Hi,
I have two TP-Link Omada switches connected via SFP+ transceivers and an LC-LC fiber cable. Both transceivers are 10G and appear to be working.

The Switchs are:

SG3428XPP-M2 v1.20 (last public firmware version)

 

SG3218XP-M2 v1.0 (last public firmware version)

 

Switch 1 (

Te1/0/26

):

 

 

• Tx Power: 5.30 mW / -2.34 dBm

• Rx Power: 0.58 mW / -4.92 dBm

• Rx LOS: False ✅

• Tx Fault: False

• Data Ready: False

 

 

 

Switch 2 (

Te1/0/18

):

 

 

• Tx Power: 7.30 mW / -2.65 dBm

• Rx Power: 0.37 mW / -4.26 dBm

• Rx LOS: False ✅

• Tx Fault: False

• Data Ready: False

 

 

Even though Rx power is received on both sides and within correct ranges, the link does not come up at the Ethernet level (show interfaces status shows the ports as “notconnect”).

 

 

 

What I have tested:

 

 

• Cleaned fiber connectors.

• Tried swapping the LC connectors (TX/RX).

• Verified that the same transceivers and cable work when connected between another switch and the main one (connection comes up correctly).

• All ports are admin up, no shutdown.

• No forced speed or duplex config — all ports are on auto-negotiation or 10G full.

• SFP+ transceivers are TP-Link branded. (TP-Link TL-SM5110-SR Red modulo transceptor Fibra óptica 10000 Mbit/s SFP+ 850 NM)

 

 

 

 

 

What could be preventing the link from coming up, even though DDM values show that signal is present? Could this be a compatibility issue, a firmware bug, or some config I’m missing?

Thanks