Two switch 2960s connectivity issue

[zeenatkhattak33]

Hai 

I have two cisco 2960s switches connected on poe of other vendor switch on different sites. If one 2690s goes UP on same time other goes down vice versa, how i can fix this issue. kindly guide 

[balaji.bandi]

Spoiler

Spoiler

2960s switches connected on poe of other vendor switch on different sites

explain more on this, PoE to other switches?

 If one 2690s goes UP on same time other goes down vice versa, how i can fix this issue.

what is the logs you see ?

[Georg Pauwen]

Hello,

what vendor/model is the other PoE switch ? Could be a spanning tree problem, depending on how the devices are connected, or a power issue, where the vendor switch cannot supply enough power to both switches...

[Richard Burts · Accepted solution]

There are several things about the description of this issue that I do not understand.

- it says "on poe of other vendor switch on different sites." Are these switches physically on different sites? Please clarify if this is a local connection or a remote connection.

- you say when one switch goes up the other switch goes down. Is this a loss of IP connectivity to the switch? Is the switch still able to do layer 2 forwarding of traffic? (can one device connected on the switch still communicate with another device connected on that switch) Or does the switch totally stop forwarding traffic?

- can you establish a console connection to one of the switches, cause the problem, and report if any messages are generated to the console indicating what happened?

- is it always which ever switch is up and the other switch comes up the first switch goes down? If switchA is up and switchB comes up then switchA goes down. And if switchA comes back up then switchB goes down?

[zeenatkhattak33]

both switches are located locally. I can connect console to both switches.

When simoultanously both switches dont goes up only one switch goes up...connect devices can communicate only but trunk port is down alway of down switch.............

below statement exact problem i am facing

If switchA is up and switchB comes up then switchA goes down. And if switchA comes back up then switchB goes down

[Richard Burts]

Thanks for the clarification that the switches are local. Please do connect to the console (having output from both switches would be nice, but output from one would probably be adequate) and post any log messages generated when the problem occurs.

Am I correct in understanding that devices connected on the "down" switch can still communicate locally but can not communicate with anything that is remote?

Am I correct in understanding that the trunk port is down? That might suggest some mismatch in configuration between the switches. Can you post the config of both switches? (if not the complete config then at least the config of the ports involved in the trunk).

[zeenatkhattak33]

only trunk goes down

[Richard Burts]

Thank you for posting the switch configuration. Is the config of the other switch very similar?  It seems pretty straightforward. There are a few ports in vlan 1 and most of the ports are access ports in vlan 12. There are 3 interfaces configured as trunk. Would I be correct in understanding that GigabitEthernet1/0/26 is the one that has problems? The output of these commands might be helpful:

show interface trunk

show interface status

show cdp neighbor

If you can get a console connection it would be good to know if any log messages are generated when the problem occurs.

[Georg Pauwen]

Good to see that the issue has been resolved. Out of curiosity, what did you do to make this work ?

[Richard Burts]

It is true that the post is marked as solved. But my understanding is that the problem is not yet really identified or resolved.

[zeenatkhattak33]

GigabitEthernet0/1 is down, line protocol is down (err-disabled)
  Hardware is Gigabit Ethernet, address is f078.167b.9081 (bia f078.167b.9081)
  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)
  Auto-duplex, Auto-speed, 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 18:40:09, output 18:40:08, 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 0 bits/sec, 0 packets/sec
     1619333 packets input, 543544079 bytes, 0 no buffer
     Received 1174445 broadcasts (721694 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 721694 multicast, 0 pause input
     0 input packets with dribble condition detected
     372455 packets output, 150663160 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     608 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



you are right not solved yet sir.Above are the configurations of interface goes down