from nx_api.h:2342
typedef struct NX_IPV4_MULTICAST_STRUCT
{
ULONG nx_ipv4_multicast_join_list;
NX_INTERFACE *nx_ipv4_multicast_join_interface_list;
ULONG nx_ipv4_multicast_join_count;
ULONG nx_ipv4_multicast_update_time;
UINT nx_ipv4_multicast_loopback_enable;
} NX_IPV4_MULTICAST_ENTRY;