/** \brief Definition of a VXLAN GBP tunnel
@param instance - optional unique custom device instance, else ~0.
@param src - Source IP address
@param dst - Destination IP address, can be multicast
@param mcast_sw_if_index - Interface for multicast destination
@param encap_table_id - Encap route table
/** \brief Definition of a VXLAN GBP tunnel
@param instance - optional unique custom device instance, else ~0.
@param src - Source IP address
@param dst - Destination IP address, can be multicast
@param mcast_sw_if_index - Interface for multicast destination
@param encap_table_id - Encap route table