Port-extender slow discovery time, high CPU?

Hi all, trying out the port extender feature with a CRS354 (controller) and CRS328 (extender). Just following the basic setup at https://help.mikrotik.com/docs/display/ROS/Controller+Bridge+and+Port+Extender

I was on v7.1.1 but tried also v7.2 on the CRS354.

I’m noticing that after I enable the controller bridge cascade ports on the CRS354:

  • CPU on CRS354 goes to 100% while it seems to loop through a process of discovering the ports on the CRS328. Lots of log messages about hardware offload activating.


  • hardware offload looks to be disabled on the bridge while this detection/discovery happens


  • it takes at least 10 mins to populate all the port extensions from the CRS328.


  • Only after all PE ports are discovered are the ports added to the bridge and hardware offload re-enabled and things settle down

I wanted to check if this is similar behaviour that anyone else had seen? Is it expected that the discovery process takes this long?
PE-discovery-loops.JPG