With the wide application of VoIP phones, IP cameras, and wireless access points, Power over Ethernet (PoE) has made great strides in recent years. And PoE network is expected to expand rapidly in the future due to the increasing number of IoT applications and smart device deployments and newly ratified standards designed to support more smart devices. In this article, we will provide an introduction covering various aspects of PoE such as PoE wiki, PoE standards, PoE types, PoE classes, and PoE applications.

What Is Power over Ethernet (PoE)?

PoE is a networking technology that can transmit both data and power over one single standard Ethernet cable. It allows us to use network cables such as Cat5/Cat5e/Cat6/Cat6a cables to provide data connections and electric power to wireless access points, IP cameras, VoIP phones, PoE lighting and other powered devices (PDs). With the use of PoE technology, we can easily deliver power to indoor or outdoor PDs without the need to install additional electrical infrastructure or to deploy power outlets at every endpoint.

Benefits of PoE Network—Why Use Power over Ethernet?

Besides the above-mentioned benefits, there are several more appealing reasons for adopting PoE in networking.

Time & Cost Saving: By using PoE in the network, we do not need to deploy electrical wiring and outlets for terminal PDs. This will help to save much power cabling cost especially when there are lots of PDs in the network. Furthermore, there is no need to hire a qualified electrician for the PoE network, so you may also save both time and money on electrical installations.

Flexibility: Since Ethernet network cables are easier to deploy than electrical ones, PoE networking allows us to install PDs nearly anywhere rather than near the electrical outlets. This offers a ton of flexibility for setting up and repositioning terminal devices.

Reliability: PoE power comes from a central and universally compatible source rather than a collection of distributed wall adapters. It can be backed up by an uninterruptible power supply (UPS) or controlled to easily disable or reset devices. By doing so, the PDs will run as usual even though Power Sourcing Equipment (PSE) breaks down.

Evolutionary Path of the Power over Ethernet (PoE)

Institute of Electrical and Electronics Engineers (IEEE), Cisco, and the HDBaseT Alliance have released several standards to define PoE. These standards include IEEE 802.3af, IEEE 802.3at, IEEE 802.3bt, Cisco UPOE, and Power over HDBaseT (PoH).

PoE Types

Due to different classification standards, PoE can be divided into different types. Currently, there are 4 PoE types based on IEEE PoE Standard: Type 1(IEEE 802.3af), Type 2(IEEE 802.3at), Type 3(IEEE 802.3bt), and Type 4(IEEE 802.3bt), as shown in the following chart.

PoE vs. PoE+ vs. PoE++ (UPoE )vs. PoH

PoE (IEEE 802.3af), also known as PoE type 1, provides up to 15.4 watts of power per port and is used for devices like IP phones and cameras. PoE+ (IEEE 802.3at), PoE type 2, offers up to 30 watts and powers devices like PTZ cameras. PoE++ or UPoE (IEEE 802.3bt), also referred to as PoE type 3, delivers up to 60 watts and 100 watts, PoE type 4, per port for high-performance devices. Power over HDBaseT (PoH) enables power and data transmission for AV equipment over a single cable. The figure below illustrates the common applications of different PoE types for your reference.

PoE Classes

Power over Ethernet (PoE) classes define standardized power levels for different network devices. These classes ensure compatibility between Power Sourcing Equipment (PSE) and Powered Devices (PD).

The classes, ranging from Class 1 to Class 8 as the above chart shows, correspond to specific IEEE standards, indicating the maximum power output of the PSE and the maximum power input of the PD. Let’s delve into more details about each class:

Class 1 is suitable for low-power devices such as IP phones, voice-over-IP (VoIP) devices, and basic sensors.

Class 2 is intended for devices that require slightly higher power, including wireless access points, small IP cameras, and IP intercom systems.

Class 3 is commonly used for devices that require moderate power, such as larger IP cameras, point-of-sale systems, and access control devices.

Class 4 provides increased power delivery capabilities and is suitable for power-hungry devices like pan-tilt-zoom (PTZ) cameras, video phones, and thin clients.

Class 5 introduces the support for four pairs of Ethernet wires, enabling higher power transmission. It is designed for devices with more demanding power requirements, including advanced PTZ cameras, multi-channel wireless access points, and small LED lighting systems.

Class 6 provides increased power delivery capabilities beyond the previous classes. It can support devices like high-power pan-tilt-zoom cameras, multi-radio wireless access points, and small LCD displays.

Class 7 offers even higher power capabilities introduced with the IEEE 802.3bt standard. It is suitable for devices like high-performance access points, large displays, and thin clients requiring substantial power.

