Tag Archives: PoE switch

Understanding Power Consumption of PoE Ethernet Switch

As PoE changes to meet today’s increasing application requirements like IP cameras or WiFi access points, it’s widely used for enterprises networks. Using a PoE or PoE+ switch, technicians can simplify the cabling installation because the PoE technology can support power and data transmission over the same cables. When choosing a PoE Ethernet switch, we always care about the ports and power consumption most. This article will introduce the power consumption of PoE Ethernet switch and take two PoE Ethernet switches as examples to explain power consumption.

What Is Power Consumption of PoE Ethernet Switch?

At present, PoE power consumption follows two standards, IEEE 802.3af and 802.3at. The original IEEE 802.3af rules that power consumption on each port of a PoE network switch can be up to 15.4W. The updated IEEE 802.3at standard also named PoE+, which is backward-compatible with IEEE 802.3af, provides up to 25.5W of power on each port. However, because the power dissipate exists in cables, the minimum output power assured on each port for PoE switch is 12.95W, and 25.5W for PoE+ switch.

power consumption standard

Figure 1: IEEE 802.3af and IEEE 802.3at standards.

The key to successful PoE installation is to ensure that the selected power over Ethernet switch provides the necessary watts of PoE required for each device, and the total power consumption also must be guaranteed for powering all devices. Simply put, the total power consumption of all the connected devices must be controlled in the range of the PoE switch max power consumption.

How Many Devices Can I Connect to My PoE Ethernet Switches?

Power consumption of 150W and 400W are the most popular choices on the market. The following are two switches from FS, 8 port PoE switch and 24 port PoE switch, and we’ll use them to further explain the question how many devices can we connect to my PoE Ethernet switches.

PoE Ethernet switches applications

Figure 2: How many devices can be connected to a PoE switch?

How Many Devices Can the 8 Port PoE Switch Connect?

FS S1150-8T2F switch is a managed PoE+ switch. It has 8 10/100/1000Base-T RJ45 ports, and 2 Gigabit SFP slots. Its PoE standard complies with IEEE802.3af/at. And designed with a max power consumption of 150W, each port can support up to 30W power. This means the switch provides the availability of PoE on all 8 RJ45 ports, and each port can potentially power devices that are connected. From the above, we know the standard PoE can supply 15.4W power for each port, and 30W for PoE+. Therefore, this switch can simultaneously connect 8(15.4W×8=123.2W<150W) devices that use IEEE 802.3af standard, and only 5(30W×5=150W) devices that use IEEE 802.3at standard. For example, if a typical outdoor IP camera needs a PoE power of 20W, the connection of 7 typical IP cameras will require 140W of PoE power (7×20W), which is well within the power consumption of this network switch.

How Many Devices Can the 24 Port PoE Switch Connect?

FS S1400-24T4F managed PoE+ switch is designed with 24 Gigabit PoE+ ports, 1 console port and 4 Gigabit SFP ports. This switch complies with IEEE 802.3af/at with a max power consumption of 400W and 30W for each port. Through a calculation, we know the 24 port switch can connect 24(15.4W×24=369.6W<400W) devices with PoE standard at the same time, and support 13(30W×13=390W<400W) devices with PoE+ standard. And as for the same outdoor IP camera with a power requirement of 20W, the 24 port switch can support 20(20×20W=400W) cameras.

Conclusion

Knowing the power consumption of PoE Ethernet switches is very important. If you want to connect multiple devices to a PoE switch, you need to calculate the total power consumption that all the devices require, and make sure you PoE switch can provide the needed current.

How to Choose a Gigabit Network Switch?

Gigabit network switch is the most commonly used equipment in data centers. Before choosing the best network switch for the current or future network, people can type “Ethernet switch” into the online shopping site or search engine, they may find a ton of listings for switches of all kinds and price levels. It’s not an easy job to find one. Then how to choose a Gigabit network switch in order to avoid buying the wrong device or overspending needlessly?

Gigabit network switch is widely used

Figure: Gigabit network switch is widely used.

Types of Gigabit Network Switch

Gigabit Ethernet switch can be divided into unmanaged, managed and PoE categories.

