I got issue on the switchport connecting to Wireless_outdoor_AP, all of a sudden the port becomes error_disable.
I shutdown the port and make the port default then it starts working again.
Cisco recommended to configure error-disable recovery and error-disable time but it doesnt help.
Can you expert can recommend solution to overcome this issue.
Switch : 2960 48 ports
Wireless_outdoor_AP : Wilan
Try the commands "show interfaces status err-disable" and " show errdisable detect" to shows which local ports are involved in the errdisabled state. port the output.
also post show log - to see what logging is setup
here is the output, appreciate your support.
show errdisable detect
ErrDisable Reason Detection status
sh interfaces status err-disabled
Port Name Status Reason
Fa0/38 err-disabled link-flap
Fa0/44 err-disabled loopback
which port the AP is connected to ?
According to your output, port Fa0/38 err-disabled due to link flap (interface state up/down). I believe the default on the switch is if an interface flaps more than 10 times in 5 seconds or the other way around, the port is err-disable. you need to investigate why the flap happened!! it could be a faulty cable or interface!!
Regarding port Fa0/44, can you post the config?
Thanks for the info.
Looks like the loopback error is a bug CSCea46385 due to a old version os IOS on your switch. By upgrading to new code should disable sending and receiving of keepalive on the AP interface. see below.
According to Cisco a loopback error occurs when the keepalive packet is looped back to the port that sent the keepalive.
The switch sends keepalives out all the interfaces by default. A device can loop the packets back to
the source interface, which usually occurs because there is a logical loop in the network that the
spanning tree has not blocked. The source interface receives the keepalive packet that it sent out, and
the switch disables the interface (errdisable). This message occurs because the keepalive packet is
looped back to the port that sent the keepalive:
Keepalives are sent on all interfaces by default in Cisco IOS Software Release 12.1EA−based
software. In Cisco IOS Software Release 12.2SE−based software and later, keepalives are not sent by
default on fiber and uplink interfaces. For more information, refer to Cisco bug ID CSCea46385
The suggested workaround is to disable keepalives and upgrade to Cisco IOS Software Release
12.2SE or later.
ETHCNTR-3-LOOP_BACK_DETECTED: Loop-back detected on gig0/2
An interface on a Catalyst switch is errordisabled after detecting a loopback.
Mar 7 03:20:40: %ETHCNTR-3-LOOP_BACK_DETECTED: Loop-back detected on
GigabitEthernet0/2. The port is forced to linkdown.
Mar 7 03:20:42: %LINK-5-CHANGED: Interface GigabitEthernet0/2, changed state
to administratively down
Mar 7 03:20:43: %LINEPROTO-5-UPDOWN: Line protocol on Interface
GigabitEthernet0/2, changed state to down
This might be seen on a Catalyst 2940, 2950, 2950-LRE, 2955, 2970, 3550, 3560 or
3750 switch running 12.1EA or 12.2SE based code.
Disable keepalives by using the no keepalive interface
command. This will
prevent the port from being errdisabled, but it does not resolve the root cause of
the problem. Please see section below for more information.
The problem occurs because the keepalive packet is looped back to the port that
the keepalive. There is a loop in the network. Although disabling the keepalive
will prevent the interface from being errdisabled, it will not remove the loop.
The problem is aggravated if there are a large number of Topology Change
on the network. When a switch receives a BPDU with the Topology Change bit set,
the switch will fast age the MAC Address table. When this happens, the number of
flooded packets increases because the MAC Address table is empty.
Keepalives are sent on the Catalyst 2940, 2950, 2950-LRE, 2955, 2970, 3550, 3560
or 3750 switch to prevent loops in the network. The primary reason for the
is to prevent loops as a result of Type 2 cabling. For more information, see:
Keepalives are sent on ALL interfaces by default in 12.1EA based software.
Starting in 12.2SE based releases, keepalives are NO longer sent by default on fiber and
3 - moderate
Cisco IOS software