Line protocol on access ports are going up and down

Answered Question
Jul 6th, 2007

A number of our 3560s are indicating ports that are going up and down. These connections are connected to printers or pcs. Here is a copy of the show log statement:

618975: Jul 6 11:22:12.352: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/22, changed state to up

618976: Jul 6 11:22:12.394: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/12, changed state to up

618977: Jul 6 11:22:12.520: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/5, changed state to up

618978: Jul 6 11:22:14.424: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/28, changed state to down

618979: Jul 6 11:22:16.429: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/28, changed state to up

618980: Jul 6 11:22:41.654: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/28, changed state to down

618981: Jul 6 11:22:43.658: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/28, changed state to up

618982: Jul 6 11:22:48.457: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/10, changed state to down

618983: Jul 6 11:22:50.462: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/10, changed state to up

618984: Jul 6 11:23:12.750: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/10, changed state to down

618985: Jul 6 11:23:14.764: %LINEPROTO-5-UPDOWN: Line protocol on Interface Fas

tEthernet0/10, changed state to up

And a Show interface on a port haivng the same problem:

FastEthernet0/20 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0019.e7df.2d16 (bia 0019.e7df.2d16)

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 00:00:01, 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 0 bits/sec, 0 packets/sec

5 minute output rate 1000 bits/sec, 2 packets/sec

660327 packets input, 132595868 bytes, 0 no buffer

Received 15372 broadcasts (0 multicasts)

0 runts, 0 giants, 0 throttles

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

0 watchdog, 45 multicast, 0 pause input

0 input packets with dribble condition detected

9714405 packets output, 1165338432 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

Anybody know why this would happen? It is happening on different switches.

I have this problem too.
0 votes
Correct Answer by xcz504d1114 about 9 years 5 months ago

More than likely cabling issues, bad end terminations, not proper clearance from things such as flourescent bulbs causing line interference, bug or rodents chewing the line, length of the cable.

Could be alot of reasons but more than likely it is a cabling issue, I see alot of linkflap errors in my buildings that have fiber to the PC due to bad cabling all the time. Most of the time for cat5 cable it will be bad end terminations or cable length.

Keep in mind cable length should not exceed 100 meters (300 feet) and to maintain proper twist on the connectors as well as make sure the cable ends touch the tip of the RJ-45 and the cable sheath should be secured by the crimp. Don't forget to check your punch downs also.

Craig

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Correct Answer
xcz504d1114 Fri, 07/06/2007 - 08:34

More than likely cabling issues, bad end terminations, not proper clearance from things such as flourescent bulbs causing line interference, bug or rodents chewing the line, length of the cable.

Could be alot of reasons but more than likely it is a cabling issue, I see alot of linkflap errors in my buildings that have fiber to the PC due to bad cabling all the time. Most of the time for cat5 cable it will be bad end terminations or cable length.

Keep in mind cable length should not exceed 100 meters (300 feet) and to maintain proper twist on the connectors as well as make sure the cable ends touch the tip of the RJ-45 and the cable sheath should be secured by the crimp. Don't forget to check your punch downs also.

Craig

Edison Ortiz Fri, 07/06/2007 - 08:37

It seems like you are forcing the speed/duplex to 100/FD on the switchports while the workstations are running auto/auto. This will produce a duplex mismatch. Please change the switchport to speed auto and duplex auto and let us know if that worked out.

faze1sari Fri, 07/06/2007 - 08:54

Speed on the ports is always set to auto on both sides. I'm guessing it might be the run from the closet to the wall jack or (crossing my fingers) the run from the switch to the jack in the closet...we do get a bad set of patch cables from time to time. Thanks for your help at least we know its not the switch that is in error, will forward this to the telecom people.

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