This means remote switch sends BPDU's on that port and the local switch receives the same on one of its ports.
It appears u have PAGP etherchannel configured ON for all ports.If its set to ON, ports on both sides of etherchannel should be ON.In such cases,switches will never try negotiating bundle by itself with PAGP negotiation packets ,as its forcefully doin so.The messages normally indicate the ether bundle getting formed on one end but not on other.When etherbundle forms BPDU's are sent on a single link.Start by checking the status with sh port 2/1 n see wats the status of the port.
If its in err-disable state it means the etherchannel misconfig creates these spanning tree loop.
there is an errdisable recovery cause all command which is useful to enable errdisable recovery for any event tat causes this state.set errdisable-timeout enable all is the cmd on cat os.
den issue a show errdisable-timeout which shows the ports currently in this state and reason.
depending on the reason rectify it.if its ether misconfig then check each port of bundle on either sides are identical in terms of speed/duplex,identical PAGP modes,port vlan memberships et al.
Fox is right. This is likely as a result of ether channel configuration mismatch on the port(s). You are receiving PAGP messages in the logs. You can either make the other connecting end PAGP or remove the configuration all together on this switch. I normally prefer turning them on instead of using the protocols (PAGP, LACP).
int range fa 1/1 - 1/2
Channel group 1 mode on
Do this on the switch ports connecting both devices. As Fox mentioned, the ports must have similar characteristic ie either all trunks, same duplex, speed, etc
The logging synchronous will not remove the messages. It will only allow your commands not to be interrupted when typing.
That just means whatever is hooked to that port has gone up to down and down to up again , its not a problem . If it really bothers you just set your logging level for PAGP to 4 and you won't see it again as the message is a level 5 message , if you set the logging level lower than 5 it will not show up again . Also it may go away if you turn etherchannel port negotiation off on ports that do not need it such as user ports.
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