%RTD-1-ADDR_FLAP ...

Unanswered Question
Apr 7th, 2010

Hello,

recently I'm getting on a syslog server messages from one of my Cisco 3500 XL Switch.

It's about 15 - 20 such messages per day.

These messages are:

Message=<185>2093: 33w3d: %RTD-1-ADDR_FLAP: GigabitEthernet0/1 relearning 5 addrs per min

....

Message=<185>2093: 33w3d: %RTD-1-ADDR_FLAP: GigabitEthernet0/1 relearning 6 addrs per min

...

Message=<185>2093: 33w3d: %RTD-1-ADDR_FLAP: GigabitEthernet0/2 relearning 5 addrs per min


...

Both interfaces GigabitEthernet0/1 and GigabitEthernet0/2 are connected to other Cisco switches (0/1 - L3 switch, 0/2 - L2 switch).

I heard that it might be caused by a loop.

My question are:

What might cause such a loop ?

Do I have to really care about this or this is a quite normal behaviour ?

Thanks,

I have this problem too.
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Leo Laohoo Wed, 04/07/2010 - 17:37

I haven't seen this error message for a loooooooooong time! 

Is STP portfast enabled?  If yes, then disable it.

Error message means that the link is flapping.  Check the cable.  But in your case the error message is coming from both interface so I am suspecting that you do have a loop somewhere.  Make sure all uplink ports have STP disabled and access ports have BPDUGuard enable.

ganeshh.iyer Wed, 04/07/2010 - 22:46

Hello,

recently I'm getting on a syslog server messages from one of my Cisco 3500 XL Switch.

It's about 15 - 20 such messages per day.

These messages are:

Message=<185>2093: 33w3d: %RTD-1-ADDR_FLAP: GigabitEthernet0/1 relearning 5 addrs per min

....

Message=<185>2093: 33w3d: %RTD-1-ADDR_FLAP: GigabitEthernet0/1 relearning 6 addrs per min

...

Message=<185>2093: 33w3d: %RTD-1-ADDR_FLAP: GigabitEthernet0/2 relearning 5 addrs per min


...

Both interfaces GigabitEthernet0/1 and GigabitEthernet0/2 are connected to other Cisco switches (0/1 - L3 switch, 0/2 - L2 switch).

I heard that it might be caused by a loop.

My question are:

What might cause such a loop ?

Do I have to really care about this or this is a quite normal behaviour ?

Thanks,

Hi,

Runtime Diagnostic (RTD) error messages can be defined in following ways

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.

Error Message   RTD-1-LINK_FLAP [chars] link down/up [dec] times per min

Explanation   This message means that an excessive number of link down-up events has been noticed on this interface: [chars] is the interface, and [dec] is the number of times the link goes up and down. This might be the result of reconfiguring the port, or it might mean a faulty device at the other end of the connection.

Recommended Action   If someone is reconfiguring the interface or device at the other side of the interface, ignore this message. However, if no one is manipulating the interface or device at the other end of the interface, it is likely that the Ethernet transceiver at one end of the link is faulty and should be replaced.

Hope to Help !!

Ganesh.H

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Posted April 7, 2010 at 6:27 AM
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