cancel
Showing results for 
Search instead for 
Did you mean: 

Cisco SFP not connecting, shows signal, but with a fault

Cisco SFP not connecting, shows signal, but with a fault

Steve_Ballantyn
Contributor
Hello,

I have an Extreme X450-G2-48P-GE4 which I am linking to a Cisco 3750 series switch using two Cisco SFP 1000base SX modules (GLC-SX-MM). I am running ExtremeXOS version 16.1.2.14. I have no link lights, and no errors in my logs.

When I pull a debug on the port it shows signal is present, but that there is a "TX fault". I have tried increasing the debounce to 150 and then to 900, and rebooted the switch several times --- but still no connection.

Does anyone have any ideas on what I can try? I have two Extreme brand SFP's on the way, but I am trying to get this connection up in a hurry as users are anxious to get into new office space.
* X450G2-48p-G4.14 # debug hal show optic port 49
Port 49
SFP or SFP+: SFP
Signal: present
TX Fault: yes
SFP/SFP+ Vendor: CISCO-AVAGO
SFP/SFP+ Part Number: QFBR-5766LP
SFP/SFP+ Serial Number: AGS104255PX
SFP/SFP+ Manufacture Date: 061018
SFP/SFP+ Type: SFP/SFP+
Connector: LC
GE Compliance: 1000BASE-SX
Wavelength: 850
Also, I am *assuming* that the physical cable is good. But I had better be sure that it's not before I have the company come out to run a new line.

16 REPLIES 16

JeremyClarkson
New Contributor
Any update?

Not really. I had to run copper between these two switches to keep things on schedule. I'm still waiting on my reseller to get my extreme modules ordered. Their main supplier didn't have any.

Necheporenko__N
Extreme Employee
Check SFP module eeprom with command:
debug hal show optic-info eeprom port 49in a case of retrieving error these transceiver does not report for GE Compliance. As a result you cannot bring up or link the port. This is most likely a sfp module issue.

Hello Nikolay, thanks for the research on this. I have ordered two 10051H modules (Extreme branded 1000BASE-SX SFP 220/550M) and I hope to have them soon. I don't have any other Cisco modules to test with to see if one is bad.

I do have a pair of Cisco GLC-SX-MMD modules. Which technically function the same way, but have more diagnostic abilities. I had tried using these modules early on my troubleshooting and I couldn't get a link with them either. I am really hoping that it's not the fiber cable itself! I guess we will see if my Extreme modules show up and don't work. 
GTM-P2G8KFN