Workaround CSCea46385 Bug

[yabilteryst]

I need some details about workaround for CSCea46385 Bug.

It is mentioned to disable keepalive on Fiber interfaces and uplink interfaces as 12.2SE releases.

I use GigaStack between 2950 switches. what is recommanded for?

Is it possible to remove keepalive on all trunk interfaces (Copper, Fiber, Gigastack) between switches?

Thanks in advaance

[Mohamed Anees Mohammed Abdulla]

You can disable keepalive on the interfaces. But it is not advisable to disable keepalives. IOS upgrade is teh recommended one. Which port is err-disable on your switch?

[yabilteryst]

err-disable ports was Fiber port.

We have a major issue on our LAN with 25 switchs. After a Gbic change on our 6513, all giga trunk ports connected on this 6513 were err-disable at the same time du to keepalive issue. One hour after the second giga port on all affected 2950 were err-disable. It was very strange because the second giga port was plugged on my secundary 6513. I never exactly understand what's happened.

I take a glance at Bug Tool Web site and there are 2 bugs referenced which could be the origin of my problem: CSCea46385 & CSCeg58877

Tht's why I would like to disable keepalive on all trunk ports, Fiber, Copper and GigaStack.

I try to have a full explanation about keepalive on cisco website but it's really confused. If you can explain me exactly how it's working.

[Pranjal Bharadwaj]

Hello Everyone,
I have a little query related to this loopback error issue causing SW port in err-disable state.
My SW version is as below which states keepalives are not sent by default on the fibre and uplink ports as per CISCO.
krse510
Switch Ports Model              SW Version            SW Image
------ ----- -----              ----------            ----------
*    1 28    WS-C3750G-24TS-1U  12.2(46)SE            C3750-IPBASE-M
 
PE------SW------(Carrier)----CE
Gi1/0/27 -- pointing towards PE
Gi1/0/23 -- pointing towards Carrier.
 
However, I got the below logs and made our Customer facing port to Err-Disable state.
 
 
Dec 16 19:15:42.885 UTC: %SW_MATM-4-MACFLAP_NOTIF: Host 7c0e.cec1.8b04 in vlan 326 is flapping between port Gi1/0/23 and port Gi1/0/27
Dec 16 19:15:45.100 UTC: %ETHCNTR-3-LOOP_BACK_DETECTED: Loop-back detected on GigabitEthernet1/0/23.
Dec 16 19:15:45.100 UTC: %PM-4-ERR_DISABLE: loopback error detected on Gi1/0/23, putting Gi1/0/23 in err-disable state
 
 
My questions are as below:
1. Could somebody please let me know is this possible getting ETHCNTR-3-LOOP_BACK_DETECTED on this port as we are on Version 12.2(46)SE ??
2. How can I overcome this situation as each time it went to err-disable mode once any logs come for mac-flap between Gi1/0/23 and port Gi1/0/27?
3. What are the possible causes that generated these logs?
 
 
krse510#sh run int Gi1/0/23
Building configuration...
Current configuration : 315 bytes
!
interface GigabitEthernet1/0/23
 description ---To XXXX
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 326
 switchport trunk allowed vlan 326,3123
 switchport mode trunk
 switchport nonegotiate
 speed 100
 duplex full
 mls qos trust cos
 no mdix auto
 spanning-tree bpdufilter enable
end