When you set the STP link type to auto, the BIG-IP® system determines
the spanning tree link type, which is based on the Active Duplex interface property.
When you set the STP link type to p2p, the BIG-IP system uses the optimizations for point-to-point spanning tree links. Point-to-point links connect two spanning tree bridges only. For example, a point-to-point link might connect a 10 Gigabit link to another bridge. For point-to-point links, the Active Duplex property interface should be set to full. Note that p2p is the only valid STP link type for a trunk.
When you set the STP link type to shared, the BIG-IP system uses the optimizations for shared spanning tree links. Shared links connect two or more spanning tree bridges. For example, a shared link might be a 10 Megabit hub. Note that for shared links, the Active Duplex interface property should be set to half.