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. For applications of PoE switch, you can read this article: Using PoE Switch for Different IP Camera Systems

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.

Deploy Network in A New House

Network has changed our lifestyle and it has become an important part of our daily life. Therefore, home network deployment is a very common project. When it comes to the components required for the network deployment, many people would say Ethernet cable and router, without hesitation. However, when you start the project, you will find it is not that simple. To deploy network in a new house, future-proof cabling and cost-effective components are two essential elements. And this article will share some tips with you based on these two elements.

home network deployment

Run Conduit

We know that conduit can protect cable from damage, in addition, it will allow you to pull new wiring in the future. No matter what wires you require in the future, you can easily replace them. Remember to run more conduit than you think you need. Run conduit to every room. Typically, run it to whichever wall you’re thinking of placing your equipment. Also, run it to locations in hallways and on floors where you may place future routers/access points for wireless networking. You will find that Power over Ethernet is useful for this.

Cat6 Cable Is Fine

For Ethernet cable, Cat6 cable is fine for all current standards unless you have a giant mansion. Cat6 cable is a standardized twisted pair cable for Ethernet and it is backward compatible with the Cat3, Cat5 and Cat5e cable standards. In addition, Cat6 cable provides performance of up to 250 MHz and is suitable for 10BASE-T, 100BASE-TX (Fast Ethernet), 1000BASE-T/1000BASE-TX (Gigabit Ethernet), and 10GBASE-T (10-Gigabit Ethernet). For transmission distance, Cat6 cable can reach 100 meters for slower network speeds (up to 1,000 Mbps) and higher network speeds over short transmission distance—it can achieve only 55 meters at the speed of 10 Gbps and 33 meters in high crosstalk conditions. You only need Cat6a cable if you plan to run cable at 10 Gbps and longer than 55 meters (180 ft). Also, remember to have “extra” cables which will save you enormous hassle and expense.

Dual Band Router Will Be Better

We know that wireless network utilizes either 2.4 GHz frequency band or 5 GHz frequency band. The 2.4 GHz wireless network covers a larger range than 5 GHz wireless network, but 5 GHz band can provides faster speed. In wireless home network, many older Wi-Fi devices do not support 5 GHz band. It is not difficult to find that 2.4 GHz and 5 GHz have their own advantages. As a result, dual band router will be better for your home network deployment.

Utilize PoE

If you want to set up multiple access points and IP cameras, PoE technology is a good option which can realize the power and data transmission over the same Ethernet cable at the same time. PoE devices utilize the original PoE standard, IEEE 802.3af, which provides up to 15.4W of DC power to each device. In addition to wireless access point and IP camera, there are some other PoE devices on the market, such as IP phone and PoE switch.

PoE technology


In fact, once you have decided to deploy network in your new house, there will be a lot of things that you have to think about, such as which type conduit to run, how long cable to buy, where to place the router, how many access points to set up, which kind PoE switch to buy, and so on. But there is another important thing that you must pay attention to, that’s where to buy what you need. FS.COM can provide you high quality products at low price, such as 305 meters (1000 ft) is US$ 120.00, 8 port PoE switch is US$ 159.00. For more details, you can visit our site.