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1705
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95
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urgent

ney25
Level 2
Level 2

Hi NetPros,

anyone can help ?

Aug 20 17:19:44.160: %RTD-1-ADDR_FLAP: GigabitEthernet0/2 relearning 5 addrs per min

Aug 20 17:20:44.175: %RTD-1-ADDR_FLAP: GigabitEthernet0/1 relearning 6 addrs per min

switch>sh spann int gi 0/1

Interface Gi0/1 (port 40) in Spanning tree 1 is FORWARDING

Port path cost 4, Port priority 128

Designated root has priority 32768, address 0003.e35c.2580

Designated bridge has priority 32768, address 0003.e35c.2580

Designated port is 40, path cost 0

Timers: message age 0, forward delay 0, hold 0

BPDU: sent 1690479, received 1352

switch>sh spann int gi 0/2

Interface Gi0/2 (port 48) in Spanning tree 1 is FORWARDING

Port path cost 4, Port priority 128

Designated root has priority 32768, address 0003.e35c.2580

Designated bridge has priority 32768, address 0003.e35c.2580

Designated port is 48, path cost 0

Timers: message age 0, forward delay 0, hold 0

BPDU: sent 1703077, received 13968

regards,

kitten

35 Replies 35

ankbhasi
Cisco Employee
Cisco Employee

Hi Kitten,

Looks like your network is hitting a STP loop. Can you brief more about topology?

Regards,

Ankur

b.petronio
Level 3
Level 3

Could u please upload the configuration of this switch and the root bridge one.

As i remenber, u should have a different value of designated bridge priority, and one port on BLOCKING instead of 2 forwarding.

****

Error Message RTD-1-ADDR_FLAP [chars] relearning [dec] addrs per min

Explanation Normally, MAC addresses are learned once on a port. Occasionally, when a switched network reconfigures, due to either manual or STP reconfiguration, addresses learned on one port are relearned on a different port. However, if there is a port anywhere in the switched domain that is looped back to itself, addresses will jump back and forth between the real port and the port that is in the path to the looped back port. In this message, [chars] is the interface, and [dec] is the number of addresses being learnt.

Recommended Action Determine the real path (port) to the MAC address. Use the debug ethernet-controller addr privileged EXEC command to see the alternate path-port on which the address is being learned. Go to the switch attached to that port. Note that the show cdp neighbors command is useful in determining the next switch. Repeat this procedure until the port is found that is receiving what it is transmitting, and remove that port from the network.

****

Hope it helps,

Best Regards,

Bruno Petr?nio

Hi Bruno,

i have followed your way, enable debug ethernet-controller address.

but, nothing came up....

what can i do now , kindly enlighten me ..

your reply will be highly appreciated.

regards,

kitten

Hello kitten,

We could do somethings in order to help u, but we will more precise if we got an idea of the design, and configuration, i.e.;

- is that both port, connected to te same switch?

- are them in Etherchannel mode ?

Try to describe ur design the most precise way, and give us knowledge about what is configured in ur switch's.

I'm sure, that if u show us more information, we help you better.

Best Regards,

Bruno Petr?nio

Hi Bruno,

nope, both port are not connected to the same switch.

no etherchannel .

but, now i have received this msg .

Aug 21 08:32:30.502: %SYS-3-LOGGER_FLUSHED: System was paused for 00:00:00 to ensure console debugging output.

regards,

Kitten

Hi kitten,

Did u/someone else change your stp configuration, before this happen?

Did someone perform any changes in patching, in your switchs ?

I could guess that u have a stp loop, like Ankur have pointed here, but u need to know where it is, in order to resolve it.

That 2nd message, "%SYS-3-LOGGER_FLUSHED", is saying that ...

"Debugging or informational messages are being generated faster than they can be displayed on the console.To guarantee that they can be seen, the rest of the system is paused until the console output catches up."

Assuming that u only have cisco switchs, in ur network, and all have the cdp active, and if u have a network design showing connections between them, u need to check up where is that loop, using "show cdp neighboors".

I would start, right on that switch and check all the connections.

If u could give us the network design topology, we would appreciate.

Hope it helps,

Best Regards,

Bruno Petr?nio

Hi Bruno,

attached with the network diagram and kindly advice.

so, when i show the spanning-tree on the switch (192.10.51.216) i saw the gi0/1 and gi0/2 became FORWARD.

your reply will be highly appreciated.

thanks a lot. and hope to hear from you.

Regards,

Kitten

Hi there,

Regarding your design, i surely believe that if the users in that switch (192.10.51.216) is experiencing problems, than u could shutdown Gi0/5 OR Gi0/6 in 192.10.51.211, in order to avoid the loop, but then i think it's harder to search the problem.

Nevertheless, oyu could perform a "show cdp neighboors" in each switch, and check for differences with the design u gave us.

Do u have any spanning tree priorities configured in any equipment ?

Perform a "show run | inc spanning" and past it here refering on which equipment its.

Hope it helps,

Best Regards,

Bruno Petr?nio

Hi Bruno,

yes, i have check all switch with using " show cdp nei " . as i can't see any loop back port in the same switch. some more i did shut down the int gi 0/6 but the switch is down imeediately.

but, i noticed something.. all of my switches which configured spanning-tree mode pvst but only this 192.10.51.216 has not spanning-tree mode pvst. well, this is 3524XL model and version 12.0(5.2)XU. and when i try to configure spanning-tree mode to this switch. that's no such spanning-tree mode function for me.

would that be the IOS version was outdated ?

Hi there,

I'm a bit surprised that u lost connection after shutting down G0/6. Do u wait for some seconds?

It should converged...

1st of all, and before we make anymore changes, i would ask u, if this was happening after some changes ? or it's happening since it was installed ?

I arrange a 3524 with the same ios version and done a "debug ethernet-controller", and "term mon", and i saw a debug output... like this :

...

Aug 22 08:44:29.185: Add address 0030.0556.d218, on port Gi0/2 vlan 1

Aug 22 08:44:29.300: Add address 0010.839f.2864, on port Gi0/1 vlan 1

Aug 22 08:44:29.539: Delete address 0016.3565.1dfb, on port Gi0/1 vlan 1

...

This should help u find where is the relearning loop.

Nevertheless, and regarding PVST (Per-Vlan Spanning Tree), i think that its not the issue, if u only use Vlan 1. (its the only vlan in use ? )

I my self, have 2 switchs in my network, similar with ur design, 1 3524 (no pvst)+ 1 2950 (pvst) Vlan1 only, but i have priority configured in 2 redundant core switchs.

Please paste your configuration of 192.10.51.215, 192.10.51.216, 192.10.51.211, and 192.10.51.210 please.

I really suspect on that cost for both interfaces (4).

Maybe some switch expert could comment this issues and give us a light on this.

Best Regards,

Bruno Petr?nio

Looking at the diagram and reading these posts... Just make SURE the switch in the middle is configured as the ROOT BRIDGE for STP. My guess is that it is not.

Once you verify you have forced that center switch to be the ROOT, then you can troubleshoot any issues that may be evident.

Hi ,

mind to tell me how to configure the middle switch as the Root Bridge for STP ?

basically i have only 1 Vlan in the entire network. (Vlan 1).

your reply will be highly appreciated.

regards,

kitten

switch# conf t

spanning-tree priority 10

end

Hi Bruno,

as requested, i have uploaded 4 switches config file.

regards,

kitten

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