Class 8 represents the highest power class defined by current PoE standards. It is designed for power-hungry devices such as video conferencing systems, advanced lighting systems, and digital signage

It’s important to note that the power levels specified for each class represent the maximum allowable values, and the actual power delivered or consumed by the PD may vary based on its specific power requirements and negotiation with the PSE. Besides, understanding PoE classes allows network administrators to ensure that the power requirements of their devices align with the capabilities of their PoE infrastructure, ensuring proper operation and avoiding potential power supply issues.

Passive PoE vs. Active PoE

Power over Ethernet can also be divided into passive PoE and active PoE in general. Active PoE is the standard PoE which refers to any type of PoE that negotiates the proper voltage between the PSE and the PD device. Passive PoE is a non-standard PoE technology. It can also deliver power over the Ethernet line but without the negotiation process.

How to Add PoE to Your Network？

The PoE supplied in the network generally comes from three different sources: PoE switch, PoE injector, and PoE splitter. The PoE switch is the easiest way to power up the PDs. You only need to run Ethernet cables from a PoE network switch port to the terminal PoE device. A PoE injector is used when there is no PoE switch in the network. It has an external power supply and is responsible to add power to data that is coming from a network switch that is not PoE-capable. PoE splitters also supply power, but they do so by splitting the power from the data and feeding it to a separate input that a non-PoE-compliant device can use. It is commonly used for deploying remote non-PoE devices with no nearby AC outlets in the network.

Common FAQs on PoE Network

Q: What is the voltage of Power over Ethernet?

A: Power over Ethernet is injected onto the Ethernet cable at a voltage between 44v and 57v DC, and typically 48v is used. This relatively high voltage allows efficient power transfer along the cable, while still being low enough to be regarded as safe.

Q: What data speed does PoE offer?

A: Generally, PoE can deliver data rates at 10/100/1000Mbps over Cat5, Cat5e and Cat6 cables. Now thanks to the widespread IEEE 802.3bt PoE standard and PoE++ technology, PoE is able to deliver speeds of 2.5 Gbps to 5 Gbps over 100m and reaches 10 Gbps in recent times.

Q: Are there any limitations of PoE network?

A: Yes, PoE network does have some pesky limitations. First, it has a restricted reach of 328 feet (100 meters) which limits the viable locations where users can operate a remote IP-enabled device. Second, a single PSE such as a PoE switch usually connects to multiple PDs. If the PSE broke down, all the PDs will stop working. Therefore, it is important to buy qualified switches from a reliable supplier. In addition, you may also consider connecting the PSE to an uninterruptible power supply system.

Q: What are PoE midspan and PoE endspan?

A: The PoE midspan is usually a PoE injector that serves as an intermediary device between a non-PoE switch and the terminal PoE-capable powered device. A PoE endspan, which is commonly called the PoE network switch, directly connects and supplies both PoE power and data to a PD. PoE endspan provides power over the data pairs, also known as PoE Mode A. PoE midspan provides power using the pins 4-5 and 7-8, also known as PoE Mode B.

Description

When working as embedded network server, Linovision LoRaWAN gateways support both sending data packets to third party MQTT/HTTP/HTTPS server or receiving the downlink commands to transfer to LoRaWAN end devices.

Requirement

• Linovision LoRaWAN Gateway: IOT-G56, IOT-G63 V1, IOT-G65, IOT-G67, IOT-G8x (Firmware version 80.0.0.64 or later)
• MQTT Server/Broker
• MQTT Client tool: take MQTT Explorer as example

Configuration

Step1. Connect gateway to MQTT broker.

Refer article How to Connect LoRaWAN Gateway to MQTT Broker？to connect gateway to MQTT broker and ensure the broker and MQTT client can receive uplinks from devices.

Step2. Send Downlink Command from Gateway

Set the gateway to send downlink commands to device directly to check if the device can receive the downlink commands and take actions.

Device EUI: the device EUI to send downlink commands

Type: downlink command type. For Linovision devices, please select hex type.

Payload: downlink command content (get from device manufacturer). For Linovision devices, please refer to downlink command contents on corresponding user guides

Port: application port of device. It is 85 by default for Linovision devices.

Confirmed: after enabled, the device will send confirmed packet back to gateway if it receives the command. If not receive, the gateway will resend the downlink command 3 times at most.

Note: for class A type devices, the gateway will add the command to queue and send it when the class A device send uplinks.

Step3. Publish Topic on MQTT Explorer to send downlink data to device. 

Set a Downlink Data topic. If you need to send MQTT downlink to specific device, please add “$deveui” on the topic.

