This post is about fixing “%PM-4-ERR_DISABLE: pagp-flap error detected” error on Cisco switch
Error log
*Dec 13 03:32:47.428: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to down
*Dec 13 03:32:49.513: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to up
*Dec 13 03:32:51.750: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/1/4, changed state to down
*Dec 13 03:32:54.040: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/1/4, changed state to up
*Dec 13 03:32:57.631: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to down
*Dec 13 03:32:58.795: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/1/4, changed state to down
*Dec 13 03:32:58.800: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to down
*Dec 13 03:32:59.863: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to up
*Dec 13 03:32:59.919: %PM-4-ERR_DISABLE: pagp-flap error detected on Te2/1/4, putting Te2/1/4 in err-disable state
*Dec 13 03:33:00.831: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan7, changed state to down
*Dec 13 03:33:00.831: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan30, changed state to down
*Dec 13 03:33:00.831: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan80, changed state to down
*Dec 13 03:33:00.831: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan131, changed state to down
*Dec 13 03:33:00.832: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan191, changed state to down
*Dec 13 03:33:00.865: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to up
*Dec 13 03:33:01.925: %LINK-3-UPDOWN: Interface TenGigabitEthernet2/1/4, changed state to down
And
*Dec 13 03:40:02.013: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to down
*Dec 13 03:40:03.029: %LINK-3-UPDOWN: Interface Port-channel44, changed state to down
*Dec 13 03:40:04.348: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to up
*Dec 13 03:40:05.339: %LINK-3-UPDOWN: Interface Port-channel44, changed state to up
*Dec 13 03:40:06.340: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to up
*Dec 13 03:40:11.011: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to down
*Dec 13 03:40:11.018: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to down
*Dec 13 03:40:12.074: %LINK-3-UPDOWN: Interface Port-channel44, changed state to down
*Dec 13 03:40:13.282: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to up
*Dec 13 03:40:14.287: %LINK-3-UPDOWN: Interface Port-channel44, changed state to up
*Dec 13 03:40:15.287: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to up
*Dec 13 03:40:20.551: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to down
*Dec 13 03:40:20.556: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to down
*Dec 13 03:40:21.606: %LINK-3-UPDOWN: Interface Port-channel44, changed state to down
*Dec 13 03:40:22.887: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to up
*Dec 13 03:40:23.881: %LINK-3-UPDOWN: Interface Port-channel44, changed state to up
*Dec 13 03:40:24.881: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to up
*Dec 13 03:40:29.301: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/4, changed state to down
*Dec 13 03:40:29.307: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel44, changed state to down
*Dec 13 03:40:30.353: %LINK-3-UPDOWN: Interface Port-channel44, changed state to down
*Dec 13 03:40:30.620: %PM-4-ERR_DISABLE: pagp-flap error detected on Te1/1/4, putting Te1/1/4 in err-disable stateRoot cause
From the log, we can see the related ports just flap like crazy
Fix
Find out the reason for the physical connectivity issue. To configure auto recovery and extend the threshold, please use the command below:
errdisable flap-setting cause pagp-flap max-flaps 10 time 30
errdisable recovery cause pagp-flap