Unmanaged switches use the plug-and-play design that means they only allow Ethernet devices to communicate with one another. They are shipped with fixed configuration and don’t allow any changes to this configuration. This type of network switch is normally found in home networks or small business.

Managed switches offer all the features of unmanaged switches and are capable of configuring, managing and monitoring one’s LAN. Users have greater control over how data travels over the network and decide which one has access to it.

PoE switches support electrical power and data transmission over one network cable, which will greatly simplify the cabling process. Using a PoE switch, people don’t need to worry about power outlet when deploying network devices.

Features of Gigabit Network Switch

With a network switch, users can have different networked devices on their desks as well as bandwidth-intensive applications that require high rates of data transmission and no tolerance for congestion. These switches are the basics of modern wired network. They can not only provide the connections to PCs and other devices in a wide variety of fields, but also support the cloud storage of servers. With new trends like SDN and the IoT transforming the industry, people have to get the features that they need from the switches, so that they would know which switch is the one that they need.

How to Choose a Gigabit Network Switch?

Here are the most important facts you should consider when choosing a Gigabit network switch.

  • Choose the role of the switch. If you are just looking for a device to extend your wired network at home, one unmanaged switch is suitable. And an 8 port Ethernet switch or 12 port switch is enough for home network. If you want to find a switch for a large network, you may buy one or more managed switches acting as core switches. 24 port and 48 port PoE managed switches are the right choice.
  • Choose the forwarding rate of the switch. Gigabit switches have different processing rate. Processing and forwarding data rates are very important. The processing rate becomes lower, the forwarding rate will be slower. This may make the switch unable to accommodate full wire-speed communication across all the ports. So people should figure out what forwarding rate they need before buying a Gigabit switch.

Conclusion

From the above, we know how to choose a Gigabit network switch. If you have decided to buy a network switch, welcome to visit FS.COM. FS has a good selection of 10Gb switch, 40G or even 100G switch and PoE switch for home and office users.

Can A Computer Connected to the PoE Switch?

The PoE switch is commonly used in various networks. It can be low-cost unmanaged edge switches with a few ports or complex multi-port rack-mounted units with sophisticated management. When used in small or home networks, many people may wonder if it can be connected directly with a computer. This post will discuss how to build a PoE connection between the PoE switch and the computer.

What Are PoE and PoE Switch

Before the discussion, it is necessary to have a basic understand of what are PoE and PoE network switch:

PoE

As demands for connection from networking devices such as IP phones, IP cameras and access points increase, deployment complexity and cost rise as well. For less cable usage and investment, Power over Ethernet (PoE) technology is developed to provide both data connection and electrical power to devices through just one Cat5/Cat5e/Cat6 cable.

PoE Switch

PoE switch is a network switch that has Power over Ethernet injection built-in, which can transmit both power and data through an Cat5/Cat5e/Cat6 Ethernet cable at the same time. This kind of switch makes it easy for different sectors to deploy powered devices like VoIP phones, wireless access points and IP surveillance cameras in challenging places like ceilings, walls, outdoors, or wherever electrical outlets are not easily available.

poe connection

Can A Computer Connected Directly to the PoE Switch?

As shown below,PoE switch usually have the same RJ45 port as a computer. So many people will think they can be connected directly. But do not forget that PoE switch may also transmit electrical power through the RJ45 port and Cat5/Cat5e/Cat6 cable to the computer. Then can a computer be connected directly to the PoE switch? This is largely depend on the switch you have:

poe switch

If you have a PoE switch that conforms to 802.3af (the PoE standard) or 802.3at (the PoE Plus standard) and doesn’t claim to be “passive”, you can definitely build a PoE connection between the PoE switch and the computer. This is because this kind of PoE switch has the function of PoE detection which is designed to avoid damage to non-PoE devices. In other words, when you connect other network devices to your PoE switch, it will communicate with the these devices whether they need power or not. Power is only injected if and when this negotiation is successful. Ethernet devices such as phones and access points are detected by the switch as accepting PoE and will receive the additional power feature from the PoE switch/port. Whereas a computer and other non-PoE devices will not be detected as having PoE capability and will just use the data communications features of the port.

computer connect to poe switch

However, there exists a class of PoE switches, usually referred to as “passive” or “always on”, which supply power without PoE detection. Why would anyone do this? Because this kind of PoE switch is significantly cheaper. Whether it damages your device depends on the voltage of the passive PoE switch and your devices. For a computer, it may be damaged for excessive voltage or current.

