Power over Ethernet technology connects smarter

Traditionally, devices connected to a network need to be connected via at least two types of cables. One is the Ethernet cable for transmitting data and the other is the power cable for power supply. The need for power cables has always been a limiting factor in device deployment, requiring either the device to be placed near an existing power outlet or a new power outlet to be installed near the device. Power over Ethernet (PoE) solves this dilemma and greatly improves the flexibility of deploying such devices.

PoE is a revolutionary technology that is rapidly being adopted in devices such as VoIP phones, IP video surveillance and wireless access points. Since the PoE (IEEE802.3af) standard was first released in 2003, the market has grown significantly. According to Infonetics, the number of PoE ports worldwide has grown from 25 million to 63 million from 2005 to 2010, and is expected to exceed 80 million by 2012. PoE technology provides both data transmission and power output over the same Ethernet cable, making device deployment easier and greatly reducing the need for power cables. Before the use of PoE technology, network devices required separate cables for power and data transmission. Since the devices had to be close to the power outlet, this has always been a limiting factor in device deployment.

As improvements in silicon manufacturing processes allow chips to become smaller and consume less power, the overall power consumption of Ethernet devices continues to decrease. This greatly expands the range of devices that can support PoE.

What is PoE?

PoE technology can transmit data and power on the same Ethernet cable at the same time. In an Ethernet Category 5 cable, there are four pairs of unshielded twisted pair (UTP) cables. In a typical Fast Ethernet connection, only two pairs of cables are used for data transmission (all four pairs of cables are used for data transmission in a Gigabit Ethernet connection). PoE uses two of the four pairs of unshielded twisted pairs to power the devices connected to the same cable. For Fast Ethernet, the two pairs of unshielded twisted pairs used for power are usually the two pairs used for data transmission (see Figure 1).

Figure 1: Category 5 cable supporting PoE in a Fast Ethernet environment

Power sourcing equipment (PSE), such as a PoE switch or a power sourcing equipment between a non-PoE switch and a PoE device, provides power to a powered device (PD). Powered devices (PD) include wireless LAN access points (APs), IP cameras, IP phones, PoE web broadcasts, or RFID devices. 802.3af classifies powered devices (PDs) based on power consumption to ensure that the power sourcing equipment (PSE) can effectively provide power output within the required power supply range (see Table 1).

As a power supply device, PSE has the following three functions:

Detects powered devices and determines how much power they require

Provides sufficient power as needed

Monitor and stop power supply as needed

Table 1: 802.3af device classification

Power over Ethernet Plus (PoE+)

The growing demand for PoE power from more devices has led to the development of the IEEE 802.3at (known as PoE+) standard. The higher power of PoE+ provides new possibilities for PoE powered devices. Today, PoE powered devices include pan and zoom (PTZ) cameras, video phones, high-definition displays, and low-power embedded systems. The new standard is backward compatible with 802.3af, increases the maximum available power for powered devices to 25.5 watts, and allows powered devices to negotiate their exact maximum power.

By eliminating the need for dedicated power cords and outlets, enterprises can increase flexibility in equipment deployment and provide power output to locations that were previously inaccessible to direct current (AC) power sources.

PoE Applications for Enterprises

The installation and use of PoE is growing significantly; as more powered devices enter the market, PoE will become a must-have feature for many enterprise and mid-sized business users. The following are some common PoE applications for enterprises:

Figure 2: Example of devices connected via PoE in a commercial environment

VoIP for Enterprise

Traditional private branch exchange (PBX) analog and digital phones receive and are powered by the connected phone lines, avoiding a separate AC power connection. Similarly, VoIP phones designed to transmit compressed digitized voice data over the network can also receive power output when connected to a PoE switch.

Although most VoIP phone manufacturers provide AC power adapters to power the phone, PoE is more commonly used than directly powering the IP phone. When the PoE switch used to power the IP phone is connected to an uninterruptible power supply (UPS), the power supply to the IP phone will not be interrupted even in the event of a power outage, greatly improving the reliability of the system. PoE also increases deployment flexibility, allowing IP phones to be deployed wherever there is a network connection, regardless of whether there is a power outlet nearby.

WLAN integration

In many environments, it is impractical to restrict the placement of wireless access points to those locations where AC power is nearby. Using PoE switches can reduce the cost of power installation and provide enterprises with the flexibility to deploy wireless access points based on coverage rather than power limitations.

Simple deployment of IP-based security solutions

The separate wiring and specialized features of traditional surveillance systems are not cost-effective. IP-based surveillance solutions - which use Ethernet networks to send video signals - offer enhanced capabilities, such as direct storage of recorded data on a standard PC or network storage device, remote access to recordings over any network connection, and integration with additional applications such as specialty point-of-sale (PoS) solutions.

PoE switches together with IP surveillance systems simplify installation and reduce overall costs by utilizing the same Ethernet cable to carry video data and power the camera.

benefit

In general, through PoE switches, enterprises benefit from the following aspects:

Simple deployment: Today, network devices only need to be equipped with one RJ-45 network port in hardware, and there is no need to provide different power supplies for devices sold in different regions;

Mobility and flexibility: Wireless access points and IP cameras can be deployed wherever they are needed, no matter how far away the AC power outlet is;

Reliability: When a PoE switch is connected to an uninterruptible power supply (UPS), power supply can be guaranteed even in the event of a power outage;

Cost efficiency: avoiding the time spent on installing power infrastructure and maintaining power systems;

Enhanced management: Centralized power and data management allows remote monitoring and management of wireless access points, IP cameras or other powered devices;

Summarize

PoE switches provide improvements in reliability, cost reduction, and ease of deployment for powered devices. As the power consumption of Ethernet devices decreases, more and more devices will be powered by PoE. NETGEAR's reliable, cost-effective and easy-to-use PoE switches will enable new and advanced powered devices to be seamlessly applied, saving time and money for enterprises. NETGEAR PoE switches: In short, smarter.

NETGEAR Delivers Smarter PoE Solutions for Converged Networks

No matter how big your business is, NETGEAR can always provide reliable, cost-effective and easy-to-use PoE solutions to meet the needs of converged network applications.

NETGEAR PoE Smart Switches are designed to deliver high performance, network intelligence, and reliability to enterprise networks without the huge cost or added complexity. PoE support makes it easier to install devices like IP network cameras, wireless access points, and IP phones without the need for a nearby power outlet.

NETGEAR PoE Smart Switches provide up to 30W of power based on the PoE+ standard—enough to power high-end PTZ cameras.

With NETGEAR PoE Smart Switches, businesses can simplify ordering, design, and installation. All Smart Switches have high availability and "intelligent" management features, making the switches easier to configure, monitor, and troubleshoot while maximizing uptime. Hardware stacking allows you to add more switching capacity without taking the switch offline.