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Switch gives CRC error?

dhirendra7
Level 1
Level 1

hi eveyone,

                           We are facing the problem for the past few days .In our company network we have a L-3 at third floor and a switch connected with a

                              backbone cable in the seventh floor . whenever the switch in seventh floor is booted it works as normal but after 5-10 minutes the 

                             switch becomes out of network . We have changed our backbone cable but the same condition still persist .when i checked the       

                            port through which the backbone is connected it gives the CRC error.

                              Can anyone tell why this happens ?

     HUDco #show int fa0/9
FastEthernet0/9 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 000f.8f7b.f409 (bia
  Description: Backbone to 745A
  MTU 1500 bytes, BW 100000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s
  input flow-control is off, output flow-control is off
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:05, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total outp
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 135000 bits/sec, 41 packets/sec
     466140 packets input, 81296434 bytes, 0 no buffer
     Received 15788 broadcasts (0 multicast)
     0 runts, 0 giants, 0 throttles
     12 input errors, 7 CRC, 5 frame, 0 overrun, 0 ignored
     0 watchdog, 8076 multicast, 0 pause input
     0 input packets with dribble condition detected
     4332369 packets output, 2005586380 bytes, 0 underruns
     0 output errors, 0 collisions, 2 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

2 Replies 2

Alvaro Garcia
Level 1
Level 1

CRC errors are normmaly caused by L1 issues, meaning hardware problem... defective port on either side of the link, bad cable, patch panel, etc. On less common situation you can also see CRC errors caused by Speed/Duplex mismatch.

I would suggest to make sure both interfaces are confugured with the exact same setting for speed and duplex. If you already change the cable and there is no patch panel in between, then you can move the link to a different port on the switch. If no errors are seeing onthe new interface than the switchport is faulty. However, if the errors follow the link then you would have to move the link to a different port on your L-3 device and define if the problem is the port or is in the line...

thanks Alvaro

the problem was with the port , we have changed the port to which the lan cable was connected and it was working properly.

Date: Fri, 27 May 2011 07:55:35 -0600

From: supportforums-donotreply@jivesoftware.com

To: thapliyal7@hotmail.com

Subject: New message: "Switch gives CRC error?"

dhirendra thapliyal,

A new message was posted in the Discussion thread "Switch gives CRC error?":

https://supportforums.cisco.com/message/3367276#3367276

Author : Alvaro Garcia

Profile : https://supportforums.cisco.com/people/agarciao

Message:

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