Extending PoE Range for Meraki MR86 Deployments: Media Converters and Power Injectors

When deploying Meraki MR86 access points (APs) across large areas, such as train platforms, the standard Power over Ethernet (PoE) distance limitation of 100 meters can become a significant hurdle. This article explores the use of media converters and PoE injectors to overcome this limitation and ensure optimal performance for your wireless network.

The Challenge: PoE Distance Limitations

Standard Ethernet cables and PoE have a distance limitation of 100 meters (328 feet). Beyond this distance, signal degradation can lead to unreliable connectivity and reduced performance. For deployments spanning hundreds of meters, like the 320m train platform mentioned, alternative solutions are necessary.

Solution 1: Media Converters and PoE Injectors

One approach is to use media converters in conjunction with PoE injectors. This involves converting the copper Ethernet signal to fiber optic, transmitting it over a longer distance, and then converting it back to Ethernet with PoE at the AP location.

• Media Converter: A device that converts Ethernet signals to fiber optic and vice versa.
• PoE Injector: A device that adds power to the Ethernet cable, allowing the AP to receive both data and power over a single cable.

How it Works:

1. The Ethernet cable from the switch connects to a media converter, which converts the signal to fiber optic.
2. Fiber optic cable runs to the location near the Meraki MR86 AP.
3. At the AP location, another media converter converts the fiber optic signal back to Ethernet.
4. A PoE injector then adds power to the Ethernet cable, which connects to the AP.

Benefits:

• Extends the distance beyond the 100-meter PoE limit.
• Fiber optic cable is less susceptible to interference than copper.
• Allows for flexible placement of APs.

Considerations:

• Requires two media converters and a PoE injector per AP.
• Adds complexity to the network design.
• Need to think about providing AC power to the media converter and PoE injector at the AP location.

Solution 2: Meraki MS120-8LP Switches

Another option is to strategically place Meraki MS120-8LP switches along the deployment path. These switches can regenerate the Ethernet signal and provide PoE to multiple APs, effectively extending the network's reach.

Benefits:

• Regenerates the Ethernet frame, ensuring signal integrity over longer distances.
• Provides PoE to multiple APs from a single switch.
• Simplifies the network design compared to individual media converters and PoE injectors.
• Can be placed in a vandal-proof enclosure for added security in public areas.

Considerations:

• Requires AC power at the switch location.
• May not be suitable for deployments where APs are spread out in a very linear fashion.

Choosing the Right Solution

The best solution depends on the specific requirements of your deployment.

• For very long, thin deployments, media converters and PoE injectors might be more suitable.
• For deployments where APs can be clustered, MS120-8LP switches offer a more streamlined approach.

Important Considerations

• 2.5G vs. Gigabit: While the MR86 supports 2.5 Gigabit Ethernet, using a Gigabit PoE injector may not significantly impact performance in most scenarios.
• Ruggedized Equipment: For outdoor deployments, consider using ruggedized media converters and PoE injectors that can withstand harsh environmental conditions.
• Power Requirements: Ensure that the PoE injector provides sufficient power (802.3bt) to the MR86 AP to support both 2.4 GHz and 5 GHz radios. Consult the MR86 Datasheet for detailed power specifications.
• 10GBASE-T Limitations: Keep in mind that 10GBASE-T (copper) is also limited to 100 meters, so it cannot be used to extend the distance beyond this limit.

Conclusion

Extending PoE range for Meraki MR86 deployments requires careful planning and the use of appropriate equipment. By understanding the limitations of PoE and exploring solutions like media converters, PoE injectors, and strategically placed switches, you can design a robust and reliable wireless network for even the most challenging environments.