Conclusion

PoE switch is a dedicated device that contains multiple Ethernet ports to provide power and network communications. It is usually used in NVR/IP camera networks. For small or home networks, if you want to connect a computer to the PoE switch, make sure your switch follows the standard 802.3af or 802.3at PoE requirements. So can you connect a computer directly to your PoE switch?

Related Article: Using 8-Port PoE Switch for IP Surveillance

PoE in Enterprise Network

In traditional data communication network, a network connection and a power connection are required. However, with PoE technology, only the ordinary Ethernet network cable is required. PoE (Power over Ethernet) is a technology designed to allow the existing Ethernet network cable to deliver direct electrical current flows. It has a lot of advantages like lower cost, easier maintenance, less down time and great flexibility during management and network installation. A variety of products have been designed to make full use of PoE technology. This post will introduce these PoE based products and how to use them in our network.

PoE switch

PoE switch is the most important device is you are going to use PoE technology. It is the PoE switch that transmission the necessary data and power flow together to other PoE devices. Not all the devices can be powered by PoE switches, as the electrical power provided by a PoE switches is limited. For instance, the IEEE 802.3af guarantees only 12.95 W of power on a given connection. Thus, if your devices required power higher than that, then the PoE cannot work out under this standard. The power that a PoE can provide for connections differs according to the technologies. And the port type and port numbers that PoE switches provided are various. Generally, PoE switches provided in the market can provide SFP ports for uplink and RJ45 ports for downlink. Here offers several different PoE

PoE Switch Port Detail Power Supply for PoE Port Max. Power Consumption
PS130W-8 8 PoE ports, 2 SFP ports 15.4W 130W
PS250W-8 8 PoE ports, 2 SFP ports 30W 250W
PS400W-24 24 PoE ports, 4 SFP ports 15.4W 400W
PS650W-24 24 PoE ports, 4 SFP ports 30W 650W
PS650W-48 48 PoE ports, 4 SFP+ ports 30W 350W

In many public places or even our own houses, camera is installed for surveillance These cameras are usually required to be connected to the Ethernet or monitor. As the power required by camera is not high and the places they deployed are usually lack of power outlet, IP camera which supports PoE is very popular. With a RJ45 port, the PoE IP Camera can be connected to the switch for data communication. The following picture shows a Camera that support both Ethernet network cable and additional power cords.

PoE IP Camera

WiFi is necessary in most places now. In the public places like hospital, hotel, or office, wireless access points are usually installed to transfer the data from Ethernet network cable into WiFi signals. Wireless access point is usually installed on the ceiling, where power outlet seldom installed. Thus, PoE wireless access pointer is a preferred choice in most public places. As wireless access point just needs low voltage power support, the network cable is able to provide enough power that it required.

PoE wireless access point

Network Making Full Use of PoE technology

Telecommunication network using PoE technology has a wide range of applications. It is usually installed at enterprise network like office building. The following picture shows a sample of small network using PoE technology.

PoE network

An 8-port PoE switch is being used to connect devices in a small office. The eight ports of PoE switch are set into support four Non-PoE ports and four PoE port. The devices like laptop and printer required high voltage power supply is connected to the non-PoE ports for data communication. Devices like 300 Mbps wireless access point with PoE function, and two PoE IP cameras that requires low voltage power supply, are connected to PoE port of this switch for both power supply and data communication.

The using of PoE switch, camera, and wireless access point is flexible and convenience. To provide higher speed data transmission and more applications is the trend of PoE devices developing. Meanwhile, the power that these PoE switch can supply is also increasing gradually.

Related Article: Introduction to PoE Networking Architectures