Cisco 2960S and Cisco 4912 (CatOS) FCS errors

[ispukrsat]

The switches are connected by an optical patch cord. When transmitting data, errors increase on port 4912. Setting the speed and duplex on auto-negotiation or without auto-negotiation - the result is the same. The same cisco 2960S in conjunction with other models (3560G, 3750G - IOS) works correctly without errors. The problem is in CatOS?

These are the ports in 4912. Тhere are errors - cisco 2960, no errors - 3560

[Reza Sharifi]

Cat OS is at least 20 years old. You may want to upgrade to a newer version of IOS.

HTH

[MHM Cisco World]

if the error in one port then we can think that this issue of cable or NIC but 
four port same issue ?
can we see 
show interface for one port 

[ispukrsat]

Yes, 2960 was recently turned on in these four ports, 3560 and 3548 were turned on in the remaining ports, they have been working for a long time, there have never been any errors.

[Leo Laohoo]

Post the complete output to the command "sh interface <PORT>".  I want to see the output from both switches.

[ispukrsat]

Сisco 4912

4912

Cisco 2960 (port 2/10)

2960

[Leo Laohoo]

BX optics on one side and LH optics on another ... I hate to ask the next question:  What is the distance between the two optics?

[ispukrsat]

Distance "between two optics" 300 meters. If the same modules are included in 3560 instead of 2960, there are no errors.

[Leo Laohoo]

---

@ispukrsat wrote:
Distance "between two optics" 300 meters.

---

Ok, that confirms the BX module has burnt out the optics of the LH.  

[ispukrsat]

This is how cisco defines the modules, they are 3km on both sides. And why does the same "burnt" link work with the same 4912 on the one side and 3560 on the other side? 

sh interfaces transceiver on cisco 2960:

on 4912 can't see levels

[Leo Laohoo]

It would be "ok" if both ends were LH optics.  Instead, with a distance of 300 metres, one is BX and another is LH. 

BX is too strong for that distance.  The LH optics is good as gone.