Unknown port flapping issues

davemac2626 · ‎03-05-2013

Hi all

I have a bizzare situation in which certain ports of certain switches are going up and down. First there were STP errors which I have managed to get rid of but there are still issues with certain ports on certain switches. Not all the affected ports are on the same VLAN either. Im at a loss as to what would cause issues on only specific ports. I have attached a quick scetch of the network. There are also 2 x Aironet AP's that are also not working correctly, as in dumping people off.

Is there anything I can specificly look for at all? there is a mixed bag of switches in this network with 3560's, SF300's and SGE2010P's. STP is configured on most of the switches except 1 and disabled on a couple of VLANs.

A show log on one switch:

05-Mar-2013 09:16:53 %LINK-I-Up: fa30

05-Mar-2013 09:25:52 %LINK-W-Down: fa42

05-Mar-2013 09:25:54 %LINK-I-Up: fa42

05-Mar-2013 09:25:56 %LINK-W-Down: fa42, aggregated (1)

05-Mar-2013 09:25:57 %LINK-I-Up: fa42, aggregated (1)

So far I have tried disablling auto negotiation for the ports, setting ports to trunks and only allowing the VLANs specified

another switch shows:

000061: Mar 5 09:38:03: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to up

000062: Mar 5 09:43:47: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to down

000063: Mar 5 09:43:48: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down

000064: Mar 5 09:43:51: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up

000065: Mar 5 09:43:52: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to up

000066: Mar 5 09:44:15: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to down

000067: Mar 5 09:44:16: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to down

000068: Mar 5 09:44:18: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up

000069: Mar 5 09:44:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to up

This is happening all over the network and im not pretty stuck as to what can be causing it. A show interface counters errors shows:

