The basic debug command options for EtherChannel are listed here. As always with the debug command in a Cisco network, you can use specific options if you have an idea about where the issues are or can enable all of the debug options for the component — if doing so does not generate too much information.
Switch2> enable Switch2#debug etherchannel ? all All debugging detail Step below all error Displaying error messages event Major events idb Agport idb related events linecard SCP messages to linecard <cr> Switch2> enable Switch2#debug pagp ? all PAgP all debugging event PAgP events fsm PAgP Finite State Machine misc PAgP Miscellaneous packet PAgP activity <cr> Switch2> enable Switch2#debug lacp ? all LACP all debugging event LACP events fsm LACP Finite State Machine misc LACP Miscellaneous packet LACP activity <cr>
In this case, both the EtherChannel and PAgP debug commands are enabled, but not LACP because you do not expect to see any LACP information on the network. Previously in this chapter, only PAgP was enabled, so if you see LACP data, something is seriously wrong.
In the production network, where someone else may be configuring the remote end of the connection, it may not hurt to turn on the LACP option as well. Notice in the output that the interface is brought up.
Switch2> enable Switch2# debug EtherChannel Switch2# debug PAgP 3d01h: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up 3d01h: FEC: pagp_switch_agc_compatable: comparing GC values of Fa0/1 Po5 flag = 1 1 3d01h: FEC: pagp_switch_port_attrib_diff: Fa0/1 Po5 same 3d01h: FEC: pagp_switch_agc_compatable: GC values are compatable 3d01h: PAgP - Fa0/1 failed - not my device_id. 0000.0000.0000 0006.d6ac.46c0 3d01h: FEC: add port (Fa0/1) to agport (Po5) 3d01h: FEC: pagp_switch_add_port_to_agport_internal: msg to PM to bundle port Fa0/1 with Po5 3d01h: FEC: pagp_switch_want_to_bundle: Bndl msg to PM for port Fa0/1 to Agport Po5 3d01h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up 3d01h: %LINK-3-UPDOWN: Interface Port-channel5, changed state to up 3d01h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel5, changed state to up