Re: Switch ports go Down and backup over and over PLEASE HELP - CISCO 2960x

Brian0040 · ‎06-14-2019

I just reconfigured this switch and created a Trunk for Gi3/0/47 because I'm wanting to connect a Cisco 2960X to another Cisco switch SFE2010. (I ran out of ports on the original 48 port) so I Enabled trunking on port 47 and now it's going crazy. Can anyone help?

GigabitEthernet3/0/47 is up, line protocol is up (connected)

GigabitEthernet3/0/47 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is b000.b493.8b2f (bia b000.b493.8b2f)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
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 2000 bits/sec, 2 packets/sec
5 minute output rate 2000 bits/sec, 1 packets/sec
     4630 packets input, 638940 bytes, 0 no buffer
     Received 4630 broadcasts (4630 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 4630 multicast, 0 pause input
     0 input packets with dribble condition detected
     2872 packets output, 544662 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     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

Jun 13 08:31:01.755: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet3/0/47, changed state to down
Jun 13 08:31:02.744: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/47, changed state to down
Jun 13 08:31:05.578: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/47, changed state to up
Jun 13 08:31:07.581: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet3/0/47, changed state to up

Hector Gustavo Serrano Gutierrez · ‎06-14-2019

Is the port continuously bouncing while connected to the SFE2010?
Does it keep bouncing the same way if you connect it to a laptop or to a different port on the SFE2010?
Is the SFE2010 also configured as
“trunk” (tag 802.1q)?

Brian0040 · ‎06-15-2019

The it only flaps when connected to the 2010. I'm NOT good at configuring a
switch. I know I didn't tag the Port. Do you happen to know the commands I
need to enter?

luis_cordova · ‎06-14-2019

Hi @Brian0040 ,

The common cause of link flap is a Layer1 issue such as a bad cable, duplex mismatch.

The problem could be Layer2, related to the wrong configured in STP, DTP or VTP.

Regards

Leo Laohoo · ‎06-14-2019

@Brian0040 wrote:

Jun 13 08:31:01.755: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet3/0/47, changed state to down
Jun 13 08:31:02.744: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/47, changed state to down
Jun 13 08:31:05.578: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/47, changed state to up
Jun 13 08:31:07.581: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet3/0/47, changed state to up

How "often" does this interface go down/up?

Does it happen every time the downstream client logs out/in? Hibernates?

If the time & date is set correctly, look at the time. 8:30 in the morning. Just in time for some people to start work, start logging in.

If the answer to my 2nd question is a YES, then this is a normal occurrence.

Brian0040 · ‎06-14-2019

Thank you so much for replying. No, the interface goes down on the down
stream switch about every 10 seconds (ish) but the up stream switch doesn't
have an issue.

Leo Laohoo · ‎06-14-2019

Ok, so you gave an example of Gi 3/0/47.
So post the complete output to the command "sh log | i 3/0/47".