I have an MX84 and thinking of connecting 2 Cisco switch to its LAN port. On the 2 switches I will set the uplink to MX84 as trunk mode. I was thinking if this can cause a switching loop?   I have looked into how the BPDU packets pass through MX. The MX receive the BPDU packet and just re-forwards it to the same broadcast domain as to where it was received, so this will send BPDU packet to the other switch until it gets back from the sender of the BPDU packets and will cause a loop.   I have thought of enabling BPDU filter on the interface pointing to the MX but this will still not stop the the loop from occurring. Please see below for the topology that I have. (Assuming that a port is blocked by STP)         ... View more