Information Technology Reference
In-Depth Information
B on ports 2/2, 2/3, and 2/4 because Switch A treats these ports as independent ports. This is why Switch
B thinks there is a spanning-tree loop. Notice that the ports on Switch B are now disabled and have a
status of errdisable.
Switch-B (enable)
2000 Jan 17 22:55:48 %SPANTREE-2-CHNMISCFG: STP loop - channel 2/1-4 is disabled in vlan
1.
2000 Jan 17 22:55:49 %PAGP-5-PORTFROMSTP:Port 2/1 left bridge port 2/1-4
2000 Jan 17 22:56:01 %PAGP-5-PORTFROMSTP:Port 2/2 left bridge port 2/1-4
2000 Jan 17 22:56:13 %PAGP-5-PORTFROMSTP:Port 2/3 left bridge port 2/1-4
2000 Jan 17 22:56:36 %PAGP-5-PORTFROMSTP:Port 2/4 left bridge port 2/1-4
Switch-B (enable)
show port channel
Port Status Channel Channel Neighbor Neighbor
mode status device port
----- ---------- --------- ----------- ------------------------- ----------
2/1 errdisable on channel
2/2 errdisable on channel
2/3 errdisable on channel
2/4 errdisable on channel
----- ---------- --------- ----------- ------------------------- ----------
Switch-B (enable)
show port
Port Name Status Vlan Level Duplex Speed Type
----- ------------------ ---------- ---------- ------ ------ ----- ------------
2/1
errdisable 1
normal auto auto 10/100BaseTX
2/2
errdisable 1
normal auto auto 10/100BaseTX
2/3
errdisable 1
normal auto auto 10/100BaseTX
errdisable
1
2/4
normal auto auto 10/100BaseTX
Correcting errdisable State
Sometimes when you try to configure EtherChannel but the ports are not configured the same, it will
cause the ports on one side of the channel to be shut down. The link lights will be yellow on the port.
You can tell this by the console by typing
show port
. The ports will be listed as errdisable. To recover
from this, you should fix the mismatched parameters on the ports involved and then re-enable the ports.
Just note that this re-enabling of the ports is a separate step that must be done for the ports to become
functional again.
