On a UniFi Switch Pro Max 24 PoE, the LEDs give the first answer. Ubiquiti's LED article says the Speed/Link/Act LED is off for no link, amber for a link at 10 or 100 Mbps, flashing amber for activity at those speeds, green for a link at 1000 Mbps and flashing green for activity at 1000 Mbps; on multi-gig ports check the port state in the Network application, since the switch has 2.5 GbE ports and SFP+ ports.
The checks in more detail
An amber port where you expect a faster link points to a poor cable, a damaged pair or a slow device at the far end. Replace the cable first, use Cat6 or better for multi-gig, and try another port. Retailer listings describe the Switch Pro Max 24 PoE as a Layer 3 switch with 24 2.5G ports, two SFP+ ports and a 400 W PoE budget. If a PoE device is slow or dropping, check the PoE budget in the application, because a switch that runs out of budget stops powering devices.
Check for a network loop, which Ubiquiti lists in its connectivity article, and that spanning tree is not blocking a port. Check VLAN tagging on the port and the network override. Look at port statistics for errors, which point to a bad cable or a duplex problem. Test with a laptop to prove the port and cable, and update firmware. Keep a port map of the switch showing which device is on which port, its VLAN and its PoE draw.
A slow port then becomes a quick lookup, and you can see at a glance which ports are on tagged VLANs. Test a slow link by moving the cable to a neighboring port, and by connecting a laptop with a short known-good patch cable, which separates the switch from the run. On a Layer 3 switch, check inter-VLAN routing is done by the gateway or by the switch as you intended, since a mistake here can send traffic the long way and look like a slow link.
Differential
Likely causes of “Ubiquiti UniFi Switch Pro Max 24 PoE Ethernet link is limited to 100 Mbps or disconnects”, and how to tell them apart
- 1
A bad cable
What separates it The port shows amber because the cable is poor
How to confirm Fit a new cable and see whether the port light turns green
- 2
An under-rated cable
What separates it Multi gigabit speed is not reached because the cable is not rated for it
How to confirm Use a Cat6 cable or better, which can carry multi gigabit speeds
- 3
A network loop
What separates it Traffic slows or fails because a loop exists in the network
How to confirm Break the loop by unplugging the cable that joins the switches in a ring
- 4
Wrong VLAN tagging
What separates it The device is given the wrong address because the port's VLAN tagging is wrong
How to confirm Correct the port's tagging so the device joins the right network
- 5
PoE budget exhausted
What separates it Devices drop because the PoE budget of the switch has been used up
How to confirm Check the PoE budget in the application, and reduce the load on the switch
Before you touch a setting
Record this first — changing settings destroys the evidence
- The port LED color and statistics
- The types of cable that are in use on the affected ports
- The PoE budget and the load on the switch
- The VLAN settings on the port that is slow
Try in this order
0 of 7 completedRead the port LED
ReversibleLook at the port light: green is a 1000 Mbps link, amber is 10 or 100 Mbps.
Replace the cable
ReversibleReplace the cable with Cat6 or better, since older cables cannot carry multi gigabit speeds.
Try another port
ReversibleMove the cable to another port on the switch to rule out damage to the original port.
Check port statistics
ReversibleCheck the port statistics in the application, and look for errors on the affected port.
Check for loops
ReversibleCheck for loops in the cabling, and look at the spanning tree settings on the switch.
Check VLAN tagging
ReversibleCheck the VLAN tagging on the port, since wrong tagging can send traffic to the wrong place.
Check the PoE budget
ReversibleCheck the PoE budget in the application, to see whether it is close to being used up.
Model-specific
What is true of this model and not of its siblings
- Model this page covers
- UniFi Switch Pro Max 24 PoE. Ubiquiti's help articles apply to all UniFi switches; the notes name what is specific to this rack switch.
- Ports
- Check techspecs.ui.com for the exact port and PoE specifications of the Switch Pro Max 24 PoE.
- Rack
- The switch is rack mounted.
- Tools and supplies
- An Ethernet cable rated Cat6 or better, a paperclip or pin for the Reset button, the UniFi mobile app, a laptop for testing ports and a pen and paper for the model, MAC address and serial number. No screwdriver is needed and the switch should not be opened.
- Repair cost
- Restarts, resets and settings changes cost nothing. UniFi hardware is replaced rather than repaired: Ubiquiti's warranty page gives a two-year warranty for products bought from its own webstore, help.ui.com routes in-warranty replacements through its RMA portal, and UI Care extends hardware coverage up to five years. Reference list prices from Ubiquiti's store and retailer listings: Dream Machine Pro $379, Dream Machine SE $499, Cloud Gateway Ultra $129, U7 Pro $189, U6 Pro $159 and Switch Pro Max 24 PoE $799. A bad cable or a provider fault costs the same whichever UniFi device you own.
Stop boundary
When this stops being a self-service repair
- !If a good cable and port stay slow, RMA the switch under warranty
- !If a loop is suspected, disconnect suspect cables
- !If PoE runs out, move devices or add power capacity
Evidence ledger
Sources behind this answer
Where the manufacturer's article stops. The figures and steps on this page are Ubiquiti's own, and the prices are its published list prices. Replacement prices are Ubiquiti store list prices and vary by retailer.
White, blue and port LEDs.
Cables, ports and RMA.
LED states, IP address checks and TCP 8080.
Update Manager, auto-updates and update troubleshooting.
The company and its products.
Exact questions
Common questions
What does an amber light on a switch port mean?+
Amber on a port means the link has negotiated only 10 or 100 Mbps.
What does green mean?+
Green on a port means a gigabit, 1000 Mbps link.
What are the port speeds?+
Retailers list the port speeds as twenty four 2.5G ports and two SFP+ ports.
What is the PoE budget?+
Retailers list the PoE budget as 400 W, which is shared across all of the ports.
Can a loop cause slowness?+
Yes, a loop can cause slowness, since traffic circles round the network.
Can a bad cable cause errors?+
Yes, a bad cable can cause errors and slow speeds on a port.
Does VLAN tagging matter?+
Yes, VLAN tagging matters, since a device may get the wrong address or none.
What does a steady white light mean on the switch?+
A steady white light means the switch is ready for adoption in the Network application.
What does a steady blue light mean on the switch?+
A steady blue light means the switch has been adopted and is in its normal operating mode.
What does an off light mean on the switch?+
An off light means the switch is offline, so check the power, the PoE and the Ethernet cables.