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New Member

CRC errors on cisco switch

Dear All,

One of my wi-fi site having 2nos cisco 2950 switchs. in that network some D-link unmanageble swithes also there

and access points also connected to cisco switchs and D-link switchs.

after one or two days i am not able to connect the wi-fi, then i need to restart the access point then only wi-fi is working fine.

I upgraded the latest ios also.

I connected some access points to the cisco switch ports, those ports are showing crc error messages like below.

145 input errors, 144 CRC, 1 frame, 0 overrun, 0 ignored

and log file also show some errors like below.

000186: Jun 23 03:44:01: %SYS-5-CONFIG_I: Configured from console by vty0 (115.1

19.187.45)

000187: Jun 23 05:44:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth

ernet0/5, changed state to down

000188: Jun 23 05:44:38: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth

ernet0/5, changed state to up

000189: Jun 23 06:38:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth

ernet0/5, changed state to down

000190: Jun 23 06:38:21: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth

ernet0/5, changed state to up

000191: Jun 23 06:38:25: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth

ernet0/5, changed state to down

000192: Jun 23 06:38:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEth

ernet0/5, changed state to up

what could be the problem,

I updated the lates IOS and changed the RJ45 connector both side.

Plz help on this.

Thanks,

Srinivas. N.

Thanks & Regards, Srinivas. N.
Everyone's tags (3)
18 REPLIES
Hall of Fame Super Gold

CRC errors on cisco switch

Kindly post the output to the following commands:

1.  sh run int f 0/5;

2.  sh contr e f 0/5

3.  sh interface f 0/5

New Member

CRC errors on cisco switch

Hi leolaohoo,

Thanks for reply and plz find the sataus.

GP_VIZAG_MAINSW_2950#sh run int fa0/5

Building configuration...

Current configuration : 122 bytes

!

interface FastEthernet0/5

description * Back Side-I (Proxim) *

switchport access vlan 10

switchport mode access

end

GP_VIZAG_MAINSW_2950#sh cont

GP_VIZAG_MAINSW_2950#sh controllers e

GP_VIZAG_MAINSW_2950#sh controllers ethernet-controller  fa0/5

  Transmit                                Receive

4111734682 Bytes                        800406706 Bytes

   5324004 Frames                         3132634 Frames

    723276 Multicast frames                   167 FCS errors

    411370 Broadcast frames                 51740 Multicast frames

         0 Pause frames                     21924 Broadcast frames

         0 Single defer frames                  0 Control frames

         0 Multiple defer frames                0 Pause frames

         0 1 collision frames                   0 Unknown opcode frames

         0 2-15 collisions                      1 Alignment errors

         0 Late collisions                      0 Length out of range

         0 Excessive collisions               122 Symbol error frames

         0 Total collisions                 61932 False carrier errors

         0 Control frames                       0 Valid frames, too small

         0 VLAN discard frames                  0 Valid frames, too large

         0 Too old frames                       0 Invalid frames, too small

         0 Tagged frames                        0 Invalid frames, too large

         0 Aborted Tx frames                    0 Discarded frames

  Transmit and Receive

   1355392 Minimum size frames

   2785635 65 to 127 byte frames

    930782 128 to 255 byte frames

    291326 256 to 511 byte frames

    284047 512 to 1023 byte frames

   2809456 1024 to 1518 byte frames

         0 1519 to 1522 byte frames

GP_VIZAG_MAINSW_2950#sh int

GP_VIZAG_MAINSW_2950#sh interfaces fa0/5

FastEthernet0/5 is up, line protocol is up (connected)

  Hardware is Fast Ethernet, address is 0012.00fe.d6c5 (bia 0012.00fe.d6c5)

  Description: * Back Side-I (Proxim) *

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 100Mb/s, media type is 100BaseTX

  input flow-control is unsupported output flow-control is unsupported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input never, output 00:00:01, output hang never

  Last clearing of "show interface" counters 2d02h

  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 0 bits/sec, 0 packets/sec

  5 minute output rate 1000 bits/sec, 1 packets/sec

     1902845 packets input, 534271423 bytes, 0 no buffer

     Received 42355 broadcasts (28994 multicast)

     0 runts, 0 giants, 0 throttles

     145 input errors, 144 CRC, 1 frame, 0 overrun, 0 ignored

     0 watchdog, 28994 multicast, 0 pause input

     0 input packets with dribble condition detected

     2943416 packets output, 2240492645 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

GP_VIZAG_MAINSW_2950#

Thanks & Regards, Srinivas. N.
Hall of Fame Super Gold

Re: CRC errors on cisco switch

Ok, good.

Your line errors are mostly coming from FCS and Symbols.

Mostly, this is attributed due to faulty cabling. 

changed the RJ45 connector both side.

What do you mean by this?

Are you using a factory pre-terminated patch cables or did you crimp them yourself?

New Member

CRC errors on cisco switch

Thanks for quick reply,

what is meangin of FCS and symbols?

The cat cable is about to 70mts and i my self crimped the connectors.

Thanks & Regards, Srinivas. N.
Hall of Fame Super Gold

CRC errors on cisco switch

The cat cable is about to 70mts and i my self crimped the connectors.

Test the cables with a TDR meter.

New Member

CRC errors on cisco switch

Hi Leolaohoo,

After reclimping the RJ45 connetors and clear the counter.

