Hi Rodjeur, thanks for reaching out. We don't have specific best practice for this per se, as using SMLT results in STP being disabled on the SMLT side. SLPP is our recommended loop prevention and protection methodology for SMLT environments, and our best practices there involve using different rx-thresholds on the SMLT links to avoid taking both down if the loop is over the SMLT itself (eg 50 one side, 500 on the second link). The specific values used for rx-threshold should be tuned based on deployment specifics, such as the number of VLANs transmitting SLPP packets on the links. For the CISCO side of this, not having STP on the SMLT links needs to be factored into the overall loop design for that portion of the network. Hope that helps!
