How to use an SFP in Ubiquiti switches

When you're setting up a UniFi network and need to push data over longer distances or want to maximize your switch's capabilities, plugging in a fiber module, aka an SFP, might be your best move. SFP stands for Small Form-factor Pluggable.

You’ll find SFP ports on most UniFi switches, especially those with higher throughput and multi-site networking in mind. If you've ever looked at the back of your switch and wondered what those small rectangular ports next to your RJ45s are, yep, those are SFP ports.

Let’s walk through how you can use them effectively.

Let's dive in !!

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What is an SFP and why use it?

At its core, an SFP port gives you flexibility. You can use copper-based SFPs if you’re just looking to extend a regular ethernet run using CAT6 over longer distances. But the real magic happens with fiber SFPs. They let you run data over hundreds of meters, even kilometers, depending on the type of fiber you use. This is a game-changer in environments like office buildings, warehouses, or when you’re trying to link two switches between floors or across buildings.

Choosing the right SFP module

Ubiquiti sells its own line of SFP modules that are guaranteed to work with UniFi switches. Here's a quick breakdown:

• Ubiquiti UF-MM-1G: Multi-mode, 1 Gbps, up to 550m
• Ubiquiti UF-SM-1G-S: Single-mode, 1 Gbps, up to 3 km
• Ubiquiti UF-RJ45-1G: RJ45 copper SFP for 1 Gbps over standard Ethernet

Most UniFi switches are not picky, but to avoid headaches, it's safest to go with Ubiquiti-branded SFPs. If you do go third-party, make sure they are labeled as “compatible with Ubiquiti” or risk them not being recognized by your switch.

Fiber types: Multi-mode vs. Single-mode

Here’s where it gets important: matching the fiber type to your SFP module.

• Multi-mode (MM): Shorter runs, usually up to 500 meters. Uses orange or aqua-colored cables. Ideal for internal building links.
• Single-mode (SM): Long-distance runs, several kilometers. Uses yellow cables. Perfect for connecting different buildings or distant network nodes.

Match the module to the cable type. Don't mix SM with MM unless you're into network issues and long debugging nights.

Installing the SFP module in a UniFi switch

This part is very straightforward:

1. Power off the switch (optional but safer).
2. Insert the SFP module gently into the SFP port until it clicks.
3. If using fiber, plug in the fiber cable. For RJ45 SFPs, plug in your CAT6/7 cable.
4. Power the switch back on.

Your UniFi Controller will pick it up like any other port. You’ll see the SFP port show up in the controller dashboard, and you can monitor link speed, usage, etc.

Configuring the port in the UniFi Controller

When the module is recognized, you'll find it listed among your switch ports in the UniFi dashboard. Click the port to manage its settings. Here you can:

• Enable or disable the port.
• Change port profile (VLAN tagging, trunk/access).
• Monitor throughput and errors.

UniFi OS is pretty good at detecting link speed automatically, especially if you're using Ubiquiti modules. Still, it's a good idea to verify that you're getting the expected speeds.

Troubleshooting tips

If you don't see a link light or the port doesn't show in UniFi:

• Make sure your fiber cables are clean and undamaged.
• Check that both ends (switch A and B) use the same SFP type.
• Use the correct cable type (MM with MM, SM with SM).
• Reboot the switch and re-seat the module.

Sometimes the issue is as silly as a reversed LC connector. Try flipping the ends.

Using SFP+ for 10G connections

For higher bandwidth needs, UniFi offers SFP+ ports (10 Gbps). The logic is the same as regular SFPs but with 10x the speed. Just ensure you're using SFP+ modules like the UF-MM-10G or UF-SM-10G and that the switch port is SFP+ compatible.

Note: Don’t put an SFP (1G) module in an SFP+ port unless the switch explicitly supports it. Some UniFi switches are okay with it; others won’t link.

Typical use cases

• Linking switches across long distances in warehouses
• Connecting server racks in different rooms
• Backhauling a rooftop AP setup
• Using a copper SFP to convert a fiber switch port to RJ45 in a pinch

Final thoughts

Using SFP modules in your UniFi switches isn't just for enterprise setups. Even in a solid home lab or small office, it gives you flexibility and scalability. Whether you’re looking to tidy up your cabling, push more data across floors, or just like the idea of fiber, an SFP port is your friend.

And if you’re looking to scale smartly, we’ve got you. At Unihosted, we manage UniFi controllers for teams who want hassle-free, cloud-based network management. If you're planning to expand your setup and need someone to keep the backend tight, we’re here to help.