable at the same time, can simplify the cabling. And recently, 8 port PoE switch is popular with many users. This article will recommend several 8 port PoE switches for you.

8 Port PoE Switch Recommendation 1—UniFi US-8-150W Switch

UniFi US-8-150W 8 port PoE switch is a managed switch which has 8 RJ45 ports and 2 SFP ports. The RJ45 ports support 10/100/1000 Ethernet connections and PoE/PoE+ functions; the hot-swappable SFP ports support 1 Gbps connections. Besides, there is a reset button on UniFi US-8-150W switch which serves two functions for the UniFi switch: restart and restore to factory default settings. For PoE/PoE+ function, by default, PoE settings for ports are set to auto-sensing PoE+. PoE will automatically be activated on the port when an 802.3af/at device is connected. The maximum power consumption of UniFi US-8-150W switch is 150W. The price is about $199.00.

8 Port PoE Switch Recommendation 2—D-Link DGS-1210-10P Switch

D-Link DGS-1210-10P 8 port PoE switch is one member of DGS-1210 series family which are the latest generation of switches to provide PoE/PoE+ capabilities, making deployment easier. Also, it support a complete lineup of L2 features, including IGMP snooping, port mirroring, Spanning Tree Protocol (STP), and Link Aggregation Control Protocol (LACP). The D-Link DGS-1210-10P switch has eight 10/100/1000 ports and two 100/1000 SFP ports. Its switching capacity is 20 Gbps and maximum power consumption is 81.9W. The price is about $133.91.

8 Port PoE Switch Recommendation 3—TP-Link TL-SG2210P Switch

TP-Link TL-SG2210P 8 port PoE switch is equipped with 8 gigabit RJ45 ports and 2 SFP slots. And all RJ45 ports support IEEE 802.3af-compliant PoE with total power supply of 53W to power any 802.3af compliant power device. The switch provides high performance, enterprise-level QoS, useful security strategies and rich layer 2 management features. The maximum power consumption of TP-Link TL-SG2210P switch is 63.4W. It is especially designed for the small and medium business networks that require efficient network management. The price is about $131.37.

8 Port PoE Switch Recommendation 4—Netgear GS110TP Switch

Netgear GS110TP 8 port PoE switch has eight 10/100/1000 Mbps copper ports and two Gigabit SFP ports. With PoE function on eight copper ports, Netgear GS110TP switch is capable of delivering up to 15.4W of power per port, up to a maximum total of 46W across all connected PoE devices. The maximum power consumption is 59.3W. in addition, the switch comes with a comprehensive set of features, such as L2 features, enhanced VLAN and QoS, access control lists (ACL), and so on. The price is about $169.99.

8 Port PoE Switch Recommendation 5—FS S1130-8T2F Switch

FS S1130-8T2F managed 8 port PoE+ switch has eight 10/100/1000Base-T RJ45 Ethernet ports, one console port, and two gigabit SFP slots. It is compliant with IEEE 802.3af/at and can supply power to PoE network equipment. The FS S1130-8T2F switch is fanless switch and it features superior performance in stability, environmental adaptability. The maximum power consumption is 130W. The price is about $159.00.

FS S1130-8T2F managed 8 port PoE+ switch

Which One to Choose?

From the above 8 port PoE switch recommendations, we can clearly see that all these five switch have similarities and differences. For example, all of them support PoE function, but UniFi US-8-150W, D-Link DGS-1210-10P and FS S1130-8T2F support both PoE and PoE+ standard; all of them have 8 RJ45 port and 2 SFP ports, but their maximum power consumption are different. Which one to choose really depends on your specific requirements. If you need to use PoE devices with larger power consumption, UniFi US-8-150W and FS S1130-8T2F switch are good options; if your budget is tight, you can choose D-Link DGS-1210-10P, TP-Link TL-SG2210P and FS S1130-8T2F switch according to the above 8 port switch price. From the comparison, we can conclude that FS S1130-8T2F switch is a cost-effective solution which can supply higher power at lower price. I hope this article—8 port PoE switch recommendations will help you choose a suitable 8 port PoE switch for your network deployment.