Switch Power Consumption——24-port PoE Switch

Switch Power Consumption——24-port PoE Switch

Power over Ethernet (PoE) switch dramatically cuts network cost while improves power efficiency – with which network managers can get simultaneous access to both power and data over a single Ethernet cable. PoE network switches come in a host of flavors, such as 8/12/24/48-port PoE switches, or unmanaged and managed PoE switch. 24-port PoE switch is considered as a cost-effective alternative for SMB networks, for it enables enough output capacity for SMB network flow with relatively lower power consumption. As people tend to be cautious about the power consumption of network switches, here we provide some indication on 24-port switch power consumption.

What Is PoE Switch Power Consumption?

Network administrators nowadays are more inclined to incorporate PoE switch into their network, anticipating to reduce the hassle of connecting equipment to a power supply. Moreover, PoE switch also significantly decreases the number of cable needed and is ideal for network upgrade. To understand 24-port PoE network switch power consumption, let’s first get some insight into two most relevant PoE standards denoting power output: 802.3af and 802.3at. The older 802.3af provides 15.4 watts of power, serving as the standard for PoE switch, whereas the newer 802.3at standard – known as PoE+, enables up to 30 watts of power. But as we plug cable into PoE port, power losses occurs, and the level of loss heavily depends on the cable length – the longer the cable is, the more the loss can be. So the minimum output power guaranteed for PoE switch is 12.95 watts, and 25.5 watts for PoE+ switch.
24-port Switch Power Consumption: How Many Devices Can I Connect to My Switch?
To better illustrate the answer, we should first obtain some knowledge about two essential components for PoE switch:
Power Sourcing Equipment (PSE): like switches or hubs, it comes with a predetermined Total PoE Budget.
Powered Devices (PDs): these are elements connected to PoE switch, such as IP cameras, WAPs and VoIPs. They also come with a variety of different wattage demands. Note that the total sum of their demands must be less than the PSE’s total PoE budget.
So, we’ve made things clear, to define how many devices you can link to a 24-port Gigabit PoE switch, you should consider at least two factors: how much power your 24-port Gigabit PoE network switch can provide, and how much power your PoE-enabled devices need.
For a 24-port PoE switch you should look for their “PoE Budget” or “Power Dedicated to PoE” value, which is the total amount of power the switch has that can be divided between PoE devices connected to it. For instance, a 24-port PoE switch based on 802.3af has a Total PoE Budget of 300 watts. When used at full capacity, the maximum power consumption per port would be 300/24 ports or 12.5 watts per port. Since 802.af PDs offers maximum 15.4 watts of power, the remaining power will stay as unused and will not overpower PDs. To calculate how many PoE-enabled devices the 24-port PoE switch supports, simply divide the total PoE budget ( in this case 300 watts ) by 15.4 watts.

Applications of 24 Port Managed PoE Switch

Apart from segmenting your network, a 24 port managed PoE switch can also offer a broad range of options in setting up network connections. Some common applications are demonstrated as following.

Collapsed Backbone for a LAN

24 port PoE switch is a perfect choice for mixing Ethernet and Fast Ethernet installations, which paves the way for any expected future expansion. When the need occurs, just connect to another hub or switch via one of the switch’s Fast Ethernet or Gigabit Ethernet ports. The figure below shows a 24 port PoE switch operating as a collapsed backbone for a small LAN. It provides dedicated 10 Mbps full-duplex connections to workstations and 100 Mbps full-duplex connections to power users and servers. Besides, connected IP phones and wireless access points are receiving PoE power from the switch.

Remote Connections With Fiber Cable

1000BASE-LX SFP or 1000BASE-LH SFP can be used on this 24 port managed PoE switch to interconnect remote network segments, or used to create a link to other buildings in a campus setting. 1000BASE-SX SFP transceivers can be used for Gigabit fiber connections between floors in the same building. The figure below illustrates this PoE switch connecting multiple segments with fiber cable.

Making VLAN Connections

This 24 port managed PoE switch supports VLAN configurations, allowing it to organize any group of network nodes into separate broadcast domains. VLANs confine broadcast traffic to the originating group, and can eliminate broadcast storms in large networks. This provides a more secure network environment to protect your sensitive information.


24-port PoE switch, as a cost-effective choice for simplifying network deployment and maintenance, is gaining in much popularity these days. When referring to switch power consumption of this device, just take this two-step guidance: figure out the watts each PoE enabled device will use, then multiple the watts used by the amount of devices for your total watts. Remember that the total watts should never exceed the total power budget of the 24-port PoE switch.
A 24 port managed PoE switch is an optimal and future-proofing choice if you ever anticipate advanced network features to meet business growth. It perfectly fits for SMB network with its full configuration capability, advanced feature sets and improved security controls.
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