CRC errors on GigabitEthernet interface

[m4rc00]

Hi,

I would like to ask how to fix CRC errors on GigabitEthernet interface.
I have problem beetween Cisco C3750 and C2950. Th errors are only on interface on C3750. According to my knowledge CRC errors are related to Layer 1. I have changed twice fiber and gbic on both ends. I have changed port on C3750 and CRC errors are still there.

The errors disappeared when i turned on an option : speed nonegotiate on GigabitEthernet on C3750. But then i lost connection to neighbour. Please have a look at below interefaces outputs:

C3750:
sh int gi 1/0/12
GigabitEthernet1/0/12 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 001c.b032.e68c (bia 001c.b032.e68c)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 254/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX SFP
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:41, output 00:00:42, output hang never
Last clearing of "show interface" counters 2d17h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 68000 bits/sec, 11 packets/sec
5 minute output rate 358000 bits/sec, 41 packets/sec
1075176 packets input, 231153588 bytes, 0 no buffer
Received 135042 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
7863 input errors, 7863 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 108334 multicast, 0 pause input
0 input packets with dribble condition detected
3294440 packets output, 512467110 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out

and C2950 :

sh int Gig 0/1
GigabitEthernet0/1 is up, line protocol is up
Hardware is Gigabit Ethernet, address is 000a.8a7a.6b71 (bia 000a.8a7a.6b71)
MTU 1500 bytes, BW 1000000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s
input flow-control is off, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:01, output 00:00:05, output hang never
Last clearing of "show interface" counters 2d17h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue :0/40 (size/max)
5 minute input rate 337000 bits/sec, 39 packets/sec
5 minute output rate 53000 bits/sec, 16 packets/sec
3297296 packets input, 515441247 bytes, 0 no buffer
Received 2365465 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 2114605 multicast, 0 pause input
0 input packets with dribble condition detected
1084481 packets output, 231525077 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out

Could you please help ?
Thank you in advance

 

[ADB100]

I'd say either a physical problem (faulty GBIC or GBIC not inserted fully or fibre cabling) or IOS bug on the 3750. I'd reinsert the GBIC's and clear the counters and see if it solves the issue. If not replace the patch cables and if its still not fixed update the IOS on the 3750.
To be honest I'd update the IOS as a matter of course anyway.

HTH

Andy