Example: /linovision/downlink/$deveui

Publish Topic Format :

/linovision/downlink/[devEUI]

Example :

From the gateway, we can get the device EUI about the device we want to control:

So we can publish a topic on the MQTT Explorer like below:

Topic: /linovision/downlink/24e124126a148401

Format: json

Content: 

send as below format and replace the data content as downlink command

{"confirmed": true, "fport": 85, "data": "CQEA/w=="}

JavaScript

After click Publish, we can go to Network Server > Packets to check. If the gateway have subscribe corresponding downlink topic data successfully, there will be at least one grayed message packet record.

Linovision Device Command Examples

The MQTT downlink command format is fixed as below:

{
"confirmed": true,       //Set as true or false
"fport": 85,            //application port of device
"data": "BwAA/w=="    //base64 format downlink command
}

----END---

Description

When working as embedded network server, Linovision LoRaWAN gateways support sending data packets to third party MQTT/HTTP/HTTPS server. We can create a new application on gateway, which can define the method of decoding the data sent from LoRaWAN end-device and choosing MQTT data transport protocol to send data to MQTT server.

Requirement

•  LoRaWAN Gateway: IOT-G8x (Firmware version 80.0.0.64 or later), IOT-G65, IOT-G67, IOT-G56, IOT-G63 V1
• MQTT Server/Broker
• MQTT client tool: take MQTT Explorer as example

Configuration

Step1. Enable the gateway built-in network server.

Go to Packet Forwarder > General to enable the localhost server address.

Enable the Network server on Network Server > General page.

Step2. Add an Application

Go to Network Server>Applications to add a new application, click save.

Name: user-defined, arbitrary value

Description: user-defined, arbitrary value

Step3. Connect gateway to MQTT broker.

Go to Network Server > Applications to add a “data transmission” for the application. One application can add only one MQTT integration.

Fill in the MQTT broker information and create topic to store different data type, click save.

Broker Address: IP address/domain of MQTT broker

Broker Port: communication port of MQTT broker

Client ID: user-defined, a unique ID identity of the client to the server.

User Credentials and TLS should be enabled and configured as required.

Note: if MQTT broker is HiveMQ, please do enable TLS and set the option as CA signed server certificate.

After MQTT configuration complete, you can check connection status here:

Step4. Add LoRaWAN nodes to the gateway.

Go to Network Server>Profiles to add a new profile, then click save. You can also use pre-defined profiles.

Name: user-defined, arbitrary value

Max TXPower: default value

Other parameters can be checked from LoRaWAN nodes user guide or you can keep all settings by default.

Go to Network Server>Device to add a new device, click Save&Apply.

Device Name: user-defined, arbitrary value

Description: user-defined, arbitrary value

Device-Profile: choose one of corresponding profiles added before.

Application: choose one of corresponding applications added before.

Other parameters can be confirmed with the LoRaWAN node manufacturers.

When the status shows as below, that’s mean above steps are done correctly.

Step5. Add uplink data topic.

Customize the uplink data to publish to MQTT broker and save the settings. If you add “$deveui” on your topic, you can replace it as real device EUI when subscribing topics. 

Example: /linovision/uplink/$deveui

Step6. Subscribe topic from MQTT client to get uplinks.

MQTT explorer is a comprehensive MQTT client and it can be replaced to other kinds of MQTT client tools(MQTT.fx, MQTT Box, etc.)

Open the MQTT Explorer, and fill in related MQTT server information in the popup window.

Name: user-defined

Protocol: mqtt://

Host: MQTT broker address

Port: broker port

User name/Password: if there is user credentials, please fill in it. If not, keep them blank.

Click ADVANCED,copy the Uplink data topic on the gateway, and paste it on the MQTT explorer, click +ADD.

Keep MQTT client ID by default,then click BACK and click CONNECT.

After while, the data will be forwarded to MQTT broker and the MQTT Exploerer can receive the data from MQTT server.

The uplink format is fixed as json and the content is as below.

{
  "applicationID": 1,                   // application ID
  "applicationName": "cloud",           // application name
  "deviceName": "24e1641092176759",     // device name
  "devEUI": "24e1641092176759",         // device EUI
  "time": "2020-0327T12:39:05.547336Z", // uplink receive time
  "rxInfo": [                           // lorawan gateway information related to lora
    {
      "mac": "24e124fffef021be",        // ID of the receiving gateway
      "rssi": -57,                      // signal strength (dBm)
      "loRaSNR": 10,                    // signal to noise ratio
      "name": "local_gateway",          // name of the receiving gateway
      "latitude": 0,                    // latitude of the receiving gateway
      "longitude": 0,                   // longitude of the receiving gateway
      "altitude": 0                     // altitude of the receiving gateway
    }
  ],
  "txInfo": {                           // lorawan node tx info
    "frequency": 868300000,             // frequency used for transmission
    "dataRate": {
      "modulation": "LORA",             // LORA module
      "bandwidth": 125,                 // bandwidth used for transmission
      "spreadFactor": 7                 // spreadFactor used for transmission
    },
    "adr": false,                       // device ADR status
    "codeRate": "4/5"                   // code rate
  },
  "fCnt": 0,                            // frame counter
  "fPort": 85,                          // application port
  "data": "AWcAAAJoAA=="                // base64 encoded payload (decrypted)
}

FAQ

Q1.How to send decoded or customize uplink content to MQTT broker?

