Enable interface...9/26-29 on 6509 Switch_6509> (enable) sh lacp-channel info Chan Port Status Channel Admin Speed Duplex Vlan id mode group ---- ----- ---------- -------------------- ----- ----- ------ ---- 1678 9/26 connected active 839 1000 full 19 1678 9/27 connected active 839 1000 full 19 1678 9/28 connected active 839 1000 full 19 1678 9/29 connected active 839 1000 full 19 Chan Port Ch-if Oper-group Neighbor Chan Oper-Distribution PortSecurity/ id Index Oper-group cost Method Dynamic Port ---- ----- ----- ---------- ---------- -------- ----------------- ------------- 1678 9/26 402 13425 1 2 ip both 1678 9/27 402 13425 1 2 ip both 1678 9/28 402 13425 1 2 ip both 1678 9/29 402 13425 1 2 ip both Chan Port Device-ID Port-ID Platform id ---- ----- ------------------------------- ------------------------- ---------- 1678 9/26 Switch_3560 GigabitEthernet0/25 cisco WS-C3560G-24TS 1678 9/27 Switch_3560 GigabitEthernet0/26 cisco WS-C3560G-24TS 1678 9/28 Switch_3560 GigabitEthernet0/27 cisco WS-C3560G-24TS 1678 9/29 Switch_3560 GigabitEthernet0/28 cisco WS-C3560G-24TS Chan Port Trunk-status Trunk-type Trunk-vlans id ----- ----- ------------ ------------- ----------------------------------------- 1678 9/26 trunking dot1q 10,19 1678 9/27 trunking dot1q 10,19 1678 9/28 trunking dot1q 10,19 1678 9/29 trunking dot1q 10,19 Then after 60 sec the ports go into errdisable due to spantree channel misconfiguration....although ports on both sides are setup the same (unless I'm missing something) Switch_6509> (enable) 2009 Jan 15 09:00:07 %SPANTREE-2-CHNMISCFG: STP loop - channel 9/26-29 is disabled in vlan/9 2009 Jan 15 09:00:07 %SPANTREE-2-CHNMISCFG2: BPDU source mac addresses: 00-23-ea-3f-56-1c, 00-16-c7-ff-ad-25 2009 Jan 15 09:00:08 %DTP-5-NONTRUNKPORTON:Port 9/26 has become non-trunk 2009 Jan 15 09:00:08 %DTP-5-NONTRUNKPORTON:Port 9/27 has become non-trunk 2009 Jan 15 09:00:08 %DTP-5-NONTRUNKPORTON:Port 9/28 has become non-trunk 2009 Jan 15 09:00:08 %DTP-5-NONTRUNKPORTON:Port 9/29 has become non-trunk Switch_3560 Switch_3560#sh lacp neigh Flags: S - Device is requesting Slow LACPDUs F - Device is requesting Fast LACPDUs A - Device is in Active mode P - Device is in Passive mode Channel group 1 neighbors Partner's information: LACP port Oper Port Port Port Flags Priority Dev ID Age Key Number State Gi0/25 SA 128 00d0.0174.5000 19s 0x3471 0x41A 0x3D Gi0/26 SA 128 00d0.0174.5000 17s 0x3471 0x41B 0x3D Gi0/27 SA 128 00d0.0174.5000 13s 0x3471 0x41C 0x3D Gi0/28 SA 128 00d0.0174.5000 9s 0x3471 0x41D 0x3D Some doco... Error Message SPANTREE-2-CHNMISCFG: STP loop - channel [dec]/[chars] is disabled in vlan [dec] Explanation This message indicates that there is a possible misconfiguration in the EtherChannel type setting (auto/desirable/on). A misconfigured channel formed, causing spanning tree loops. [dec] is the module number, [chars] is the port number, and vlan [dec] is the VLAN number. EtherChannel misconfiguration In order for EtherChannel to work, the ports that are involved must have consistent configurations. The ports must have the same VLAN, the same trunk mode, the same speed, the same duplex, and so on. Most of the configuration differences within a switch are caught and reported when you create the channel. If one switch is configured for EtherChannel and the other switch is not configured for EtherChannel, the spanning tree process can shut down the channeled ports on the side that is configured for EtherChannel. The on mode of EtherChannel does not send PAgP packets to negotiate with the other side before channeling; it just assumes that the other side is channeling. In addition, this example does not turn on EtherChannel for the other switch, but leaves these ports as individual, unchanneled ports. If you leave the other switch in this state for a minute or so, Spanning Tree Protocol (STP) on the switch where the EtherChannel is turned on thinks that there is a loop. This puts the channeling ports in the errdisabled state.