Troubleshooting Common Issues in PoE Enterprise Networks

Network users will flood IT departments with complaints when applications don’t respond or web pages load slowly. If the problem persists, staff can get frustrated or even combative. Unfortunately, the complexities of enterprise networks make resolving issues challenging, especially as infrastructures morph to address continual change. For PoE enterprise networks, troubleshooting requires a systematic approach for the best outcomes. Just as physicians have standard treatment protocols to help diagnose and treat patients, network administrators need established best practices for troubleshooting network problems to minimize downtime—a playbook that technicians can use to quickly identify issues, fix those they can, and escalate those they can’t.

A playbook should reflect the enterprise infrastructure, organizational priorities, and available tools. It should be adaptable and keep up with an enterprise network’s organic evolution and mutation. When crafting your best practices, it can help to start with the most common issues that power-over-Ethernet (PoE) enterprise networks experience. 

What is PoE?

PoE technology sends power and data over a single Ethernet cable, eliminating the need for an external power source. Typically, a PoE-managed switch, like Versa Technology’s VX-GPU2626, transmits power to connected devices while sending and receiving data from the same devices. The technology has advanced from a Cat 3 cable capable of sending 30 watts of power and megabytes of data, to a Cat 5e cable supporting 100 watts of power and gigabytes of data. These cables have quickly become an integral part of modern digital infrastructure.

PoE switches can have as many as 54 ports, allowing deployment in large network configurations. Many managed switches offer built-in tools to simplify network monitoring and management. These tools can help resolve connectivity issues, identify misconfigurations, and highlight network incompatibilities.

Physical Connectivity

When a network experiences connectivity issues, many issues could be the cause. One cause that few think to consider is the physical cabling itself. After all, if Ethernet cables have worked fine for years with minimal disruption, why would they cause issues now? 

Any time devices are added or removed from a network, there is a potential for cables to become disturbed or improperly seated. Cables could be flung over tables or left on the floor during installation, or even after. Building maintenance could accidentally run a cable over ductwork. Any of these scenarios could weaken connections and occur without IT knowing.

With centralized monitoring features, anyone can check the PoE managed switch with built-in diagnostics to confirm connections, assess cable type, and determine cable length. Cable testers can evaluate cable integrity. These tools help IT staff check connection statuses and eliminate physical concerns as a potential cause.

Device Compatibility and Power

PoE switches can support both PoE and non-PoE devices. When troubleshooting PoE devices, confirm whether devices are compliant. The Institute of Electrical and Electronics Engineering (IEEE) issues standards for identifying power requirements and data volumes. Although most standards are backward compatible, the specific device may not be.

The power source, cable, and device must align. Cat 5e cables should be used at a minimum when connecting devices. Even if not required, this step ensures continued compatibility as a network scales. Knowing that network cabling can handle more power and data demands without upgrading reduces the stress of network management.

Managed switches can monitor the power levels sent to attached devices and display the data on a central console. The power supply may be insufficient if devices are not performing as expected. Confirming the overall power budget ensures the correct configuration is in place. If the power source is not delivering sufficient electricity, a DC adapter can support the device while troubleshooting possible solutions. Adapters must provide the correct voltage to avoid damaging them.

Configurations

IT departments should check PoE-specific and network configuration settings. Misconfigurations can impact network performance as well as PoE-enabled subnetworks.

PoE Configurations 

Part of PoE deployment is determining the total power budget of a switch, and exceeding it will disrupt operations. Every device has a power requirement. Technicians should first determine the power demands for each device, then calculate the total power requirement. As an example, let’s say IT wants to deploy four big-screen monitors in a training room.  Each flat screen uses 50 watts, so the total power requirement is 200 watts.

A four-port managed switch delivering 60 watts per port would have a power budget of 240, which is certainly more than the power requirement. However, having a 10% to 20% buffer offers further protection against unexpected power draws.  At 10%, the switch in our example has some headroom, but at 20%, this configuration would be at the top of the range. Engineers should evaluate future needs to determine if a switch with more power per port is advisable.

Network Configurations 

When troubleshooting PoE issues at the network level, administrators should consider their domain name system (DNS), the dynamic host configuration protocol (DHCP), firewall settings, and traffic congestion.

DNS servers match IP addresses to domain names. When a request arrives at a DNS server, the application uses the information stored locally to resolve the name. If the data is unavailable, the request is forwarded to the next DNS server in the network. A well-managed system can respond quickly, while slower systems may time out or be unable to resolve and disrupt operations.

DHCP assigns IP addresses to network devices. It maintains a pool of assigned addresses and assigns each device a different address. Managed switches from Versa Technology support IPv6 addressing to relieve the congestion that often occurs in IPv4-only environments.

Firewall settings are always an issue in PoE enterprise networks where multiple systems must communicate seamlessly. Ensuring the PoE switch and devices are whitelisted on the appropriate firewalls minimizes possible disruptions. Also, monitoring network traffic to avoid congestion can ensure that PoE-acquired data is transmitted efficiently.

Troubleshooting Tools for PoE Enterprise Networks

Most IT departments have their preferred tools for troubleshooting. Pings help confirm devices are connected and trace routing to identify roadblocks along a communications path. Capturing data packets can help monitor traffic and identify issues like dropped or incomplete packets. Combining these tools with the built-in capabilities of Versa’s managed switches can help IT minimize disruptions from frustrated coworkers. Versa Technology is a leader in PoE solutions and offers technical support for those needing help configuring a switch.