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New Member

Nexus 5548: command failed: port not compatible [speed]


I connected a set of 5548's with vPC to 3945.  I have a port-channel (po1) configured on the 3945 with g0/0/0 and g0/1/0.  I set the speed on the 5548's to 1g and tried to create a channel-group (po1) on the 5548 eth1/1.  I received the following error: 

C5548-2(config-if)# channel-group 1 mode active
command failed: port not compatible [speed]

I removed the channel-group from the interface and set the speed.  Essentially, I have a channel-group on the 3945 connected to each 5548 as individual L-2 links (non-vPC).  I have essentially created a loop and now receiving "FWM-2-STM_LOOP_DETECT: Loops detected in the network".


My question(s) to the group are:

1.  Is the issue a speed discrepancy between the vPC link; which is 10gig and the eth 1/1 set to 1 gig?

2.  Can I create a channel-group on an 5548 with vPC ethernet interface that is set to 1gig ?

3.  Any recommendation other then shutting down one of the uplinks from the 5548?



   po1 /        \

 5548    =    5548


  • LAN Switching and Routing
New Member

I was able to resolve the

I was able to resolve the port-channel create.  Order of operation issue; I ran interface default for eth 1/1 and then recreated the port-channel. 


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