SMT_EVENT_BASE
#define SMT_EVENT_MAC_PATH_CHANGE (SMT_EVENT_BASE+0)
#define SMT_EVENT_MAC_NEIGHBOR_CHANGE (SMT_EVENT_BASE+1)
#define SMT_EVENT_PORT_PATH_CHANGE (SMT_EVENT_BASE+2)
#define SMT_EVENT_PORT_CONNECTION (SMT_EVENT_BASE+3)