A1:  Yes, this needs to use Payload Codec feature on the gateway. Reference articles:

IOT-G56/G65/G67: How to Use Payload Codec on Linovision Gateway

IOT-G63 V1/G8x: How to Use Payload Codec on Linovision Gateway (Old)

Q2.What’s the troubleshooting when the status of MQTT server connection is “Disconnected”.

A2: 

1) Go to Maintenance > Tools >Ping , check if the gateway can ping to the broker address successfully.

2) Check if your MQTT client tool can connect to MQTT broker well, then follow the settings of MQTT client tool to configure the gateway.
3) Check if the gateway MQTT client ID is conflict with other MQTT clients.
4) Check if CPU load is too high, and if there is little available RAM and eMMC.
5) Change the log severity to Debug and replicate the disconnection problem, then download all log files and send them to support@linovision.com.

Q3.Why the connection status shows “connected” but MQTT client does not receive any data?
A3:
1)Ensure the devices has been added to gateway and go to Network Server > Packets to check if there are uplink packets from devices regularly.
2) Ensure the devices has been added to the correct Application.
3) Ensure the gateway firmware is upgraded to latest version. 
4) Change the log severity to Debug and replicate the disconnection problem, then download all log files and send them to support@linovision.com.

To enhance comprehension of the PoE network system, it is essential to become acquainted with the PoE devices, as the initially published IEEE802.3af standard categorized Power over Ethernet (PoE) technology into two primary types of power devices: power sourcing equipment (PSE), which supplies power over the Ethernet cable, and powered devices (PD), which receive the power. Presented below is an introduction to power sourcing equipment and a selection of frequently asked questions.

• PoE PSE (Power Sourcing Equipment): PoE PSE denotes the equipment supplying power to PoE PDs. It can take the form of a PoE switch or a PoE injector. The PoE PSE injects power into the Ethernet cable, alongside data signals, enabling connected PoE PDs to receive both power and data through a single cable. It serves as the power source for PoE devices.

• PoE PD (Powered Device): PoE PD refers to the device that draws power from the PoE network infrastructure. It encompasses various device types, such as IP phones, wireless access points, IP cameras, and network switches. The PoE PD consumes power from the PoE PSE, allowing it to operate without the need for a separate power source. Typically, it features an Ethernet input for data communication and a power input to receive power from the PoE PSE.

IOT-S300WS7 is an ultimate all-in-one RS485 Modbus weather monitoring system for various and continuous atmospheric conditions including air temperature, relative humidity, barometric pressure, light intensity, rainfall(optical), wind speed, and wind direction (ultrasonic). It boasts high resolution and accuracy with rugged and aesthetic housing.

1. Highly Integrated Design: Solar PoE Switch streamlines the installation and maintenance. Users only need to deal with one device instead of separately configuring and managing the solar controller and PoE switch, this integrated design allows for smoother energy flow within the system by optimizing the collaboration between components. From the cost perspective, purchasing a single unit is often a lower cost than buying two separate devices. Additionally, you will save on labor costs associated with installation and maintenance.

2. Compact Size: The integrated design can decrease the number of devices and overall physical size, saving space. It can eliminate the need for separate cables, power supplies, making installation and maintenance much easier. This is particularly crucial in setups with limited space.

3. Simplified Deployment and reduced system complexity: the integrated device reduces the complexity of configuring multiple components. Simplifying the device's installation process. It can decrease the technical complexity, especially for users with limited technical expertise.

1. Complexity of installation: Users would need to individually install solar power controllers and PoE switches, which could consume more time and require additional technical expertise. The configuration process may involve coordinating between different devices. Installing and managing two separate devices is more complex than installing a single integrated device.

2. Space Occupancy: Independently deployed devices typically require more space, as they cannot be integrated into a relatively compact design. This can be a challenge in applications with space constraints.

3. Technical Challenges: Configuring two separate devices may pose higher demands on technical personnel. Ensuring effective collaboration between the two systems may require additional technical expertise. Separate systems may require distinct maintenance and monitoring efforts for solar power and PoE networks. This can introduce additional complexity in troubleshooting issues and monitoring overall system performance.

4. Lack of Integrated User Experience: Users might need to deal with independently sourced devices from different vendors, potentially involving different user interfaces and some incompatible issues.