Main_1#sh interfaces counters errors

Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize

Fa0/1 0 0 0 0 0

Fa0/2 0 0 0 0 0

Fa0/3 0 0 0 0 0

Fa0/4 0 0 0 0 0

Fa0/5 0 0 0 0 0

Fa0/6 0 0 0 0 0

Fa0/7 0 0 0 0 0

Fa0/8 0 0 0 0 0

Fa0/9 0 0 0 0 0

Fa0/10 0 0 0 0 0

Fa0/11 0 0 0 0 0

Fa0/12 0 0 0 0 0

Fa0/13 0 0 0 0 0

Fa0/14 0 0 0 0 0

Fa0/15 0 0 0 0 0

Fa0/16 0 0 0 0 0

Fa0/17 0 0 0 0 0

Fa0/18 0 0 0 0 0

Fa0/19 0 0 0 0 0

Fa0/20 0 0 0 0 0

Fa0/21 0 0 0 0 0

Fa0/22 0 0 0 0 0

Fa0/23 0 0 0 0 0

Fa0/24 0 0 0 0 0

Fa0/25 0 0 0 0 0

Fa0/26 0 0 0 0 0

Fa0/27 0 0 0 0 0

Fa0/28 0 0 0 0 0

Fa0/29 0 0 0 0 0

Fa0/30 0 0 0 0 0

Fa0/31 0 0 0 0 0

Fa0/32 0 0 0 0 0

Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize

Fa0/33 0 0 0 0 0

Fa0/34 0 0 0 0 0

Fa0/35 0 0 0 0 0

Fa0/36 0 0 0 0 0

Fa0/37 0 0 0 0 0

Fa0/38 0 0 0 0 1747

Fa0/39 0 0 0 0 0

Fa0/40 0 0 0 0 0

Fa0/41 0 0 0 0 0

Fa0/42 0 0 0 0 0

Fa0/43 0 0 0 0 0

Fa0/44 0 0 0 0 0

Fa0/45 0 0 0 0 2004

Fa0/46 0 0 0 0 11537

Fa0/47 0 0 0 0 0

Fa0/48 0 0 0 0 0

Gi0/1 0 0 0 0 0

Gi0/2 0 0 0 0 0

Gi0/3 0 0 0 0 4310

Gi0/4 0 0 0 0 0

Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts Giants

Fa0/1 0 0 0 0 0 0 0

Fa0/2 0 0 0 0 0 0 0

Fa0/3 0 0 0 0 0 0 0

Fa0/4 0 0 0 0 0 0 0

Fa0/5 0 0 0 0 0 0 0

Fa0/6 0 0 0 0 0 0 0

Fa0/7 0 0 0 0 0 0 0

Fa0/8 0 0 0 0 0 0 0

Fa0/9 0 0 0 0 0 0 0

Fa0/10 0 0 0 0 0 0 0

Fa0/11 0 0 0 0 0 0 0

Fa0/12 0 0 0 0 0 0 0

Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts Giants

Fa0/13 0 0 0 0 0 0 0

Fa0/14 0 0 0 0 0 0 0

Fa0/15 0 0 0 0 0 0 0

Fa0/16 0 0 0 0 0 0 0

Fa0/17 0 0 0 0 0 0 0

Fa0/18 0 0 0 0 0 0 0

Fa0/19 0 0 0 0 0 0 0

Fa0/20 0 0 0 0 0 0 0

Fa0/21 0 0 0 0 0 0 0

Fa0/22 0 0 0 0 0 0 0

Fa0/23 0 0 0 0 0 0 0

Fa0/24 0 0 0 0 0 0 0

Fa0/25 0 0 0 0 0 0 0

Fa0/26 0 0 0 0 0 0 0

Fa0/27 0 0 0 0 0 0 0

Fa0/28 0 0 0 0 0 0 0

Fa0/29 0 0 0 0 0 0 0

Fa0/30 0 0 0 0 0 0 0

Fa0/31 0 0 0 0 0 0 0

Fa0/32 0 0 0 0 0 0 0

Fa0/33 0 0 0 0 0 0 0

Fa0/34 0 0 0 0 0 0 0

Fa0/35 0 0 0 0 0 0 0

Fa0/36 0 0 0 0 0 0 0

Fa0/37 0 0 0 0 0 0 0

Fa0/38 0 0 0 0 0 0 0

Fa0/39 0 0 0 0 0 0 0

Fa0/40 0 0 0 0 0 0 0

Fa0/41 0 0 0 0 0 0 0

Fa0/42 0 0 0 0 0 0 0

Fa0/43 25538 20679 40251 0 0 0 0

Fa0/44 0 0 0 0 0 0 0

Fa0/45 0 0 0 0 0 0 0

Fa0/46 0 0 0 0 0 0 0

Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts Giants

Fa0/47 0 0 0 0 0 0 0

Fa0/48 0 0 0 0 0 0 0

Gi0/1 0 0 0 0 0 0 0

Gi0/2 0 0 0 0 0 0 0

Gi0/3 0 0 0 0 0 0 0

Gi0/4 0 0 0 0 0 0 0

If anyone has any ideas on what it may be or anything else that I can try it would be greatly appreciated. I plan to do a wireshark capture at some point as well.

Cheers

Dave

Leo Laohoo · ‎03-05-2013

Post the output to the command "sh interface Fa0/4".

davemac2626 · ‎03-05-2013

Main_1#sh int fa0/4

FastEthernet0/4 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 001c.5803.5906 (bia 001c.5803.5906)

Description: Wynyard-PC

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 10/100BaseTX

input flow-control is off, output flow-control is unsupported

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

Last input never, 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 output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

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

5 minute output rate 6000 bits/sec, 8 packets/sec

50419 packets input, 5104541 bytes, 0 no buffer

Received 2196 broadcasts (0 multicast)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 136 multicast, 0 pause input

0 input packets with dribble condition detected

171967 packets output, 19068405 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 PAUSE output

0 output buffer failures, 0 output buffers swapped out

Leo Laohoo · ‎03-08-2013

Output looks clean. Normally, when a users logs-in in the morning, you'll notice the switch logs showing that the port goes down/up four times.

Maybe this is what you are seeing?

dynamitec1 · ‎03-08-2013

looking at the time stamp, UP and DOWN is within a few seconds apart. So, this cant be users going ON or OFFline.

I'm curious to see int fa0/42 config. The "Aggregated" part looks interesting...

When I see a port flapping, I tend to examine the RJ45 jack on both ends, reterminating usually fix my flapping ports.

Sent from Cisco Technical Support iPhone App

Raul Ricano · ‎08-15-2013

Was this ever resolved? I am seeing this accross multiple client enviroments with multiple small business line switches.