08-07-2017 02:55 AM - edited 03-08-2019 11:38 AM
Hi,
We have a 3750x (running 15.0(2)SE10a ), and for some reason there is an interface falling out of a port channel by the looks of it as we are getting a mac flap on one of the interfaces in the port channel and the Po interface itself.
We have both ends set to active/ active, at the moment both Ten interfaces and bundled and seem to be working fine, however occasionally we get a mac flap, any ideas?
08-07-2017 06:09 AM
What is the output from the following -
sh etherchannel summary
Can we see a show run of each of the Interfaces in the port channel on the 3750 and also a show run of the port channel itself.
What is on the other end of the port channel? Can we see the same info from the opposite end?
08-07-2017 09:34 AM
Sounds like one of the sides is not set up correctly and the ports on the 3750x are running in stand-alone mode (I).
08-07-2017 12:06 PM
You mentioned you are using LACP and not using static ether channel then most likely LACP will suspend all member ports if there is any misconfiguration as it has built in loop prevention mechanism and ether channel won't come up until you fix the issue.
You didn't mention if you have ether channel configured between switches or a downstream server, if ether channel is configured between a switch and server that is hosting virtual machines then there is a possibility that you see a mac flapping between member ports because of active active configuration on the server side.
08-08-2017 01:02 AM
Morning,
As we have removed one of the interfaces the show etherchannel summary wont be of any benefit,
However below is the config of the port-channels, both ends (router to switch)
One side: (core)
description Core: 3750x-dc2
switchport
switchport trunk allowed vlan 122,166,176,177,192,200,207,216,257-262,265,267
switchport trunk allowed vlan add 268,270-272,282,283,297,298,302,500,501,503
switchport trunk allowed vlan add 609,635,638,655-658,663,664,699-701,722,725
switchport trunk allowed vlan add 802,804,810,850-852,860,861,898-921,999,2004
switchport trunk allowed vlan add 2006,2008
switchport trunk pruning vlan none
switchport mode trunk
channel-group 18 mode active
other side:
interface TenGigabitEthernet2/1/1
description Link to WMBC-6509E
switchport trunk encapsulation dot1q
switchport mode trunk
history BPS
srr-queue bandwidth share 1 30 35 5
priority-queue out
udld port
mls qos trust cos
channel-protocol lacp
channel-group 48 mode active
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