04-24-2013 07:25 PM - edited 03-07-2019 01:01 PM
Guys,
I see many crc errors on the interface, how will I face and resolve this issue? Is there any initial fault isolation that I must do? Sometimes crc errors occur on the GigE interface. Thanks.
FastEthernet0/13 is up, line protocol is up
Hardware is Fast Ethernet, address is 0004.4d27.66cd (bia 0004.4d27.66cd)
Description: EDL-P-Box-NO-4
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 250/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not set
Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 18:52:43, output 00:00:01, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 12000 bits/sec, 6 packets/sec
5 minute output rate 24000 bits/sec, 6 packets/sec
14488019 packets input, 2783320210 bytes
Received 345346 broadcasts, 0 runts, 0 giants, 0 throttles
261028 input errors, 259429 CRC, 1599 frame, 0 overrun, 0 ignored
0 watchdog, 84207 multicast
0 input packets with dribble condition detected
19658279 packets output, 3529106068 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Solved! Go to Solution.
04-24-2013 08:19 PM
Hello, please manually set both sides to 'speed 100' and 'duplex full' if its still occurring, here's reference to Cisco's document:
1. Use the show interfaces ethernet exec command to determine the status of the router's Ethernet interfaces. The presence of many CRC errors but not many collisions is an indication of excessive noise.
2. Check cables to determine whether any are damaged.
3. Look for badly spaced taps causing reflections.
4. If you are using 100BaseTX, make sure you are using Category 5 cabling and not another type, such as Category 3.
I believe Cat6 should be fine too
http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1904.html
http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00801f5d9e.shtml
Hope this helps
Sent from Cisco Technical Support iPhone App
04-24-2013 08:51 PM
HI Josiah,
Usualy CRC error will not be bcz of link/bandwidth utilization.
CRC errors are mainly Layer-1 issues, hence I would request you to check the
following physical connectivities:-
1- Kindly change the cable connecting between these ports.
2- Clear the counters and unshut the ports.
3- If possible can you try swapping the ports between switches?
4- I believe speed/duplex setting are same both the ends.
HTH
Regards
Inayath
04-24-2013 07:38 PM
check the port speed, duplex settings and the physical cable. there might be speed and duplex mismatch. is this port connected to another switch or any networking equipment or just to an endpoint? if this connected to another switch or router, ensure that speed and duplex setting are matching. please check the physical cable also.
04-24-2013 07:56 PM
What could be the preferred cable type that supports 100M full duplex?
04-24-2013 08:17 PM
hi Josiah,
CRC errors and/or late collisions can be caused by a duplex mismatch. When one site of a link is configured on full-duplex and the other on half-duplex you will see the CRC errors at the interface which is configured on full-duplex.
This problem occurs also when one site of a link is configured on auto-duplex and the other fixed (full-duplex).
Duplex mismatches caused very big performance problems, so be very sure both sites of a link are configured the same.
Regarding the cables;
https://learningnetwork.cisco.com/thread/47405
HTH
REgards
Inayath
*Plz rate all usefull posts.
04-24-2013 08:19 PM
Hello, please manually set both sides to 'speed 100' and 'duplex full' if its still occurring, here's reference to Cisco's document:
1. Use the show interfaces ethernet exec command to determine the status of the router's Ethernet interfaces. The presence of many CRC errors but not many collisions is an indication of excessive noise.
2. Check cables to determine whether any are damaged.
3. Look for badly spaced taps causing reflections.
4. If you are using 100BaseTX, make sure you are using Category 5 cabling and not another type, such as Category 3.
I believe Cat6 should be fine too
http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1904.html
http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00801f5d9e.shtml
Hope this helps
Sent from Cisco Technical Support iPhone App
04-24-2013 08:24 PM
Is it possible that CRC errors may occur if bandwidth is highly utilized?
04-24-2013 08:51 PM
HI Josiah,
Usualy CRC error will not be bcz of link/bandwidth utilization.
CRC errors are mainly Layer-1 issues, hence I would request you to check the
following physical connectivities:-
1- Kindly change the cable connecting between these ports.
2- Clear the counters and unshut the ports.
3- If possible can you try swapping the ports between switches?
4- I believe speed/duplex setting are same both the ends.
HTH
Regards
Inayath
04-25-2013 04:06 PM
reliability 250/255, txload 1/255, rxload 1/255
Gotcha!
Fix could be as easy as replacing the cable.
Can you also tell us what exactly is the switch model?
04-25-2013 08:19 PM
with 250/255 reliability, what does it tells?
04-25-2013 08:24 PM
Reliability must ALWAYS be 255/255. Either values should never be lower.
This means you have a faulty cable. I can't give you any details unless you have, for example, a 2960G/2960S or a 3750G/E/X switch.
04-25-2013 08:56 PM
I'm getting a lot of cases about crc errors, did you encounters some of these problems?
Rx Discards :51688 Tx Discards : 0
Rx Runts : 0 Rx Unknown Protos : 0
Rx Giants :3 Rx Crc Errors :539
Tx CongDscrd Pkt:0 Tx Cong Dscrd Byte:0
Tx MTU Exced Pkt:0
These are data from shown at our PE routers.
04-25-2013 08:59 PM
I dunno. I still say you have a faulty cable issue.
04-25-2013 09:03 PM
Thanks so much
04-25-2013 09:19 PM
If you have another switch, with GigabitEthernet interface, I can tell you where the fault is.
2960G/S or 3750G/E/X or 3850 would be nice.
04-25-2013 09:34 PM
I can't verify what kind of switch were connected because its part of clients demarcation and its off limits to us. But in this case, if any switch will be, where can be the problem is?
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