07-15-2013 07:23 AM - edited 03-07-2019 02:24 PM
Dear all,
1. Description
We have a Stack of 3x c3750-X with 12.2(58)SE IOS version. We use port-channels in mode PAgP (same switch, known limitation) and mode ON (on different switches, MEC).
We use this Stack for Dual-active detection of a 4500x VSS with an ePAgP port-channel.
Additionnally, we also use 2x Port-channels in mode ON.
No problem so far...
2. Issue with LACP
Finally, I wanted to configure a port-channel in LACP for server dual-attachment. But obviously, LACP mode is not accepted by IOS while this limitation is actually involved by PAgP (known limitation on same single switch). The error message is related to PAgP while configuring LACP !?
Personnally I am pretty sure it is a bug, can you confirm ? Is it a known issue? any known workaround?
3. Error Messages
Please find the error messages related to LACP Port-channel creation
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SW012(config)#int range gi 2/0/1, gi 3/0/1
SW012(config-if-range)#channel-group 10 mode ?
active Enable LACP unconditionally
auto Enable PAgP only if a PAgP device is detected
desirable Enable PAgP unconditionally
on Enable Etherchannel only
passive Enable LACP only if a LACP device is detected
SW012(config-if-range)#channel-group 10 mode active ?
<cr>
W012(config-if-range)#channel-group 10 mode active
%With PAgP enabled, all ports in the Channel should belong to the same switch
Command rejected (Port-channel10, Gi2/0/1): Invalid etherchnl mode
SW012(config-if-range)#int gi 2/0/1
SW012(config-if)#channel-group 10 mode active
%With PAgP enabled, all ports in the Channel should belong to the same switch
Command rejected (Port-channel10, Gi2/0/1): Invalid etherchnl mode
SW012(config-if)#int gi 3/0/1
SW012(config-if)#channel-group 10 mode active
%With PAgP enabled, all ports in the Channel should belong to the same switch
Command rejected (Port-channel10, Gi3/0/1): Invalid etherchnl mode
---------------------------------------------------------------------------------------------------------------------------------------
Let me know
Laurent
07-15-2013 11:07 AM
what does your switch stack look like? Im just curious.
07-15-2013 12:37 PM
Hello Laurent
Could you try the following:
1.
no interface port-channel 10
2.
int gi 2/0/1
channel-group 10 mode active
int gi 3/0/1
channel-group 10 mode active
- Gabriel
07-15-2013 01:23 PM
Only with LACP can you bundle network ports from different physical switches in a stack configuration. I would follow Gabriel's advice and remove the interfaces from the port-channel they are in currently and then add them back as LACP. Be sure that at least one side is using active mode for negotiation to properly take place. If the other side is not using a form of LACP then I don't think it will work but most non-Cisco switches should support LACP configuration since it's non-proprietary.
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