Exploring PoE Watchdog: Ensuring System Reliability

Posted on Oct 13, 2023 by

In today's digital environment, monitoring systems are crucial for overseeing and protecting resources and equipment. Security camera failures can lead to lost surveillance footage, potentially causing network problems. To tackle these issues, network switch manufacturers have introduced the watchdog function. It's both a tech innovation and a vital tool for system stability.

What Is Watchdog in PoE Network?

The PoE watchdog function on a PoE network switch is a "self-healing" network feature designed to monitor the status of connected PoE-enabled devices and provide a method to reset them if they become unresponsive or malfunction. If a PoE-enabled device or Powered Device (PD) fails to respond or provides incorrect responses within a specified timeframe, the switch will automatically reset the device by cutting off and then restoring power. This process is aimed at preventing network downtime and ensuring the continued operation of connected devices.

The PoE watchdog function is particularly valuable in applications where the connected devices are critical for network operation, such as in surveillance environments. It contributes to enhancing network stability and reliability. In essence, the watchdog function acts as a guardian of network devices, ensuring their continuous operation. In environments where uninterrupted network service is essential, such as monitoring systems, the watchdog function is particularly crucial as it prevents downtime and maintains system reliability.

Why PoE Watchdog Is Used?

Ensuring Device Reliability

A watchdog helps ensure that network devices, such as network cameras or servers, operate reliably. It monitors their status and can automatically reset them if they become unresponsive or malfunction, reducing the risk of prolonged downtime.

Preventing Network Disruptions

In scenarios where network devices play a critical role, like surveillance systems or industrial applications, the watchdog prevents disruptions by swiftly addressing issues. This is essential for maintaining continuous network service.

Minimizing Manual Intervention

Without a watchdog, IT personnel might need to manually troubleshoot and reset devices when they fail. Watchdog automation reduces the need for constant human intervention, saving time and effort.

Improving System Availability

The use of a watchdog function contributes to higher system availability by reducing the impact of device failures. This is especially crucial in mission-critical environments where uninterrupted operation is paramount.

Enhancing Network Stability

The watchdog function enhances network stability by proactively monitoring and addressing device problems, preventing cascading failures, and maintaining a consistent network performance.

PoE switch

How PoE Watchdog Works in Security Surveillance?

Health Status Monitoring

The watchdog function periodically (typically in seconds) sends signals or queries to network cameras to confirm their proper operation. This signal can be a heartbeat signal or a specific request, with the purpose of verifying whether the cameras are responsive.

Timeout Setting

The watchdog function sets a timeout threshold indicating that network cameras must respond within a specified time. If a network camera fails to respond or provide the correct response within the timeout threshold, the watchdog function considers the camera to be in an abnormal state.

Issue Detection

When the watchdog function detects that a network camera fails to provide the correct response or does not respond within the specified time, it determines that the camera has an issue. This may be due to network failures, camera hardware malfunctions, crashed camera software, or other reasons.

Automatic Restart Trigger

Once the watchdog function determines that a network camera has an issue, it takes action to trigger an automatic restart. Typically, this involves sending a command to the network camera or triggering a restart switch to attempt to reboot the camera.

Restart Attempt

After receiving the automatic restart command, the camera attempts to perform a restart. This may involve reinitializing hardware, rebooting the operating system, or restarting applications, depending on the camera's design and manufacture.

Status Monitoring Reset

Once the network camera successfully restarts and returns to normal operation, the watchdog function continues to monitor its health status. If everything is functioning correctly, the monitoring continues to ensure the camera remains stable.

PoE watchdog

PoE Watchdog-Supported Switches for Network Reliability

FS offers PoE switches with watchdog functionality, such as the S3250 series. These switches are designed to enhance network reliability and stability, ensuring that your network devices remain operational and minimizing potential downtime.


Switch Model S3250-16TF-U S3250-24TF-U
Description 16-Port Gigabit Ethernet L2+ PoE+ Switch, 16 x PoE+ Ports @230W, with 2 x 1GbRJ45, 2x1GbSFP Uplink 24-Port Gigabit Ethernet L2+ PoE+ Switch, 24 x PoE+ Ports @370W, with 2 x 1GbRJ45, 2x1GbSFP Uplinks
RJ45 Ports 18x 10/100/1000BASE-T RJ45 26x 10/100/1000BASE-T RJ45
Fiber Ports 2x 1G SFP 2x 1G SFP
Switch chip Marvell 98DX225SA1 Marvell 98DX225SA1
Switching capacity 56 Gbps 56 Gbps
Forwarding rate 29.76 Mpps 41.7 Mpps
Total Number of IPv4 Routes 16 16
RAM 2 Gbit 2 Gbit
Flash memory 128 Mb 128 Mb
Latency Max: 4.28us; Min: 3.29us Max: 4.28us; Min: 3.29us
Packet buffer 12 Mbit 12 Mbit
Power supply 1 1
Fan number 1 2
Airflow Left-to-Right Left-to-Right
Max. power consumption 365W 420W
PoE standard IEEE802.3af/ IEEE802.3at/IEEE802.3bt IEEE802.3af/ IEEE802.3at/IEEE802.3bt
PoE power budget Port 1-2 ≤ 90W, Port 3-16 ≤ 30W, total ≤ 230W Port 1-2 ≤ 90W, Port 3-24 ≤ 30W, total ≤ 370W


The PoE watchdog function is an indispensable tool for ensuring network reliability and stability, playing a crucial role in both network devices and security surveillance. In the ever-evolving and digitized networking landscape, utilizing switches and devices equipped with the watchdog feature has become the optimal choice for safeguarding network stability. In addition to the aforementioned distinctive technologies, FS also offers smart PoE support, fanless designs, and high-power managed PoE switches, meeting diverse deployment scenarios in enterprises.

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