Now that port status like below

GP_VIZAG_MAINSW_2950# sh controllers e f0/5

  Transmit                                Receive

880211912 Bytes                        342010269 Bytes

   1214521 Frames                          913135 Frames

    139288 Multicast frames                     0 FCS errors

     96737 Broadcast frames                  5471 Multicast frames

         0 Pause frames                      2198 Broadcast frames

         0 Single defer frames                  0 Control frames

         0 Multiple defer frames                0 Pause frames

         0 1 collision frames                   0 Unknown opcode frames

         0 2-15 collisions                      0 Alignment errors

         0 Late collisions                      0 Length out of range

         0 Excessive collisions                 0 Symbol error frames

         0 Total collisions                   134 False carrier errors

         0 Control frames                       0 Valid frames, too small

         0 VLAN discard frames                  0 Valid frames, too large

         0 Too old frames                       0 Invalid frames, too small

         0 Tagged frames                        0 Invalid frames, too large

         0 Aborted Tx frames                    0 Discarded frames

  Transmit and Receive

    406912 Minimum size frames

    681005 65 to 127 byte frames

    205184 128 to 255 byte frames

     63193 256 to 511 byte frames

     82091 512 to 1023 byte frames

    689271 1024 to 1518 byte frames

         0 1519 to 1522 byte frames

GP_VIZAG_MAINSW_2950#

now advice me,...

Thanks & Regards, Srinivas. N.
Hall of Fame Super Gold

CRC errors on cisco switch

Looks good to me.  FCS and Symbol errors are "0", no collisions. 

New Member

CRC errors on cisco switch

what about the

134 False carrier errors

no problem?

Thanks & Regards, Srinivas. N.

CRC errors on cisco switch

No problem?  Are you looking for one?  Because with all the counters I am sure you can find one if you look hard enough. 

My boss once told me there was no such thing as a perfect design, I disagreed...I said "What about Holly Madiison, now thats a perfect design ".  I am just saying lol!

Moving on ....  Check out:

https://supportforums.cisco.com/thread/157286

and from Ciscos site:

False carrier errors

The number of occurrences in which the interface detects a false carrier when frames are not sent or received.

IMO, while I have not seen this type of error before, you are seeing speed/duplex mismatches disguised as false carrier or a  pure layer one issue.

Hall of Fame Super Gold

CRC errors on cisco switch

134 False carrier errors

I'm with Jimmy.  I have never seen this line error before.  I didn't miss this.

Keep an eye on the counter.  If the counter goes up, by 50%, daily then you have a problem. 

New Member

CRC errors on cisco switch

As of now the fales carrier errors are 539...

Is it make any problem?.. if i want fix the problem what i need to do?

Transmit                                Receive

945130476 Bytes                        704286385 Bytes

  4627987 Frames                         2896862 Frames

   493692 Multicast frames                     0 FCS errors

   310672 Broadcast frames                 24905 Multicast frames

        0 Pause frames                      5318 Broadcast frames

        0 Single defer frames                  0 Control frames

        0 Multiple defer frames                0 Pause frames

        0 1 collision frames                   0 Unknown opcode frames

        0 2-15 collisions                      0 Alignment errors

        0 Late collisions                      0 Length out of range

        0 Excessive collisions                 0 Symbol error frames

        0 Total collisions                   539 False carrier errors

        0 Control frames                       0 Valid frames, too small

        0 VLAN discard frames                  0 Valid frames, too large

        0 Too old frames                       0 Invalid frames, too small

        0 Tagged frames                        0 Invalid frames, too large

        0 Aborted Tx frames                    0 Discarded frames

Transmit and Receive

  1496870 Minimum size frames

  2061206 65 to 127 byte frames

   813245 128 to 255 byte frames

   225429 256 to 511 byte frames

   261930 512 to 1023 byte frames

  2711638 1024 to 1518 byte frames

        0 1519 to 1522 byte frames

P_VIZAG_MAINSW_2950#

Thanks & Regards, Srinivas. N.

CRC errors on cisco switch

1)  Is there a problem from a end user perspective?

2) Can you move it to a diff port to see if problem stays on port or cable

3)  If problem follows cable, on  the remote device can you move port to see if problem stays with port or cable.

4) I believe problem will be with cable, if so, new cabling (or ends). 

Hall of Fame Super Gold

CRC errors on cisco switch

Dude,

Let's settle this once and for all.

How important is this client connected to this port?  If it's that important, GET A TDR TEST DONE!

CRC errors on cisco switch

For the OP:

How to use Time-Domain Reflectometer (TDR)

https://supportforums.cisco.com/docs/DOC-18983

Post results.

Hall of Fame Super Gold

CRC errors on cisco switch

How to use Time-Domain Reflectometer (TDR)

https://supportforums.cisco.com/docs/DOC-18983

Nice one Jimmy!

LOL

CRC errors on cisco switch

I will admit, I do not have it bookmarked...lol. But google produced it quite easily.....

New Member

Re: CRC errors on cisco switch

Sorry if I missed it but what brand and model of access point are these?

Sent from Cisco Technical Support iPhone App

New Member

CRC errors on cisco switch

is there any logs on the WAP side?

try to connect the device directly using a small  (1 meter or so ) cable.

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