Switch Port light changing from Green,Amber then off

[mahesh18]

                   Hi everyone,

On Switch port light is changing from green then light is amber then off.

Then again port light is green amber and off.

I check port is flapping between up and down.

sh int shows no errors

Cable is good.

sh controller ethernet-controller fastEthernet 0/35

     Transmit FastEthernet0/35                Receive
   4232401614 Bytes                       2857531374 Bytes
     25678995 Unicast frames                15212740 Unicast frames
      3038531 Multicast frames                    59 Multicast frames
      2500688 Broadcast frames                 15644 Broadcast frames
            0 Too old frames              2854088124 Unicast bytes
            0 Deferred frames                   6766 Multicast bytes
            0 MTU exceeded frames            3380346 Broadcast bytes
            0 1 collision frames                   0 Alignment errors
            0 2 collision frames                  17 FCS errors
            0 3 collision frames                   0 Oversize frames
            0 4 collision frames                   0 Undersize frames
            0 5 collision frames                  14 Collision fragments
            0 6 collision frames
            0 7 collision frames            10645225 Minimum size frames
            0 8 collision frames             1542974 65 to 127 byte frames
            0 9 collision frames             1038746 128 to 255 byte frames
            0 10 collision frames             748973 256 to 511 byte frames
            0 11 collision frames             242603 512 to 1023 byte frames
            0 12 collision frames            1009983 1024 to 1518 byte frames
            0 13 collision frames                  0 Overrun frames
            0 14 collision frames                  0 Pause frames
            0 15 collision frames
            0 Excessive collisions                54 Symbol error frames
            0 Late collisions                      0 Invalid frames, too large
            0 VLAN discard frames                  0 Valid frames, too large
            0 Excess defer frames                 24 Invalid frames, too small
      5910938 64 byte frames                       0 Valid frames, too small
      2629277 127 byte frames
      1997672 255 byte frames                      0 Too old frames
       473202 511 byte frames                      0 Valid oversize frames
       330469 1023 byte frames                     0 System FCS error frames
     19876656 1518 byte frames                     0 RxPortFifoFull drop frame
            0 Too large frames
            0 Good (1 coll) frames
            0 Good (>1 coll) frames

Does this indicate hardware issue with  port?

Thanks

Mahesh

[mahmoodmkl]

Hi
most prpbably yes it seems hardware issue with the n confrim whether the end system connected on this port is ok

Sent from Cisco Technical Support iPhone App

[mahesh18]

Hi,

I checked PC  it has nic light on and off.

Now i changed user to different vlan now  port is not flapping.

May be current vlan which has connection to dhcp server  might have issues

If PC do not get IP from DHCP can that cause this sympton?

thanks

Mahesh

[mahesh18]

Hi,

Seems when i hard code to duplex full and speed 10 link is stable.

also if it auto negotiate to duplex full and speed 10 it is stable but if it is hard coded to duplex full and speed 100 it flaps.

PC  speed was set to auto.

Same PC when connected to different port  works fine.

Connected another PC to same wall jack port is flapping and NIC light goes on and off continously.

Thanks

MAhesh

[mahmoodmkl]

Hi
no tht could not be the issue
can u paste the config of the before n now

Sent from Cisco Technical Support iPhone App

[mahesh18]

Hi,

Config when link is stable

switchport access vlan 100

switchport mode access

switchport port-security maximum 2

switchport port-security

switchport port-security aging time 5

switchport port-security violation protect

switchport port-security aging type inactivity

no logging event link-status

speed 10

duplex full

spanning-tree portfast

or when it auto negotiates to speed 10 duplex full link is stable

switchport access vlan 100

switchport mode access

switchport port-security maximum 2

switchport port-security

switchport port-security aging time 5

switchport port-security violation protect

switchport port-security aging type inactivity

no logging event link-status

  spanning-tree portfast

Thanks

Mahesh

[mahmoodmkl · Accepted solution]

Hi
i suspect this to be cable issue

Sent from Cisco Technical Support iPhone App

[mahesh18]

Hi,

thanks for reply.

after doing further troubleshooting found that issue is of cabling between patch panel and wall jack.

when i connect laptop directly to switch port no flapping.

Many thanks

Regards

Mahesh

[Leo Laohoo · Accepted solution]

Hi Mahesh,

In your first post, you included the result to the command "sh controller e".  Look at the "receive" column on the right.  Notice there are some tiny FCS errors?  It's cable.

May I know what EXACT switch model this is?  If this is a 2960 then you can probably use TDR to find out WHERE the cable fault is.

[mahesh18]

Hi,

Thanks for reply and letting me  know to look for FCS errors  in the future.

    WS-C3560-48PS  is model number.

I already tried test cable command it does  not support it.

Regards

Mahesh

[Leo Laohoo]

If you look at the link I've posted, TDR is not supported on 3560 or 3750 that are NOT GigabitEthernet.